Oral probiotic

Abstract

The present invention relates to a bacterial strain of Streptococcus salivarius with oral probiotic properties and a minimum inhibitory concentration of at least 500 ppm.

Description

[0001]ORAL PROBIOTIC Technical Field The invention relates to strains of Streptococcus salivarius and the use thereof as oral probiotics to obtain essential amino acids. Background Humans need to assimilate essential amino acids (EAs) through external input, since our body is not able to synthesize them, or does so at a rate too low to allow optimal growth and functionality. These EAs, traditionally incorporated through the diet, are also produced by bacteria that colonize different niches of the human body, with the contribution of bacteria associated with the digestive system and more specifically the mouth being particularly relevant. EAs play an important role in the regulation of metabolism and functions of the immune system, while acting as neurotransmitters or as precursors thereof, among other functionalities.A decrease in amino acid-producing bacteria due to changes in dietary habits, an aging population, or excessive antibiotic use can have a negative effect on human health. The use of probiotics capable of restoring this capacity for amino acid production can be a support in the treatment and prevention of diseases with significant social and economic impact. The alternative to using oral probiotics to compensate for essential amino acid deficiencies is the intake of amino acids in the form of dietary supplements. The disadvantage of this strategy is that the absorption of essential amino acids is limited to the intestine, obviating the contribution of the oral cavity through mucosal permeability.On the other hand, the amounts provided through supplements are usually equal to or greater than the recommended daily dose and are generally ingested in a single daily dose, while synthesis by a microorganism is lower, although sustained over time, including periods of fasting. The Streptococcus salivarius strains object of this invention are capable of producing L-amino acids, both essential and non-essential, and secreting them into the environment in free form. This means that they can be immediately incorporated into human metabolism by direct absorption in the oral cavity, or transported with saliva to the intestine, where they are absorbed together with the amino acids released after the lysis of the bacteria that takes place in the stomach. EP1483366B1 discloses a strain of S. salivarius called M18; this does not disclose the use of the strain as a producer of EOs.Additionally, the strains of the present invention show better probiotic capabilities than said strain. The S. salivarius strains currently marketed as probiotics for oral health (M18 and K12) do not have their functionality described as producers of essential amino acids. Streptococcus salivarius K12 is characterized by producing the bacteriocins salivaricin A2 and salivaricin B, while the reference strain M18 produces four bacteriocins, salivaricins A2, 9, MPS, and M, which act against the cariogenic bacteria Streptococcus mutans. In addition, it produces dextranses and ureases, which help reduce the accumulation of dental plaque and the acidification that causes caries. In the present invention, we additionally show through comparative experiments that the strains of the state of the art have inferior or even adverse probiotic capabilities with respect to the S.salivarius object of the invention, such as a reduced capacity to produce EOs, reduced resistance to fluoride and increased acidogenic capacity. Description of the invention The expression "a strain of the invention", as used herein, is a collective term that refers to any S. salivarius strain described herein and its derived strains.An object of the invention relates to an oral probiotic strain of Streptococcus salivarius that: sequence with SEQ ID NO: 1, 2 or 3; (b) is Streptococcus salivarius CDWN00916 deposited in the Spanish Type Culture Collection (CECT) with accession number CECT 30898, (c) is Streptococcus salivarius CDWN00918 deposited in the Spanish Type Culture Collection (CECT) with accession number CECT 30899, or (d) is Streptococcus salivarius CDWN00921 deposited in the Spanish Type Culture Collection (CECT) with accession number CECT 30900, which has a minimum inhibitory concentration to the fluorine ion of at least 500 ppm. In a particular embodiment, the identity of the 16S rRNA, with the sequence of one more of SEQ ID NO: 1, 2 or 3; A bacterial strain of the invention may comprise a gene encoding S. salivarius CECT 30898 rRNA (SEQ ID NO: 1). For example, the gene encoding 16S rRNA may have ID NO: 1.The 16S rRNA-encoding gene of the bacterial strain of the invention may differ from SEQ ID NO: 1 S. salivarius. A bacterial strain of the invention may comprise a gene encoding S. salivarius CECT 30899 rRNA (SEQ ID NO: 2). For example, the 16S rRNA-encoding gene may have ID NO: 2. The 16S rRNA-encoding gene of the bacterial strain of the invention may S. salivarius. A bacterial strain of the invention may comprise a gene encoding S. salivarius CECT 30900 rRNA (SEQ ID NO: 3). For example, the 16S rRNA-encoding gene may have ID NO: 3. The 16S rRNA-encoding gene of the bacterial strain of the invention may differ from SEQ ID NO: 3 S. salivarius. In a particular embodiment, the identity of the 16S rRNA SEQ ID NO: 2 or 3; An object of the invention relates to an oral probiotic strain of Streptococcus salivarius that: (b) comprises a genome that is identical to the genome of S.salivarius, CDWN00916, CDWN00918, CDWN00921; (b) is Streptococcus salivarius CDWN00916 deposited in the Spanish Type Culture Collection (CECT) under accession number CECT 30898, (c) is Streptococcus salivarius CDWN00918 deposited in the Spanish Type Culture Collection (CECT) under accession number CECT 30899, or (d) is Streptococcus salivarius CDWN00921 deposited in the Spanish Type Culture Collection (CECT) under accession number CECT 30900, which has a minimum inhibitory concentration for fluorine ion of at least 500 ppm. The genomes of strains CDWN00916, CDWN00918, CDWN00921 are accessible in the GenBank database under accession number JAXKQD000000000; JAXKQE000000000 and JAXKLG000000000 respectively. S. salivarius CDWN00916, Genbank ID JAXKQD000000000. The genome of said strain being understood as all the sequences or “contigs” that appear for GenBank: JAXKQD000000000.1 S. salivarius CDWN00918, Genbank ID JAXKQE000000000.The genome of said strain being understood as the totality of the sequences or "contigs" that appear in GenBank: J JAXKQE000000000.1 S. salivarius CDWN00921, Genbank ID JAXKLG000000000. The genome of said strain being understood as the totality of the sequences or "contigs" that appear in GenBank: JAXKLG000000000.1 In this specification "oral probiotic" means one or more strains of S. salivarius beneficial for oral use, which do not come from a sample of respiratory, oral tissue, or the digestive tract of a human subject with pathologies, preferably inflammatory pathologies and that among their beneficial characteristics are their antimicrobial activity, effect on pH, capacity to produce essential amino acids and help in the digestion of dairy products. The strains of microorganisms of the present invention surprisingly have the characteristic of having a high resistance to the fluoride ion.The resistance of oral probiotics to fluoride is important to prevent their viability from being affected by tooth brushing or the use of mouthwashes. Surprisingly, the strains of the invention exhibit greater resistance to fluoride-derived compounds commonly present in oral hygiene products compared to prior-art strains. This allows the beneficial oral effects to last longer, as it will not be necessary to take another dose of probiotics after, for example, brushing, which can remove other probiotics from the oral cavity.The usual concentration of fluoride in toothpastes is 1500 ppm, saliva produces a dilution effect of approximately 1 / 3 to 1 / 4, resulting in approximately 500 ppm. As will be shown later, strains M18 and K12 have a Minimum Inhibitory Concentration (MIC) of ppm of sodium fluoride (NaF) while that of the strains of the present invention is higher. In a particular embodiment, the fluorine ion is sodium fluoride. In a particular embodiment, the S. salivarius strains of the invention have a minimum inhibitory concentration for the fluorine ion of at least 250 or 251 or 252 or 253 or 254 or 280 or 281 or 282 or 22 or 323 or 324 or 365 or 366 or 408 or 50 or 535 549 or 550 ppm of fluorine ion. In a particular embodiment, the S.salivarius of the invention have a minimum inhibitory concentration to the fluorine ion of at least 550 ppm, preferably 1500 ppm in an in vitro experiment, preferably between 800 and 1200 ppm, more preferably between 850 and 1100 ppm or between 900 and 1000 ppm of NaF. In another particular embodiment, the MIC of the strains of the invention is at least 600 to at least 800 ppm of NaF and even more preferably at least 900 ppm of NaF. As indicated above, a high resistance to the fluorine ion is a beneficial characteristic of an oral probiotic.In a particular embodiment, the strain of the invention exhibits one or more oral probiotic properties in addition to fluoride resistance. The “oral probiotic properties” are selected from one or more of the following: production of essential amino acids, antimicrobial capacity against oral pathogens, a reduced acidogenic capacity compared to prior art strains, preferably strains M18 and K12, and aid in the digestion of dairy products. In a particular embodiment, the EOs produced by the strains of the invention in greater quantities than prior art strains are one or more of the following: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. In a particular embodiment, the essential amino acids are: isoleucine, leucine, tryptophan, phenylalanine + tyrosine, threonine, valine, and methionine + cysteine.In another particular embodiment, the essential amino acids are: isoleucine, leucine, phenylalanine + tyrosine, threonine, and valine. In another particular embodiment, the essential amino acids are: leucine, valine, and phenylalanine. Reduced acidogenic activity of oral bacteria is of great importance in the field of health, since it can lead to acidification that favors the development of caries and in turn promotes the proliferation of other acidogenic and aciduric microorganisms, including species such as Streptococcus mutans and Lactobacillus spp., among others. This leads to rapid fermentation of sugars present in the diet, which results in a decrease in pH and consequently in demineralization of the teeth, triggering caries. As will be seen below, the strains of the invention have reduced acidogenic activity compared to the strains of the prior art. In general, the number of S.salivarius of the invention administered to the individual will range from approximately 10. 