Application of bacteroides fragilis or capsular polysaccharide A of bacteroides fragilis extract in preparation of composition for improving or treating skin and soft tissue infection

Abstract

The invention provides application of bacteroides fragilis and / or an extract capsular polysaccharide A thereof in preparation of a composition for improving and / or treating skin and soft tissue infection. Different animal skin and soft tissue infection model tests prove that viable bacteria, lysate, inactivated bacteria and zwitter-ion capsular polysaccharide A of Bacteroides fragilis ZY-312 with the preservation number of CGMCC No.10685 have the effects of improving and treating skin and soft tissue infection. The inactivated bacteroides fragilis powder has a good effect of improving skin and soft tissue infection under formulas with different concentrations, does not have side effects on organisms, has very good edible and application prospects, and is a good product which is suitable for human body to eat and is used for health care and improving skin and soft tissue infection.

Description

Technical Field

[0001] The present invention relates to the field of biomedicine, and in particular to an application of Bacteroides fragilis or a capsular polysaccharide A of an extract thereof in the preparation of a composition for improving or treating skin and soft tissue infections. Background Art

[0002] Skin and soft tissue infections (SSTIs) are inflammatory diseases caused by purulent pathogens invading the epidermis, dermis, and subcutaneous tissues, characterized by epidermal discoloration, erythema, burning, and pain or tenderness. Local manifestations may be accompanied by systemic signs and symptoms, such as fever, chills, fatigue, and sometimes hemodynamic instability. Common superficial soft tissue infections include furuncles, carbuncles, erysipelas, superficial acute lymphangitis and lymphadenitis, wound infections, surgical incision infections, pressure ulcers, and subcutaneous acute cellulitis. These infections affect a variety of tissues, are caused by a variety of microorganisms, and present with a wide range of clinical manifestations.

[0003] Common pathogens include Staphylococcus aureus, hemolytic streptococci, anaerobic bacteria, etc., which invade areas with abundant hair follicles or areas of tissue damage to cause infection. They can also be secondary to other diseases and spread through lymph or blood. The most common pathogens in SSTI are Streptococcus and Staphylococcus, including methicillin-resistant Staphylococcus aureus (MRSA), which is a common pathogen in the United States. The most common pathogen found in the SENTRY antimicrobial drug monitoring program in the United States and Canada is Staphylococcus aureus, accounting for about a quarter to a half of all infections.

[0004] SSTIs are a major clinical problem due to their morbidity and severity. Most cases are mild and can be treated with oral medications, but moderate or severe SSTIs may require hospitalization and parenteral therapy. SSTIs present considerable challenges in diagnosis and treatment because culture and screening for pathogens are difficult and time-consuming, and because host factors contributing to the development and recurrence of SSTIs may not be initially apparent.

[0005] SSTI can be divided into four grades according to the severity of local and systemic symptoms and signs of infection, as well as the presence and stability of any comorbidities: 1) Fever and health, except cellulitis; 2) Fever and symptoms, but no unstable comorbidities; 3) Toxic symptoms, or at least one unstable comorbidity, or limb-threatening infection; 4) Septic syndrome or life-threatening infection, such as necrotizing fasciitis. The recommended antimicrobial agents for the treatment of different grades of SSTI are different. Grade 1 SSTI: dicloxacillin, flucloxacillin, and cefixime are recommended; Grade 2 SSTI: Ceftriaxone is recommended; Grade 3 SSTI: Cefazolin, semi-synthetic penicillins, flucloxacillin combined with benzylpenicillin; Grade 4 SSTI requires parenteral treatment. Over time, antibiotic resistance in SSTI isolates has increased significantly, and antibiotic treatment can increase gastrointestinal side effects in patients, and in severe cases, it can even aggravate the condition.

[0006] Many studies have demonstrated the ability of specific probiotics (such as Lactobacillus acidophilus and Lactobacillus casei) to act as antimicrobial agents against MRSA, significantly inhibiting the growth of pathogenic bacteria (eliminating 99%); Lactobacillus reuteri and Lactobacillus rhamnosus reduced the ability of pathogenic bacteria to induce keratinocyte death; probiotic treatment increased wound closure accompanied by induced nitric oxide (NO) production, mediating the wound healing process by promoting the production of IL-1, TGF-β and cytokines. The above research results show that probiotic treatment plays an important role in immune response and inflammation. Paraprobiotics are defined as "inactive microbial cells that, if taken orally or topically in sufficient quantities, can provide benefits to the user", which includes both incomplete and complete microbial cells (see Taverniti V, Guglielmetti S. The immunomodulatory properties of probiotic microorganisms beyond their viability (ghost probiotics: proposal of paraprobiotic concept) [J]. Genes & Nutrition, 2011, 6 (3): 261-274.). The mainstream research view is that broken microbial cells can better release functional molecules and therefore have better effects; however, for intact inactivated microbial cells, there is no unified view that can explain why they are superior to live bacteria in certain applications. At present, research on paraprobiotics focuses on first-generation probiotics such as lactobacillus and bifidobacterium, and the research direction is relatively fixed. Therefore, it is necessary to develop new paraprobiotics and expand the range of indications for paraprobiotics.

[0007] Bacteroides fragilis (B. fragilis) is a Gram-negative, rod-shaped, blunt-end and densely stained, capsule-free, non-spore-free, non-motile obligate anaerobic bacterium. It is divided into enterotoxigenic (ETBF) and non-enterotoxigenic (NTBF). It is part of the normal intestinal flora of humans and animals, mainly present in the colon, and can also colonize and grow in the mucosa of the respiratory tract, gastrointestinal tract and urogenital tract. The Bacteroides fragilis ZY-312 used in the present invention has been sequenced and experimentally verified to be NTBF. Studies have found that non-enterotoxigenic Bacteroides fragilis (NTBF) has an important prebiotic effect and is essential for colon mucosal integrity and immune development. The relationship between Bacteroides fragilis and the host depends to a large extent on its highly complex and dynamic capsule structure. B. fragilis capsule polysaccharide A (PSA) is the most abundant and immunologically active of the 8 different capsule polysaccharides expressed by Bacteroides fragilis. At the same time, Bacteroides fragilis, as a pioneer probiotic, is part of the normal intestinal flora of humans and animals, and its safety is more guaranteed. The development of zwitterionic capsular polysaccharide A of Bacteroides fragilis extract for the improvement and / or treatment of skin and soft tissue infection drugs is promising and necessary. Summary of the invention

