Antibacterial peptide and application thereof

Abstract

This invention relates to an antimicrobial peptide and its applications. The amino acid sequence of the antimicrobial peptide is at least one of the sequences shown in SEQ ID No. 1 to SEQ ID No. 8. The antimicrobial peptide exhibits excellent broad-spectrum antimicrobial activity, for example, against Acinetobacter spp. (…). Acinetobacter ), Pseudomonas aeruginosa ( Pseudomonas aeruginosa ) and Bacillus spp. ( Bacillus This bacterium possesses antibacterial activity. Against the backdrop of increasingly severe global bacterial resistance and the gradual ineffectiveness of traditional antibiotics against multidrug-resistant bacteria, this provides a new treatment option for carbapenem-resistant bacteria such as Acinetobacter baumannii, Pseudomonas aeruginosa, and Bacillus subtilis, which pose a significant threat to public health, and offers new possibilities for solving the clinical dilemma of "no available drugs."

Description

[0001] This patent application is a divisional application of the invention entitled "An Antimicrobial Peptide and Its Application", filed on April 13, 2026, with application number 2026104801463. Technical Field

[0002] This invention relates to the field of biomedicine, and in particular to an antimicrobial peptide and its applications. Background Technology

[0003] Acinetobacter baumannii ( Acinetobacter baumannii Acinetobacter baumannii, a Gram-negative opportunistic pathogen, is renowned for its strong environmental adaptability (it can survive on dry surfaces for more than 30 days) and colonization ability in medical environments, earning it the nickname "nightmare bacterium" in the medical community. It is primarily transmitted through contact and can easily cause outbreaks in intensive care units, burn units, and neurosurgery departments, leading to ventilator-associated pneumonia (VAP), bloodstream infections, wound infections, urinary tract infections, and meningitis. It poses a particularly significant threat to mechanically ventilated patients, burn patients, and those with weakened immune systems, where the infection mortality rate can reach as high as 60%. Its most worrying aspect is drug resistance: listed by the WHO as a "critical priority pathogen requiring novel antibiotics," Acinetobacter baumannii can develop resistance to β-lactams, aminoglycosides, quinolones, and other antibiotics through multiple mechanisms, including acquiring resistance genes, altering membrane permeability, and producing inactivating enzymes. It has even produced pan-drug-resistant strains (PDR-AB) resistant to almost all commonly used antibiotics. Global drug resistance surveillance data from 2024 showed that Acinetobacter baumannii had a resistance rate of 78% to carbapenems, and cases of resistance to "last resort" drugs such as colistin and tigecycline were also increasing year by year, leading to multiple clinical dilemmas of "no drugs available." In addition, its strong ability to spread drug resistance genes (such as through plasmid and transposon transfer) makes it a "number one challenge" in hospital infection control.

[0004] Pseudomonas aeruginosa ( Pseudomonas aeruginosa*Pseudomonas aeruginosa* is a Gram-negative, aerobic, opportunistic pathogen widely distributed in various ecological niches, including water, soil, plants, and hospital environments. Due to its strong environmental adaptability and inherent drug resistance, it is one of the leading pathogens causing hospital-acquired infections, especially in immunocompromised and critically ill patients. The harm caused by *Pseudomonas aeruginosa* lies primarily in its ability to cause a variety of serious and refractory infections, including but not limited to: 1) respiratory infections: such as chronic lung infections and ventilator-associated pneumonia in patients with cystic fibrosis; 2) bloodstream infections: particularly common in patients with neutropenia, with extremely high mortality rates; 3) burn wound infections: leading to sepsis and poor wound healing; 4) urinary tract infections and central nervous system infections. An even more serious challenge comes from the increasingly severe drug resistance problem of *Pseudomonas aeruginosa*, with multidrug-resistant (MDR), extensively drug-resistant (XDR), and even pan-drug-resistant (PDR) strains emerging. The WHO has listed it as a "critical priority" pathogen, urgently requiring novel antimicrobial agents. Therefore, developing novel anti-Pseudomonas aeruginosa drugs with entirely new mechanisms of action that can effectively overcome existing drug resistance pathways has become a major need in the field of anti-infective drug research.

