Use of a bacterial line, probiotic / prebiotic composition or functional food and use of probiotic / prebiotic composition or functional food

Abstract

ANTICARIES AND PROBIOTICS / PREBIOTICS COMPOSITIONS. The present invention discloses different specific bacterial strains isolated from caries-free individuals that are characterized by exhibiting inhibitory activity against cariogenic organisms. The invention also discloses a process for isolating such strains, as well as a bioactive peptide, such as an antimicrobial peptide of human and bacterial origin, which also exhibits anticariogenic activity. Furthermore, the present invention also discloses pharmaceutical and / or probiotic / prebiotic compositions, functional foods, mouthwash, toothpaste, chewing gum, etc., comprising at least one of the strains and / or at least one of the bioactive peptides described in the invention, or a combination thereof, which are useful in the treatment and / or prevention of infectious diseases of the oral cavity, preferably caries.

Description

1 / 82 “USE OF A BACTERIAL STRAIN, PROBIOTIC / PREBIOTIC COMPOSITION OR FUNCTIONAL FOOD AND USE OF THE PROBIOTIC / PREBIOTIC COMPOSITION OR FUNCTIONAL FOOD” FIELD OF THE INVENTION

[0001] The present invention relates to the field of human health, more specifically, to the field of oral health. BACKGROUND OF THE INVENTION

[0002] The human oral cavity is inhabited by hundreds of species of bacteria, most of which are commensal species and necessary to maintain the balance of the oral ecosystem. However, some of them play a key role in the development of oral infections, primarily dental caries and periodontal infections (1). Oral infections begin with the growth of dental plaque, a biofilm formed by the accumulation of bacteria along with glycoproteins from human saliva and polysaccharides secreted by microbes (2). Subgingival plaque, located in the alkaline and neutral subgingival pocket, is typically inhibited by anaerobic gram-negative microorganisms and is responsible for the development of gingivitis and periodontitis. Supragingival dental plaque is formed on the tooth surface and includes acidogenic and acidophilic bacteria, which, under fermentation of sugars ingested in the diet, produce acids and reduce the pH.When the pH is too acidic (generally with a value less than 5.5), the tooth enamel is demineralized and destroyed, and therefore, these bacteria are responsible for dental caries, which are considered the most common infectious disease. Petition 870210029859, dated 03 / 30 / 2021, page 10 / 97 2 / 82 widespread in the world, affecting more than 80% of the human population (3). Poor oral health can be associated with other pathologies, such as, for example, stomach ulcers, stomach cancer or cardiovascular diseases, among others.

[0003] One of the main reasons why, as of today, oral pathogens have not yet been eradicated is the difficulty involved in studying microbial communities inhabiting the oral cavity, since, on the one hand, the complexity of the ecosystem (several hundred species have been detected, with various levels of interaction) makes it difficult to detect potential pathogenic species (4) and, furthermore, no single etiological agent can be identified, as in classic diseases, following Koch's postulates. This fact has been clearly demonstrated in periodontal disease, where there are at least three species of bacteria belonging to very different taxonomic groups (the so-called “red complex” of periodontal pathogens) that have been associated with the development and progression of periodontal disease (5).On the other hand, a large proportion of oral bacteria cannot be cultured (6) and therefore traditional microbiological methods give an incomplete picture of the natural communities that inhabit dental plaque. However, the current development of metagenomic techniques and next-generation sequencing technologies allows the study of the bacterial community as a whole, through the analysis of the total DNA of complex microbial samples (Metagenomics) without the need to culture bacteria themselves. Petition 870210029859, dated 03 / 30 / 2021, page 11 / 97 3 / 82

[0004] In this regard, pioneering studies in metagenomics have focused on the gut ecosystem mainly through a shotgun approach, in which DNA is cloned into small plasmids, followed by traditional Sanger sequencing (7,8). More recent approaches include sequencing the ends of large plasmids (9) and using “Illumina” sequencing technology, which provides good coverage of short sequences (10). Studies on the oral cavity microbiota, as well as other habitats of the human body, such as the skin, vagina or respiratory tract, have focused on sequencing ribosomal RNA amplicons (11,12).These studies have provided a substantial improvement in our knowledge of these bacterial communities compared to previous culture-based research, but estimates of microbial diversity are hampered by biases in PCR amplification (i.e., PCR only detects bacteria that are most similar to those already known, and based on which amplification primers are used, giving an incomplete picture of the diversity present), cloning bias (a large number of genes are not cloned because they are toxic to the host bacteria and, consequently, this method does not allow the study of the complete genetic reservoir of the sample), and a small sequence length (sequences in Illumina technology have only between 35 and 70 nucleotides, which in most cases makes reliable taxonomy or functional assignment impossible), along with the fact that, as... Petition 870210029859, dated 03 / 30 / 2021, page 12 / 97 4 / 82 mentioned above, a large proportion of oral bacteria cannot be cultured.

[0005] In order to solve the problems mentioned above, the present invention describes obtaining the metagenome of dental plaque by direct metagenomic DNA sequencing, using the 454 pyrosequencing method, thus eliminating the potential biases imposed by PCR and cloning techniques, and, in addition, provides access to the entire genetic repertoire of the oral bacterial community under different health conditions, as well as the possibility of analyzing which bacterial species among those found in the obtained metagenome can be associated with good oral health, since individuals who have never suffered from caries have a different bacterial flora than those individuals who have suffered or are currently suffering from it.Through the oral metagenomes obtained in the present invention, it is possible to target the isolation, cultivation, and identification of strains with anticariogenic activity from the bacterial cluster in the oral cavity sample, specifically, the supragingival plaque of individuals who have never suffered from caries, that is, the strains capable of inhibiting the growth of cariogenic bacteria.

[0006] Another strategy described in the present invention is obtaining a metagenomic library of phosmids (long DNA insertions, approximately 35 to 45 Kb) from the dental plaque of individuals who have never suffered from caries. By obtaining said phosmid library, it is possible to isolate and identify the anticariogenic bioactive peptides. Petition 870210029859, dated 03 / 30 / 2021, page 13 / 97 5 / 82 synthesized by bacteria present in the oral cavity of individuals who have never suffered from caries. In this regard, as, in the current state of the art, Streptococcus mutans has been shown to be the main causative agent of caries (13), it is not surprising that most strategies against this disease have been directed against the aforementioned microorganism. These strategies include the development of vaccines that use known surface antigens, passive immunization strategies that can neutralize bacteria, the co-aggregation of S. mutans with probiotic strains and the use of specific S. mutans inhibitor proteins, among others (14).

[0007] Other different strategies have been disclosed in different patent documents, which propose the use of different strains of bacteria, preferably S. mutans, which produce a lower concentration of acid (15), or the use of the same media, for example, nutrients, by pathogenic and non-pathogenic strains, which continuously provide high concentrations of non-pathogenic bacteria, resulting in the displacement of pathogenic bacteria, provided they share the same resource (16), or even a lower adhesion of cariogenic bacterial strains to the tooth (17). Conversely, the bioactive strains and peptides disclosed in the present invention have antibiotic activity, preferably anticariogenic activity, against caries-producing microorganisms.On the other hand, patent WO20040072093 (18) describes a number of antimicrobial agents that are primarily active against gram-negative microorganisms, but the main ones. Petition 870210029859, dated 03 / 30 / 2021, page 14 / 97 6 / 82 caries-causing agents, S. mutans and S. sobrinus, are Gram-positive microorganisms. Furthermore, the S. mitis and S. oralis isolates that produce the antimicrobial peptides described in WO20040072093 (18) were isolated from the throat of patients with cystic fibrosis, and not from the mouth of caries-free individuals, as in the case of the peptides and / or strains of the present invention. Similarly, the therapeutic use of said peptides is directed to the treatment of respiratory tract diseases and not caries, as in the case of the bioactive peptides disclosed in the present invention.

[0008] In this regard, the main technical characteristics that make the bacterial strains isolated and disclosed in the present invention different from the other strains disclosed in the prior art are that they can be cultivated using conventional microbiological techniques, that they exhibit inhibitory activity against organisms that produce infectious diseases of the oral cavity, preferably caries, without the need to be genetically modified, and that they have been isolated from individuals who have never suffered from caries.Consequently, both the anti-cariogenic bacteria themselves and the anti-cariogenic bioactive compounds, preferably peptides, described in the present invention can be used as probiotic and / or prebiotic compositions as such, or as part of different pharmaceutical compositions used for the treatment of infections of the oral cavity, such as, for example, caries, periodontitis, etc., or even as functional foods. Furthermore, the present invention also describes a... Petition 870210029859, dated 03 / 30 / 2021, page 15 / 97 7 / 82 ​​method of preventing and / or treating infectious diseases of the oral cavity, preferably caries, comprising administering a pharmaceutically effective amount of at least one of the strains and / or at least one of the antimicrobial compounds, preferably the peptides described above, or the probiotic or pharmaceutical composition or functional foods comprising at least one of the strains and / or at least one of the compounds, preferably the peptides of the present invention. DESCRIPTION OF THE INVENTION Brief description of the invention

[0009] The difficulty existing in the state of the art in identifying bacterial strains that directly inhibit the growth of pathogenic germs related to the appearance of diseases of the oral cavity is thus caused by the large number of bacterial species in said cavity, consequently, the difficulty in isolating, among all of them, the strains that directly inhibit the growth of pathogenic species, many of which are non-cultivable species, and this makes this problem difficult to solve, until now.

[0010] The present invention solves this problem by creating the metagenome of the oral cavity of individuals who have never suffered from caries. The creation of said metagenome, using massive sequencing, preferably pyrosequencing, of the DNA present in samples collected from the oral cavity of said individuals who have never suffered from caries, causes that Petition 870210029859, dated 03 / 30 / 2021, page 16 / 97 8 / 82 it is possible to identify the genera and species of bacteria that are most frequent in the bacterial population present in the oral cavity of the aforementioned individuals. This quantification of the frequency of each bacterium in the sample had not been possible, until now, using cloning, culture, cloning or PCR techniques, since these techniques only identify part of the bacteria and the proportions of those that are identified are biased depending on the methodology itself (mainly due to the preferential culture, cloning, or amplification of certain species, respectively).

[0011] Initially, the invention has been based on humans, but it can be applied to any higher mammal, particularly pets or livestock, or even wildlife. It would be sufficient to determine the characteristic metagenome of each species in individuals who have never suffered from caries, as a representative disease of typical oral cavity diseases. Once the bacterial strains that are most frequent in the oral cavity of healthy individuals have been identified from the metagenome data, the next step of the present invention consists of cultivating the samples obtained from the oral cavity of these individuals in a favorable culture medium and under favorable conditions, so that the most common genera and species identified in the metagenome of the studied mammalian species can develop.

[0012] A second alternative to solve the problem mentioned above consists of trying to isolate compounds, Petition 870210029859, dated 03 / 30 / 2021, page 17 / 97 9 / 82 especially active peptides, secreted, among others, by bacterial strains present in the oral cavity of individuals who have never suffered from caries and which exhibit direct inhibitory activity against the growth of cariogenic species. In the present invention, direct inhibitory capacity is defined as the ability to completely inhibit growth, through the creation of inhibition halos in plaque cultures of said pathogenic species, due to their antibiotic action, without excluding the fact that, in addition to said inhibition caused by their antibiotic effect, the strains and compounds may exert their antimicrobial effect, preferably an anticariogenic effect, by preventing cariogenic action through other pathways, such as modifying the optimal pH for the growth of said cariogenic strains, which hinders their adhesion to teeth, etc.

[0013] To this end, the invention has once again begun with samples of the oral cavity taken from healthy individuals, but in this alternative, it has not only focused on compounds of bacterial origin, which may be secreted, among others, as the isolated strains mentioned above. Furthermore, compounds secreted by other bacterial strains that may exist are not cultivable and therefore cannot be isolated using the strategy proposed above. Finally, in addition to compounds of bacterial origin from the population of bacterial strains inhabiting the oral cavity, said cavity also contains compounds secreted by mammalian cells, in particular those of humans, where the present invention is preferably Petition 870210029859, dated 03 / 30 / 2021, p. 18 / 97 10 / 82 based. Some of these compounds may have a direct inhibitory activity against the growth of cariogenic microorganisms. To this end, samples obtained from the oral cavity of healthy individuals were lysed, DNA was extracted from them, fosmids were constructed with said fragments and cloned into a host cell that could be cultured and tested in cultures of cariogenic species, in order to observe whether inhibition halos against the growth of cariogenic pathogenic species are produced.

[0014] It should be noted that although the inhibitory isolates and compounds were obtained from oral cavity samples and are active against caries-producing (cariogenic) pathogenic bacterial species, given their inhibitory capacity against the growth of pathogenic bacteria that preferentially inhabit the oral cavity, in principle, the isolated bacterial strains and compounds can be found in other parts of the body and produce or are associated with other diseases. For this reason, an objective of the present invention is the use of isolated strains and compounds as medicaments, in particular as antimicrobial agents and, more specifically, as antibacterial agents.

[0015] Therefore, the present invention describes the isolation of cultivable bacterial strains and compounds, mainly bioactive peptides, with an inhibitory capacity against the growth of pathogenic microorganisms involved in the appearance of diseases of the oral cavity. Throughout the Petition 870210029859, dated 03 / 30 / 2021, page 19 / 97 11 / 82 of the present invention, the appearance of caries has been taken as a representative disease of typical diseases of the oral cavity, but the invention can be applied to any infectious disease attributable to pathogenic microorganisms of the oral cavity. For this reason, the present invention preferably focuses on the isolation of bacterial strains and compounds, mainly bioactive peptides, with an inhibitory capacity against the growth of pathogenic microorganisms, especially those involved in the appearance of caries.