[0008] In order to overcome the above-mentioned defects existing in the prior art, the purpose of the present invention is to provide an application of Bacteroides fragilis and / or its extract capsular polysaccharide A in improving and / or treating skin and soft tissue infections. The present invention proves through different animal skin and soft tissue infection model tests that the live bacteria, lysate, inactivated bacteria and zwitterionic capsular polysaccharide A of Bacteroides fragilis ZY-312 with a preservation number of CGMCC No. 10685 have the effect of improving and treating skin and soft tissue infections. The inactivated bacteria powder of Bacteroides fragilis with complete morphology provided by the present invention has good effect on improving skin and soft tissue infections and has no side effects on the body under different concentration formulas, and has a good application prospect.

[0009] In order to achieve the above object, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides the use of one or more of Bacteroides fragilis and zwitterionic capsular polysaccharides of Bacteroides fragilis in the preparation of a composition for improving and / or treating skin and soft tissue infections, wherein the Bacteroides fragilis is selected from Bacteroides fragilis ZY-312 with a deposit number of CGMCC No.10685.

[0011] In an embodiment of the present invention, the Bacteroides fragilis is a live bacterium, a lysate or an inactivated bacterium.

[0012] Exemplarily, the Bacteroides fragilis is an inactivated bacterium; preferably, the Bacteroides fragilis is inactivated by any one or more of dry heat, wet heat, filtration, organic solvents, chemical reagents, ultraviolet or infrared rays, fermentation, freeze-drying, genetic recombination, genetic modification or transformation; further preferably, the Bacteroides fragilis is a morphologically complete inactivated bacterium and / or a morphologically incomplete inactivated bacterium.

[0013] Exemplarily, the Bacteroides fragilis is an inactivated bacterial powder of Bacteroides fragilis, which is prepared by fermentation, washing and centrifugation with a sodium chloride aqueous solution, resuspending with an excipient, inactivating and drying.

[0014] Preferably, the inactivated Bacteroides fragilis powder is prepared by the following method, comprising the following steps:

[0015] (1) fermenting Bacteroides fragilis;

[0016] (2) After the fermentation culture is completed, the fermentation broth is centrifuged to collect the bacterial cells, and sodium chloride aqueous solution is added at a weight volume ratio of 1 g of bacterial cells to sodium chloride aqueous solution (10 to 30) mL) for washing and centrifugation to obtain washed bacterial cells;

[0017] (3) adding the first excipient solution to the washed bacterial cells, mixing and resuspending the cells to obtain a bacterial solution, then performing an inactivation treatment, centrifuging, and collecting the inactivated bacterial sludge;

[0018] (4) adding a second excipient solution to the inactivated bacteria sludge obtained in step (3) to obtain an inactivated bacteria powder stock solution;

[0019] (5) Drying the inactivated bacteria stock solution obtained in step (4) until the residual moisture is less than 5 wt %, thereby obtaining inactivated Bacteroides fragilis bacteria powder.

[0020] Further preferably, in step (2), the bacterial count of the fermentation liquid reaches 10 8 CFU / mL and above.

[0021] Further preferably, in step (2), the mass concentration of the sodium chloride aqueous solution is 0.6-1.5wt%, preferably 0.65-1.2wt%, more preferably 0.8-1.0wt%, most preferably 0.85-0.95wt%, for example 0.9wt% sodium chloride aqueous solution.

[0022] Further preferably, in step (3), the excipient includes at least one of mannitol, sorbitol, maltodextrin, lactose, sodium chloride, maltose, sucrose, glucose, trehalose, dextran, proline, lysine, alanine, casein, and skim milk.

[0023] Further preferably, in step (3), the weight-to-volume ratio of the bacteria to the first excipient solution is 1 g:(5-15) mL.

[0024] Further preferably, in step (3), the mass fraction of the excipient in the first excipient solution is 4 to 30 wt %.

[0025] Further preferably, in step (3), the solvent of the first excipient solution is selected from sodium chloride aqueous solution, wherein the sodium chloride aqueous solution has the meaning as described above; preferably, the solvent of the first excipient solution is selected from physiological saline, such as 0.9 wt % sodium chloride aqueous solution.

[0026] Further preferably, in step (3), the inactivation method is selected from at least one of heat inactivation, freeze inactivation or chemical inactivation, preferably heat inactivation.

[0027] Further preferably, the temperature of the heat inactivation is 60-100° C., and the time of the heat inactivation is 10-60 min.

[0028] Further preferably, in step (4), a second excipient solution is added to make the total weight of the inactivated bacterial powder stock solution consistent with the weight of the bacterial solution before inactivation in step (3); further preferably, the second excipient solution is the same as or different from the first excipient solution.

[0029] More preferably, in the second excipient solution, the mass fraction of the excipient is 4 to 30 wt %, and the excipient has the meaning as described above.

[0030] More preferably, the solvent of the second excipient solution is selected from sodium chloride aqueous solution, wherein the sodium chloride aqueous solution has the meaning as described above.

[0031] Further preferably, in step (5), the drying method is selected from vacuum freeze drying and / or spray drying, preferably vacuum freeze drying.

[0032] More preferably, the vacuum freeze-drying conditions include: freezing temperature of -20 to -40°C, freezing time of 1 to 3 hours, and vacuum degree of 0.20 to 0.25 mbar.

[0033] More preferably, the vacuum freeze-drying process includes: pre-freezing at -40±2°C for 1 to 3 hours, pre-freezing at -20±2°C for 0.5 to 1 hour, and finally pre-freezing at -40±2°C for another 0.5 to 2 hours, and preparing the inactivated bacterial powder by primary drying and analytical drying under a vacuum degree of 0.25 mbar.

[0034] Further preferably, in the preparation method, the centrifugal conditions are not specifically limited, as long as the desired centrifugal effect can be achieved, for example, the centrifugal speed is 10000-20000 rpm.

[0035] According to an embodiment of the present invention, the zwitterionic capsular polysaccharide comprises capsular polysaccharide A or a Bacteroides fragilis extract containing capsular polysaccharide A.