2 up to 10 15 colony forming units (CFU), preferably from around 10 3 up to 10 14 UFCs, more preferably from around 105 to 1012 UFCs, usually around 10 to 10 10CFUs per dose. This dose may comprise one or more of the strains of the invention. In a particular embodiment, the strain of the invention may be present in its live or inactivated form, that is, as a postbiotic. Postbiotics are bioactive compounds derived from probiotic microorganisms, generated through their metabolism or released upon cell rupture. These include metabolites, cellular components, and other beneficial products that offer positive effects on the host's health. Unlike probiotics, postbiotics do not contain live microorganisms, which can facilitate their preservation, transport, and administration. Their benefits include modulation of the immune system, reinforcement of the intestinal barrier, and the provision of bioactive compounds such as amino acids, short-chain fatty acids, and antimicrobial peptides.In a particular embodiment, Streptococcus salivarius strains can be subjected to an inactivation process (e.g., by heat or pressure) to generate a bacterial lysate, thus obtaining a postbiotic. The lysate contains bioactive components released during the rupture of the bacterial cell and those adhered to the cell wall or in the immediate environment of the bacteria, including specific metabolites and cell fragments that retain the ability to provide essential amino acids. The use of the strain as a postbiotic presents additional advantages in terms of product stability, transport and safety, by eliminating the risk associated with the viability of live microorganisms. The lysate or postbiotic is obtained by subjecting the strain of the invention to a controlled cell lysis process, which may include thermal, mechanical or chemical treatments; any process common in the area and known to a person skilled in the art is suitable.This process guarantees the preservation of the bioactive compounds responsible for the aforementioned benefits, also ensuring the elimination of viable microorganisms. Subsequent processing may include the concentration of the inactivated strain and / or the supernatant, as well as its possible lyophilization or spray drying. As will be shown in the exemplary embodiments, the strains of the invention can improve the digestion of dairy products and dairy derivatives by a subject, since the study of the genome of these strains has found that they present genes involved in the metabolism of lactose and galactose that are not present in other strains of the prior art. This additional advantage would be especially useful for lactose-intolerant subjects. In a particular embodiment, the S. salivarius strains of the invention present in their genome the EC 3.2.1.23 gene (B-galactosidase) and / or the lactose / galactose permease gene.A person skilled in the art will understand that the sequence of these genes in the genome of S. salivarius strains may vary with respect to the canonical sequence recognized for S. salivarius but that in any case it will give rise to a functional protein that is active. An additional object of the invention relates to a strain of Streptococcus salivarius deposited in the Spanish Type Culture Collection with number CECT 30898 or strains derived therefrom, wherein said derived strains have the same, better or inferior oral probiotic properties than the CECT 30898 strains. This strain was deposited on July 25, 2023 in the Spanish Type Culture Collection, Calle Catedrático Agustín Escardino, 9, CP46980, Paterna (Valencia), Spain in accordance with the provisions of the Budapest Treaty. In the present invention, the CECT 30898 strain and CDWN00916 are interchangeable terms and are used interchangeably.Variants of this strain refer to strains that are derived from CECT 30898, or obtained from CECT 30898, and may have mutations compared to S. salivarius. Preferably, the derived strain has the same, better, or inferior oral probiotic properties than the original CECT 30898 strain. Preferably, the oral probiotic properties compared to the CECT 30898 strain under equal conditions. In a particular embodiment, the number of S. salivarius cells of strain CDWN00916 administered to the individual will be at least about 10. 9 UFC, o approximately 10 9 up to 10 12colony forming units (CFU). This dose is sufficient to administer to a subject the recommended amount of daily essential amino acids: Ile, Leu, Phe / Tyr, Thr, Val, Trp and Met / Cys. The present invention also relates to a strain of Streptococcus salivarius deposited in the Spanish Type Culture Collection with number CECT 30899 or strains derived therefrom, wherein said derived strains have the same, better or inferior oral probiotic properties than strain CECT 30899. This strain was deposited on July 25, 2023 in the Spanish Type Culture Collection. In the present invention, strain CECT 30899 and CDWN00918 are interchangeable terms and are used interchangeably. Variants of this strain refer to strains that are derived from CECT 30899, or obtained from CECT 30899, and may have mutations compared to S.salivarius, preferably, the derived strain has the same, better or inferior oral probiotic properties than the original strain CECT 30899. Preferably, the oral probiotic properties compared to the CECT 30899 strain under equal conditions. In a particular embodiment, the number of S. salivarius cells of strain CDWN00918 administered to the individual will be at least about 10. 9 UFC, or approximately 10 9 up to 10 11colony forming units (CFU). This dose is sufficient to administer to a subject the recommended amount of daily essential amino acids: Ile, Leu, Phe / Tyr, Thr and Val. The present invention also relates to a strain of Streptococcus salivarius deposited in the Spanish Type Culture Collection with number CECT 30900 or strains derived therefrom, wherein said derived strains have the same, better or inferior oral probiotic properties than strain CECT 30900. This strain was deposited on July 25, 2023 in the Spanish Type Culture Collection. In the present invention, strain CECT 30900 and CDWN00921 are interchangeable terms and are used interchangeably. Variants of this strain refer to strains that are derived from CECT 30900, or obtained from CECT 30900, and may have mutations compared to S. salivarius, preferably, the derived strain has the same, better or inferior oral probiotic properties than the original CECT 30900 strain.Preferably, the strain derived from d has oral probiotic properties compared to the CECT 30900 strain under equal conditions. In a particular embodiment, the number of S. salivarius cells of the CDWN00921 strain administered to the individual will be at least approximately 10 CFU, or approximately 10 to 109 colony-forming units (CFU). This dose is sufficient to administer to a subject the recommended daily amount of essential amino acids: Ile, Leu, Phe / Tyr, Thr and Val. The variants or strains derived from the strains of the invention usually retain the oral probiotic properties of their corresponding original strain. For all the above, the advantages of the strains of the present invention are: 1. Harnessing the natural properties of the oral commensal microbiota. 2. Due to their capacity to produce essential amino acids, these strains represent a prevention strategy for the development of pathologies associated with a deficiency of said amino acids. 3.Production and release of amino acids in a sustained manner over time, even during fasting hours. 4. The strains also display antimicrobial activity, which is a beneficial addition to oral health by preventing the growth of oral pathogenic microorganisms involved in the development of certain oral pathologies such as cavities and periodontal diseases. 5. The strains are more resistant to fluoride compounds than those of the prior art, which allows them to be more resistant to oral hygiene processes, including brushing with fluoride toothpastes. This allows the administered probiotic bacteria to be unaffected by oral hygiene processes. 