[0016] The process of isolating cultivable bacterial strains with anticariogenic capacity is based on obtaining the oral metagenome of individuals who have never suffered from caries, in order to determine which types of bacteria are most frequently found in their oral cavity and to analyze which of them are associated with good oral health, through the inhibition of the growth of cariogenic bacteria. This process has made it possible to isolate, characterize, cultivate, and deposit different strains with anticariogenic activity in the Spanish Collection of Culture Types (CECT): CECT 7746, CECT 7747, CECT 7773, CECT 7774, and CECT 7775. Through sequence homology analysis, it was concluded that four of the strains that showed anticariogenic activity and that were deposited in the CECT, especially strains CECT 7746, 7747, 7773, and 7775, belonged to the same bacterial genus: Streptococcus; therefore, in addition to its functionality (anticariogenic activity) and the process of obtaining it, these strains share a structural similarity and Petition 870210029859, dated 03 / 30 / 2021, page 20 / 97 12 / 82 taxonomic, provided that they belong, as mentioned above, to the same bacterial genus, Streptococcus.

[0017] On the other hand, the process of isolating and characterizing anticariogenic bioactive peptides is based on obtaining a metagenomic library of fosmids from individuals who have never suffered from caries. Using this method, it is possible to characterize peptides with anticariogenic capacity produced by bacteria found in individuals who have never suffered from caries, including non-cultivable bacteria, as well as antimicrobial compounds, for example, of the defensin type, synthesized by the individuals themselves. These peptides are assayed to determine their inhibitory activity against the growth of cariogenic bacteria, such as, for example, S. mutans and S. sobrinus.

[0018] Another aspect of the present invention reveals different specific cultivable bacterial strains, CECT 7746, CECT 7747, CECT 7773, CECT 7774, and CECT 7775, isolated from individuals with excellent oral health who have never suffered from caries, characterized by the fact that they exhibit inhibitory activity against organisms that produce infectious diseases of the oral cavity, preferably against caries-producing microorganisms. From the metagenome of bacteria present in the dental plaque of people who have never suffered from caries, the genera and species of bacteria that appeared most frequently in healthy individuals who have never suffered from caries were identified by homology with current bacterial DNA libraries. The bacteria that Petition 870210029859, dated 03 / 30 / 2021, page 21 / 97 13 / 82 appeared more frequently in individuals without caries and appeared to be absent or very infrequent in individuals with caries. These bacteria belonged to one of the following genera: Rothia, Globicatella, Johnsonella, Kingella, Cardiobacterium, Phocoenobacter, Mannheimia, Haemophilus, Neisseria, Streptococcus, and Aggregatibacter, with the genus Streptococcus being among the most abundant. In this regard, the preferred bacterial strains of the present invention are strains CECT 7746, CECT 7747, CECT 7773, and CECT 7775, all belonging to the genus Streptococcus.

[0019] Another aspect disclosed in the present invention describes bioactive compounds, preferably peptides, which inhibit the growth of organisms that produce infectious diseases of the oral cavity, preferably caries-producing microorganisms. Specifically, this describes peptides encoded by DNA sequences included in any of the following phosmid inserts with inhibitory activity against organisms that produce infectious diseases of the oral cavity, preferably caries-producing microorganisms: SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 13, SEQ ID NO: 14.

[0020] More specifically, the peptides encoded by the DNA sequences included in the fosmid inserts with inhibitory activity against organisms that cause infectious diseases of the oral cavity: SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4 and SEQ ID NO: 5, are characterized by being of bacterial origin and possessing characteristics similar to those of bacteriocins. Similarly, the encoded peptides Petition 870210029859, dated 03 / 30 / 2021, page 22 / 97 14 / 82 by the DNA sequences included in the fosmid inserts with inhibitory activity against organisms that produce infectious diseases of the oral cavity: SEQ ID NO: 1, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 13 and SEQ ID NO: 14, are characterized by the fact that they are of human origin and have characteristics similar to defensins.

[0021] More specifically, the invention describes two specific peptides: SEQ ID NO: 8, an antimicrobial peptide of human origin, with characteristics similar to defensins; SEQ ID NO: 9, a peptide of bacterial origin, with characteristics similar to bacteriocins.

[0022] Furthermore, the invention discloses solid compositions, powders (for direct consumption or in solution) or paste compositions for oral hygiene, such as toothpaste, chewing gum, candies, bars, etc., or liquid mouthwash solutions, such as mouthwashes, syrups, drinks, etc., or probiotic and / or prebiotic food compositions, the composition of which comprises both the strains and / or compounds, preferably the peptides of the invention, with inhibitory activity against organisms that produce infectious diseases of the oral cavity, preferably caries-producing microorganisms. In a preferred embodiment of the present invention, the strains and / or peptides of the present invention are added to compositions that exhibit antimicrobial activity against the flora of the oral cavity and that can be found commercially, such as Listerine®-type mouthwashes, said mouthwashes showing an effect Petition 870210029859, dated 03 / 30 / 2021, page 23 / 97 15 / 82 improved inhibitory effect against organisms that produce infectious diseases of the oral cavity, preferably caries-producing microorganisms, when the strains and / or peptides of the present invention are added to the composition.

[0023] A preferred embodiment of the present invention is probiotics / prebiotics or functional foods, the composition of which comprises the strains and / or compounds, preferably the peptides of the invention, with inhibitory activity against organisms that produce infectious diseases of the oral cavity, preferably caries-producing microorganisms. The concept of probiotics or functional foods includes, but is not limited to: dairy products, such as yogurts, for example, juices, solid foods, such as sweets, for example, as well as teas, parapharmaceutical and herbal products, such as vitamin complexes, nutritional supplements, etc.

[0024] For the purposes of the present invention, the following terms are explained:

[0025] Infectious disease of the oral cavity: for the purposes of the present invention, infectious diseases of the oral cavity are preferably caries, gingivitis, periodontitis and halitosis.

[0026] Probiotics: For the purposes of the present invention, the term probiotic refers to the use of live microorganisms that are added to foods (milk, yogurt, etc.), nutritional supplements (in the form of capsules, tablets, pills, powders, etc.) or others, which remain Petition 870210029859, dated 03 / 30 / 2021, page 24 / 97 16 / 82 active ingredients exert their physiological effects on the individual who ingests the food product or similar product containing said probiotic. When ingested in sufficient quantities, it has beneficial effects, in this case, on oral health.

[0027] Prebiotics: For the purposes of the present invention, the term prebiotic refers to the use of substances that are added to foods, chewing gum, dietary supplements or others, which exert an effect on the composition of the oral microbiota, favoring the establishment of bacteria that are beneficial to oral health and / or hindering the establishment of pathogenic bacteria.

[0028] Metagenome: represents the genomes of all bacteria that are present in a sample, from an individual or an ecosystem, etc.

[0029] Microbiome: is the collection of microbes or bacteria that coexist with humans.

[0030] Antimicrobial bioactive compounds: These are compounds such as biologically active peptides, proteins, antibiotics, pigments, etc., found in vertebrates and invertebrates that act as natural antibiotics, being part of the innate immune response. Some of these compounds, for example, peptides, are produced by humans, such as defensins and cathelicidins, among others. They are active against enclosed bacteria, fungi, and viruses.

[0031] Bacteriocins: are biologically active peptides secreted by bacteria that possess properties Petition 870210029859, dated 03 / 30 / 2021, page 25 / 97 17 / 82 bactericides against other species that are closely related to the producing lineage, or against lineages that are phylogenetically distant from the producing lineage.

[0032] Fosmids: circular DNA fragments that can be easily introduced into host cells, generally bacterial cells, and bacterial transport fragments or human DNA.

[0033] Functional foods: These are defined as foods that are prepared not only for their nutritional characteristics, but also to fulfill a specific function, such as improving health or reducing the risk of contracting diseases. To this end, biologically active compounds, such as minerals, vitamins, fatty acids, beneficial bacteria, nutritious fiber and antioxidants, etc., are added to them.

[0034] Cultivable bacterial strains: Cultivable bacterial strains are considered to be those that grow in pure culture and continue to grow in a stable manner in an artificial laboratory culture medium under standard aerobic or anaerobic conditions. Description of the figures

[0035] Figure 1. A. Photograph of a Petri dish, which shows the initial scan of E. coli clones containing DNA fosmids from dental plaque of caries-free individuals that produce inhibition halos on a grass culture of S. mutans. B. Photograph of a Petri dish, which shows the Petition 870210029859, dated 03 / 30 / 2021, page 26 / 97 18 / 82 confirmation scan of E. coli clones containing DNA fosmids from dental plaque of caries-free individuals that produced inhibition halos on a grass culture of S. mutans.

[0036] Figure 2. Growth curves of cariogenic bacteria S. mutans (positive control, without the addition of the karyogenesis inhibitor, exemplified in the graph as a solid line) in BHI culture medium (cattle brain and heart infusion), and in BHI medium enriched with 100 pL (dashed line), 150 pL (short dash line), 200 pL (short dash and dot line), 300 pL (long dash line) or 400 pL (long dash and two dot line) of the 3-10 kD fraction of the concentrated supernatant produced by, respectively, 1.5-, 2.25-, 3.0-, 4.5- and 6 mL of cell cultures carrying the S12E fosmid containing the antimicrobial bacteriocin-like peptide of bacterial origin of the invention. The data collected every half hour for 19 hours shows the average of the three experiments. The X-axis of the graph shows time, expressed in hours, and the Y-axis shows the optical density (OD) of the bacterial cultures.

[0037] Figure 3. Growth curves of cariogenic bacteria S. mutans in BHI culture medium (solid line, positive control without the addition of the karyogenesis inhibitor) and in BHI medium with 50 pL (dashed line) and 100 pL (dotted line) of the 0-3 kD fraction of the concentrated supernatant produced by, respectively, 2- and 4 mL of cell cultures carrying the T5A fosmid containing the human-derived antimicrobial peptide-type defensin of the present Petition 870210029859, dated 03 / 30 / 2021, page 27 / 97 19 / 82 invention. The data collected every half hour for 12 hours shows the average of three experiments. The X-axis of the graph shows time, expressed in hours, and the Y-axis shows the optical density (OD) of the bacterial cultures.

[0038] Figure 4. Growth curves of cariogenic bacteria S. mutans in the presence of Listerine® and the bacterial inhibitor S12E. Data were collected over 19 hours at 37°C in BHI culture medium and represent the average of three experiments. The solid line represents the negative control, without bacteria. The short dashed line represents the positive control, the growth of S. mutans in the absence of Listerine® and the inhibitor S12E. The long dashed line represents the growth of S. mutans in the presence of 100 pL of Listerine®. The dashed line represents the growth of S. mutans in the presence of 100 pL of inhibitor S12E. The line with short dashes and dots represents the growth of S. mutans in the presence of 100 pL of Listerine® + 100 pL of inhibitor S12E. The X-axis of the graph shows time, expressed in hours, and the Y-axis shows the optical density (OD) of the bacterial cultures.

[0039] Figure 5. Growth curves of cariogenic bacteria S. mutans in the presence of the inhibitor S12E (a bacteriocin-like antimicrobial peptide of bacterial origin of the invention) chemically synthesized in the laboratory and resuspended in 0.1% tricarboxylic acid. The data show the growth of S. mutans, measured as absorbance at 600 nm, for 30 minutes, for 30 hours at a temperature of 37°C in 100 µL of BHI culture medium, from three experiments. Petition 870210029859, dated 03 / 30 / 2021, page 28 / 97 20 / 82 independent. The solid line represents the negative control, without bacteria. The line with black squares represents the growth of S. mutans in BHI culture medium. The dashed line represents the positive control, the growth of S. mutans in BHI culture medium in the presence of 10 pL of 0.1% tricarboxylic acid. The line with short dashes and dots represents the growth of S. mutans in BHI culture medium in the presence of 0.3 mg of S12E peptide resuspended in 10 pL of 0.1% tricarboxylic acid. The short dash line represents the growth of S. mutans in BHI culture medium in the presence of 0.03 mg of S12E peptide resuspended in 10 pL of 0.1% tricarboxylic acid. The X-axis of the graph shows time, expressed in hours, and the Y-axis shows the optical density (OD) of the bacterial cultures.

[0040] Figure 6. Growth curves of the cariogenic bacteria S. mutans (A) and S. sobrinus (B), in the presence of the inhibitor S12E (antimicrobial bacteriocin-like peptide of bacterial origin of the invention) chemically synthesized in the laboratory and resuspended in ultrapure water. The data show the growth of S. mutans, measured as absorbance at 600 nm, for 30 minutes, over 48 hours, at a temperature of 37°C in 200 pL of BHI culture medium, being the average of three independent experiments. In both graphs A and B, the solid lines represent the negative control, without bacteria; the dashed lines represent the growth of S. mutans (A) or S. sobrinus (B) in BHI culture medium. The short dashed line represents the positive control, the growth of S. mutans (A) or S. sobrinus (B) in BHI culture medium, in the presence of water. The line with black squares represents the Petition 870210029859, dated 03 / 30 / 2021, page 29 / 97 21 / 82 Growth of S. mutans (A) or S. sobrinus (B) in BHI culture medium, in the presence of 0.23 mg of S12E peptide of the invention, resuspended in ultrapure water. The line with black diamonds represents the growth of S. mutans (A) or S. sobrinus (B) in BHI culture medium, in the presence of 0.047 mg of S12E peptide of the invention, resuspended in ultrapure water. The line with black triangles represents the growth of S. mutans (A) or S. sobrinus (B) in BHI culture medium, in the presence of 0.094 mg of S12E peptide of the invention, resuspended in ultrapure water. The X-axis of the graph shows time, expressed in hours, and the Y-axis shows the optical density (OD) of the bacterial cultures.