[0036] Exemplarily, the content of lipid in the capsular polysaccharide A is less than 0.02 wt%, the protein residue is less than 1%, and the nucleic acid residue is less than 0.05%;

[0037] Exemplarily, the structure of the capsular polysaccharide A is shown below:

[0038]

[0039] Exemplarily, the weight average molecular weight of the capsular polysaccharide A is 80-90 kD, and the ratio of weight average molecular weight to number average molecular weight (Mw / Mn) is 1.0-1.2.

[0040] According to an embodiment of the present invention, in the above-mentioned applications and / or uses, the composition may be any one of a pharmaceutical composition, a food, a health product or a food additive.

[0041] Illustratively, the pharmaceutical composition comprises one or more of the Bacteroides fragilis and the zwitterionic capsular polysaccharide A of Bacteroides fragilis or a Bacteroides fragilis extract containing capsular polysaccharide A, and pharmaceutically acceptable excipients.

[0042] Preferably, the excipients include one or more of diluents, wetting agents, adhesives, disintegrants, lubricants, color and flavor regulators, solvents, solubilizers, cosolvents, emulsifiers, antioxidants, metal complexing agents, inert gases, preservatives, local analgesics, pH regulators, and isotonic or isotonic regulators.

[0043] Illustratively, in the application, the pharmaceutical composition contains a pharmaceutically effective dose of inactivated Bacteroides fragilis ZY-312 powder with a preservation number of CGMCC No. 10685 prepared by the above preparation method.

[0044] Illustratively, the pharmaceutical composition is in the form of pills, tablets, granules, capsules, powders, suspensions, gels, oral solutions or enemas, etc.

[0045] Exemplarily, the pharmaceutical composition is administered orally, by application or enema.

[0046] Exemplarily, the administration cycle of the pharmaceutical composition is intermittent administration, periodic administration, continuous administration or long-term administration.

[0047] Illustratively, the pharmaceutical composition comprises a human drug or a veterinary drug.

[0048] According to an embodiment of the present invention, the skin and soft tissue infection is one or more of carbuncle, ecthyma, folliculitis, furuncle, impetigo, herpes simplex, and smaller skin abscess.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] The present invention proves through different animal skin and soft tissue infection model tests that the live bacteria of Bacteroides fragilis ZY-312, lysate, inactivated bacteria and zwitterionic capsular polysaccharide A with a deposit number of CGMCC No. 10685 have the effect of improving and treating skin and soft tissue infections. The inactivated bacteria powder of Bacteroides fragilis with complete morphology provided by the present invention has good effect on improving skin and soft tissue infections and has no side effects on the body under different concentration formulas, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a colony morphology diagram of Bacteroides fragilis ZY-312 after anaerobic culture of the present invention;

[0052] Figure 2 This is a Gram staining microscopic image of Bacteroides fragilis ZY-312 of the present invention;

[0053] Figure 3 This is a transmission electron microscope image of the inactivated Bacteroides fragilis ZY-312 powder of the present invention;

[0054] Figure 4A -E are the 1H spectrum, 13C spectrum, COSY spectrum, HSQC spectrum, and HMBC spectrum of the capsular polysaccharide A analyzed by nuclear magnetic resonance spectrometer in Example 2;

[0055] Figure 5 is the chemical structural formula of Bacteroides fragilis capsular polysaccharide A prepared in Example 2;

[0056] Figure 6 This is a graph showing the weight changes of mice infected with deep II degree scalds in Example 3 of the present invention (mean±SD);

[0057] Figure 7 The healing time and healing rate (mean±SD) of mice with deep II degree burn infection in Example 3 of the present invention are compared with the model group, ****P<0.0001; compared with the low-dose group of inactivated Bacteroides fragilis powder, + P<0.05, ++ P<0.01, +++ P < 0.001, ++++ P < 0.0001;

[0058] Figure 8 This is the recovery score diagram (mean ± SD) of furuncle and carbuncle in furuncle mice of Example 5 of the present invention. Compared with the model group, *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001; compared with the Bactroban group, # P<0.05, ## P<0.01; compared with the Bacteroides fragilis NCTC 9343 inactivated gel group, ++ P < 0.01;

[0059] Fig. 9 This is a graph showing the volume changes of skin abscesses in mice during drug administration in Example 6 of the present invention (mean±SD).

[0060] The microbial strains used in the implementation of the present invention have been deposited in the General Microbiological Center (CGMCC) of the China Microbiological Culture Collection Committee (No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing) on ​​April 2, 2015. Classification name: Bacteroides fragilis ZY-312, deposit number CGMCC No.10685. Bacteroides fragilis ZY-312 was isolated and obtained by the applicant of the present invention, and has been protected by a patent (patent number 201510459408.X). According to the provisions of the Patent Examination Guidelines, the public can buy it from commercial channels or it has been authorized, and no deposit is required, that is, no deposit certificate is required. DETAILED DESCRIPTION

[0061] The technical scheme of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0062] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0063] In the following examples and comparative examples, unless otherwise specified, Bacteroides fragilis was fermented and cultured using a method known in the art, wherein the Bacteroides fragilis was Bacteroides fragilis ZY-312 with a preservation number of CGMCC NO.10685.

[0064] Unless defined otherwise or clearly indicated by the context, all technical and scientific terms in the present disclosure have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure belongs.

[0065] Example 1: Fermentation culture of Bacteroides fragilis

[0066] The Bacteroides fragilis ZY-312 strain was streaked onto a blood plate and cultured anaerobically for 48 hours. The colony morphology, staining characteristics, size, club shape, and distribution were observed.

[0067] Colony characteristics: After 48 hours of culture on a blood plate, Bacteroides fragilis ZY-312 is round, slightly convex, translucent, white, smooth, and non-hemolytic. The colony diameter is between 1 and 3 mm. Figure 1 .

[0068] Microscopic morphology: Gram staining of Bacteroides fragilis ZY-312 showed that it was a Gram-negative bacterium with a typical rod shape, blunt and darkly stained ends, and a non-stained part in the middle of the bacteria that looked like a vacuole. Figure 2 .