[0005] Bacillus subtilis ( Bacillus subtilis As a Gram-positive facultative anaerobic bacillus, Bacillus subtilis possesses a unique dual nature: on the one hand, it is widely distributed in soil, water, air, and on the surfaces of plants and animals. Due to its clear genetic background and ease of cultivation, it has become a "model bacterium" in microbiology and molecular biology research, and is often used as a primary screening model in antibacterial agent development (its cell wall structure and membrane permeability are highly similar to pathogenic Gram-positive bacteria such as MRSA, effectively reflecting the effect of compounds on Gram-positive bacterial targets); on the other hand, as an opportunistic pathogen, it can also pose an infection risk under certain conditions. Clinically, Bacillus subtilis infection is more common in individuals with severely compromised immune function, those receiving long-term broad-spectrum antibiotic treatment, or those with damaged skin and mucous membrane barriers, and can lead to sepsis, endocarditis, pneumonia, meningitis, and eye infections. In the medical environment, it may contaminate medical devices, biological products, or pharmaceuticals, causing iatrogenic infections. For example, several cases of related infections have occurred in neonatal intensive care units, with an infection mortality rate of approximately 12%. More importantly, it exhibits natural resistance to some traditional antibiotics, and its spore structure is highly resistant to physical and chemical disinfection, making it difficult to eradicate completely. This poses a challenge to treatment and also provides a potential vector for the horizontal transfer of resistance genes. Therefore, research on the inhibition of Bacillus subtilis has dual value in both clinical treatment and basic research. Summary of the Invention

[0006] One aspect of the present invention provides an antimicrobial peptide having an amino acid sequence as shown in at least one of SEQ ID No. 1 to SEQ ID No. 8. For example, the antimicrobial peptide can be a combination of any two antimicrobial peptides with amino acid sequences as shown in SEQ ID No. 1 to SEQ ID No. 8; the antimicrobial peptide can be a combination of any three antimicrobial peptides with amino acid sequences as shown in SEQ ID No. 1 to SEQ ID No. 8; the antimicrobial peptide can be a combination of any four antimicrobial peptides with amino acid sequences as shown in SEQ ID No. 1 to SEQ ID No. 8; the antimicrobial peptide can be a combination of any five antimicrobial peptides with amino acid sequences as shown in SEQ ID No. 1 to SEQ ID No. 8; the antimicrobial peptide can be a combination of any six antimicrobial peptides with amino acid sequences as shown in SEQ ID No. 1 to SEQ ID No. 8; the antimicrobial peptide can be a combination of any seven antimicrobial peptides with amino acid sequences as shown in SEQ ID No. 1 to SEQ ID No. 8; or the antimicrobial peptide can be a combination of eight antimicrobial peptides with amino acid sequences as shown in SEQ ID No. 1 to SEQ ID No. 8.

[0007] The second invention provides a composition comprising an antimicrobial peptide as described in the first invention and a pharmaceutically acceptable carrier.

[0008] The third invention provides the use of the antimicrobial peptide according to the first invention or the composition according to the second invention in the preparation of antibacterial and / or bactericidal drugs.

[0009] In one specific embodiment, the application is the use of the antimicrobial peptide in the preparation of a drug for inhibiting and / or killing bacteria.

[0010] In one specific embodiment, the bacteria is Acinetobacter spp. ( Acinetobacter ), Pseudomonas spp. Pseudomonas ) and Bacillus spp. ( Bacillus At least one of the bacteria in ).

[0011] In one specific embodiment, the bacteria is Acinetobacter baumannii (… Acinetobacter baumannii ), Pseudomonas aeruginosa ( Pseudomonas aeruginosa ) and Bacillus subtilis ( Bacillus subtilis At least one of the bacteria in ).

[0012] In one specific embodiment, the bacteria is at least one of Acinetobacter baumannii ATCC BAA-1605 strain, Pseudomonas aeruginosa PAO1, and Bacillus subtilis CMCC (B) 63501 strain.

[0013] In one specific embodiment, the application is that the antimicrobial peptide is used in the preparation of a treatment for Acinetobacter (Acinetobacter) Acinetobacter ), especially Acinetobacter baumannii ( Acinetobacter baumannii The drug is used in the treatment of at least one of the following diseases: ventilator-associated pneumonia (VAP), bloodstream infection, wound infection, urinary tract infection, and meningitis.