6. The strains have a lower acidogenic capacity than those of the prior art, which translates into a lower capacity to induce dental caries. Another additional object of the invention relates to active extracts obtained from S.salivarius of the invention described above. An active extract is defined as a concentrated mixture of bioactive compounds obtained from an organism, cell or tissue, through specific extraction and purification processes. These compounds are responsible for exerting specific biological effects, such as antimicrobial activity, immunomodulation, nutritional support or improvement of physiological functions. Active extracts may contain secondary metabolites, peptides, proteins, lipids, amino acids, polysaccharides and other components with functional properties generally in a more concentrated form. These active extracts can be used similarly in therapeutic formulations and uses. The extracts can be obtained following protocols known in the art, conveniently by cell culture and centrifugation and / or microfiltration.This extract is rich in essential amino acids, in addition to comprising other compounds with antimicrobial activity. Another additional object of the invention relates to an orally administered probiotic formulation comprising one or more of the strains indicated above, or extract of the invention. In a particular embodiment, the probiotic formulation comprises the same amount of the strains CDWN00916, CDWN00918, and CDWN00921.In another particular embodiment, the probiotic formulation comprises strains CDWN00916, CDWN00918 and CDWN00921, in a ratio of approximately 1:2:1 to 1:3:1. In another particular embodiment, the probiotic formulation comprises strains CDWN00918, CDWN00916 and CDWN00921, in a ratio of approximately 1:2:1 to 1:3:1. In another particular embodiment, the probiotic formulation comprises strains CDWN00916, CDWN00921 and CDWN0018, in a ratio of approximately 1:2:1 to 1:3:1. In a further embodiment, the probiotic formulation for oral administration comprises: at least one pharmaceutically acceptable carrier, diluent, and / or excipient and / or at least one active agent. Formulations for oral administration may include powders or granules, suspensions or solutions in water or non-aqueous media, capsules, sachets or tablets. Thickeners, flavorings, diluents, emulsifiers, dispersion aids, or binders may be desirable.A “carrier, diluent, and / or excipient” means a vehicle for the delivery of a S. salivarius strain or extract of the invention to an individual, wherein the vehicle is compatible with the viability of the bacterial cell or the activity of the extract. Acceptable carriers suitable for use in administering viable S. salivarius strains of the invention and extracts are well known to those skilled in the art. Suitable carriers are generally inert and may be solid or liquid. By “pharmaceutically acceptable” is meant a material that is not biologically or otherwise undesirable, i.e., the material may be administered to a subject together with the selected compound without causing any undesirable biological effects or interacting in a deleterious manner with any of the other components of the pharmaceutical composition in which it is contained.Pharmaceutically acceptable carriers, diluents, and / or excipients include, but are not limited to, water, buffered saline solutions (e.g., phosphate-buffered saline), pharmaceutically acceptable culture media (e.g., Brain Heart Infusion (BHI), Tryptic Soy Agar (TSA), Blood Agar, etc.), or other solutions that maintain the viability of the bacteria or the activity of the extract. Additionally, such pharmaceutically acceptable carriers can be aqueous or non-aqueous solutions, suspensions, and emulsions. A variety of pharmaceutically acceptable carriers suitable for the oral administration of viable or lyophilized bacteria are well known in the art.Suitable solid carriers known in the art include, for example, magnesium carbonate; magnesium stearate; celluloses; talc; sugars such as fructose, sucrose, mannitol, lactose; starches; flours; and skimmed milk, and similar edible powders, but are not limited thereto. Similarly, carriers for administering extracts are well known. Typical diluents, by way of example, are: starches; lactose; mannitol; kaolin; calcium phosphate or sulfate; inorganic salts such as sodium chloride; and powdered sugars or celluloses. The compositions may also include excipients such as tableting aids; resins; fillers; binders; lubricants; solvents; glidants; disintegrants; preservatives; buffers; flavorings; colorants; sweeteners; and fragrances, as appropriate. Typical binders include starch; gelatin; sugars, such as lactose, fructose, and glucose; and the like.Natural and synthetic gums, including acacia, alginates; methylcellulose; polyvinylpyrrolidone; tragacanth; and the like, are also suitable. Polyethylene glycol; ethylcellulose; and waxes may also serve as binders. Lubricants to prevent adhesion to the die during forming include slippery solids such as talc, silica, magnesium and calcium stearate, polyethylene glycol, stearic acid, and hydrogenated vegetable oils. Disintegrants are substances that swell when moistened, breaking the tablet and releasing the S. salivarius or extract. Disintegrants include starches; clays; celluloses; algins and gums; more particularly, corn and potato starches; methylcellulose; agar; bentonite; wood cellulose; cation exchange resins; alginic acid; guar gum; citrus pulp; carboxymethylcellulose; sponge powder; and sodium lauryl sulfate.In a particular embodiment, the strain of the invention or the composition comprising it is administered as a food, beverage, or nutraceutical. The active strain(s) or extract(s) may also be administered in the form of a mouthwash, oral rinse, toothpaste, oral spray, gargle, capsule, lozenge, syrup, dental floss, chewing gum, or chewable tablet, among other possible presentations. In one embodiment, the food or beverage is a dairy-based food or beverage, including, for example, yogurt, cheese, milk, powdered milk, milk biscuits, and flavored milks. In a particular embodiment, the orally administered composition of S. salivarius is a mixture of lyophilized S. salivarius strains with skimmed powdered milk or the like, which has been flavored to enhance its pleasant flavor. Preferably presented as lozenges, chewable tablets, or capsules.A lozenge according to the invention comprises a S. salivarius strain or extract of the invention, isomalt, and EMDEX®. The lozenge may be prepared by direct compression, wet granulation, or dry granulation. The lozenges may be coated according to well-known pharmaceutical practice. The probiotic composition may additionally contain nutrients or preservatives to maintain the viability of the bacteria(s) in the formulation. As noted above, the formulation may also contain flavoring agents, coloring agents, fragrances, or other compounds that enhance the palatability of the composition and / or enhance patient acceptance without compromising the efficacy of the formulation. Methods for preparing formulations for oral administration are well known in the art.In a particular embodiment, the composition of the invention may further comprise one or more active agents that may be another strain of S. salivarius than those previously defined or a different one, or that are not microorganisms such as xylitol, fluoride, Manuka honey, and tannins. In a particular embodiment, the probiotic formulation for oral administration comprises strains CDWN00916 and CDWN00921. In another particular embodiment, the probiotic composition comprises the S. salivarius strain CDWN00916 and CDWN00921 in an appropriate concentration of CFUs to obtain the necessary daily amount of essential amino acids for an individual. In a particular embodiment, the essential amino acids are isoleucine, leucine, tryptophan, phenylalanine + tyrosine, threonine, valine and methionine + cysteine. In another particular embodiment, the essential amino acids are: leucine, valine and phenylalanine. In another particular embodiment, the formulation also comprises strain CDWN00918.An expert would know how to determine the necessary quantity of essential amino acids for a subject, according to his weight and health conditions, consulting for example the article Joint FAO / WHO / UNU Expert Consultation on Protein and Amino Acid Requirements in Human Nutrition (2002: Geneva, Switzerland), Food and Agriculture Organization of the United Nations, World Health Organization & United Nations University. ( . Protein and amino acid requirements in human nutrition: report of a joint FAO / WHO / UNU expert consultation, or other similar documents and from there determine the necessary concentration of CFUs of the S. salivarius strains. In another particular embodiment, the orally administered probiotic composition of the invention comprises approximately 10. 