[0069] A single colony was selected and inoculated into the culture medium for fermentation culture for 8 hours (temperature was 37°C). The obtained bacterial solution was centrifuged at a speed of 3000 r / min for 15 min. The supernatant was removed and the precipitate was collected to obtain Bacteroides fragilis ZY-312 bacterial sludge.

[0070] Example 2. Sample preparation

[0071] 1. Preparation of Bacteroides fragilis live bacterial solution, lysis solution and inactivated bacterial solution

[0072] (1) Enrichment: A single colony was selected from the anaerobically cultured colonies in Example 1 and inoculated into TSB (tryptone soy broth containing 5% fetal bovine serum) for enrichment and fermentation. The resulting bacterial solution was stored for later use.

[0073] (2) Live bacterial solution of Bacteroides fragilis: The bacterial solution prepared in step (1) was used to measure the bacterial count using a McFarland turbidimeter tube and diluted to 10 with physiological saline. 6 CFU / mL, 10 7 CFU / mL, 10 8 CFU / mL, 10 9 CFU / mL and 10 10 CFU / mL, save for future use.

[0074] (3) Bacteroides fragilis lysis solution: Bacteroides fragilis lysis solution was prepared by ultrasonic disruption. Specific steps: 5 mL of the Bacteroides fragilis live bacterial solution prepared in step (2) was used for lysis by ultrasonic instrument for 30 minutes, with the on state for 10 seconds and the off state for 10 seconds. The bacterial cell lysis efficiency of the system reached 99%. After lysis, the solution was centrifuged at 6000 rpm for 10 minutes and 4°C, and filtered for later use.

[0075] (4) Inactivated Bacteroides fragilis solution: Prepare inactivated Bacteroides fragilis solution by high temperature or ultraviolet irradiation.7 Cells / mL and 10 9 Cells / mL of Bacteroides fragilis live bacterial solution 5mL was placed in a beaker, and the beaker containing the bacterial solution was placed in a constant temperature water bath at 100°C for 20-30min or placed in an ultraviolet environment for 30-60min to prepare the inactivated bacterial solution of Bacteroides fragilis. The inactivated bacterial solution of Bacteroides fragilis NCTC 9343 was prepared in the same way.

[0076] 2. Preparation of inactivated Bacteroides fragilis powder

[0077] (1) Take the fermentation broth of Bacteroides fragilis prepared in Example 1, centrifuge the fermentation broth, collect wet bacteria, add physiological saline at a ratio of bacteria: physiological saline = 1: (10-30) (m:v) to resuspend and wash the bacterial sludge, and centrifuge again to collect the washed bacteria. m represents mass and v represents volume.

[0078] (2) Add an excipient prepared by mixing 5% maltodextrin and 0.9% sodium chloride to the bacterial cells obtained in step (1) at a ratio of bacterial cells: excipient = 1: (5-15) (m:m), stir and disperse, heat inactivate at (70-100) ± 5°C for (20-40) ± 5 minutes, and then centrifuge to collect the bacterial sludge.

[0079] (3) adding excipients to the inactivated bacteria sludge collected in step (2) to make the total weight consistent with the weight of the bacteria solution before inactivation, stirring to completely dissolve, and obtaining an inactivated bacteria powder stock solution.

[0080] (4) The inactivated bacterial powder stock solution obtained in step (3) is subjected to vacuum freeze drying, pre-frozen at -40±2°C for 1 to 3 hours, pre-frozen at -20±2°C for 0.5 to 1 hour, and finally pre-frozen at -40±2°C for 0.5 to 2 hours, and then dried once (at -5±2°C and 0±2°C) and dried by desorption (at 35±2°C) under a vacuum degree of 0.25 mbar to prepare inactivated bacterial powder, wherein the bacterial count of the bacterial powder reaches 1×10 11 Cells / g or more. Figure 3 The microscopic examination shows that the bacterial morphology in the prepared inactivated bacterial powder is intact.

[0081] The same method as above was used to prepare NCTC 9343 inactivated bacteria powder.

[0082] 3. Preparation of Bacteroides fragilis inactivated gel

[0083] (1) 1×10 8 Cells / g specification Bacteroides fragilis inactivated gel, for every 500g preparation amount, weigh the above-prepared Bacteroides fragilis inactivated bacterial powder (based on the bacterial content of 1×10 11Cells / g calculation, 0.5g), carbomer homopolymer (type B) (2.5g), triethanolamine (2.5g), glycerol (25g), ethylparaben (0.5g), polysorbate 80 (0.5g), purified water (468.5g) for later use.

[0084] (2) Take ethylparaben and place it in a tilting vacuum emulsifier, add 300 g of purified water, start stirring, heat to 80°C and keep warm for 30-60 minutes, cool the room temperature water to below 40°C, add glycerin, stir evenly and stop stirring, add carbomer homopolymer (type B), soak for at least 5 hours until there is no white core. If white core is observed, the soaking time should be extended.

[0085] (3) Take 20 g of purified water, add it to triethanolamine, stir evenly, and set aside.

[0086] (4) Take 30 g of purified water and add it to the inactivated Bacteroides fragilis powder, stir to disperse it, and set aside.

[0087] (5) Take 15 g of purified water, heat it to 80°C, add polysorbate 80, stir until completely dissolved, cool to room temperature, and set aside.

[0088] (6) Set the stirring speed of the tilting vacuum emulsifier to 50 Hz, start stirring, and keep it for 15 minutes.

[0089] (7) Add the inactivated Bacteroides fragilis powder solution into a tiltable vacuum emulsifier and keep stirring for 15 minutes.

[0090] (8) Slowly drop about 1 / 6 of the triethanolamine solution into the glue solution and stir for 5 minutes. Then drop about 1 / 6 of the triethanolamine solution into the glue solution again and stir for 5 minutes. Then slowly drop the remaining triethanolamine solution all at once. Then add the polysorbate 80 solution and the remaining purified water and keep stirring. After stirring for 45 minutes, turn on the vacuum pump and keep the vacuum degree at -90 KPa or above. Then, evacuate for 15 minutes.

[0091] (9) Transfer to the filling machine and fill according to the specification of 10g / tube.