[0014] In one specific embodiment, the application is that the antimicrobial peptide is used in the preparation of a treatment for Pseudomonas aeruginosa (… Pseudomonas ), especially Pseudomonas aeruginosa ( Pseudomonas aeruginosa Its use in drugs for at least one of the following diseases: pneumonia, structural lung disease, sepsis, gangrenous pustular lesions, and green nail syndrome.

[0015] In one specific embodiment, the application is that the antimicrobial peptide is used in the preparation of a treatment for Bacillus subtilis (Bacillus) Bacillus ), especially Bacillus subtilis ( Bacillus subtilis Use in medications for at least one of the following diseases: sepsis, endocarditis, pneumonia, meningitis, and eye infection caused by [the disease].

[0016] Beneficial effects of the present invention: The present invention has discovered that the antimicrobial peptides of the present invention have excellent broad-spectrum antimicrobial activity, for example, against Acinetobacter spp. ( Acinetobacter (especially Acinetobacter baumannii), Pseudomonas spp. ( Pseudomonas (especially Pseudomonas aeruginosa) and Bacillus spp. ( Bacillus Antimicrobial peptides (especially Bacillus subtilis) exhibit antibacterial activity. They demonstrate microgram-level killing efficacy against carbapenem-resistant Acinetobacter baumannii and Pseudomonas aeruginosa. Against the backdrop of increasingly severe global bacterial resistance and the gradual ineffectiveness of traditional antibiotics against multidrug-resistant bacteria, this provides a new treatment option for carbapenem-resistant Acinetobacter baumannii, Pseudomonas aeruginosa, and Bacillus subtilis, which pose a significant threat to public health, and offers new possibilities for overcoming the clinical dilemma of "no available drugs." Furthermore, antimicrobial peptides also possess the excellent characteristic of low resistance risk. Attached Figure Description

[0017] Figure 1 The survival rate curves of Acinetobacter baumannii ATCC BAA-1605 after treatment with different concentrations of antimicrobial peptide-1 are shown.

[0018] Figure 2 The survival rate curves of Pseudomonas aeruginosa PAO1 after treatment with different concentrations of antimicrobial peptide-1 are shown.

[0019] Figure 3The survival rate curves of Bacillus subtilis CMCC (B) 63501 after treatment with different concentrations of antimicrobial peptide-1 are shown.

[0020] Figure 4 The survival rate curves of Acinetobacter baumannii ATCC BAA-1605 after treatment with different concentrations of antimicrobial peptide-2 are shown.

[0021] Figure 5 The survival rate curves of Bacillus subtilis CMCC (B) 63501 after treatment with different concentrations of antimicrobial peptide-2 are shown.

[0022] Figure 6 The survival rate curves of Acinetobacter baumannii ATCC BAA-1605 after treatment with different concentrations of antimicrobial peptide-3 are shown.

[0023] Figure 7 The survival rate curves of Bacillus subtilis CMCC (B) 63501 after treatment with different concentrations of antimicrobial peptide-3 are shown.

[0024] Figure 8 The survival rate curves of Acinetobacter baumannii ATCC BAA-1605 after treatment with different concentrations of antimicrobial peptide-4 are shown.

[0025] Figure 9 The survival rate curves of Bacillus subtilis CMCC (B) 63501 after treatment with different concentrations of antimicrobial peptide-4 are shown.

[0026] Figure 10 The survival rate curves of Acinetobacter baumannii ATCC BAA-1605 after treatment with different concentrations of antimicrobial peptide-5 are shown.

[0027] Figure 11 The survival rate curves of Bacillus subtilis CMCC (B) 63501 after treatment with different concentrations of antimicrobial peptide-5 are shown.

[0028] Figure 12 The survival rate curves of Bacillus subtilis CMCC (B) 63501 after treatment with different concentrations of antimicrobial peptide-6 are shown.

[0029] Figure 13 The survival rate curves of Bacillus subtilis CMCC (B) 63501 after treatment with different concentrations of antimicrobial peptide-7 are shown.

[0030] Figure 14 The survival rate curves of Bacillus subtilis CMCC (B) 63501 after treatment with different concentrations of antimicrobial peptide-8 are shown. Detailed Implementation

[0031] The present invention will be further described in detail below through preferred embodiments, but these embodiments do not constitute a limitation thereof.