5 to 10 12 , preferably 10 8 to 10 10CFUs of one or more of the strains defined above. Another additional object of the invention relates to the use of a strain described above or an orally administered composition for the production of essential amino acids. In a particular embodiment, the essential amino acids are isoleucine, leucine, tryptophan, phenylalanine + tyrosine, threonine, valine and methionine + cysteine. In another particular embodiment, the essential amino acids are: leucine, valine and phenylalanine. This is especially relevant in situations of essential amino acid deficiency, and also in situations where the intake of essential amino acids acquired in the diet is desired to be reinforced. Another additional object of the invention relates to a strain of S. salivarius selected from CDWN00916, CDWN00918 and CDWN00921, or an extract or a formulation comprising as defined above for use in the prevention or treatment of oral pathologies.In a particular embodiment, the oral pathologies are selected from caries and periodontal diseases. These oral pathologies may be caused in whole or in part by pathogenic microorganisms. In this document, the term "prevent" refers to the administration of at least one probiotic strain or formulation for oral administration before the onset of clinical symptoms of a disease or condition in order to prevent a physical manifestation of the alterations associated with the disease or condition. In the context of dental caries, the term "prevent" refers to the administration of at least one strain or composition before the onset of clinical symptoms of dental caries, in order to prevent the physical manifestation of pathologies associated with dental caries.The terms "treatment" and "treat" refer to the medical treatment of a subject with the intent to cure, improve, stabilize, or prevent a disease, pathological condition, or disorder. This term includes active treatment, i.e., treatment specifically directed at improving a disease, pathological condition, or disorder, and also includes causal treatment, i.e., treatment directed at eliminating the cause of the associated disease, pathological condition, or disorder.Furthermore, this term includes palliative treatment, i.e., treatment designed to alleviate symptoms rather than cure the disease, pathological condition, or disorder; preventative treatment, i.e., treatment aimed at minimizing or partially or completely inhibiting the development of the associated disease, pathological condition, or disorder; and supportive treatment, i.e., treatment used to complement another specific therapy aimed at ameliorating the associated disease, pathological condition, or disorder. It is understood that treatment, although intended to cure, ameliorate, stabilize, or prevent a disease, pathological condition, or disorder, need not actually result in the cure, amelioration, stabilization, or prevention. The effects of treatment may be measured or evaluated as described herein and as known in the art, as appropriate for the disease, pathological condition, or disorder in question.Such measurements and evaluations can be performed qualitatively and / or quantitatively. Thus, for example, the characteristics or features of a disease, pathological condition, or disorder and / or the symptoms of a disease, pathological condition, or disorder can be reduced to any effect or in any amount. In the context of a subject suffering from dental caries, the terms "treatment" and "treating" refer to the medical management of a subject with the intent to cure, ameliorate, or stabilize the dental caries. In the context of a subject at risk of developing dental caries, the terms "treatment" and "treating" refer to the medical management of a subject with the intent to prevent dental caries. In a particular embodiment, the caries is caused, at least partially, by acidogenic and / or aciduric microorganisms such as Streptococcus mutans, Scardovia wiggsiae, and species of the Lactobacillaceae family.such as, for example: Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus plantarum, Lactobacillus rhamnosus, Lactobacillus fermentum, Lactobacillus salivarius, Lactobacillus reuteri, Lactobacillus brevis, Lactobacillus helveticus, Lactobacillus delbrueckii, and Lactobacillus bulgaricus. Another additional object of the invention relates to a strain of S. salivarius selected from CDWN00916, CDWN00918 and CDWN00921, or an extract or a formulation comprising as defined above for use in the prevention or treatment of dysbiosis or imbalance of the oral microbiota. As used herein, the term “subject” includes, but is not limited to, animals. The subject may be a vertebrate, more specifically a mammal (e.g., a human, horse, pig, rabbit, dog, sheep, goat, nonhuman primate, cow, cat, guinea pig, or rodent). The term does not denote a particular age or sex.Therefore, adult and newborn subjects, whether male or female, are covered by the present invention. A patient is a subject afflicted with a disease or disorder, preferably dental caries. In a particular embodiment, the subject is an adult human, that is, 18 years of age or older. The term "dose" refers to physically discrete units suitable as a unitary dosage for the subject, each unit containing a predetermined quantity of active material (viable S. salivarius or active extract thereof), calculated to produce the desired therapeutic effect in association with the required diluent, carrier, or excipient. Specific dosages may vary widely depending on various individual variables, including size, weight, age, disease severity (e.g., virulence and / or number of S.mutans resident in the caries-causing organism) and sensitivity to therapy (e.g., the susceptibility of an individual's oral cavity to colonization or dysbiosis by the native microbiome). Methods for determining the appropriate route of administration and dosage can be determined by the dentist or other physician. Additionally, the invention includes the following clauses: 1.An oral probiotic strain of Streptococcus salivarius that: (a) comprises a sequence with SEQ ID NO: 1, 2 or 3; (b) is Streptococcus salivarius CDWN00916 deposited in the Spanish Type Culture Collection (CECT) with accession number CECT 30898, (c) is Streptococcus salivarius CDWN00918 deposited in the Spanish Type Culture Collection (CECT) with accession number CECT 30899, or (d) is Streptococcus salivarius CDWN00921 deposited in the Spanish Type Culture Collection (CECT) with accession number CECT 30900, which has a minimum inhibitory concentration to the fluorine ion of at least 500 ppm 2. The strain according to any one of the previous clauses, which has one or more oral probiotic properties selected from: production of essential amino acids and antimicrobial activity. 3.The strain according to the preceding clause, wherein the essential amino acids are selected from one or more of the following: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. 4. The strain according to any one of the preceding clauses, wherein the fluoride resistance comprises an MIC of at least 550 ppm fluoride ion. 5. The strain according to any one of the preceding clauses that is obtained from a respiratory or oral tissue sample from a human subject. 6. The strain according to the preceding clause, wherein the subject does not have a pathology that would affect the probiotic use of the strain, for example, an inflammatory pathology. strain of Streptococcus salivarius according to any one of the previous clauses 1 to 6, deposited in the Spanish Type Culture Collection with number CECT 30899 or strains derived therefrom, wherein said derived strains have the same or lower oral probiotic properties than strain CECT 30899. 8.The Streptococcus salivarius strain according to any one of the preceding clauses 1 to 6, deposited in the Spanish Type Culture Collection with number CECT 30898 or strains derived therefrom, wherein said derived strains have the same or lower oral probiotic properties than strain CECT 30898. 9. The Streptococcus salivarius strain according to any one of the preceding clauses 1 to 6, deposited in the Spanish Type Culture Collection with number CECT 30900 or strains derived therefrom, wherein said derived strains have the same or lower oral probiotic properties than strain CECT 30900. 10. An active extract obtained from one or more of the strains defined in any one of clauses 1 to 9. 11. An orally administered probiotic formulation comprising one or more of the strains defined in any one of clauses 1 to 9 and / or the active extract of the previous clause. 12.The formulation according to the previous clause comprising: at least one pharmaceutically acceptable carrier, diluent, and / or excipient and / or at least one active agent. 13. The formulation according to any one of the previous clauses 11 to 12 wherein the active agent is at least one other different strain defined according to any one of clauses 1 to 9 and / or another strain of S. salivarius. 14. The formulation according to any one of the previous clauses 11 to 13 comprising S. salivarius strain CECT 30898 and CECT 30900. 15. The formulation according to any one of the previous clauses 11 to 14, which is included in a food, beverage and / or nutraceutical. 16. The formulation according to any one of the previous clauses 11 to 15, comprising approximately 10. 5 to 10 12 , preferably 10 8 to 10 10CFU of one or more of the strains defined in any one of clauses 1 to 9. The formulation according to the previous clause, comprising an adequate concentration of CFUs to obtain the daily required amount of essential amino acids for a subject. 18. Use of one or more of the strains defined in any one of clauses 1 to 9 and / or the formulation defined in any one of the essential amino acids clauses 19. The use according to the previous clause, wherein the production of essential amino acids comprises the daily required amount of a subject. 20. A strain according to any one of clauses 1 to 9, or an active extract according to clause 10, or a formulation according to any one of the use clauses in the prevention or treatment of an oral pathology. 21. The strain for use, according to the previous clause, wherein the oral pathology is selected from dental caries and periodontal disease 22.The strain for use according to the preceding clause wherein the dental caries is caused at least in part by S. mutans. 