[0092] 4. Preparation of Capsular Polysaccharide A from Bacteroides fragilis ZY-312 Extract

[0093] (1) Centrifuge the fermentation broth of Bacteroides fragilis and collect the bacterial sludge. Take 50 g of bacterial sludge, add 300 g of purified water to resuspend the bacterial sludge, adjust the pH to 3.5 with 1 mol / L hydrochloric acid solution, extract at 100°C for 1.5 h, cool to room temperature, centrifuge at 12000g for 10 min at room temperature, and collect the supernatant to obtain a crude sugar solution.

[0094] (2) the crude sugar solution is ultrafiltered and concentrated through a 10KD ultrafiltration membrane to remove small molecular impurities until the conductivity is stable, and the reflux liquid is collected;

[0095] (3) Add an equal volume of 40 mmol / L Tris-HCl (pH=8.5) to the reflux liquid for salt conversion; chromatograph on a DEAE Sepharose Fast Flow ion exchange column (16 mm×200 mm) at a flow rate of 20 mL / min, use a linear gradient elution of 25 column volumes with 0.2 mol / L sodium chloride in 20 mmol / L Tris-HCl (pH=8.5) (within 25 column volumes, the sodium chloride concentration in the mobile phase increased from 0 mol / L to 0.2 mol / L), collect the fractions in sections, 100 mL / bottle (components), monitor by SEC-HPLC tracking, merge the fractions with a single, symmetrical absorption peak at 206 nm, ultrafilter with a 10KD ultrafiltration membrane, add purified water and repeat ultrafiltration until the conductivity is stable, collect the reflux liquid, and freeze-dry;

[0096] (4) The capsular polysaccharide A of Bacteroides fragilis was obtained and named “PSA-ZY-312”.

[0097] Test analysis:

[0098] Test method: Weigh 30 mg of the Bacteroides fragilis extract described in step (3) of method 4, dissolve in 0.5 mL of D2O, and add 1 μl of acetone (1H, 2.22; 13C, 30.89) for calibration. Use a 500 MHz Bruker NMR spectrometer to analyze the 1H, 13C, COSY, HSQC, and HMBC spectra (see Appendix). Figure 4A -E).

[0099] Test results: The extract of Bacteroides fragilis collected in step (3) of method 4 was confirmed to be capsular polysaccharide A, with a bound lipid content of less than 0.02%, a protein residue of less than 1%, and a nucleic acid residue of less than 0.05%. The obtained capsular polysaccharide A had a weight average molecular weight of 80-90 kDa and a Mw / Mn of 1.0-1.2 by GPC (gel permeation chromatography) analysis. The chemical structure is shown in the attached Figure 5 .

[0100] This Example The samples were prepared for use in the following examples.

[0101] Example 3. Therapeutic effect of Bacteroides fragilis on burn-infected mice infected with Staphylococcus aureus

[0102] 1. Experimental methods

[0103] Take SPF BlaB / c mice weighing 18-22g, half male and half female, and disinfect them with freshly prepared 0.1% chlorhexidine for 30s and set aside. Anesthetize with 10% water and chloral intraperitoneally (0.1mL / 20g), shave the back, and disinfect routinely. Boil the water, use a homemade water bath scalding plate (scalding hole diameter 8mm), stick it horizontally to the skin on the left and right sides of the spine of the mouse back, and scald one circular wound each (center and slightly above), with a distance of 1cm between two adjacent wounds, and stay for 10s. After 2 minutes, smear 20μL of Staphylococcus aureus ATCC25923 (made with physiological saline to have a bacterial content of less than 1×10 8 CFU / mL of experimental bacterial solution) until absorbed, covered with sterile gauze after 5 minutes, fixed with paper tape, and observed the general condition of the mouse wound surface after 72 hours. The skin edge of the mouse wound surface was obviously swollen, a small amount of yellow-white pus was seen under some wounds, and the necrotic focus expanded by 1-2mm at the edge of the wound surface, which was considered to be a successful model.

[0104] The mice with successful modeling were randomly divided into 9 groups, with 12 animals in each group, half of which were male and half were female. Group 1 (G1): model group, Group 2 (G2): Bacteroides fragilis live bacterial liquid group, Group 3 (G3): Bacteroides fragilis inactivated bacterial liquid group, Group 4 (G4): Bacteroides fragilis lysate group, Group 5 (G5): Bacteroides fragilis inactivated bacterial powder low-dose group, Group 6 (G6): Bacteroides fragilis inactivated bacterial powder medium-dose group, Group 7 (G7): Bacteroides fragilis inactivated bacterial powder high-dose group, Group 8 (G8): NCTC9343 inactivated bacterial powder group, Group 9 (G9): PSA-ZY-312 group. The drug was administered for a total of 21 days.

[0105] Dosage regimen: Add inactivated Bacteroides fragilis powder to normal saline to make a suspension for later use. Except for the model group (Group1) which was given an equal amount of normal saline by gavage, each group from Group2 to Group8 was given a single gavage of the corresponding drug (about 0.2 mL) at 10 μL / g body weight, and Group9 was given a single gavage of the corresponding drug at 8 mg / kg body weight, and the treatment was continued for 21 days. The weight of the mice, the wound healing time and the healing rate of the mice were recorded on D1, D2, D5, D7, D14 and D21. The specific experimental groups and dosing regimens are shown in Table 1.

[0106] Table 1 Effects of Bacteroides fragilis on burn mice infected with Staphylococcus aureus Experimental groups and drug administration regimen

[0107]

[0108]

[0109] 2. Experimental results

[0110] Body weight changes of mice infected with deep second-degree burns Figure 6 As shown, the weight of mice in the model group decreased significantly, and it took 14 days to basically return to the pre-trauma level, indicating that when the mice were obviously infected, their mental state was poor and their food intake was reduced; while the weight of the Bacteroides fragilis live bacteria liquid, inactivated bacteria liquid, lysate, various doses of inactivated bacteria powder and PSA-ZYZ-312 groups decreased slightly within 3 days, and then recovered and increased, which could accelerate the weight recovery of traumatized mice, and returned to the pre-trauma level about 6 days after administration. The weight of the Bacteroides fragilis NCTC 9343 inactivated bacteria powder group decreased in the first 5 days, and then recovered and increased, and returned to the pre-trauma level about 7 days after administration.