[0032] Unless otherwise specified, the strains and reagents used in the embodiments of this invention can be purchased commercially.

[0033] The amino acid sequences of the antimicrobial peptides-1 to-8 of the present invention are as shown in SEQ ID Nos. 1 to 8, and were synthesized by Sangon Biotech Co., Ltd.

[0034] Antimicrobial peptides 1 to 8 were dissolved in sterile distilled water to prepare aqueous solutions of antimicrobial peptides 1 to 8 at the desired concentrations.

[0035] Acinetobacter baumannii ( Acinetobacter baumannii The ATCC BAA-1605 strain was purchased from the China Industrial Microbial Culture Collection Center.

[0036] Pseudomonas aeruginosa ( Pseudomonas aeruginosa The PAO1 strain was purchased from the China Microbial Culture Collection Center.

[0037] Bacillus subtilis ( Bacillus subtilis CMCC (B) 63501 was purchased from Beijing Solarbio Technology Co., Ltd.

[0038] Tryptone-Soy Agar (TSA) medium: 15 g tryptone, 5 g soybean peptone, 5 g sodium chloride, 15 g agar, distilled water to a final volume of 1 L, adjust pH to 7.2 ± 0.2. Autoclave at 121°C for 20 minutes.

[0039] Tryptone-Soybean Broth (TSB) medium: 15 g tryptone, 5 g soybean peptone, 5 g sodium chloride, distilled water to a final volume of 1 L, adjust pH to 7.2 ± 0.2. Autoclave at 121°C for 20 minutes. Example 1: Biological activity of antimicrobial peptide-1

[0040] Biological activity of antimicrobial peptide-1 against Acinetobacter baumannii: Acinetobacter baumannii ATCC BAA-1605, stored at -80°C, was streaked onto TSA agar plates and incubated at 37°C for 16 h to activate the strain. A single colony was picked and inoculated into an Erlenmeyer flask containing 20 ml of TSB medium and cultured at 37°C and 180 rpm for 16 h with shaking to prepare a seed culture. 1 ml of the seed culture was inoculated into 100 ml of TSB medium at a volume ratio of 1:100 and cultured at 37°C and 180 rpm with shaking until the OD of the culture was reached. 600When the pH reaches 0.8 (incubation time approximately 3 to 4 hours), the propagation bacterial suspension is prepared. The concentration of the propagation bacterial suspension is determined using a McFarland turbidimeter and diluted to 1×10⁻⁶ with TSB medium. 6 CFU / ml was used to obtain diluted bacterial suspensions. 999 μL of diluted bacterial suspension was first added to each well of a 48-well plate, followed by 1 μL of antimicrobial peptide-1 solution at concentrations of 30, 25, 20, 18, 17, 16, 15, 14, 13, 12, 11, 10, 8, 7, 5, and 1 mg / mL, respectively, to achieve final antimicrobial peptide-1 concentrations of 30, 25, 20, 18, 17, 16, 15, 14, 13, 12, 11, 10, 8, 7, 5, and 1 μg / mL in each well. A blank control group was also set up, consisting of 1 μL of sterile distilled water and no culture medium. Each treatment was replicated in 5 wells. After thorough mixing, the plates were incubated at 37°C for 16 h, and the absorbance (OD) of the bacterial suspension in each well was measured at 600 nm. 600 The bacterial survival rate was calculated according to formula (1). Based on the survival rate of the antimicrobial peptide-1 treatment groups at each concentration, the survival curve of antimicrobial peptide-1 concentration versus survival rate was obtained by plotting using GraphPad Prism software. Based on the survival curve, the antimicrobial peptide-1 concentration (half-inhibitory concentration, IC50) at which the survival rate was 50% was calculated using GraphPad Prism software. 50 The concentration of antimicrobial peptide-1 at a survival rate of 0% (minimum inhibitory concentration, MIC).