23. A strain according to any one of clauses 1 to 9, or an active extract according to clause 10, or a formulation according to any one of clauses use in the prevention or treatment of dysbiosis or imbalance of the oral microbiota, including caries, periodontitis and halitosis. Each of the terms “comprising”, “consisting essentially of” and “consisting of” may be replaced by any two other terms. The terms “a” or “an” may refer to one or a plurality of the elements they modify (for example, “a reagent” may mean one or more reagents), unless it is contextually clear that one or more of the elements are being described. The term “about” “about 100 grams” may include a weight between 90 grams and 110 grams).The use of the term “approximately” at the beginning of a listing of values ​​modifies each of the values ​​(e.g., “about 1, 2, and 3” refers to “about 1, about 2, and about 3”). When describing a listing of values, the listing includes all intermediate values ​​and all fractional values ​​thereof (e.g., a listing of “ ” includes is followed by the term “or more,” the term “or more” applies to each of the listed values ​​(e.g., a listing of “ ” or “more” refers to “ ”). When describing a listing of values, the listing includes all ranges between any two of the listed values ​​(e.g., a listing of “ ” includes ranges of “ ,” “ ,” and “ ”). Some examples of how the technology is applied are set forth below.Brief description of the figures Figure 1 Phylogenetic tree obtained with the Maximum Likelihood (ML) method based on the genomic similarity distances obtained with the TYGS tool. The nodes show the bootstrap values ​​after 100. Kolthoff, Joaquim Sardà Carbasse, Rosa L Peinado-Olarte, Markus Göker, TYGS and LPSN: a database tandem for fast and reliable genome-based classification and nomenclature of prokaryotes, Nucleic Acids Research, Volume 50, –https: / / doi.org / 10.1093 / nar / gkab902. NCTC 8616 and ATCC strains are the same strain. Figure 2: Concentration of essential amino acids measured by Nuclear Magnetic Resonance (NMR) in supernatants of S. salivarius strains CDWN00916, CDWN00918, CDWN00921 and the reference strain M18 for 2 hours. Average values ​​and standard deviation of biological duplicates are represented. Figure 3: Concentration of essential (A) and non-essential (B) amino acids measured by UPLC in supernatants of S. salivarius strains CDWN00916, CDWN00918 and CDWN00921 and the reference strain M18 1 (w / v) dextrose and sucrose (w / v) in static conditions for 6 hours. Mean values ​​and standard deviation of biological duplicates are represented.Figure 4: Growth curves of S. salivarius strains CDWN00916, CDWN00918 and CDWN00921 and reference strains K12 and M18. Strains were grown in BHI to stationary phase, after which an OD was adjusted. 600initial concentration of 0.05 in fresh BHI medium supplemented with NaF at different concentrations (0-125-250-500-1000 ppm, parts per million). 200 µl of each condition tested was distributed in duplicate in a 96-well microplate and the absorbance of the culture was measured at 600 nm in a TECAN Infinite® 200 PRO plate reader. Measurements were made every 30 min for 6.5 h C. Average net OD values ​​are represented after deducting the corresponding blank value, for each strain under the conditions tested according to the experimental design. Figure 5: Minimum inhibitory concentration (MIC) of the strains of the invention CDWN00916, CDWN00918 and CDWN00921 and the reference strains K12 and M18 against NaF supplemented in the medium after 6 h of incubation. The data represented are the mean net OD values ​​at time 6h for each NaF concentration tested, as described in Figure 4. Figure 6: Inhibitory effect of the supernatants of the three S.salivarius of the invention on the growth of Streptococcus mutans. T. Mean net OD values ​​from two independent experiments are represented. Figure 7: Growth curve of S. salivarius strains CDWN00916 (3), CDWN00918 (1) and CDWN00921 (2) in MRS medium supplemented with sucrose (w / v) and incubating the cultures. OD600 values ​​were recorded to quantify bacterial growth. Figure 8: Growth curve of S. salivarius strains CDWN00916 (3), CDWN00918 (1) and CDWN00921 (2) in MRS medium supplemented with dextrose (w / v) and incubating the cultures. OD600 values ​​were recorded to quantify bacterial growth. Figure 9: Growth curve of S. salivarius strains CDWN00916 (3), CDWN00918 (1) and CDWN00921 (2) in MRS medium supplemented with cellobiose (w / v) and incubated for hours. OD600 values ​​were recorded to quantify bacterial growth. Figure 10: Lysine concentration measured by UPLC in supernatants of S. salivarius strains.salivarius strains CDWN00916, CDWN00918 and CDWN00921 and the reference strain M18 after 6 hours of incubation in M9 minimal medium without amino acids. Average values ​​and standard deviation of biological duplicates are represented. Figure 11: Lysine concentration measured by UPLC in supernatants of S. salivarius strains CDWN00916, CDWN00918 and CDWN00921 and the reference strain M18 after 6 hours of incubation in modified M9 minimal medium. Average values ​​and standard deviation of biological duplicates are represented. Embodiments 1. Isolation and identification of the strains of the invention and evaluation of their capacity to produce essential amino acids From the study of microbial metabolism, the key genes and their metabolic functions involved in the biosynthesis pathways of several Aes described previously have been identified.Table 1 shows the description of the key genes involved in Aes biosynthesis pathways, as well as the function of the protein(s) they encode. Table 1. Key genes involved in essential amino acid biosynthesis pathways. Taking into account the presence / absence of key genes previously identified in the biosynthetic pathways, the abundance of these pathways in oral bacteria was quantified in silico based on the analysis of their genomes (Table 2). According to the results obtained, the genus Streptococcus is the one with the largest number of species associated with oral environments with Aes biosynthetic pathways. Table 2: Abundance of key genes in the biosynthetic pathways of several essential amino acids in oral bacteria based on in silico analysis. Abundance of key genes for the synthesis of tryptophan, phenylalanine, lysine, histidine, and methionine in the most representative bacterial genera that are part of the native oral microbiota. Frequencies are indicated as follows: (+) Present in species not present in many species; (+++) Present in many oral species; (--) Absent / not detected in databases. Subsequently, we proceeded to selectively isolate potentially Aes.-producing Streptococcus strains belonging to species with isolates classified as GRAS. Briefly, 1 ml saliva samples were collected from volunteer individuals in sterile Eppendorf tubes. Sampling was performed early in the morning in healthy volunteers aged 20 to 50 years, who had not eaten or brushed their teeth since the previous night.After sample collection, serial dilutions were made in PBS buffer and plated on Mitis Salivarius Agar medium (Sigma-Aldrich -500G-F), a selective and differential medium for the isolation of Streptococcus salivarius and S. mitis. The Petri dishes were incubated at 120°C and purified using MRS culture medium (MRS (de Man, Rogosa, and Sharpe) medium composition: 4:2:4 + H2O) and taxonomically identified by partial sequencing of the 16S ribosomal gene using the methodology described in Latorre-Pérez, A., Gimeno-Valero, H., Tanner, K., Pascual, J., Vilanova, C., & Porcar, M. (2021). A round trip to the desert: in situ nanoporesequencing informs targeted bioprospecting. Frontiers in Mic To determine the taxonomic affiliation of the isolates and the phylogenetically closest species, the online tool EzBioCloud (https: / / www.ezbiocloud.net / ) was used.Among other microorganisms, strains CDWN00916, CDWN00918 and CDWN00921 were isolated, identified as members of the genus Streptococcus based on the similarity of the 16S rRNA gene. Subsequently, the genomic sequence of the three strains was obtained following the methodology described in Vidal-Verdú, À., Molina-Menor, E., Pascual, J., Peretó, J., & Porcar, M. (2023). Gillisia lutea sp. Nov., isolated from marine aluminum residues from the Mediterranean sea. International Journal of Systematic and Evolutionary Microbiolog . From the genomic sequences, the taxonomic assignment of the three strains was analyzed with greater precision based on the ANIb (Average Nucleotide Identity) genomic similarity index with the ANIb genomic index-based tool. Index calculated with the JspeciesWS tool and a phylogenomic tree was obtained with the TYGS tool.In order to assess the safety of the three strains, the profile of virulence factors and resistance to antibiotics for clinical use was analyzed in silico following the recommendations of the EFSA (2021) (European Food Safety Authority (EFSA). (2021). EFSA statement on the requirements for whole genome sequence analysis of microorganisms intentionally used in the food chain. 06.). To identify virulence factors, the PathogenFinder and Abricate tools were used with the VFDB 2022 database, while to detect antibiotic resistance, the CARD tool was used using the “Perfect and Strict hits” criterion. The results are shown in Tables 3, 4 and 5. The S. salivarius strain denominations, is a bacterial strain isolated from the blood of a patient with acute articular rheumatism, and its use as an oral probiotic is ruled out as it was isolated from a subject with pathologies.Other names for this strain are as follows: Table 3. Phylogenetic species closest to the three strains included in the invention based on the similarity of the 16S rRNA ribosomal gene. Table 4. Phylogenetic species closest to the three strains included in the invention based on the ANIb genomic index. Index calculated with the JspeciesWS tool: Richter M, Rosselló-Móra R, Glöckner FO, and Peplies J (2015) JSpeciesWS: a web server for prokaryotic species circumscription based on pairwise genome comparison. Bioinformatics. 