[0041] Figure 7. Growth curves of cariogenic bacteria S. mutans in the presence of 4 pg, 40 pg, and 80 pg of the T5A inhibitor of the invention, chemically synthesized in the laboratory and resuspended in ultrapure water. The data show the growth of S. mutans, measured as absorbance at 600 nm, for 30 minutes, for 44 hours, at a temperature of 37°C in 200 pL of BHI culture medium, being the average of three independent experiments. The solid line represents the negative control, without cells. The short dashed line represents the growth of S. mutans in BHI culture medium (positive control) with ultrapure water. The line with black squares represents the growth of S. mutans in BHI culture medium in the presence of 1 pL of the T5A peptide of the invention (antimicrobial defensin-like peptide of human origin). The line with black diamonds represents the growth of S. mutans in BHI culture medium, in the presence of 10 pL of T5A peptide of the invention. The line with black triangles Petition 870210029859, dated 03 / 30 / 2021, page 30 / 97 22 / 82 represents the growth of S. mutans in BHI culture medium, in the presence of 20 pL of T5A peptide of the invention. The X-axis of the graph shows time, expressed in hours, and the Y-axis shows the optical density (OD) of the bacterial cultures.

[0042] Figure 8. Growth curves of cariogenic bacteria S. mutans in liquid culture medium, in the presence of a 10-fold concentrated supernatant isolated as a function of its molecular mass, produced by bacterial cell cultures of E. coli carrying the W4D phosmid comprising the polynucleotide sequence SEQ ID NO: 13, which encodes a human-derived defensin-like antimicrobial peptide of the present invention. Data taken every half hour for 24 hours show the average of three experiments. As a control, the graph shows the growth curve of S. mutans in the presence of the concentrated supernatant of an untransformed epi300 E. coli bacterial culture. The X-axis of the graph shows time, expressed in hours, and the Y-axis shows the optical density (OD) of the bacterial cultures.

[0043] Figure 9. Growth curves of cariogenic S. mutans bacteria in liquid culture medium, in the presence of a 10-fold concentrated supernatant isolated as a function of its molecular mass, produced by bacterial E. coli cell cultures carrying the T5H phosmid comprising the polynucleotide sequence SEQ ID NO: 14, which encodes the human-derived antimicrobial defensin-like peptide of the present invention. Data collected every half hour for 24 hours show the average of three experiments. Petition 870210029859, dated 03 / 30 / 2021, page 31 / 97 23 / 82 As a control, the graph shows the growth curve of S. mutans in the presence of the concentrated supernatant of an untransformed epi300 E. coli bacterial culture. The X-axis of the graph shows time, expressed in hours, and the Y-axis shows the optical density (OD) of the bacterial cultures.

[0044] Figure 10. Growth curves of cariogenic S. mutans bacteria in liquid culture medium, in the presence of a 10-fold concentrated supernatant isolated as a function of its molecular mass, produced by E. coli bacterial cell cultures carrying the A5D11 phosmid comprising the polynucleotide sequence SEQ ID NO: 6, which encodes the human-derived antimicrobial defensin-like peptide of the present invention. Data collected every half hour for 24 hours show the average of three experiments. As a control, the graph shows the growth curve of S. mutans in the presence of the concentrated supernatant of an untransformed epi300 E. coli bacterial culture. The X-axis of the graph shows time, expressed in hours, and the Y-axis shows the optical density (OD) of the bacterial cultures.

[0045] Figure 11. Growth curves of cariogenic S. mutans bacteria in liquid culture medium, in the presence of a 10-fold concentrated supernatant isolated as a function of its molecular mass, produced by bacterial cell cultures of E. coli carrying the A4H11 phosmid comprising the polynucleotide sequence SEQ ID NO: 7, which encodes the human-derived antimicrobial defensin-like peptide of the present invention. Data collected every half hour for 24 hours show the average of three experiments. Petition 870210029859, dated 03 / 30 / 2021, page 32 / 97 24 / 82 As a control, the graph shows the growth curve of S. mutans in the presence of concentrated supernatant from an epi300 non-transformed E. coli bacterial culture. The X-axis of the graph shows time, expressed in hours, and the Y-axis shows the optical density (OD) of the bacterial cultures.

[0046] Figure 12. Photographs of Petri dishes demonstrate the inhibition of the growth of S. mutans grass cultures in the presence of the CECT 7746 (A), CECT 7747 (B), CECT 7773 (C), CECT 7774 (D) and CECT 7775 (E) isolates described in the present invention.

[0047] Figure 13. Photographs of the Petri dishes demonstrate the inhibition of the growth of S. sobrinus grass cultures in the presence of isolates CECT 7746 (A), CECT 7747 (B) and CECT 7775 (C), strains described in the present invention.

[0048] Figure 14. Growth curves of cariogenic S. mutans bacteria in BHI culture medium, in the presence of a 10-fold concentrated supernatant isolated as a function of its molecular mass, obtained from CECT 7746 (A) and CECT 7747 (B) strain cultures in the stationary phase. Data, obtained every 15 minutes for 20 h, show the average of 4 experiments. The line marked as antb represents treatment with the antibiotic chloramphenicol (positive control). The X-axis of the graph shows time, expressed in hours, and the Y-axis shows the optical density (OD) of the bacterial cultures.

[0049] Figure 15. Growth curves of cariogenic bacteria S. mutans in BHI culture medium, in the presence of Petition 870210029859, dated 03 / 30 / 2021, page 33 / 97 25 / 82 supernatant, concentrated 10 times and isolated as a function of its molecular mass, obtained from cultures of the CECT 7746 strain in the stationary phase (est) and in the exponential phase (EXP). The data, obtained every 15 minutes for 24 h, show the average of 4 experiments. The line marked as chlorf represents treatment with the antibiotic chloramphenicol (positive control). The X-axis of the graph shows time, expressed in hours, and the Y-axis shows the optical density (OD) of the bacterial cultures.

[0050] Figure 16. Growth curves of cariogenic bacteria S. mutans in BHI culture medium, in the presence of supernatant concentrated 10 times and less than 3 kDa, obtained from cultures of the CECT 7746 (A) and strains CECT 7747 (B), subjected to treatment at 100°C for 10 minutes. The data, obtained every 15 minutes for 24 h, show the average of 4 experiments. The X-axis of the graph shows the time, expressed in hours, and the Y-axis shows the optical density (OD) of the bacterial cultures.

[0051] Figure 17. Photographs of Petri dishes demonstrate the inhibition of growth of S. mutans grass cultures in the presence of culture supernatants from CECT 7746 (shown as 46 in the photograph) and CECT 7747 (shown as 47 in the photograph) strains under aerobic and anaerobic conditions.

[0052] Figure 18. The concentration of lactic acid, expressed in mM, produced by the biofilm of human saliva culture in an artificial tooth model under aerobic and anaerobic conditions, where the bacterial strains CECT 7746 and CECT Petition 870210029859, dated 03 / 30 / 2021, page 34 / 97 26 / 82 7747, or their respective supernatants, were added. For more details, see Example 15. The negative control was strain C7.1, which is an isolate belonging to the Streptococcus mitis / oralis / infantil species group, obtained from a caries-free individual, but which does not inhibit the growth of cariogenic species. Detailed description of the invention

[0053] An object of the present invention is a cultivable antimicrobial bacterial strain selected from any of the following: CECT 7746, CECT 7747, CECT 7773, CECT 7774 and CECT 7775. In a preferred embodiment, the bacterial strains of the present invention are characterized by belonging to the genus Streptococcus, selected from: CECT 7746, CECT 7747, CECT 7773 and CECT 7775. In another preferred embodiment, the antimicrobial bacterial strains described in the present invention have inhibitory activity against the growth of organisms that produce infectious diseases of the oral cavity, preferably caries-producing organisms. In a preferred embodiment, the strains of the present invention are characterized by the fact that, in addition to competitive growth to occupy the tooth, they are capable of producing inhibitory substances against the growth of cariogenic bacteria.

[0054] Another objective of the present invention relates to cultivable antimicrobial bacterial strains selected from any of the following: CECT 7746, CECT 7747, CECT 7773, CECT 7774 and CECT 7775, or a combination thereof, for use as a medicament. In one embodiment Petition 870210029859, dated 03 / 30 / 2021, p. 35 / 97 27 / 82 preferred, the antimicrobial bacterial strains described in the present invention are characterized by belonging to the genus Streptococcus and are selected from: CECT 7746, CECT 7747, CECT 7773 and CECT 7775.

[0055] Another objective of the present invention relates to the use of at least one of the cultivable antimicrobial bacterial strains selected from any of the following: CECT 7746, CECT 7747, CECT 7773, CECT 7774 and CECT 7775, or a combination thereof, in the manufacture of a medicament. In a preferred embodiment, said use is characterized in that the bacterial strain belongs to the genus Streptococcus, selected from: CECT 7746, CECT 7747, CECT 7773 and CECT 7775.

[0056] Another objective of the present invention relates to an antimicrobial cultivable bacterial strain selected from any of the following: CECT 7746, CECT 7747, CECT 7773, CECT 7774 and CECT 7775, or a combination thereof, for use as an antimicrobial agent, preferably an antibacterial agent. In a preferred embodiment, the antimicrobial bacterial strain is characterized in that it belongs to the genus Streptococcus and is selected from: CECT 7746, CECT 7747, CECT 7773 and CECT 7775.

[0057] Another objective of the present invention relates to the use of at least one of the cultivable antimicrobial bacterial strains selected from any of the following: CECT 7746, CECT 7747, CECT 7773, CECT 7774 and CECT 7775, or a combination thereof, in the production of a Petition 870210029859, dated 03 / 30 / 2021, p. 36 / 97 28 / 82 antimicrobial composition, preferably an antibacterial composition. In a preferred embodiment, said use is characterized by the fact that the bacterial strain belongs to the genus Streptococcus and is selected from: CECT 7746, CECT 7747, CECT 7773 and CECT 7775.

[0058] Another objective of the present invention relates to an antimicrobial cultivable bacterial strain selected from any of the following: CECT 7746, CECT 7747, CECT 7773, CECT 7774 and CECT 7775, or a combination thereof, for use in the treatment of infectious diseases of the oral cavity, preferably the treatment of caries. In a preferred embodiment, the bacterial strain of the present invention is characterized by belonging to the genus Streptococcus and being selected from: CECT 7746, CECT 7747, CECT 7773 and CECT 7775.

[0059] Another objective of the present invention relates to the use of at least one of the cultivable antimicrobial bacterial strains selected from any of the following: CECT 7746, CECT 7747, CECT 7773, CECT 7774 and CECT 7775, or a combination thereof, in the preparation of a composition designed for the treatment of infectious diseases of the oral cavity, preferably the treatment of caries. In a preferred embodiment, the use of the strains of the present invention is characterized by the fact that the cultivable bacterial strain belongs to the genus Streptococcus can be selected from: CECT 7746, CECT 7747, CECT 7773 and CECT 7775. Petition 870210029859, dated 03 / 30 / 2021, p. 37 / 97 29 / 82

[0060] Another objective of the present invention relates to cultivable antimicrobial bacterial strains selected from any of the following: CECT 7746, CECT 7747, CECT 7773, CECT 7774 and CECT 7775, or a combination thereof, for use as a probiotic or functional food designed to improve oral health, preferably to prevent caries. In a preferred embodiment, the strains of the present invention are characterized by belonging to the genus Streptococcus, selected from: CECT 7746, CECT 7747, CECT 7773 and CECT 7775.

[0061] Another objective disclosed in the present invention relates to the use of at least one of the cultivable antimicrobial bacterial strains selected from any of the following: CECT 7746, CECT 7747, CECT 7773, CECT 7774 and CECT 7775, or a combination thereof, in the preparation of a probiotic or functional food, intended to improve oral health, preferably to prevent caries. In a preferred embodiment, the use of at least one of the aforementioned bacterial strains is characterized by said strains belonging to the genus Streptococcus and being selected from: CECT 7746, CECT 7747, CECT 7773 and CECT 7775.

[0062] Another objective disclosed in the present invention relates to a probiotic / prebiotic composition or functional food comprising at least one cultivable antimicrobial strain, as mentioned throughout the present invention, as well as the anticariogenic substances, compounds or molecules secreted by said strains. Petition 870210029859, dated 03 / 30 / 2021, page 38 / 97 30 / 82

[0063] Another objective disclosed in the present invention relates to a medical or pharmaceutical composition, a composition intended for oral health comprising at least one cultivable antimicrobial strain, as described through the present invention, or the anticariogenic substances, compounds or molecules secreted by said strains.

[0064] Another objective disclosed in the present invention relates to an antimicrobial compound comprising SEQ ID NO: 8 or an antimicrobial compound encoded by a DNA sequence comprising any of the following sequences: SEQ ID NO: 1, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 13, SEQ ID NO: 14.