[0041] Biological activity of antimicrobial peptide-1 against *Pseudomonas aeruginosa*: *Acinetobacter baumannii* ATCC BAA-1605 was replaced with *P. aeruginosa* PAO1, and the final concentrations of antimicrobial peptide-1 aqueous solution in the diluted bacterial culture were adjusted appropriately (50, 25, 12.5, 6.25, 3.125, 1.5625, 0.78125, 0.390625 μg / mL). All other biological activity assays were performed in the same manner as for *Acinetobacter baumannii*. The OD values ​​of the bacterial culture in each well were measured after incubation at 37°C for 16 h. 600 The value was then used to calculate the survival rate based on formula (1). Survival curves of antimicrobial peptide-1 concentration versus survival rate were obtained based on the survival rates of the antimicrobial peptide-1 treatment groups at each concentration. The antimicrobial peptide-1 concentration (half-inhibitory concentration, IC50) at a survival rate of 50% was calculated using GraphPadprism software. 50 The concentration of antimicrobial peptide-1 at a survival rate of 0% (minimum inhibitory concentration, MIC).

[0042] Biological activity of antimicrobial peptide-1 against Bacillus subtilis: Acinetobacter baumannii ATCC BAA-1605 was replaced with Bacillus subtilis CMCC (B) 63501, and the final concentrations of antimicrobial peptide-1 aqueous solution in the diluted bacterial solutions were appropriately adjusted (30, 25, 20, 15, 12.5, 12, 10, 7.5, 6.25, 6, 5, 3.75, 3.125, 3, 2.5 μg / mL). All other parameters were the same as those used for the biological activity assay of Acinetobacter baumannii. The OD values ​​of the bacterial solutions in each well were measured after incubation at 37°C for 16 h. 600 The value was then used to calculate the survival rate based on formula (1). Survival curves of antimicrobial peptide-1 concentration versus survival rate were obtained based on the survival rates of the antimicrobial peptide-1 treatment groups at each concentration. The antimicrobial peptide-1 concentration (half-inhibitory concentration, IC50) at a survival rate of 50% was calculated using GraphPad Prism software. 50 The concentration of antimicrobial peptide-1 at a survival rate of 0% (minimum inhibitory concentration, MIC).

[0043] Survival rate = (OD of antimicrobial peptide treatment groups at different concentrations) 600 Value - OD of the culture medium 600 (value) ÷ (OD value of blank control group) 600 Value - OD of the culture medium 600 (value) × 100% Formula (1).

[0044] The survival rate curves of Acinetobacter baumannii ATCC BAA-1605 after treatment with different concentrations of antimicrobial peptide-1 are shown in the figure. Figure 1 The survival rate curves of Pseudomonas aeruginosa PAO1 after treatment with different concentrations of antimicrobial peptide-1 are shown in the figure. Figure 2 The survival rate curves of Bacillus subtilis CMCC (B) 63501 after treatment with different concentrations of antimicrobial peptide-1 are shown in the figure. Figure 3 .

[0045] The results showed that the IC50 of antimicrobial peptide-1 against Acinetobacter baumannii ATCC BAA-1605 was [missing information]. 50 The concentration was 13.09 μg / mL, and the MIC was 20.00 μg / mL; the IC50 of antimicrobial peptide-1 against Pseudomonas aeruginosa PAO1 was 13.09 μg / mL. 50 The concentration was 13.94 μg / mL, and the MIC was 50.00 μg / mL; the IC50 of antimicrobial peptide-1 against Bacillus subtilis CMCC (B) 63501 was 13.94 μg / mL. 50 The concentration was 3.77 μg / mL, and the MIC was 12.50 μg / mL. Example 2: Biological activity of antimicrobial peptide-2

[0046] In Example 1, antimicrobial peptide-1 was replaced with antimicrobial peptide-2 to determine the biological activity of antimicrobial peptide-2 against Acinetobacter baumannii (final concentrations at the time of determination were 100, 80, 50, 40, 25, 20, 12.5, 10, 1.5625, 0.78125, and 0.390625 μg / mL), Bacillus subtilis (final concentrations at the time of determination were 37.5, 30, 25, 22.5, 18.75, 15, 12.5, 11.25, 9.375, 7.5, and 5.625 μg / mL), and Pseudomonas aeruginosa. All other aspects were the same as in Example 1.

[0047] The survival rate curves of Acinetobacter baumannii ATCC BAA-1605 after treatment with different concentrations of antimicrobial peptide-2 are shown in the figure. Figure 4 The survival rate curves of Bacillus subtilis CMCC (B) 63501 after treatment with different concentrations of antimicrobial peptide-2 are shown in the figure. Figure 5 .