2015 Nov 16. pii: btv681 (https: / / jspecies.ribohost.com / jspeciesws / ). Table 5. Genomic similarity between the three strains included in the invention based on the ANIb genomic index. (JspeciesWS). Based on the study of the 16S rRNA gene, the three strains object of the invention, CDWN00916, CDWN00918 and CDWN00921, belong to the genus Streptococcus and are phylogenetically related to the species Streptococcus salivarius subsp. Salivarius. The values ​​obtained with the ANIb genomic index confirmed that the three strains belong to the species Streptococcus salivarius, being phylogenetically more related to the subspecies Streptococcus salivarius subsp. Salivarius than to Streptococcus salivarius subsp. Thermophilus (Tables 3, 4 and 5 and Figure 1). However, since the ANIb value is close to the threshold value, the bioinformatic analysis of the genomes confirms that none of the three strains presents genes that encode virulence factors or resistance to antibiotics in clinical use. The absence of virulence factors and resistance genes in its genome confirms that the three strains claimed in the invention are safe for use in humans.The amount of essential amino acids (EAs) produced and released into the medium by the three strains included in the invention was then quantified. Strains CDWN00916, CDWN00918, and CDWN00921 were cultured in minimal medium in the absence of amino acids, and the concentration of free amino acids in the supernatants was measured after 2 hours of incubation using nuclear magnetic resonance (NMR). It is important that the culture medium does not contain amino acids, since this activates the biosynthetic pathways, which are tightly regulated by the presence of the metabolite. Furthermore, the absence of amino acids allows the quantification of those produced by the strain without contamination from the culture medium. The study included the state-of-the-art reference strain M18, which is marketed as an oral probiotic (Figure 2). The strains were grown in liquid heart infusion medium with optical density (O.D) of the culture at an absorbance of 600 nm and adjusted to an OD value equal to 2 in 1 ml. The culture was washed by centrifugation at 4000 rpm for 5 minutes at room temperature, after which the supernatant was discarded and the pellet was resuspended in 1 ml of sterile 1x phosphate buffered saline. It was centrifuged again as previously described and the pellet was resuspended in 1 ml of minimal medium (12.8 g / L Na2HPO4-mM MgSO4- -sucrose (w / v)), after which it was incubated static after incubation for 2 hours the supernatant was recovered and kept for analysis by NMR. The metabolites were analyzed with the ChenomX 8.6 program and using TSPd4 in the buffer. The use of NMR as an analytical technique avoids the need to pre-process the sample, although in contrast it is less sensitive than other analytical techniques and requires higher concentrations of the metabolite in the supernatant for correct identification and quantification.Therefore, an optimization of the experimental conditions was carried out as described for the most complete characterization possible of the profile of metabolites of commercial interest secreted by the selected isolates and the analysis by complementary techniques such as liquid chromatography coupled to mass spectrometry (UPLC-QtoF-MS), taking strain M18 as reference and incubating S. salivarius cells with the minimal culture medium for 6 hours (Figure 3). The samples were prepared as described in Figure 2. Briefly, the cultures were grown to stationary phase and an OD was adjusted to a value equal to 2 in 1 ml. The culture was washed in phosphate-buffered saline, after which the pellet was resuspended in 1 ml in minimal medium supplemented with 1 (w / v) dextrose and sucrose (w / v) for 6 hours. After the incubation period, the culture was centrifuged at 13,000 rpm for 5 min at 4 C and the supernatant was recovered and kept at -80 C.Prior to the analysis of free amino acids by UPLC, a precipitation of the proteins present in the sample was performed with ACN (2:1, v / v), after which the supernatant was recovered and concentrated using a SpeedVac vacuum system. The samples were reconstituted in 0.3 mL of H2 formic acid and analyzed on a UPLC-QtoF-MS platform. Both the NMR and UPLC analysis are routine analysis for an expert in the field and as long as the same experimental conditions described here are used, such as strain growth, same type of equipment, standards... From the concentration of Aes produced by the strains, the amount of colony forming units (CFUs) of each of the three microorganisms that are necessary to ingest daily to cover the Aes needs of an adult of kg] was calculated (Table 6).The method used to calculate the recommended daily allowance (RDA) was the one described in Protein and amino acid requirements in human nutrition: joint FAO / WHO / UNU expert consultation, (https: / / apps.who.int / iris / handle / 10665 / 43411), specifically based on the data in Table 23 of said report. The values ​​are calculated based on the amino acid concentration detected in the supernatant and the viable cell count at the final incubation time (6h) for the same sample analyzed. The amount of amino acid produced per 1 CFU / 1h is calculated and the number of CFUs needed to cover the RDA is extrapolated. It should be noted that in the case of phenylalanine and tyrosine, as is the case with methionine and cysteine, the RDA is grouped into a single value, since these are amino acids that are easily transformed into each other. Table 6. CFUs of S. salivarius needed to cover the daily requirement of essential amino acids. As can be seen in Table 6, S. salivarius strain CDWN00921 is the one that produces the highest amount of Aes and therefore requires a lower dose of microorganisms to cover daily needs. 2. Fluoride tolerance assay: evaluation of the growth of Streptococcus salivarius strains CDWN00916, CDWN00918, CDWN00921, and reference strains M18 and K12 in the presence of increasing concentrations of sodium fluoride (NaF). In this assay, the resistance of bacterial strains to sodium fluoride (NaF), a common component in toothpastes used to prevent caries, was evaluated. The ability of these strains to resist NaF gives them a significant advantage by increasing their tolerance to oral hygiene procedures, which, in turn, allows them to colonize the oral cavity more effectively and for a longer period of time.This benefit is reflected in the potential reduction in the number of probiotic strains required for administration and / or in the decrease in the frequency of administration required. Growth curves and calculation of the minimum inhibitory concentration (MIC): The strains were seeded from glycerinated stock on BHI (Brain Heart Infusion Broth) plates (Oxoid) and C for 3 days, after which 10 ml of BHI liquid pre-culture (Oxoid) was inoculated with 1 CFU, incubated in C in aerobiosis overnight. The following day, the OD600 of the pre-culture was measured and the inoculum was adjusted to an initial OD600 of 0.1 in BHI. NaF (Sigma) solutions corresponding to 2000, 1000, 500 and 250 ppm were prepared in BHI medium.In a sterile 96-well flat-bottom plate, 100 µl of culture and 100 µl of the corresponding medium were distributed in duplicate according to the experimental design, resulting in an initial OD600 of the culture of 0.05 and NaF concentrations of 1000, 500, 250, 125 and 0 ppm. The plate was incubated in a TECAN infinite microplate reader. ®Absorbance readings at 600 nm were taken every 30 min until the cultures generally reached stationary phase at 6.5 h (Fig. 4) following a standard protocol in the area. To calculate the minimum inhibitory concentration (MIC), the absorbance values ​​at 6 h were plotted for each NaF concentration tested (Fig. 5). These data confirm that the strains of the present invention (CDWN00916, CDWN00918 and CDWN00921) exhibit significant resistance to NaF, in contrast to conventional state-of-the-art strains (M18 and K12). This translates into a substantially higher growth rate in the presence of fluoride. This increased bacterial growth is evident even at normal concentrations of fluoride exposure in the oral cavity, such as those found in toothpaste. In contrast, the state-of-the-art strains exhibit slower growth or are even unable to develop under these conditions.The usual concentration in adult toothpastes is 1500 ppm, saliva produces a dilution effect of approximately 1 / 3 to 1 / 4, resulting in 500 ppm- , a concentration at which the strains of the invention still grow while that is the MIC value for the state-of-the-art strains M18 and K12. Fig.5 Consequently, it can be concluded that the strains included in the patent, CDWN00916, CDWN00918 and CDWN00921, present a greater tolerance to NaF compared to the reference strains, facilitating their viability in the human oral cavity. 