[0065] Another objective disclosed in the present invention relates to an antimicrobial compound consisting of SEQ ID NO: 8 or an antimicrobial compound encoded by a DNA sequence consisting of any of the following sequences: SEQ ID NO: 1, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 13, SEQ ID NO: 14. In a preferred embodiment of the invention, the antimicrobial compounds described above exhibit inhibitory activity against the growth of organisms that produce infectious diseases of the oral cavity, preferably caries-producing organisms. In another preferred embodiment, said antimicrobial compounds are peptides.

[0066] Another objective of the present invention relates to the antimicrobial compounds mentioned in the preceding paragraphs, or a combination thereof, for use as a medicament. Petition 870210029859, dated 03 / 30 / 2021, page 39 / 97 31 / 82

[0067] Another objective disclosed in the present invention relates to the use of at least one antimicrobial compound, as described above, or a combination thereof, in the production of a medicament.

[0068] Another objective of the present invention relates to the antimicrobial compounds described above, or a combination thereof, for use in the production of an antimicrobial composition, preferably an antibacterial composition.

[0069] Another objective disclosed in the present invention relates to the use of at least one antimicrobial compound, as described above, or a combination thereof, in the production of an antimicrobial composition, preferably an antibacterial composition.

[0070] Another objective of the present invention relates to the above-described antimicrobial compounds, or a combination thereof, for use in the treatment of infectious diseases of the oral cavity, preferably the treatment of caries.

[0071] Another objective disclosed in the present invention relates to the use of at least one antimicrobial compound, as described above, or a combination thereof, in the preparation of a composition designed for the treatment of infectious diseases of the oral cavity, preferably an anti-caries composition.

[0072] Another objective of the present invention relates to the aforementioned antimicrobial compounds in the present invention, for use as a prebiotic food or Petition 870210029859, dated 03 / 30 / 2021, page 40 / 97 32 / 82 functional product designed to improve oral health, preferably to prevent cavities.

[0073] Another objective disclosed in the present invention relates to the use of at least one antimicrobial compound, as described above, or a combination thereof, in the preparation of a prebiotic or functional food, intended to improve oral health, preferably to prevent caries.

[0074] Another objective disclosed in the present invention relates to a probiotic / prebiotic composition or functional food comprising at least one antimicrobial compound, as described throughout the present invention.

[0075] Another objective disclosed in the present invention relates to a pharmaceutical composition or oral health composition comprising at least one antimicrobial compound, as described throughout the present invention.

[0076] Another objective disclosed in the present invention relates to an antimicrobial compound comprising the sequence SEQ ID NO: 9, or an antimicrobial compound encoded by a DNA sequence comprising any of the following sequences: SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5.

[0077] Another objective disclosed in the present invention relates to an antimicrobial compound consisting of the sequence SEQ ID NO: 9, or an antimicrobial compound encoded by a DNA sequence consisting of any of the following Petition 870210029859, dated 03 / 30 / 2021, p. 41 / 97 33 / 82 sequences: SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5. In a preferred embodiment, the aforementioned antimicrobial compound exhibits inhibitory activity against the growth of organisms that cause infectious diseases of the oral cavity, preferably caries-producing organisms. In another preferred embodiment, the antimicrobial compounds described above are characterized by being peptides. In yet another preferred embodiment, the antimicrobial compounds described above are characterized by inhibiting the production of acid, preferably lactic acid, in the oral cavity.

[0078] Another objective disclosed in the present invention relates to an antimicrobial compound, as described above, or a combination thereof, for use as a medicament.

[0079] Another objective of the present invention relates to the use of at least one antimicrobial compound, as described in the present invention, or a combination thereof, in the production of a medicament.

[0080] Another objective of the present invention relates to an antimicrobial compound, as mentioned above, or a combination thereof, for use in the production of an antimicrobial composition, preferably an antibacterial composition.

[0081] Another objective of the present invention relates to the use of at least one antimicrobial compound, as described above, or a combination thereof, in the production of a Petition 870210029859, dated 03 / 30 / 2021, page 42 / 97 34 / 82 antimicrobial composition, preferably an antibacterial composition.

[0082] Another objective disclosed in the present invention relates to an antimicrobial compound, as described above, or a combination thereof, for use in the treatment of infectious diseases of the oral cavity, preferably the treatment of caries.

[0083] Another objective disclosed in the present invention relates to the use of at least one antimicrobial compound, as described above, or a combination thereof, in the preparation of a composition designed for the treatment of infectious diseases of the oral cavity, preferably an anti-caries composition.

[0084] Another objective of the present invention relates to antimicrobial compounds, as described above, or a combination thereof, for use as prebiotic or functional foods intended to improve oral health, preferably to prevent caries.

[0085] Another objective disclosed in the present invention relates to the use of at least one antimicrobial compound, as described above, or a combination thereof, in the preparation of a prebiotic, or a functional food, intended to improve oral health, preferably to prevent caries.

[0086] Another objective disclosed in the present invention relates to a probiotic / prebiotic composition or food. Petition 870210029859, dated 03 / 30 / 2021, page 43 / 97 35 / 82 functional comprising at least one antimicrobial compound, as described in the present invention.

[0087] Another objective disclosed in the present invention relates to a medical-pharmaceutical composition, or a composition for oral health comprising at least one antimicrobial compound, as described in the present invention.

[0088] Another objective disclosed in the present invention relates to a process for isolating cultivable antimicrobial bacterial strains, preferably with inhibitory activity against the growth of organisms that produce infectious diseases of the oral cavity and, more preferably, caries-producing organisms, characterized by comprising: a) Obtaining samples of supragingival bacterial plaque from people who have never suffered from dental caries. b) Inoculation of samples in appropriate media and under appropriate conditions in order to grow and isolate only the bacteria that are most frequent in individuals who have never suffered from caries, the latter being estimated by means of metagenome pyrosequencing. c) Cultivation of the isolated strains in a growth medium for cariogenic bacteria and selection, after an appropriate cultivation period, of those strains that exhibit inhibition halos against said growth.

[0089] In a preferred embodiment, the process described above is characterized by, in step b), the bacteria that Petition 870210029859, dated 03 / 30 / 2021, page 44 / 97 36 / 82, the most frequent in individuals who have never suffered from caries, are estimated by means of metagenome pyrosequencing, a technique that allows estimating the proportions of each of the bacterial species. In another preferred embodiment, the process described above is characterized by, in step c), the bacteria belonging to the following genera are preferably selected: Streptococcus, Rothia, Neisseria, Globicatella, Johnsonella, Haemophilus, Kingella, Cardiobacterium, Mannheimia, Phocoenobacter and Aggregatibacter. Specifically, the following strains are selected: CECT 7746, CECT 7747, CECT 7773, CECT 7774, and CECT 7775. More specifically, bacteria belonging to the genus Streptococcus are preferentially selected, with preference given to those belonging to the following species: S. sanguis, S. oralis, S. mitis, S. infantis, or new species that have not been described but belong to the Streptococcus subgroup that includes these four species.More specifically, at least one antimicrobial bacterial strain is selected from: CECT 7746, CECT 7747, CECT 7773, and CECT 7775.

[0090] Another objective disclosed in the present invention relates to a method of preventing and / or treating infectious diseases, preferably of the oral cavity and, more preferably, caries, which comprises administering an amount that is effective in inhibiting the growth of pathogenic microorganisms, preferably cariogenic microorganisms, usually present in said cavity, of at least one of the cultivable antimicrobial strains described in the present invention, or the probiotic / prebiotic composition or functional foods described in the Petition 870210029859, dated 03 / 30 / 2021, page 45 / 97 37 / 82 present invention comprising the aforementioned strains; or the pharmaceutical composition, or the oral health composition described in the present invention, which comprise the aforementioned strains.

[0091] Another objective of the present invention relates to a process for obtaining antimicrobial compounds, preferably with inhibitory activity against the growth of organisms that produce infectious diseases of the oral cavity and, more preferably, caries-producing organisms, characterized by comprising: a) Obtaining samples of supragingival bacterial plaque from people who have never suffered from dental caries. b) Lysis of the aforementioned samples followed by extraction of intact genomic DNA. c) From the remaining extracted DNA, prepare a metagenomic library of vectors, preferably plasmids or fosmids, capable of being inserted and expressing the extracted DNA they possess in a host cell. d) Insertion of vectors into a host cell. e) Inoculation of host cell clones containing vectors with a culture of caries-producing microorganisms and selection, after an appropriate cultivation period, of those clones with halos of growth inhibition. Petition 870210029859, dated 03 / 30 / 2021, page 46 / 97 38 / 82 f) Sequencing the DNA of the vector clones that exhibited inhibitory activity, and the synthesis and / or purification of the compound encoded by said DNA.

[0092] In a preferred embodiment, the process described above is characterized in that the concentration of extracted DNA is at least 300 μg / mL. In another preferred embodiment, said process is characterized in that, after the DNA extraction process, fosmids are constructed to contain DNA with a size range, preferably, between 35 and 45 kb. In another preferred embodiment, said fosmids contain DNA with a size smaller than 1 kb. In another preferred embodiment, said process is characterized in that the host cell where the fosmids are inserted is E. coli.

[0093] In another preferred embodiment, said process is characterized by the fact that the culture of microorganisms where the clones with DNA insertions contained in the fosmids are fed is a cariogenic bacterium, preferably S. mutans or S. sobrinus. In another preferred embodiment, said process is characterized by the fact that the DNA sequence of fosmids is selected from the following sequences: SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 13, SEQ ID NO: 14, or combinations thereof. In another preferred embodiment, the aforementioned process is characterized by the fact that the DNA sequence of fosmids is selected from the following sequences: SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID Petition 870210029859, dated 03 / 30 / 2021, p. 47 / 97 39 / 82 NO: 7, SEQ ID NO: 13, SEQ ID NO: 14, or combinations thereof.

[0094] In another preferred embodiment, the said process is characterized by the fact that at least one antimicrobial peptide comprising a sequence selected from SEQ ID NO: 8 or SEQ ID NO: 9, or an antimicrobial compound encoded by a DNA sequence comprising any of the following: SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 13, SEQ ID NO: 14, is obtained. In another preferred embodiment, the aforementioned process is characterized by the fact that an antimicrobial peptide consisting of a sequence selected from SEQ ID NO: 8 or SEQ ID NO: 9, or an antimicrobial compound encoded by a DNA sequence consisting of any of the following sequences: SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 13, SEQ ID NO: 14, is obtained.

[0095] In another preferred embodiment, the fosmid DNA sequences SEQ ID NO: 1, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 13 and SEQ ID NO: 14, and the antimicrobial peptide with SEQ ID NO: 9 are of bacterial origin, preferably bacteriocins. In another preferred embodiment, the fosmid DNA sequences SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4 and SEQ ID NO: 5 are of human origin, preferably defensins / cathelicidins.

[0096] Another objective disclosed in the present invention relates to a method of preventing and / or treating diseases. Petition 870210029859, dated 03 / 30 / 2021, p. 48 / 97 40 / 82 infectious diseases, preferably of the oral cavity and, more preferably, caries, comprising the administration of an amount that is effective in inhibiting the growth of pathogenic microorganisms usually present in said cavity, of at least one antimicrobial compound as described through the present invention, or the probiotic / prebiotic composition or functional foods comprising at least one of the antimicrobial compounds described in the present invention, or the pharmaceutical composition or oral health composition comprising at least one of the antimicrobial compounds described in the present invention. Microorganism storage facility in accordance with the Budapest Treaty.

[0097] The microorganisms used in the present invention were deposited in the Spanish Type Culture Collection (CECT), located in the Research Building of the University of Valencia, Campus Burjassot, Burjassot 46100 (Valencia, Spain), with the following deposit numbers: • CECT 7746: bacterial strain of the genus Streptococcus deposited on June 7, 2010. • CECT 7747: bacterial strain of the genus Streptococcus deposited on June 7, 2010. • CECT 7773: bacterial strain of the genus Streptococcus deposited on July 22, 2010. • CECT 7774: bacterial strain of the genus Rothia deposited on July 22, 2010. Petition 870210029859, dated 03 / 30 / 2021, page 49 / 97 41 / 82 • CECT 7775: bacterial strain of the genus Streptococcus deposited on July 22, 2010.

[0098] The intention of the examples listed below is to illustrate the invention without limiting its scope. Example 1. Obtaining the metagenome of supragingival dental plaque

[0099] First, supragingival plaque samples were taken from volunteers who had never suffered from caries, and, for comparative purposes, similar samples were obtained from volunteers who had previously suffered from caries and from volunteers who suffer from caries and, in addition, present lesions in said caries, after signing informed consent. The sampling process was approved by the Clinical Ethics Committee for Public Health Research of the Regional Government of Valencia (GSP-CSISP). The oral health status of each volunteer was assessed by a dentist following the recommendations and nomenclature of Oral Health Studies of the World Health Organization (WHO), and samples were taken with sterile probes. Volunteers were instructed not to brush their teeth for 24 hours before sample collection.

[0100] In order to study the microbial diversity in dental plaque and obtain its metagenome, material collected from the surface plaque of all teeth of each individual was mixed in order to subsequently lyse it and obtain the total DNA from each dental plaque. The DNA was extracted using the MasterPure™ Complete DNA and RNA purification kit (Epicentre). Petition 870210029859, dated 03 / 30 / 2021, page 50 / 97 42 / 82 Biotechnologies), following the manufacturer's instructions, and the addition of a lysozyme treatment (1 mg / mL at 37°C for 30 minutes) during the lysis step. DNA concentration was measured using NanoDrop (Thermo Scientific), and the selected samples preferably had a DNA concentration greater than 300 pg / mL and a total quantity of at least 5 pg (due to the sensitivity threshold of the equipment and the processes involved in pyrosequencing). Furthermore, the DNA samples were run on an agarose gel to verify the integrity of the genomic DNA extracted from the volunteers' dental plaques. Subsequently, pyrosequencing of the extracted DNA was performed using the GS FLX-Titanium chemical sequencer (Roche).Pyrosequencing involves fragmenting DNA into fragments of approximately 500-800 nucleotides using nitrogen under pressure, with the addition of adapters at the ends that allow the DNA to be attached to spheres less than one micrometer in diameter. The spheres are introduced into a specific oil that acts as a microreactor in order to perform an emulsion PCR (emPCR), where the DNA embedded in each sphere is amplified.