[0111] The healing time and healing rate of deep second-degree burns in infected mice Figure 7 As shown, the wounds of the mice in the model group were basically completely healed until 21 days, while the wounds of the mice in each drug-treated group were basically healed after 14 days of drug administration, and the wounds were completely healed after 21 days of drug administration. The efficacy of the inactivated Bacteroides fragilis powder was positively correlated with the dose, indicating that the Bacteroides fragilis isolated by the present invention can accelerate the healing of the wounds of mice with deep II degree burns and infection and shorten the healing time.

[0112] Example 4. Therapeutic effect of Bacteroides fragilis on subcutaneous soft tissue infection in mice caused by hemolytic streptococci

[0113] 1. Experimental methods

[0114] SPF male Kunming mice weighing 20-22g were taken. 24h before the experiment, 8% Na2S was applied to both sides of the back spine to remove hair, with an area of ​​about 2cm×2cm. They were randomly divided into 6 groups according to body weight, with 8 animals in each group. Group 1 (G1): blank control group, Group 2 (G2): model group, Group 3 (G3): low-dose group of inactivated Bacteroides fragilis powder, Group 4 (G4): medium-dose group of inactivated Bacteroides fragilis powder, Group 5 (G5): high-dose group of inactivated Bacteroides fragilis powder, Group 6 (G6): inactivated Bacteroides fragilis NCTC 9343 powder group.

[0115] Dosage regimen: Add inactivated Bacteroides fragilis powder to physiological saline to prepare suspension for later use. The blank group and model group mice were smeared with white vaseline at 0.4 g / mouse on the hair removal area, and the experimental group mice were smeared with the corresponding inactivated Bacteroides fragilis powder suspension at 0.2 mL / mouse, once a day for 3 days. 6 hours after the last administration, the model group and experimental group mice were subcutaneously injected with 2.4×10 4CFU / mL A group beta-hemolytic streptococcus infection carrier 0.4mL (3% agar, 60℃ insulation), the whole process is aseptic operation, and the drug administration is continued for 6 days (D1-D6). Before administration, the color and morphology of the skin papules of mice after infection are observed and quantitatively scored. The scoring criteria are determined according to clinical symptoms.

[0116] Table 2 Effect of Bacteroides fragilis on subcutaneous soft tissue infection in mice caused by hemolytic streptococci Experimental groups and dosing regimen

[0117]

[0118] 2. Experimental results

[0119] The results showed that the inactivated bacterial powder groups of Bacteroides fragilis and the inactivated bacterial powder group of Bacteroides fragilis NCTC 9343 had a significant inhibitory effect on the infection caused by subcutaneous injection of group A beta-hemolytic streptococcus in mice, the clinical score was significantly reduced, and the infection symptoms were significantly improved. Compared with the model group, the difference was statistically significant (P<0.0001, P<0.01 or P<0.05). The medium-dose group and high-dose group of Bacteroides fragilis inactivated bacterial powder had better effects than the inactivated bacterial powder group of Bacteroides fragilis NCTC 9343 (P<0.0001, P<0.01 or P<0.05). See Table 3 for details.

[0120] Table 3 Effect of Bacteroides fragilis on subcutaneous soft tissue infection in mice caused by hemolytic streptococci

[0121]

[0122]

[0123] Compared with the model group, *P<0.05, **P<0.01, ****P<0.0001; compared with the Bacteroides fragilis NCTN9343 inactivated bacteria powder group, # P<0.05, ## P<0.01, #### P<0.0001. Unpaired t test.

[0124] Example 5. The therapeutic effect of Bacteroides fragilis on furunculosis in mice

[0125] Furuncles are skin abscesses caused by Staphylococci that spread to hair follicles and surrounding tissue. Carbuncles are multiple furuncles that fuse together under the skin, causing deep suppuration and scarring. They are smaller and more superficial than subcutaneous abscesses. Diagnosis is based on clinical findings. Treatment is warm compresses and usually oral antistaphylococcal antibiotics.

[0126] 1. Experimental methods

[0127] SPF Kunming mice weighing 18-22g were selected, half of which were male and half were female. The mice were anesthetized by intraperitoneal injection of 100g / L-1 chloral hydrate (0.4mg / g). The back hair was removed (3cm×3cm). A turpentine mixture containing 0.002 volume fraction of croton oil was used to inject 0.06mL intradermally at the middle back spine of each mouse using a 1mL insulin syringe. The model was completed when white furuncles accompanied by redness and swelling, and the upper cut surface of the abscess was 1-2mm higher than the surrounding skin.

[0128] The mice with successful modeling were randomly divided into groups, with 10 animals in each group, half male and half female, for a total of 6 groups. Group 1 (G1): model group, Group 2 (G2): Bactroban group, Group 3 (G3): low-dose group of inactivated Bacteroides fragilis gel, Group 4 (G4): medium-dose group of inactivated Bacteroides fragilis gel, Group 5 (G5): high-dose group of inactivated Bacteroides fragilis gel, Group 6 (G6): NCTC9343 inactivated gel group. The drug was applied twice a day from D1 to D3, and once a day from D4 to D9, for a total of 9 days, and the recovery was observed on D10. The drug efficacy grade scoring method was used, divided into 4 grades: recovery, effectiveness, improvement, and ineffectiveness (reference: Zheng Qingshan et al., Common problems in the classification of drug efficacy indicators and data processing, Chinese Journal of Clinical Pharmacology and Therapeutics, 2002, 7 (5): 469-472). The specific experimental groups and dosing regimens are shown in Table 4.

[0129] Table 4 Effects of Bacteroides fragilis on furunculosis in mice Experimental groups and drug administration regimen

[0130]

[0131] 2. Experimental results

[0132] The scoring results after 9 days of administration are as follows Figure 8 As shown, compared with the model group, each drug administration group can improve the drug efficacy grade score. The effects of each group of the inactivated Bacteroides fragilis gel separated by the present invention are particularly significant. The furuncle and carbuncle at the modeling site can be observed with the naked eye, which is significantly different from the model group (P<0.001), the Bactroban group (P<0.05), and the Bacteroides fragilis NCTC9343 group (P<0.01); there is no significant difference between the groups of the inactivated Bacteroides fragilis gel (P>0.05).