3.Evaluation of the antimicrobial activity of Streptococcus salivarius strains CDWN00916, CDWN00918 and CDWN00921, and reference strains M18 and K12 A beneficial characteristic of oral probiotic microorganisms is their ability to produce biomolecules with antimicrobial properties, capable of inhibiting the development of pathogenic microorganisms, including those that play a crucial role in the formation of caries, such as, for example, Streptococcus mutans. Reference strain M18 is a probiotic that produces bacteriocins that act against the cariogenic bacteria S. mutans. In addition, it produces dextranase and urease enzymes, which help reduce the accumulation of dental plaque and acidification. In this context, the ability of the strains of the present invention to exhibit an inhibition capacity against oral pathogens equal to or greater than that observed in the reference strains of the state of the art was evaluated.To carry out the study, a microplate growth inhibition assay was used as described in López-López A, Camelo-Castillo A, Ferrer MD, Simon-Soro Á, Mira A. Health-Associated Niche Inhabitants as Oral Probiotics: The Case , which allows the evaluation of the capacity of the strain supernatants to inhibit the pathogenic strain S. mutans CECT479 (Figure 6). The strains of the invention and the S. salivarius strain M18 were grown to stationary phase in BHI and the cultures were centrifuged at 4000 rpm for 4 min at 4 C. The supernatant was passed through a 0.2 µm filter and then concentrated in an IKA RV8 rotary evaporator at 10x. The concentrated supernatant was sterilized by 0.2 µm filtration. S. mutans CECT (type strain) was then grown to stationary phase in BHI after which an initial OD600 of 0.125 was adjusted in fresh BHI medium.In a 96-well microplate, 160 µl of the culture / well were distributed, to which 40 µl of 10x concentrated supernatant or 10x concentrated BHI were added as a control, giving rise to an OD 600initial culture of 0.1 and a final concentration of the supernatants and BHI of 2x in the corresponding wells. The absorbance of the culture at 600 nm was measured in a TECAN Infinite® 200 PRO plate reader. Each condition was tested in triplicate and measurements were taken every 30 C. The results showed that the inhibition capacity of the three strains object of the present invention is similar to that of the reference strain of the state of the art. 4. Evaluation of the acidogenic activity of the Streptococcus salivarius strains CDWN00916, CDWN00918 and CDWN00921, and the reference strains M18 and K12 The objective of this experiment was to quantify the acidogenic activity of the Streptococcus salivarius strains of the invention using sugars typically consumed in the diet, specifically sucrose, dextrose and cellobiose, in comparison with the reference strains of Streptococcus salivarius M18 and K12.The acidogenic activity of bacteria is undesirable, as it promotes the development of dental caries. To evaluate acidogenic activity, the strains were grown in a culture medium optimal for the growth of Streptococcus salivarius (MRS medium) to which 0.2% sugar was added as the sole source of carbon and energy. Three sugars typically consumed in the diet were tested: sucrose, dextrose, and cellobiose. Therefore, a total of three variants of the medium were prepared, one with each type of sugar tested. Each of the Streptococcus salivarius strains of the invention was inoculated into each of the three MRS media at a final inoculum concentration equivalent to one OD. 600 of 0.1. The growth dynamics of the strains with each of the different sugars was evaluated by measuring the OD 600at 30-minute intervals for 24 hours (Figures -9). The acidogenic activity of the microorganisms was evaluated by quantifying the pH of the , under aerobic conditions, in static for 48 hours. For the pH measurement, the PL- pH meter was used. Each measurement was obtained in duplicate. In addition, the production of lactic acid of each microorganism in the three culture media was quantified with the Y15 analyzer (Biosystems) using the Multical (Ref 12818) and L-lactic Acid (Ref 12802) Kits from BioSystems. The production of lactic acid in the culture media reflects the fermentative metabolism of the microorganisms. After culturing the microorganisms at rpm for 3 minutes in an Eppendorf Centrifuge 5910R centrifuge, filtering the supernatant with Y15 analyzer filters. As a negative control, the culture medium supplemented with the corresponding sugar and without any inoculated microorganism was tested.Among the three strains of Streptococcus salivarius object of the invention, strain CDWN00921 has the shortest generation time, regardless of sugar, reaching the stationary phase in less time than the others. In contrast, strain CDWN00918 shows the longest generation time, however, it reaches a cell density comparable to that of strain CDWN00921 in the stationary phase. Strain CDWN00916 is the one that reaches the lowest cell density after growth (Figures -9). Strain CDWN00918 is the one that produces less acidification of the medium and less amount of lactic acid compared to the other strains of Streptococcus salivarius tested, including the prior art strains M18 and K12 (see Table 4). Strains CDWN00916 and CDWN00921 have acidification and lactic acid production values ​​similar to those of the state-of-the-art strains using the sugars sucrose and dextrose.However, with cellobiose, strain CDWN00916 exhibited values ​​comparable to those of strain CDWN00918 and, therefore, higher than those of the prior-art strains. As expected, a positive correlation was observed between the pH value of the medium after growth and the concentration of lactic acid produced. These results indicate that strain CDWN00918 is less acidogenic than the prior-art strains and, consequently, the least favorable for the growth of pathogenic bacteria involved in cariogenic processes, regardless of the sugar tested. In the case of cellobiose, CDWN00916 also showed lower acidogenic activity than the prior-art strains (see Tables 4 and 5). Table 4. Acidification (pH) values ​​of the media after 48 h of incubation in the culture media with each of the sugars. mean values ​​and their corresponding standard deviation (n=3). Table 5. Lactic acid concentration values ​​(g / l) produced by the microorganisms with each of the sugars tested after 48h of incubation. mean values ​​and their corresponding standard deviation (n=3). 5. Comparison between the genomes of the strains of the invention CDWN00916, CDWN00918 and CDWN00931 and the strain NCTC 8618 The genomes of the strains CDWN00916 (Genbank ID JAXKQD000000000), CDWN00918 (Genbank ID JAXKQE000000000), CDWN00921 (Genbank ID JAXKLG000000000) and NCTC 8618 (ENA ID. .1), were annotated with the available BV-BRC Genome Annotation service (Olson, RD, Assaf, R., Brettin, T., Conrad, N., Cucinell, C., Davis, JJ, ... & Stevens, RL (2023). Introducing the bacterial and viral bioinformatics resource center (BV-BRC): a resource combining PATRIC, IRD and ViPR. -D689), using the RAST tool (RASTtk) [Aziz, RK et al. The RAST Server: rapid annotations using subsystems technology. The pangenome of the strains was subsequently analyzed using the tool available in BV-BRC The Protein Family Sorter (PFS) by selecting the PATRIC genus-specific families (PLfams) option.It was observed that the beta-galactosidase (EC 3.2.1.23; PLF_1301_00011912) and lactose / galactose permease (PLF_1301_00015661) genes are present in the three strains of the invention, but absent in the reference strain. Surprisingly, these results suggest a possible additional advantage of the strains of the invention, which is the improvement in the digestion of milk and dairy products, which would help people with lactose intolerance. 6. Quantification of lysine in supernatants in minimal medium without amino acids This protocol is identical to that used in example 1 and Fig. 3. The amount of lysine (lys) produced and released into the medium by the three strains included in the invention CDWN00916, CDWN00918 and CDWN00921 was quantified. The study included the state-of-the-art reference strain M18, which is marketed as an oral probiotic. Strains were grown in brain-heart infusion (BHI) liquid medium in optical culture (O.D) of the culture at an absorbance of 600 nm and adjusted to an OD value equal to 2 in 1 ml. The culture was washed by centrifugation at 4000 rpm for 5 minutes at room temperature, after which the supernatant was discarded and the pellet was resuspended in 1 ml of sterile 1x phosphate buffered saline. It was centrifuged again as previously described and the pellet was resuspended in 1 ml of M9 minimal medium (12.8 g / L Na2HPO4- gSO4-- after which it was incubated statically for 6 hours. After the incubation period, a precipitation of the proteins present in the sample was performed with ACN (2:1, v / v), after which the supernatant was recovered and concentrated using a Spee vacuum system and analyzed on a UPLC-QtoF-MS platform. The results are shown in Fig. 10. 7.Quantification of lysine in supernatants in medium supplemented without lysine The amount of lysine (lys) produced and released into the medium by the three strains included in the invention CDWN00916, CDWN00918 and CDWN00921 was quantified. The state-of-the-art reference strain M18 was included in the study. The strains were grown in liquid heart-stationary phase infusion medium. The optical density (OD) of the culture was measured at an absorbance of 600 nm and adjusted to an OD value equal to 2 in 1 ml. The culture was washed by centrifugation at 4000 rpm for 5 minutes at room temperature, after which the supernatant was discarded and the pellet was resuspended in 1 ml of sterile 1x phosphate buffered saline. It was centrifuged again as previously described and the pellet was resuspended in 1 ml of modified M9 minimal medium (12.8 g / L Na2HPO4- 2O, 3 g / L KH2PO4, 0.5 g / L NaCl, 1 g / L NH4Cl, 2 mM MgSO4- 2O, 0.1 mM CaCl2-2H2O)except lysine, Table 1) and 2X MEM vitamins (Gibco™), after which it was incubated in static for 6 hours. After the supernatant that was kept at - free by UPLC was recovered, a precipitation of the proteins present in the sample was carried out with ACN (2:1, v / v), after which the supernatant was recovered and concentrated using a SpeedVac vacuum system. The samples were reconstituted in 0.3 mL of H2O + 0.1 lysed on a UPLC-QtoF-MS platform. The results are shown in Fig.11 Table 6: List of amino acids and final concentration (mg / L) in the modified M9 medium. Sequence listing SEQ ID NO: 1 Sequence of the 16S rRNA ribosomal gene of strain CDWN00916 SEQ ID NO: 2 Sequence of the 16S rRNA ribosomal gene of strain CDWN00918 SEQ ID NO: 3 Sequence of the 16S rRNA ribosomal gene of strain CDWN00921