[0101] Following an enrichment of the spheres containing the amplified DNA, the solution is placed on titanium plates in the GS FLX sequencer (Roche), where the pyrosequencing reaction is performed. This reaction consists of transforming each pyrophosphate molecule released by the polymerase after the addition of a nucleotide into a beam of light, by means of a set of enzymes, such as luciferase. This beam of light is proportional to the number of nucleotides. Petition 870210029859, dated 03 / 30 / 2021, page 51 / 97 43 / 82 added and, in this way, a high-sensitivity chamber converts the light pulses into the corresponding DNA sequence (19). The average size of said DNA was 425 bp. These artificially replicated sequences using the 454 pyrosequencing technique that appeared systematically were eliminated from the final dataset using the “454 Replicate Filter” (20), such that the number of readings of a given sequence was related only to its frequency in the sample.

[0102] The amount of human DNA in metagenomes ranged from 0.5% to 40% in supragingival plaque samples (Table 1) and were identified using the human genome database, by means of Megablast (21) and removed from the final dataset. Petition 870210029859, dated 03 / 30 / 2021, page 52 / 97 Table 1. Characteristics of pyrosequenced oral samples and their metagenome. Sample 1 CAO Index 2 No. of reads % of human DNA Total Mbp Contigs > 5kbp Largest contig 16S3 readings Simpson Index 4 Shannon Index 4 Chao Index 14 NOCA_01P 0 347927 40.59 77.54 13 12856 543 0.93 3.19 100 ± 24.6 NOCA_03P 0 347927 22.76 100.13 49 43857 374 0.91 2.94 92 ± 28.4 CA1_01P 8 (1) 494659 2.23 203.71 657 46856 1160 0.94 3.21 120 ± 24.8 CA1_02P 6 (4) 315892 2.74 129.85 154 15919 575 0.92 3.11 85.2 ± 9 CA_04P 25 (15) 402049 11.54 142.37 181 19835 663 0.89 2.89 74.4 ± 9.9 CA_06P 11 (8) 354192 10.83 123.27 47 51033 615 0.95 3.38 129.2 ± 41 CA_06_1.6 11 (8) 305820 66. 97 37.52 0 3376 194 0.92 3.21 77 ± 13.3 CA_05_4.6 10 (7) 291162 74.99 27.67 2 29784 130 0.88 2.82 55.3 ± 8.3 44 / 82 Petition 870210029859, dated 03 / 30 / 2021, page 53 / 971P, indicates the samples of supergingival dental plaque. Samples with a number code indicate the tooth from which the samples were taken and from which the carious cavity was removed. 2. Number of teeth with caries (C), missing (A), and obstructed (O). The number in parentheses indicates the number of exposed caries in the patient. 3. Number of 16S rRNA sequences detected in the metagenome and signed using an RDP classifier. 4Simpson, Shannon, and Chao diversity index1, conducted at the gender level. 45 / 82 Petition 870210029859, dated 03 / 30 / 2021, page 54 / 97 46 / 82 Subsequently, an average of 425 base pairs were allowed for functional assignment in a significant fraction of the metagenome (Table 2). Furthermore, the assembly of said reads produced 1103 reuni [contigs] larger than 5 kbp and larger than 10 kbp. We obtained an average of 12 9.5 Mbp of high-quality filtered sequences (greater than 100 bp and where more than 90% of the nucleotides had an accuracy of 99.99%). The probability that the nucleotide read by the pyrosequencer is correct; that is, an accuracy of 99.99% means that only 0.01% of the nucleotides are incorrect (sequencing errors) for every 6 oral samples. In the two samples with caries lesions, approximately 70% of the sequences belonged to human DNA, and in this case, a range of 32.5 Mbp of high-quality filtered reads were obtained. Table 2. Functional assignments of samples present in the oral metagenome based on different classification systems. Sample Dental Health1 Total Readings cdd (n) a cd (%) cog (n) b cog (%) Tfam (n) c Tfam (%) Seed (n) d Seed (%) NOCA_01P h 204218 126729 62 108929 53 82457 40 111497 50 NOCA_03P h 244881 116575 48 95327 39 74356 30 93391 38 CA1_01P c 464594 321997 69 280652 60 214050 46 271868 59 CA1_02P c 295072 182091 62 150966 51 118716 40 146161 55 CA_04P ac 339503 192003 57 161384 48 126281 37 158887 48 Petition 870210029859, dated 03 / 30 / 2021, p. 55 / 97 47 / 82 CA_06P ac 306740 182349 59 151524 49 119477 39 146032 47 CA_05_4.6 cav 70503 40999 58 31864 45 26245 37 29625 42 CA_06_1.6 cav 97722 54305 56 45440 46 35395 36 44552 46 1h: healthy individuals without caries; c: individuals with caries in the past; ac: individuals with active caries; cav: caries lesion samples. (n): absolute count (%): total percentage of readings in the sample that were assigned to a function. acdd: assignment of the preserved domains analyzed in the NCBI preserved domains database. bcog: assignment to sets of orthologous groups. cTfam: assignment to Tigr Fams. dsemente: assignment to the Seed / MG-RAST subsystems. Example 2. Construction of a metagenomic library of fosmids from supragingival dental plaque.

[0103] Using intact DNA samples extracted from supragingival plaque of healthy volunteers included in the study, which had not been used for the pyrosequencing process, a metagenomic library of fosmids (inserts that have a preferred length between 35-45 kb) from the dental plaque of said volunteers was created, using, for this purpose, the Production Kit of Petition 870210029859, dated 03 / 30 / 2021, pp. 56 / 97 48 / 82 EpiFOS™ Fosmid Library (Epicentre Biotechnologies), following the instructions provided by the manufacturer. In summary, in a preferred alternative to the process of constructing the metagenomic library of the invention, the fosmids are inserted into a host, preferably Escherichia coli. The library is prepared, as explained above, using the EpiFOS™ Fosmid Library Production Kit (Epicentre), following the manufacturer's instructions with some modifications, such as increasing the ligation time (12 hours in a 20°C bath), using the total DNA for insertion, and not the DNA extracted from the field pulse gel, slightly modifying the DNA extraction process so that the latter breaks as little as possible (using cutting pipette tips, avoiding vortexing, using Centricom membranes (Millipore) to concentrate the DNA).

[0104] DNA insertion into the host E. coli is performed by packaging the fosmids into lambda phage particles and subsequently infecting them into E. coli Epi300T1R strains. During packaging, the ligation product is brought into contact with the virus for 3 hours at 30°C in 1 mL of phage buffer. Infection is performed at 37°C for minutes by bringing the virus particles into contact with the E. coli strain. Prior titration is performed to select the best colony concentration on a plate (sufficiently spaced to allow propagation of a single colony with the aid of a sterile stick), by culturing different dilutions of the mixture on LB agar medium with chloramphenicol. Petition 870210029859, dated 03 / 30 / 2021, pp. 57 / 97 49 / 82

[0105] Next, each colony was inoculated onto a plate of 96-well ELISA plates are stored in liquid LB medium with chloramphenicol, where they will be allowed to grow once more before being stored. The clones are stored in 96-well ELISA plates (NUNC) at a temperature of -80°C with 19% glycerol in order to prevent the formation of ice crystals and maintain cell integrity. The fosmids are frozen without being induced to multiple copies in order to avoid recombination processes between the two.

[0106] Different E. coli clones with different fosmid insertions are then seeded into cultures of cariogenic bacteria, such as Streptococcus mutans and Streptococcus sobrinus. These clones are selected in the culture where they exhibit an inhibition halo around the seeding point (Figure 1). The resulting clones are identified by homology of the DNA sequence contained in each fosmid, based on different publicly available sequence databases. In order to obtain the DNA sequence of each fosmid, total DNA is extracted from it, separating it from the DNA vector using QIAGEN midiprep kits, and performing direct pyrosequencing. This is how the respective ORFs, and subsequently the peptides encoded in this way, are obtained. Example 3. Analysis of the diversity of the human oral metagenome.

[0107] Once the metagenome of supragingival plaque from caries-affected and healthy individuals has been obtained following the process described in the present invention, the Petition 870210029859, dated 03 / 30 / 2021, pp. 58 / 97 50 / 82 The diversity of the aforementioned oral metagenomes was analyzed using three different techniques:

[0108] Taxonomic assignment through rRNA analysis 16S: 16S rRNA sequences were extracted from the reads obtained from each metagenome by means of similarity search with BLASTN (26) against the RDP (Ribosomal Database Ribosomal) database. Sequences smaller than 200 bp were eliminated. Phylogenetic assignment of the sequences was performed using the RDP classifier (27), with a confidence limit of 80%.

[0109] Gene taxonomic assignment: the taxonomic assignment of all ORFs was performed based on the lowest common ancestor (LCA) algorithm, using the characteristics described in the MEGAN software (28). In order to obtain the LCA of each sequence, homology searches were performed using the BLASTx database against another custom database that includes non-eukaryotic sequences from the NCBI non-redundant database (NR). For each sequence read, only the results that showed a match of at least 90% were considered in obtaining the LCA.

[0110] Taxonomic assignment of reads (PhyMM): the aforementioned taxonomic assignment is performed using PhymmBL (29), which combines sequence assignment by both homology and nucleotide composition; for this purpose, hidden Markov models are used. All available complete genomes were obtained from the Human Oral Microbiome Database (HOMD) (30), as well as Petition 870210029859, dated 03 / 30 / 2021, page 59 / 97 51 / 82 The NCBI (RefSeq) database, which contains all bacterial and archaeal genomes (March 2010), was used to construct a local database designed to perform taxonomic model building and homology searching using PhymmBL. In this analysis, only sequences longer than 200 bp were used to predict taxonomic identification. Using this read length, the class-level accuracy of the PhymmBL search was estimated to be greater than 75%. All taxonomic and functional results were analyzed in a MySQL database for subsequent analysis.

[0111] The results obtained using these three methods show that a small number of 16S genes in directly sequenced metagenomes are sufficient to describe the main taxonomic groups present in the buccal metagenome, without the biases related to cloning or PCR techniques.

[0112] From the samples examined, interesting differences can be observed between healthy and sick individuals. The trend shown by the three methods was that bacilli and gamma proteobacteria taxonomic groups were the most common in healthy individuals, where typically anaerobic taxa, such as Clostridials and Bacteroidetes, are more frequent in samples from sick individuals. Readings attributed to beta proteobacteria (mainly Neisserials) and the phylum TM7 (still unnamed and no members having been cultured so far) were present in a Petition 870210029859, dated 03 / 30 / 2021, p. 60 / 97 52 / 82 is a very low proportion in samples from sick individuals and, therefore, may be associated with health conditions.

[0113] Metagenome correspondence analysis, based on the taxonomic assignment of the 16S rRNA readout, showed that samples from individuals with poor oral health tend to cluster together, while different bacterial consortia can be found in healthy individuals. Through the present metagenomic study, the invention demonstrates that the genera Streptococcus and Rothia, more preferably the genus Streptococcus, are prevalent genera in caries-free individuals. For this reason, when selecting, from supragingival plaque samples of individuals who have never suffered from caries, those that may have anticariogenic activity, the selection was aimed at researching (culture media, culture parameters, microscopic morphology of bacteria, colony morphology, etc.) species belonging to the aforementioned genera, Streptococcus and Rothia, more preferably the genus Streptococcus.

[0114] One of the powerful applications of LCA and approaches PhymmBL suggests that most readings with significant coincidences can be attributed to a taxonomic origin and, moreover, to a possible function. By relating taxonomy and function, it has been possible to predict the ecological or metabolic behavior that each bacterial group may exhibit. Using the COG (Cluster of Orthologus Groups) functional classification system, it can be observed that the categories are not uniformly distributed, and that certain bacterial groups are especially suited to perform certain functions. Petition 870210029859, dated 03 / 30 / 2021, pp. 61 / 97 53 / 82 functions. For example, a large proportion of genes involved in defense mechanisms (e.g., restriction endonucleases and drug discharge pumps) are encoded by bacilli, which, along with a higher presence of streptococci in caries-free individuals, allowed us to predict that these bacteria could be potential producers of natural inhibitors of human pathogens in a possible therapeutic substitution strategy for the treatment of oral infectious diseases. Example 4. Analysis of microbial richness and abundance in the present human oral metagenome.

[0115] Initial studies based on traditional culture techniques and pioneering molecular work, including amplification and cloning of the 16S rRNA gene, predicted a diversity of approximately 500 different species in the oral cavity (6). The use of next-generation technologies (Next Generation Sequencing, NGS) has given estimates of between 4000 and 19000 operational taxonomic units (OTUs). OTUs are estimates of the number of species, based on DNA sequences, which take into account the fact that 16S rRNA gene sequences with a similarity lower than a given threshold belong to different species. The threshold used is the standard for the 16S rRNA gene, a sequence identity of 97%, therefore, if the similarity is greater than 97%, it is considered to be the same species, but if it is less than 97%, it is probably a different species.Further pyrosequencing readings (250 pbs) in three healthy individuals estimated approximately 600 UTOs per person, and a projected... Petition 870210029859, dated 03 / 30 / 2021, p. 62 / 97 54 / 82 recently attempted to sequence 11,447 amplicons with nearly the entire length of 16S rRNA amplicons using Sanger-type sequencing (22), reducing estimates to less than 300 UTOs in 10 individuals.