[0048] The results showed that the IC50 of antimicrobial peptide-2 against Acinetobacter baumannii ATCC BAA-1605 was [missing information]. 50 The concentration was 4.04 μg / mL, and the MIC was 50.00 μg / mL; the IC50 of antimicrobial peptide-2 against Bacillus subtilis CMCC (B) 63501 was 4.04 μg / mL. 50 The concentration was 15.65 μg / mL, and the MIC was 22.50 μg / mL. Example 3: Biological activity of antimicrobial peptide-3

[0049] In Example 1, antimicrobial peptide-1 was replaced with antimicrobial peptide-3 to determine the biological activity of antimicrobial peptide-3 against Acinetobacter baumannii (final concentrations of 50, 45, 40, 35, 30, 25, 20, 15, and 10 μg / mL), Bacillus subtilis (final concentrations of 50, 25, 12.5, 11, 10, 9, 8, 7, 6.25, 3.125, 1.5625, 0.78125, and 0.390625 μg / mL), and Pseudomonas aeruginosa. All other aspects were the same as in Example 1.

[0050] The survival rate curves of Acinetobacter baumannii ATCC BAA-1605 after treatment with different concentrations of antimicrobial peptide-3 are shown in the figure. Figure 6 The survival rate curves of Bacillus subtilis CMCC (B) 63501 after treatment with different concentrations of antimicrobial peptide-3 are shown in the figure. Figure 7 .

[0051] The results showed that the IC50 of antimicrobial peptide-3 against Acinetobacter baumannii ATCC BAA-1605 was [missing information]. 50 The concentration was 31.61 μg / mL, and the MIC was 50.00 μg / mL; the IC50 of antimicrobial peptide-3 against Bacillus subtilis CMCC (B) 63501 was 31.61 μg / mL.50 The concentration was 7.82 μg / mL, and the MIC was 12.50 μg / mL. Example 4: Biological activity of antimicrobial peptide-4

[0052] In Example 1, antimicrobial peptide-1 was replaced with antimicrobial peptide-4 to determine the biological activity of antimicrobial peptide-4 against Acinetobacter baumannii (final concentrations at assays were 50, 25, 12.5, 6.25, 3.125, 1.5625, 0.78125, and 0.390625 μg / mL), Bacillus subtilis (final concentrations at assays were 50, 25, 24, 21, 18, 15, 12.5, 6.25, and 3.125 μg / mL), and Pseudomonas aeruginosa. All other aspects were the same as in Example 1.

[0053] The survival rate curves of Acinetobacter baumannii ATCC BAA-1605 after treatment with different concentrations of antimicrobial peptide-4 are shown in the figure. Figure 8 The survival rate curves of Bacillus subtilis CMCC (B) 63501 after treatment with different concentrations of antimicrobial peptide-4 are shown in the figure. Figure 9 .

[0054] The results showed that the IC50 of antimicrobial peptide-4 against Acinetobacter baumannii ATCC BAA-1605 was [missing information]. 50 The concentration was 14.02 μg / mL, and the MIC was 50.00 μg / mL; the IC50 of antimicrobial peptide-4 against Bacillus subtilis CMCC (B) 63501 was 14.02 μg / mL. 50 The concentration was 17.29 μg / mL, and the MIC was 25.00 μg / mL. Example 5: Biological activity of antimicrobial peptide-5

[0055] In Example 1, antimicrobial peptide-1 was replaced with antimicrobial peptide-5 to determine the biological activity of antimicrobial peptide-5 against Acinetobacter baumannii (final concentrations at assays were 30, 25, 20, 15, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 2, and 1 μg / mL), Bacillus subtilis (final concentrations at assays were 30, 25, 20, 15, 12.5, 12, 10, 7.5, 6.25, 6, 5, 3.75, 3.125, 3, 2.5, and 1.5 μg / mL), and Pseudomonas aeruginosa. All other aspects were the same as in Example 1.

[0056] The survival rate curves of Acinetobacter baumannii ATCC BAA-1605 after treatment with different concentrations of antimicrobial peptide-5 are shown in the figure. Figure 10 The survival rate curves of Bacillus subtilis CMCC (B) 63501 after treatment with different concentrations of antimicrobial peptide-5 are shown in the figure. Figure 11 .