Claims

Claims 1. An oral probiotic strain of Streptococcus salivarius which: (a) is Streptococcus salivarius CDWN00916 deposited in the Spanish Type Culture Collection (CECT) with accession number CECT 30898, (b) is Streptococcus salivarius CDWN00918 deposited in the Spanish Type Culture Collection (CECT) with accession number CECT 30899, or (c) is Streptococcus salivarius CDWN00921 deposited in the Spanish Type Culture Collection (CECT) with accession number CECT 30900, which has a minimum inhibitory concentration to the fluorine ion of at least 500 ppm.

2. The strain according to the preceding claim, which has the properties of an oral probiotic: production of essential amino acids and antimicrobial activity.

3. The strain according to the preceding claim, wherein the essential amino acids are selected from one or more of the following: isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. 4.The strain according to any one of the preceding claims, wherein the fluoride resistance comprises a MIC of at least 550 ppm fluoride ion.

5. The strain according to any one of the preceding claims, wherein it is in the form of a postbiotic.

6. An active extract obtained from one or more of the strains defined in any one of claims 1 to 5. An orally administered probiotic formulation comprising one or more of the strains defined in any one of claims 1 to 5 and / or the active extract of the preceding claim.

8. The formulation according to the preceding claim comprising: at least one pharmaceutically acceptable carrier, diluent, and / or excipient and / or. at least one active agent.

9. The formulation according to any one of claims preceding to 8 wherein the active agent is at least one other different strain defined according to any one of claims 1 to 5 and / or another strain of S. salivarius.

10. The formulation according to any one of claims preceding to 9 comprising S. salivarius strain CECT 30898 and CECT 30900.

11. The formulation according to any one of claims preceding to 10, which is included in a food, beverage and / or nutraceutical.

12. The formulation according to any one of claims preceding to 11, comprising approximately 10 5 to 10 12 , preferably 10 8 to 10 10CFU of one or more of the strains defined in any one of claims 1 to 5.

13. Use of one or more of the strains defined in any one of claims 1 to 5 and / or the formulation defined in any one of claims to 12 for the production of essential amino acids 14. A strain according to any one of claims 1 to 5, or an active extract according to claim 6, or a formulation according to any one of claims to 12 for use as a medicament.

15. A strain according to any one of claims 1 to 5, or an active extract according to claim 6, a formulation according to any one of claims to 12, or a strain for use as a medicament according to claim 14, for use in the prevention or treatment of an oral pathology.

16. The strain for use according to the preceding claim, wherein the oral pathology is selected from dental caries and periodontal disease.The strain for use according to the preceding claim wherein the dental caries is caused at least in part by S. mutans.

18. A strain according to any one of claims 1 to 5, or an active extract according to claim 6, or a formulation according to any one of claims to 12 for use in the prevention or treatment of dysbiosis or imbalance of the oral microbiota, including caries, periodontitis and halitosis.

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