[0116] Although estimates of microbial diversity are closer to those obtained using sequenced Sanger reads (6,22), 16S rRNA reads extracted from our metagenome data identified 186 new UTOs that had not been previously detected by PCR amplification. Rarefaction curves (the saturation of the number of species with increasing sampling tension) and different diversity indices, as described in Table 1 (specifically, the Shannon, Simpson, and Chao indices1), based on 4254 rRNA reads, indicated an estimated 73120 genera for the dental plaque samples (Tables 1 and 2). Clear differences between samples from volunteers with different health conditions were not observed with respect to diversity, although the two samples with caries lesions tended to show lower diversity.

[0117] An effective tool for quantifying the presence of selected species in metagenomes is sequence recruitment. Those individual metagenomic reads with matches exceeding a determined identity threshold against a reference bacterial genome are “recruited” to plot a graph that varies in density according to the abundance of that organism in the sample. If the average nucleotide identity shown is greater than 94%, the Petition 870210029859, dated 03 / 30 / 2021, pp. 63 / 97 55 / 82 recruitment was probably performed against readings from the same species (23).

[0118] By comparing with our metagenomes with 1117 genomes available so far, using the Nucmer and Promer v 3.06 algorithms, we have been able to estimate the abundance of these species in our samples. Surprisingly, bacteria related to Aggregatibacter and Streptococcus sanguis were among the most abundant in caries-free individuals, which is consistent with the higher frequency of amplification of these species in the oral cavity of healthy individuals. The genus Neisseria was also frequent in samples from healthy individuals. Furthermore, recruitment plots indicate that a few taxonomic domains are typically dominant in each metagenome, suggesting that although there is a great diversity of bacteria in the oral cavity, a few taxonomic domains comprise the majority of bacterial cells. Example 5. Functional diversity in the oral ecosystem

[0119] In order to analyze the functional diversity of organisms that are part of the oral ecosystem of the individuals analyzed in the present invention, all metagenomic sequence reads obtained were compared with different databases: Conserved Domain Database (CDD) (24), Subsystems-Based Annotation System (SEED) and TigrFams profiles (25).

[0120] Correspondence analysis (CoA) of samples based on the functional assignment of the readings provided with Petition 870210029859, dated 03 / 30 / 2021, pp. 64 / 97 56 / 82 similar clustering patterns for the three functional classification systems (CDD, SEED, and TigrFams). Samples from caries-affected individuals tend to cluster, indicating that a similar group of functions were encoded in their metagenomes, and samples from individuals who had never suffered from caries, together with one of the individuals who presented a low number, are clustered separately. When comparing the functional assignment of oral metagenomes with the gut microbiome of adults (8), the oral samples are clustered, indicating that the gut and mouth are two different ecosystems in terms of relative frequencies of encoded functions. The present invention demonstrates that there are blocks of functions that are overrepresented in the gut microbiome, while others are overrepresented in oral samples.

[0121] In oral samples, individuals are grouped based on their health status. From an applied point of view, it is interesting to note that many functional categories are over-represented in samples from caries-free individuals. These include DNA genes involved in competition capture in Gram-positive bacteria, others involved in phospholipid metabolism, fructose- and mannose-induced phosphotransferase systems, the Streptococcus mga regulon, proteins involved in mixed acid fermentation, with quorum-sensing genes and bacteriocin-type antibacterial peptides. These bioactive compounds, bacteriocins, are potential anti-caries agents, and therefore, the present invention demonstrates that the dental plaque of individuals who have never suffered from caries is Petition 870210029859, dated 03 / 30 / 2021, pp. 65 / 97 57 / 82 a genetic reservoir of new antimicrobial and potentially anticariogenic substances. Example 6. Inhibition assays of clones obtained from the fosmid library of the invention in cariogenic Streptococcus cultures.

[0122] Once the phosmid library from supragingival plaque of caries-free individuals was obtained, different clones of E. coli, with different phosmid insertions, were seeded in cultures of cariogenic bacteria, such as Streptococcus mutans and Streptococcus sobrinus. A replica of the metagenomic phosmid libraries from these caries-free volunteers was fixed onto the plaques using a 96-well Nunc replicator, such that each Petri dish could accommodate the growth of the 96 clones from each plaque in the library, previously induced to multiple copies using an inducer (Epicentre Technologies). Using this simple screening, a high-throughput activity assay of hundreds of clones could be performed over a limited time, selecting the clones that produce an inhibition halo on cariogenic bacteria (Figure 1).

[0123] The DNA sequences or insertions of these fosmids, as explained in Example 2 of this invention, are those that potentially produce excreted substances that propagate in the agar and prevent the growth of bacteria that cause dental caries. Subsequently, a second activity screening was performed with the clones. Petition 870210029859, dated 03 / 30 / 2021, pp. 66 / 97 58 / 82 positives, in order to eliminate false positives (Figure 1B). The clones obtained are identified by means of sequence homology of the DNA contained in each fosmid, against different publicly available sequence databases.

[0124] In order to obtain the DNA sequence of each fosmid, the DNA from the same total is extracted, separating it from vector DNA using QIAGEN midiprep kits, and performing direct sequencing. The ends of 20 fosmids were sequenced using classical Sanger technology via reverse (SEQ ID NO: 10 and SEQ ID NO: 11) and T7 (SEQ ID NO: 12) commercial PCC1Fos vector primers. Of the 20 fosmids sequenced, four sequences show homology with bacterial DNA (30%-98%), and five other sequences show 99%-100% homology with human DNA. Therefore, one of the sequences at the fosmid ends exhibits inhibitory capacity, four are of bacterial origin, and five others are of human origin. In two cases (one bacterial and one human), the insertion ended up being very short, and for this reason, the sequence of one of the two ends overlapped, thus obtaining the total length of the insertion.The human-derived insertion fully sequenced using this process has 244 nucleotides (SEQ ID NO: 1) and the bacterial insertion has 666 nucleotides (SEQ ID NO: 2).

[0125] The sequence of the other seven insertions was obtained by pyrosequencing, using groups of 2-5 fosmids, and combining their DNA on a 1 / 16 or 1 / 8 plate of the Genome Sequencer FLX (Roche). The sequences Petition 870210029859, dated 03 / 30 / 2021, pp. 67 / 97 59 / 82 of the obtained samples were assembled using the Newbler program (Roche), using conventional parameters, and the resulting sets were related to the corresponding fosmids based on the sequences of the ends of the previously obtained insertion. The characteristics of the nine insertions are shown in Table 3. Table 3. Characteristics of the DNA insertions of fosmids with inhibitory capacity against cariogenic bacteria. Name Origin Insertion Length (bp) Sequence No. T5A Human 244 SEQ ID NO: 1 S12E Bacterial 666 SEQ ID NO: 2 T1F Bacterial 42797 SEQ ID NO: 3 T4H Bacterial 28023 SEQ ID NO: 4 T9B Bacterial 33804 SEQ ID NO: 5 A5D11 Human 45166 SEQ ID NO: 6 A4H11 Human 32692 SEQ ID NO: 7 W4D Human 34079 SEQ ID NO: 13 T5H Human 27661 SEQ ID NO: 14 Petition 870210029859, dated 03 / 30 / 2021, pp. 68 / 97 60 / 82 Example 7. Identification of antimicrobial peptides in short fosmids S12E and T5A.

[0126] Once the sequences of seven fosmids were obtained as described in Example 6, the DNA sequence of two short-length DNA inserts was analyzed to obtain all ORFs encoded in the 3'-5' and 5'-3' directions. From these ORFs, we selected those that possessed ribosome-binding sequences (with a sequence complementary to the 3' end of the 16S of E. coli) and therefore could be efficiently translated, and those that could be excreted, either by the presence of a signal peptide (identified using the SIGNAL-IP software) or through a non-classical secretion pathway (identified using the SECRETOME-P software). Using the aforementioned methods, a candidate ORF was obtained from a human-derived fosmid (T5A), only 26 amino acids in length (SEQ ID NO: 8), and another candidate ORF was obtained from a bacterial-derived fosmid (S12E), 39 amino acids in length (SEQ ID NO: 9).Furthermore, those genes showed an amino acid composition characteristic of antimicrobial peptides, and, additionally, in the case of T5A, of human origin, the presence of two cysteines that can form a disulfide bridge was observed. This, along with their short length and net positive charge, suggests that they may be bioactive antimicrobial peptides.

[0127] Subsequently, the aforementioned peptides were purified. For this purpose, they were separated from the rest of the secreted products based on their molecular weight. Thus, Petition 870210029859, dated 03 / 30 / 2021, pp. 69 / 97 61 / 82 mL of each clone induced to multiple copying were cultured in brain heart infusion (BHI) medium, centrifuging the cells and collecting the supernatant, which was filtered through Millipore filters with a pore size of 0.2 micron to eliminate any bacterial residue. This supernatant, containing the secreted products, was filtered once more through Amicon 10-kD Millipore filters, and the filtrate was run once more through Amicon 3-kD Millipore filters, thus obtaining the fraction between 3 and 10 kD for a volume of 1 mL. The fraction with a size smaller than 3 kD (0-3 kD fraction) was concentrated under cold conditions in a Speed-vac to a volume of 1 mL.

[0128] Subsequently, 50-, 100- and 150-pL volumes of these two fractions, 3-10 kD and 0-3 kD, respectively, were added to a liquid culture of S. mutans and a liquid culture of S. sobrinus, and the optical density was measured in a 48-well Fluostar luminometer every half hour, with each treatment in triplicate, for 12-19 hours. As can be seen in Figures 2 and 3, the growth curves of cariogenic bacteria show that, in the case of the human-derived defensin-type antimicrobial peptide (Figure 3), the fraction smaller than 3 kD has a dose-dependent inhibitory effect on cariogenic bacteria, whereas, in the case of the bacterial-derived bacteriocin antimicrobial peptide, the 3-10 kD fraction has a dose-dependent inhibitory effect on said cariogenic bacteria (Figure 2), which is consistent with the molecular weights estimated from the amino acid sequence for each of the phosmids. Petition 870210029859, dated 03 / 30 / 2021, pp. 70 / 97 62 / 82 Example 8. Comparative assay of the inhibitory activity of the bioactive peptides of the present invention against cariogenic bacteria.

[0129] In order to compare the inhibitory effect of bacteriocin with that of other competitive products available on the market, the same S. mutans growth experiments in BHI liquid medium were performed as described in the previous example, but now with the addition of: a) 100 pL of one of the leading mouthwashes on the market (Listerine®, which is a dental anti-plaque and oral antiseptic agent), b) 100 pL of concentrated supernatant (as explained in the previous example) of clone S12E containing bacteriocin (3-10 kDa fraction), and c) 100 pL of Listerine® + 100 pL of supernatant of clone S12E containing bacteriocin. The inhibitory effect of bacteriocin at this concentration, 100 pL, on the growth of S. mutans is greater than that of the commercially available product against this species of bacteria (Figure 4), and, moreover, it can be observed in the aforementioned Figure 4 that the addition of bacteriocin to the commercially available product significantly improves the inhibitory activity of said product against S. mutans. Example 9. Analysis of the cariogenic activity of chemically synthesized peptides S12E and T5A.

[0130] The chemical synthesis of the two isolated inhibitory peptides (SEQ ID NO: 8 and 9) was carried out according to the solid-phase synthesis method (32 and 33). Peptide synthesis via SPFS (Solid-Phase Peptide Synthesis) is the most common method used to synthetically create peptides and proteins in the laboratory, and enables the synthesis of peptides. Petition 870210029859, dated 03 / 30 / 2021, pp. 71 / 97 63 / 82 natural amino acids that are difficult to express in bacteria, incorporation of non-natural amino acids, or peptide modification (e.g., formation of disulfide bridges).

[0131] In the case of human-derived peptides, a protecting group, Fmoc-Cys(trt)-OH, was used to protect the —SH groups, which are equally reactive and were relatively frequent in this peptide. The peptides are covalently linked to the beads, leading the free N-terminal amino group so that it can bind to a single N-protected amino acid. After binding, it is deprotected and washed. After repeated cycles of binding, washing, deprotection, and washing, the peptide chains are built. When the peptide is complete, it is released by the addition of a reagent (in this case, anhydrous hydrogen fluoride). Quality control, designed to verify that the synthesized peptide is correct and does not contain impurities, was performed by mass spectrometry and HPLC.

[0132] In order to confirm that the identified peptides are those responsible for the inhibitory activity against cariogenic bacteria, the peptides S12E (bacteriocins of bacterial origin) and T5A (a peptide of human origin with a structure similar to that of defensins) were chemically synthesized, obtaining approximately 4 mg of each peptide with a purity greater than 80%. They were fully resuspended in 0.1% trichloroacetic acid (TCA) and the experiments planned to test the inhibition of liquid cultures of S. mutans by the aforementioned chemically synthesized components were carried out. Petition 870210029859, dated 03 / 30 / 2021, pp. 72 / 97 64 / 82

[0133] In the case of a bacteriocin-type S12E peptide of bacterial origin, an inhibitory activity against S. mutans cultures was confirmed, especially at high concentrations (Figure 5). Consequently, more S12E peptide was chemically synthesized, now with a purity greater than 95%, and said peptide was resuspended in ultrapure water in order to demonstrate that the previously obtained inhibitory effects were not due to ATC, but rather due to the chemically synthesized S12E peptide itself. Once again, it was observed that treatment of S. mutans and S. sobrinus cultures with the chemically synthesized S12E peptide at high purity produced a dose-dependent inhibitory effect on both cariogenic bacteria, S. mutans (Figure 6A) and S. sobrinus (Figure 6B).