[0057] The results showed that the IC50 of antimicrobial peptide-5 against Acinetobacter baumannii ATCC BAA-1605 was [missing information]. 50 The concentration was 6.73 μg / mL, and the MIC was 12.00 μg / mL; the IC50 of antimicrobial peptide-5 against Bacillus subtilis CMCC (B) 63501 was 6.73 μg / mL. 50 The concentration was 12.21 μg / mL, and the MIC was 20.00 μg / mL. Example 6: Biological activity of antimicrobial peptide-6

[0058] In Example 1, antimicrobial peptide-1 was replaced with antimicrobial peptide-6 to determine the biological activity of antimicrobial peptide-6 against Acinetobacter baumannii, Pseudomonas aeruginosa, and Bacillus subtilis (final concentrations of 50, 25, 22, 20, 18, 16, 14, 12.5, 6.25, 3.125, 1.5625, 0.78125, and 0.390625 μg / mL). All other aspects were the same as in Example 1.

[0059] The survival rate curves of Bacillus subtilis CMCC (B) 63501 after treatment with different concentrations of antimicrobial peptide-6 are shown in the figure. Figure 12 .

[0060] The results showed that antimicrobial peptide-6 had an IC50 value against Bacillus subtilis CMCC (B) 63501. 50 The concentration was 15.96 μg / mL, and the MIC was 22.00 μg / mL. Example 7: Biological activity of antimicrobial peptide-7

[0061] In Example 1, antimicrobial peptide-1 was replaced with antimicrobial peptide-7 to determine the biological activity of antimicrobial peptide-7 against Acinetobacter baumannii, Pseudomonas aeruginosa, and Bacillus subtilis (final concentrations of 50, 25, 22, 20, 18, 16, 14, 12.5, 6.25, 3.125 μg / mL). All other aspects were the same as in Example 1.

[0062] The survival rate curves of Bacillus subtilis CMCC (B) 63501 after treatment with different concentrations of antimicrobial peptide-7 are shown in the figure. Figure 13 .

[0063] The results showed that antimicrobial peptide-7 had an IC50 value against Bacillus subtilis CMCC (B) 63501. 50 The concentration was 19.56 μg / mL, and the MIC was 25.00 μg / mL. Example 8: Biological activity of antimicrobial peptide-8

[0064] The antimicrobial peptide-1 in Example 1 was replaced with antimicrobial peptide-8. The biological activity of antimicrobial peptide-8 against Acinetobacter baumannii, Pseudomonas aeruginosa, and Bacillus subtilis (final concentrations of 50, 25, 12.5, 6.25, 3.125, 1.5625, 0.78125, and 0.390625 μg / mL) was measured, while all other aspects remained the same as in Example 1.

[0065] The survival rate curves of Bacillus subtilis CMCC (B) 63501 after treatment with different concentrations of antimicrobial peptide-8 are shown in the figure. Figure 14 .

[0066] The results showed that antimicrobial peptide-8 had an IC50 value against Bacillus subtilis CMCC (B) 63501. 50 The concentration was 8.08 μg / mL, and the MIC was 50.00 μg / mL.

Claims

1. An antimicrobial peptide having the amino acid sequence shown in SEQ ID No.

4.

2. A composition comprising the antimicrobial peptide as described in claim 1 and a pharmaceutically acceptable carrier.

3. Use of the antimicrobial peptide according to claim 1 or the composition according to claim 2 for the preparation of a medicament for inhibiting and / or killing bacteria, said bacteria being Acinetobacter baumannii ( Acinetobacter baumannii ) and / or Bacillus subtilis ( Bacillus subtilis ).

4. Use according to claim 3, characterized in that, The bacteria are Acinetobacter baumannii ATCC BAA-1605 strain and / or Bacillus subtilis CMCC (B) 63501 strain.

5. The application according to claim 3 or 4, characterized in that, The application is the use of the antibacterial peptide in the preparation of a drug for treating at least one disease of ventilator-associated pneumonia, bloodstream infection, wound infection, urinary tract infection and meningitis caused by Acinetobacter baumannii Acinetobacter baumannii .

6. The application according to claim 3 or 4, characterized in that, The application is that the antimicrobial peptide is used in the preparation of a treatment for diseases caused by Bacillus subtilis (… Bacillus subtilis Use in medications for at least one of the following diseases: sepsis, endocarditis, pneumonia, meningitis, and eye infection caused by [the disease].

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