[0133] Example 6. Therapeutic effect of Bacteroides fragilis on mice with skin abscesses

[0134] Skin abscess is a localized accumulation of pus on the skin, which can occur anywhere on the skin surface. Symptoms and signs include pain, tenderness, solid or fluctuating swelling. When the patient's immunity is low, the abscess can develop into repeated infection or severe infection, which is fatal to some patients with chronic diseases (such as diabetes). Therefore, the study of abscess is very necessary.

[0135] 1. Experimental methods

[0136] SPF female SKH-1 hairless mice aged 6-8 weeks, weighing 24-29g. The animals were randomly divided into a blank control group of 8, a model group of 10, a positive drug group of 10, and a test substance group of 30. After 7 days of adaptive feeding, the animals were given the following treatments: the blank control group was subcutaneously injected with 0.05mL of sterile PBS buffer; the other groups were subcutaneously injected with a concentration of 1×10 9 CFU / mL of methicillin-resistant Staphylococcus aureus (MRSA), the positive drug group was injected with teicoplanin (120 mg / kg) locally for 3 consecutive days after 24 hours, and the test group was smeared with inactivated Bacteroides fragilis solution for 22 days. The specific experimental groups and dosing schedules are shown in Table 5.

[0137] The mice were randomly divided into 8 groups. Group 1 (G1): control group, Group 2 (G2): model group, Group 3 (G3): positive drug group, Group 4 (G4): low-dose group of inactivated Bacteroides fragilis, Group 5 (G5): medium-dose group of inactivated Bacteroides fragilis, Group 6 (G6): high-dose group of inactivated Bacteroides fragilis, Group 7 (G7): NCTC9343 inactivated bacteria group, Group 8 (G8): PSA-ZY-312 group.

[0138] Table 5 Experimental groups and dosing regimens for the effects of Bacteroides fragilis on mice with skin abscesses

[0139]

[0140]

[0141] 2. Experimental results

[0142] The changes of abscess volume in each group of mice Fig. 9 As shown, compared with the model group, each medication group was able to effectively accelerate the reduction of abscess volume. The high-dose group of inactivated Bacteroides fragilis powder was able to completely eliminate the abscess after 22 days of administration, and the effect was better than that of the positive drug teiraconine.

[0143] Example 7. Therapeutic effect of Bacteroides fragilis on herpes simplex in guinea pig skin

[0144] Skin herpes simplex is a common clinical manifestation of herpes simplex virus type 1 (HSV-1) infection. A guinea pig skin herpes simplex model was established to evaluate the efficacy of Bacteroides fragilis.

[0145] 1. Experimental methods

[0146] Male guinea pigs weighing 300 to 500 g were selected, their backs were depilated (3 cm in diameter), disinfected with iodine, and subcutaneously injected with 0.1 mL of HSV-1 (10 6 TCID 50 / L) virus solution, and the control group was injected with an equal volume of cell culture medium.

[0147] When obvious herpes appeared in the guinea pig modeling area (the third day after HSV-1 infection), the model guinea pigs were randomly divided and administered, with a total of 6 groups. Group 1 (G1): model group, Group 2 (G2): positive drug group, Group 3 (G3): low-dose group of inactivated Bacteroides fragilis powder, Group 4 (G4): medium-dose group of inactivated Bacteroides fragilis powder, Group 5 (G5): high-dose group of inactivated Bacteroides fragilis powder, Group 6 (G6): inactivated Bacteroides fragilis NCTC9343 powder group. The inactivated Bacteroides fragilis powder was resuspended with PBS, the positive drug acyclovir was heated in a 50°C water bath, and 0.1 mL of each test substance was taken with a micropipette and dropped on the herpes, 3 times a day, for 4 consecutive days. The control group was dripped with the same amount of PBS. The specific experimental groups and dosing schedule are shown in Table 6.

[0148] The time for the herpes scab to completely fall off (heal) was used as the efficacy observation indicator, and the results were observed and recorded every 8 hours after medication.

[0149] Table 6 Effect of Bacteroides fragilis on skin herpes simplex in guinea pigs Experimental groups and dosing regimen

[0150]

[0151]

[0152] 2. Experimental results

[0153] The time for complete shedding (healing) of the skin herpes of guinea pigs in each group is shown in Table 7. The healing time of the skin herpes of guinea pigs in each drug-treated group was significantly lower than that in the model group (P<0.0001). Compared with the positive drug group, the healing time of the herpes in the high-dose group of inactivated Bacteroides fragilis powder was significantly reduced (P<0.0001). Compared with the inactivated Bacteroides fragilis NCTC9343 powder group, the healing time of the herpes in the medium-dose group of inactivated Bacteroides fragilis powder was significantly reduced (P<0.001).

[0154] The inhibitory effect of each drug administration group on HSV-1 in the skin lesions is shown in Table 8. On the third day after treatment, each drug administration group showed an inhibitory effect on the virus, and the virus titer continued to decrease on the fifth day after treatment. On the fifth day of administration, the virus titer in the skin lesions of guinea pigs in the positive drug group, each drug administration group of inactivated Bacteroides fragilis powder, and inactivated Bacteroides fragilis NCTC9343 powder group was significantly lower than that in the model group at the same time (P<0.0001); the virus titer in the skin lesions of guinea pigs in each drug administration group of inactivated Bacteroides fragilis powder was significantly lower than that in the positive drug acyclovir group (P<0.001); the virus titer in the skin lesions of guinea pigs in each drug administration group of inactivated Bacteroides fragilis powder was significantly lower than that in the NCTC9343 powder group of inactivated Bacteroides fragilis powder (P<0.001).

[0155] Table 7 Observation on the efficacy of inactivated Bacteroides fragilis powder on herpes simplex in guinea pigs

[0156] Group <![CDATA[Time to herpes simplex healing (d) a > Model Group 13.98±0.56 Positive drug group 8.82±0.35**** Low-dose group of inactivated Bacteroides fragilis powder 9.15±0.32**** Medium dose group of inactivated Bacteroides fragilis powder <![CDATA[8.61±0.41**** +++ ]]> High-dose group of inactivated Bacteroides fragilis powder <![CDATA[7.71±0.38**** #### ]]> Bacteroides fragilis NCTC9343 inactivated bacteria powder group 9.14±0.55****

[0157] Note: a: mean±SEM; compared with the model group, ****P<0.0001; compared with the positive drug group, #### P<0.0001; compared with the inactivated Bacteroides fragilis NCTN9343 powder group, +++ P<0.001. Unpaired t test.