[0134] In the case of the T5A peptide (of human origin, defensin type), initially, it did not show an inhibitory effect. This is because this peptide has several reactive amino acids, including two cysteines, the presence of which is typical in human antimicrobial peptides, and generally a disulfide bridge between these two cysteines is necessary for the peptide to be active. For this reason, the peptide was synthesized again, adding a disulfide bridge between cysteines 3 and 12, and protecting the reactive amino acids during synthesis. After these modifications, it was confirmed that the peptide is capable of inhibiting the growth of the cariogenic bacterium, S. mutans, at different concentrations, with total inhibition of growth when the maximum peptide concentration, 80 pg, is added (Figure 7). Petition 870210029859, dated 03 / 30 / 2021, pp. 73 / 97 65 / 82 Example 10. Identification of inhibitory genes in long fosmids.

[0135] Considering the rest of the potential antimicrobial compounds, DNA was isolated from fosmids that produced an inhibition halo, and its ends and complete insertion were sequenced (Table 3). This makes it possible to obtain a catalog of bacteria that produce antimicrobial substances (not just antibacterial peptides), as well as the regions of the human genome that encode them. Inhibition experiments were performed on liquid cultures of S. mutans, by adding concentrated bleaching agent (as indicated in the previous examples) produced by the corresponding clones, in fractions of 0-3 kDa, 3-10 kDa, 10-100 kDa and > 100 kDa. These experiments reveal that the size of the fractions that cause inhibition are the 0-3 kDa fraction in the bacterial fosmids T9B and T4H, and the human fosmids W4D (Figure 8), T5H (Figure 9), A5D11 (Figure 10) and A4H11 (Figure 11), and the 3-10 kDa fraction in the bacterial fosmid T1F. Therefore, these results again showed that inhibition is produced by small-sized peptides, i.e., peptides with a size between 0-3 kDa or 3-10 kDa, which is consistent with the fact that they are antibacterial peptides of the bacteriocin or defensin / cathelicidin type.

[0136] Similarly, a search for ORFs encoding peptides with these sizes (i.e., 0-3 kDa or 3-10 kDa, as the case may be) was carried out on the sequences of the aforementioned fosmids, and the following genes were selected. Petition 870210029859, dated 03 / 30 / 2021, pp. 74 / 97 66 / 82 as possible candidates to be inhibitor-coding genes: those with a ribosome-binding sequence, the presence of signal peptides and an amino acid usage similar to antibacterial peptides and / or a sequence similar to other known antibacterial peptides, and / or with hydrophobicity and / or a net positive charge. Example 11. Identification of anti-caries bacteria

[0137] The existence of a small proportion of the adult human population that has never suffered from caries has led to the suggestion of the presence of bacterial species with a potentially aggressive effect against cariogenic bacteria (23). The replacement of pathogenic strains with harmless isolates obtained from healthy individuals has satisfactorily proven to prevent pharyngeal infections and is the basis for probiotics designed to prevent infectious diseases in the intestine and other human ecosystems (31). Metagenomic recruitment of cariogenic bacteria against the oral microbiome of healthy subjects shows a total absence of S. mutans and S. sobrinus. Surprisingly, the non-detection of cariogenic bacteria is accompanied by an intense recruitment of other Streptococcus species (mainly those similar to S. sanguis). Aggregatibacter and Neisseria are the most abundant genera in these individuals.

[0138] Given the possibility that isolates of these dominant genera may be involved in aggressive interactions with cariogenic bacteria, fresh dental plaque samples were taken from 10 healthy individuals (including the 2 Petition 870210029859, dated 03 / 30 / 2021, pp. 75 / 97 67 / 82 healthy individuals from whom metagenomic sequences were obtained) and used in culture, under optimal growth conditions, species of Neisseria, Rothia, and Streptococcus (specifically, on blood agar, chocolate agar, brucella agar, and TSA culture medium, under aerobic and anaerobic conditions). After microscopic examination, diplococcus and streptococcus were selected (in order to maximize the possibility of finding species of Streptococcus, Rothia, and Neisseria), and a set of 249 isolates were obtained.

[0139] Those that were able to grow in the same medium as S.mutans and S.sobrinus were transferred to cultures in the presence of the aforementioned cariogenic bacteria. This simple scan identified 16 strains with inhibition halos (Figures 12 and 13). Using PCR techniques and 16S rRNA sequencing, most of these strains were identified as belonging to Streptococcus species, showing a sequence identity of 96%-99% with S. oralis, S. mitis and S. sanguis species or other related species, and also with Rothia species, with a sequence identity of 100% with R. mucilaginosa species in the 16S gene. The strains that showed inhibition halos against S. mutans and / or S. sobrinus were deposited in the CECT, with the assigned numbers CECT 7746, CECT 7747, CECT 7773, CECT 7774, and CECT 7775.As previously discussed, the strains CECT 7746, CECT 7747, CECT 7773, and CECT 7775 belong to the same genus Streptococcus and, therefore, in addition to the method of obtaining them, share a taxonomic and structural similarity, since they belong to the same bacterial genus. Petition 870210029859, dated 03 / 30 / 2021, pp. 76 / 97 68 / 82

[0140] Specifically, based on the 16S ribosomal gene sequence, the aforementioned lineages, which belong to the bacterial genus Streptococcus, are similar to the species S. mitis (CECT 7746 and CECT 7775) and S. oralis (CECT 7747 and CECT 7779). Complete genome sequencing of the CECT 7746 and 7747 lineages reveals that they are new species of the genus Streptococcus (see Example 12), that they are sister lineages although they come from different individuals and, moreover, belong to the S. mitis / oralis / infantis species group. The other bacterial lineage deposited at CECT, with number CECT 7774, belongs to the genus Rothia and, more specifically, to the species R. mucilaginosa. The inhibition halos against cultures of cariogenic species, S. mutans or S. sobrinus, from the aforementioned strains deposited in CECT can be observed in Figures 12 and 13, respectively. Example 12. Characterization of bacterial strains CECT 7746 and CECT 7747.

[0141] Characterization of bacterial strains CECT 7746 and CECT 7747 was performed using different techniques. First, the complete genome of the two strains was obtained by shotgun pyrosequencing (7,8) and end-pair pyrosequencing; the latter consists of breaking the DNA into 3000 nucleotide fragments and sequencing approximately 200 nucleotides from each end, such that the known distance between these two ends helps in assembling the sequences.

[0142] In order to obtain the complete genome of each of the CECT 7746 and CECT 7747 cell lines, we started from Petition 870210029859, dated 03 / 30 / 2021, pp. 77 / 97 69 / 82 samples were collected from each of the cultures of the aforementioned strains; specifically, one quarter of the culture plate was used for pyrosequencing experiments using a shotgun system (7,8), using the Roche GS-FLX pyrosequencer (Titanium Chemistry), and another quarter of the culture plate was used for pyrosequencing experiments using an end-pair system. The amount of sequence obtained for each strain using both systems was: Lineage 7746

[0143] Shotgun type: 441,549 readings, with a total of 165,105,921 nucleotides

[0144] End pair type: 187,530 reads, with a total of 32,721,622 nucleotides Lineage 7747

[0145] Shotgun type: 28,021 readings, with a total of 5,711,998 nucleotides

[0146] End pair type: 305,826 reads, with a total of 51,501,510 nucleotides

[0147] The expected genome size for each of the lineages was approximately 2.1 Mb. For the CECT 7746 lineage, the size of assemblies larger than 500 bp is 2,122,087 bp. In the case of the CECT 7747 lineage, the size of contigs larger than 1,953,989 bp.

[0148] The sequences were filtered and assembled using Newbler software (Roche), adapted by inventors with Petition 870210029859, dated 03 / 30 / 2021, pp. 78 / 97 70 / 82 conventional parameters were used to obtain a total of 109 assemblies > 500 bp for the CECT 7746 cell line and 51 contigs for the CECT 7747 cell line. Subsequently, these genomes were automatically annotated to obtain the complete sequence of the CECT 7746 and CECT 7747 cell lines.

[0149] Once the complete genome of the CECT 7746 and CECT 7747 strains was obtained, said isolates were taxonomically located at the base of the phylogenetic trees obtained based on the complete sequence of the 16S and 23S rRNA genes, which are most common when preparing bacterial phylogenetic trees.

[0150] By linking the sequences of the 16S and 23S rRNA genes, a single fragment larger than 4000 nucleotides was obtained, which was aligned with the same fragment from sequenced Streptococcus species as a distant result. The sequences were aligned using the free computer software MAFFT, by aligning the 16S and 23S genes separately, and subsequently linking the alignment simultaneously. The alignment was then purified using the free computer software GBlocks to select the conserved informative positions. The tree was obtained using the RAxML program, by the maximum likelihood method, with 50 repetitions. The phylogenetic tree obtained showed that both lineages are sister lineages, although originating from different individuals, and furthermore, belong to the S. mitis / oralis / infantis species group, and the tree topology suggests that they are lineages belonging to a new, undiscovered species. Petition 870210029859, dated 03 / 30 / 2021, pp. 79 / 97 71 / 82

[0151] In order to determine which of the aforementioned lineages belong to different species, the IMN (important nucleotide identity) was used. When the genomes of the sequenced lineages are compared, the indication of similarity between homologous genes of the same species at the nucleotide level is greater than 95% (34, 35). In fact, taxonomists accept this 95% ANI value as the limit for separating bacterial isolates belonging to different species and as an alternative to the classic limit value of DNA-DNA hybridization (36). Using the free computer software J-species to determine the IMN value between the two sequenced lineages of the invention, CECT 7746 and CECT 7747, and the rest of the sequenced Streptococcus, it was demonstrated that we are two lineages belonging to new species that have not yet been discovered.In the case of the bacterial strain of invention CECT 7746, there is no strain with a similarity greater than the 95% threshold and, in the case of the bacterial strain of invention CECT 7747, only another strain of those sequenced, Streptococcus M143, exceeds the said threshold. The said strain M143 is a strain that, despite containing an out-of-line genome sequence, has not been taxonomically described as a species. The results used to calculate the ANIs were obtained through two different methodologies: Mummer and Blast (36), and both methodologies presented practically identical results. Petition 870210029859, dated 03 / 30 / 2021, pp. 80 / 97 72 / 82 Example 13. Inhibition assays of cariogenic bacteria, S. mutans, in the presence of supernatants obtained from cultures of the CECT 7746 and CECT 7747 strains disclosed in the invention.

[0152] The two strains of the invention, CECT 7746 and CECT 7747, were grown in BHI culture medium at a temperature of 37°C. Consequently, the culture supernatants collected in the exponential and stationary phases were filtered through a 0.2 micron filter in order to eliminate any bacterial residue. Subsequently, said supernatants were filtered once more by centrifugation, using membranes with pore sizes of 100, 10 and 3 kDa (Amicon, Millipore), as described in the previous examples shown in the present invention.

[0153] The fraction of supernatants obtained from each of the CECT 7746 and 7747 strains, collected in the stationary growth phase, which produced inhibition of the growth of S. mutans bacterial cultures, was concentrated in the fraction smaller than 3 kDa for both strains tested, CECT 7746 (Figure 14 A) and CECT 7747 (Figure 14 B). These results show that the inhibitory substance synthesized by these strains, which exhibit a specific bactericidal effect against cariogenic species, must be of a small size, preferably <3 kDa, as in the case of bacteriocins.

[0154] Conversely, when the same experiment was performed with samples of culture supernatants from the CECT 7746 and 7747 strains of the invention collected in the exponential growth phase, no inhibition was observed. Petition 870210029859, dated 03 / 30 / 2021, pp. 81 / 97 73 / 82 growth of S. mutans bacterial cultures (Figure 15), which indicates that the inhibiting agent is only produced in the stationary phase of bacterial growth of the strains of the invention.

[0155] When samples of the concentrated supernatant obtained in the stationary phase, and smaller than 3 kDa, were subjected to a temperature of 100°C for 10 minutes, it was found that the inhibitory activity of said supernatant on S. mutans cultures was maintained and even increased (Figure 16). These results are consistent with the fact that the inhibitory agent is a bacteriocin and not another type of peptide, since small-sized bacteriocins are extremely thermostable and further increase their antimicrobial effect, provided they are better eluted in the medium after their aggregates are dissolved by thermal shock.

[0156] Consequently, inhibition assays against S.mutans cultures were performed with supernatants obtained from cultures of bacterial strains of the invention CECT 7746 and CECT 7747, but altering the feeding order and growth temperature of the cultures of said cariogenic bacteria, in order to verify which said modifications had any effect on the inhibition activity of the supernatants of the strains of the invention.

[0157] Initially, the culture plates were fed with the cariogenic bacterium S. mutans and, after 24 hours of rest, the strains of the invention were fed onto the same culture plates. After a period of rest, no inhibition halos were observed. Conversely, when the culture plates Petition 870210029859, dated 03 / 30 / 2021, pp. 82 / 97 74 / 82 were fed with both strains at the same time, and inhibition of S. mutans growth was observed, as we showed previously. The best inhibition of S. mutans culture growth was observed when the strains of the invention, CECT 7746 and 7747, were fed first and, 24 h later, the S. mutans strains were fed, indicating that there is a higher concentration of the inhibiting agent or substance that prioritizes the growth of the cariogenic bacteria, and that, moreover, the presence of said bacteria is not necessary to activate the production of the inhibiting agent by the strains of the invention.

[0158] Consequently, the inhibition experiments against the growth of cariogenic bacteria were carried out in a solid medium, through the first feeding of the strains of the invention with a drop of the culture in a liquid medium in the stationary phase, followed by a spot culture of S. mutans at different temperatures: 30°C, 33°C and 36°C. No growth of S. mutans was observed at a temperature of 30°C, however inhibition was observed at 33°C, being in fact greater than the inhibition obtained at 36°C. Example 14. Inhibition assays against cariogenic bacteria, S. mutans, cultivated in the presence of supernatants obtained from the bacterial strain cultures of the invention CECT 7746 and CECT 7747, under aerobic and anaerobic conditions.

[0159] In order to determine where the inhibitory action of the strains of the invention against the growth of cariogenic bacteria was modified by an aerobic or anaerobic environment, inhibition experiments were carried out in a Petition 870210029859, dated 03 / 30 / 2021, pp. 83 / 97 75 / 82 BHI solid medium, first by feeding the strains of the invention with a drop of the culture in a liquid medium, in the stationary phase, in an anaerobic vessel for 12 hours, followed by spot cultivation of S.mutans at 37°C, or followed by feeding with a drop of S.mutans culture at 37°C.

[0160] The results of both experiments showed that the inhibition of S.mutans growth is much lower under anaerobic conditions, especially for the CECT 7746 strain (Figure 17). Therefore, the results demonstrate that, for the strains of the invention, the inhibition exerted on cariogenic bacteria is more effective during the aerobic stage of dental plaque formation, i.e., during the period of adhesion and initial formation of the biofilm on the tooth. Example 15. Anticariogenic effect of the bacterial strains CECT 7746 and CECT 7747 and their supernatants on the biofilm in an artificial tooth mold.

[0161] In order to demonstrate the anticariogenic effect of the bacterial strains disclosed in the present invention, inhibition assays against acid production were performed with CECT 7746 and CECT 7747 strains on the biofilm in an artificial tooth mold. These experiments were performed on the Active Attachment biofilm model of the Academic Center of Dentistry Amsterdam (ACTA, Amsterdam). The biofilm model was described by Exterkate RA et al. (37). In short, hydroxyapatite or glass discs are inoculated with human saliva from a volunteer with a high percentage of S. mutans (greater than 4%), with or without the presence of a probiotic strain, or its supernatant. Petition 870210029859, dated 03 / 30 / 2021, pp. 84 / 97 In the present assays, the CECT 7746 and 7747 strains, disclosed in the present invention, were tested, as was the C7.1 strain, an isolate belonging to the Streptococcus mitis / oralis / infantis group of species, obtained from a caries-free individual, but which does not inhibit the growth of cariogenic species and therefore acts as a negative control.

[0162] Human saliva is stored at -80°C. Probiotic strains CECT 7746 and 7747 and the control strain C7.1 are grown in BHI culture medium with sucrose for 12 hours, until a culture density of approximately 4 x 10⁸ cfu (colony forming units) is obtained. Subsequently, the saliva sample is mixed 50% with the inoculum of the probiotic strains of the invention (CECT 7746 or 7747) or the inoculum of the control strain (C7.1), and applied inside the glass disc.

[0163] Biofilms are formed for 48 hours in modified artificial saliva medium (38) under aerobic and anaerobic conditions, and, once formed, are incubated for 3 hours at a temperature of 37°C in a water / peptone / cysteine ​​mixture (SigmaAldrich, St. Louis, USA) containing 0.2% glucose, in order to measure acid production. During this incubation period, the strains will produce acid, which is measured by a colorimetric reaction: the biofilm is transferred to an Eppendorf tube and incubated at a temperature of 80°C for 5 min. in order to interrupt the metabolism of the bacteria. The amount of L-lactic acid is enzymatically determined by colorimetric analysis using the Spectra spectrophotometer. Petition 870210029859, dated 03 / 30 / 2021, pages 85 / 97 77 / 82 Max M2 (Molecular Devices, USA), following the protocol provided by Pham LC et al. (38).

[0164] With the intention of analyzing the inhibition of acid production by the supernatants of the strains of the invention (CECT 7746 and 7747) as well as the control strain (C7.1), firstly, the supernatants of the cultures of said bacterial strains were obtained. For this purpose, cultures of said strains were grown in BHI medium for 12 hours. Then, the bacterial cells were eliminated by centrifugation followed by filtration through 0.2 micron pores. The medium is filtered through 100-, 10- and 3-kDa ultramembranes (Millipore). The fraction smaller than kDa is concentrated to half its volume in a rotary evaporator and mixed 50% with a saliva sample; Subsequently, as in the case of probiotics, the biofilm is formed over 48 hours and incubated for 3 hours in a buffered water and peptone culture medium (38) containing 0.2% glucose, and only then should acid production be measured. Each treatment is repeated in quadruplicate under aerobic and anaerobic conditions. The experimental groups analyzed were:

[0165] 1. Biofilms formed with saliva inoculum.

[0166] 2. Biofilms formed with saliva inoculum + CECT 7746.

[0167] 3. Biofilms formed with saliva inoculum CECT 7746. Petition 870210029859, dated 03 / 30 / 2021, pages 86 / 97 78 / 82

[0168] 4. Biofilms formed with saliva inoculum + CECT 7747.

[0169] 5. Biofilms formed with saliva inoculum CECT 7747.

[0170] 6. Biofilms formed with saliva inoculum + non-inhibitory Streptococcus strain (C7.1 strain).

[0171] 7. Biofilms formed with saliva inoculum + supernatant from the CECT 7746 cell line, which contains the active inhibitory substance.

[0172] 8. Biofilms formed with saliva inoculum + supernatant from the CECT 7747 cell line, which contains the active inhibitory substance.

[0173] 9. Biofilms formed with saliva inoculum + supernatant from the non-inhibitory strain (C7.1 strain).

[0174] 10. Biofilms formed with the non-inhibitory Streptococcus strain (C7.1 strain).

[0175] The results are shown in Figure 18, and indicate that the monospecific biofilm formed exclusively by the CECT 7746 (experimental group 3) or CECT 7747 (experimental group 5) strains produces a significantly lower amount of acid than saliva (experimental group 1). Considering human saliva as a reference value (experimental group 1), the supernatants from the CECT 7747 strain (experimental group 8) significantly reduced acid production, both under aerobic and anaerobic conditions, wherein the supernatant from the CECT 7746 strain Petition 870210029859, dated 03 / 30 / 2021, pages 87 / 97 79 / 82 (experimental group 7) reduced the amount of acid produced by biofilms only under anaerobic conditions. The addition of the CECT 7747 strain to the biofilm reduced acid production in both aerobic and anaerobic conditions, while the addition of the CECT 7746 strain to the biofilm caused a reduction only under aerobic conditions.

[0176] Acid reduction, particularly in the case of the CECT 7747 strain and its supernatants, is highly relevant for the treatment and prevention of dental caries, since the latter is formed due to acid production by microorganisms when they ferment sugars ingested in the diet. Acidic pH is precisely what demineralizes enamel and produces caries, and therefore any acidogenic species, and not just Streptococcus mutans, could be potentially cariogenic (2). Consequently, the reduction in acid production is an indicator that the overall effect of treatment with the probiotic strain or its supernatant is acid reduction and, consequently, a lower probability of caries development. BIBLIOGRAPHY

[0177] 1.PD Marsh, Dental Clinics of North America 54, 441 (2010).

[0178] 2.P. Marsh, BMC Oral Health 6, S14 (2006).

[0179] 3.PE Petersen, Zhonghua Kou Qiang Yi Xue Za Zhi 39, 441 (Nov., 2004). Petition 870210029859, 03 / 30 / 2021, pág. 88 / 97 80 / 82

[0180] 4.SS Socransky, AD et al. J Clin Periodontol 25, 134 (Fev., 1998).

[0181] 5.RP Darveau, Nat Rev Microbiol 8, 481 (1 Jun. 2010).

[0182] 6.BJ Paster et al. , J Bacteriol 183, 3770 (Jun., 2001).

[0183] 7. S. R. Gill et al., Science 312, 1355 (2 Jun. 2006).

[0184] 8.K. Kurokawa et al., DNA Res 14, 169 (31 Aug. 2007).

[0185] 9.PA Vaishampayan et al., Genome Biol Evol 2010, (2010).

[0186] 10.J. Qin et al., Nature 464, 59 (4 Mar. 2010).

[0187] 11.JA Aas et al., J Clin Microbiol 43, 5721 (Nov., 2005).

[0188] 12.EA Grice et al., Genome Res 18, 1043 (Jul., 2008).

[0189] 13.WJ Loesche, Microbiol Rev 50, 353 (Dez., 1986).

[0190] 14.M. W. Russell et al., Caries Res 38, 230 (MaioJun., 2004).

[0191] 15.WO 2007 / 077210 “Probiotic oral health promoting product”.

[0192] 16.WO 2005 / 018342 “Compositions and methods for the maintenance of oral health”. Petição 870210029859, de 30 / 03 / 2021, pág. 89 / 97 81 / 82

[0193] 17.EP 0195672 “Dental caries preventive preparations and methods for preparing said preparations.

[0194] 18.WO 2004 / 072093 “Antimicrobial agents.

[0195] 19.Margulies M et al., Nature 15; 437(7057) (2005).

[0196] 20.Gomez-Alvarez V et al., ISME J. 3(11) (Nov. 2009).

[0197] 21.Zheng Zhang et al., J Comput Biol. 7(1-2) (2000).

[0198] 22.E. M. Bik et al., Isme J (25 Mar. 2010).

[0199] 23.K. T. Konstantinidis et al., Proc Natl Acad Sci U S A 102, 2567 (15 Fev. 2005).

[0200] 24.Marchler-Bauer A et al., Nucleic Acids Res. 37:D205-10 (Jan. 2009).

[0201] 25. Selengut JD et al., Nucleic Acids Res. 35:D260-4 (Jan. 2007).

[0202] 1990). 26.Altschul et al., J Mol Bio. 215 (3 ):403-10 (5 Out.

[0203] 2009). 27.Cole JR. et al., Nucleic Acid Res. 37:D141-5 (Jan.

[0204] 2007). 28.Huson DH et al., Genome Res. 17 (3):377-86 (Mar.

[0205] 29.Brady A and Salzberg SL. Nature Methods. 6 (9): 673-6 (Sep. 2006).

[0206] 30.Chen T et al., Database (Oxford) 6 (Julho 2010). Petition 870210029859, 03 / 30 / 2021, pág. 90 / 97 82 / 82

[0207] 31.JR Tagg et al., Trends Biotechnol 21, 217 (Maio, 2003).

[0208] 32.RB Merrifield (1963), J. Am. Chem. Soc 85(14): 2149-2154.

[0209] 33.Albericio, F. (2000). Solid-Phase Synthesis: A Practical Guide (1st ed.). CRC Press. pp. 848. ISBN 0824703596.

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Claims

1 / 2 CLAIMS 1. Use of a cultivable antimicrobial bacterial strain belonging to the bacterial genus Streptococcus selected from any of the following: CECT 7747, CECT 7746, CECT 7773 and CECT 7775, or a combination thereof, characterized in that it is for preparing a medicament for the treatment of infectious diseases of the oral cavity selected from the group consisting of caries, gingivitis, periodontitis and halitosis.

2. Use of a cultivable antimicrobial bacterial strain belonging to the Streptococcus bacterial genus selected from any of the following: CECT 7747, CECT 7746, CECT 7773 and CECT 7775, or a combination thereof, characterized by being for preparing a probiotic or functional food designed to improve oral health for the treatment of infectious diseases of the oral cavity selected from the group consisting of caries, gingivitis, periodontitis and halitosis.

3. Probiotic / prebiotic composition or functional food characterized by comprising at least one antimicrobial strain belonging to the bacterial genus Streptococcus selected from any of the following: CECT 7747, CECT 7746, CECT 7773 and CECT 7775, wherein the probiotic / prebiotic composition is selected from the group consisting of: solid composition, powder composition, paste composition or liquid mouthwash solution, and wherein the functional food is selected from the group Petition 870210029859, dated 03 / 30 / 2021, page 92 / 97 2 / 2 consisting of: a dairy product, a juice and a solid food.

4. Probiotic / prebiotic composition or functional food, according to claim 3, characterized in that the probiotic / prebiotic composition or functional food comprises at least one ingredient selected from the group consisting of minerals, vitamins, fatty acids, nutritious fiber and antioxidants.

5. Use of the probiotic / prebiotic composition or functional food as defined in claim 3 or 4, characterized by being for the preparation of oral antimicrobial agents, oral health solutions or oral health medications.

6. Use of the probiotic / prebiotic composition or functional food, according to claim 5, characterized by the oral antimicrobial agents, oral health solution or oral health medication being for the treatment of infectious diseases of the oral cavity selected from the group consisting of caries, gingivitis, periodontitis and halitosis. Petition 870210029859, dated 03 / 30 / 2021, pp. 93 / 97

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