[0158] Table 8 Inhibitory effect of Bacteroides fragilis on HSV-1 in skin lesions

[0159]

[0160] Note: Compared with the model group, **P<0.01, ****P<0.0001; compared with the positive drug group, ### P < 0.001, #### P<0.0001; compared with the inactivated Bacteroides fragilis NCTN9343 powder group, + P<0.05, +++ P<0.001, ++++ P<0.0001. Unpaired t test.

[0161] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. Use of one or more of Bacteroides fragilis and zwitterionic capsular polysaccharides of Bacteroides fragilis in the preparation of a composition for improving and / or treating skin and soft tissue infections, characterized in that: The Bacteroides fragilis is selected from Bacteroides fragilis ZY-312 with a deposit number of CGMCC No. 10685.

2. The use according to claim 1, characterized in that: The Bacteroides fragilis is a live bacterium, a lysate or an inactivated bacterium.

3. The use according to claim 1 or 2, characterized in that: The Bacteroides fragilis is an inactivated bacterium; preferably, the inactivated Bacteroides fragilis is inactivated by any one or more of dry heat, wet heat, filtration, organic solvents, chemical reagents, ultraviolet or infrared rays, fermentation, freeze drying, genetic recombination, genetic modification or transformation; Further preferably, the Bacteroides fragilis is a morphologically complete inactivated bacterium and / or a morphologically incomplete inactivated bacterium.

4. The use according to claim 3, characterized in that: The Bacteroides fragilis is an inactivated bacterial powder of Bacteroides fragilis, which is prepared through the steps of fermentation, washing and centrifugation with a sodium chloride aqueous solution, resuspending with an excipient, inactivation and drying; Preferably, the inactivated Bacteroides fragilis powder is prepared by the following method, comprising the following steps: (1) fermenting Bacteroides fragilis; (2) After the fermentation culture is completed, the fermentation broth is centrifuged to collect the bacterial cells, and sodium chloride aqueous solution is added at a weight volume ratio of 1 g of bacterial cells to sodium chloride aqueous solution (10 to 30) mL) for washing and centrifugation to obtain washed bacterial cells; (3) adding the first excipient solution to the washed bacterial cells, mixing and resuspending the cells to obtain a bacterial solution, then performing an inactivation treatment, centrifuging, and collecting the inactivated bacterial sludge; (4) adding a second excipient solution to the inactivated bacteria sludge obtained in step (3) to obtain an inactivated bacteria powder stock solution; (5) drying the inactivated bacteria stock solution obtained in step (4) until the residual moisture content is less than 5 wt %, thereby obtaining inactivated Bacteroides fragilis bacteria powder; Further preferably, in step (2), the bacterial count of the fermentation liquid reaches 10 8 CFU / mL or above; Further preferably, in step (2), the mass concentration of the sodium chloride aqueous solution is 0.6-1.5wt%, preferably 0.65-1.2wt%, more preferably 0.8-1.0wt%, most preferably 0.85-0.95wt%, for example, 0.9wt% sodium chloride aqueous solution; Further preferably, in step (3), the excipient includes at least one of mannitol, sorbitol, maltodextrin, lactose, sodium chloride, maltose, sucrose, glucose, trehalose, dextran, proline, lysine, alanine, casein, and skim milk; Further preferably, in step (3), the weight volume ratio of the bacterial cells to the first excipient solution is 1 g: (5-15) mL; Further preferably, in step (3), the mass fraction of the excipient in the first excipient solution is 4 to 30 wt %; Further preferably, in step (3), the solvent of the first excipient solution is selected from a sodium chloride aqueous solution, and the mass concentration of the sodium chloride aqueous solution is 0.6-1.5wt%, preferably 0.65-1.2wt%, more preferably 0.8-1.0wt%, most preferably 0.85-0.95wt%, for example, 0.9wt% sodium chloride aqueous solution; Further preferably, in step (3), the inactivation method is selected from at least one of heat inactivation, freeze inactivation or chemical inactivation, preferably heat inactivation; Further preferably, the temperature of the heat inactivation is 60-100°C, and the time of the heat inactivation is 10-60 minutes; Further preferably, in step (4), a second excipient solution is added to make the total weight of the inactivated bacterial powder stock solution consistent with the weight of the bacterial solution before inactivation in step (3); further preferably, the second excipient solution is the same as or different from the first excipient solution; More preferably, in the second excipient solution, the mass fraction of the excipient is 4 to 30 wt%, including at least one of mannitol, sorbitol, maltodextrin, lactose, sodium chloride, maltose, sucrose, glucose, trehalose, dextran, proline, lysine, alanine, casein, and skim milk; More preferably, the solvent of the second excipient solution is selected from a sodium chloride aqueous solution, wherein the mass concentration of the sodium chloride aqueous solution is 0.6-1.5wt%, preferably 0.65-1.2wt%, more preferably 0.8-1.0wt%, most preferably 0.85-0.95wt%, for example, 0.9wt% sodium chloride aqueous solution; Further preferably, in step (5), the drying method is selected from vacuum freeze drying and / or spray drying, preferably vacuum freeze drying; More preferably, the vacuum freeze-drying conditions include: freezing temperature of -20 to -40°C, freezing time of 1 to 3 hours, vacuum degree of 0.20 to 0.25 mbar; More preferably, the vacuum freeze-drying process includes: pre-freezing at -40±2°C for 1 to 3 hours, pre-freezing at -20±2°C for 0.5 to 1 hour, and finally pre-freezing at -40±2°C for another 0.5 to 2 hours, and preparing the inactivated bacteria powder by primary drying and analytical drying at a vacuum degree of 0.25 mbar; Further preferably, in the preparation method, the centrifugal conditions are not specifically limited, as long as the desired centrifugal effect can be achieved, for example, the centrifugal speed is 10000-20000 rpm.

5. The use according to claim 1, characterized in that: The zwitterionic capsular polysaccharide comprises capsular polysaccharide A or is a Bacteroides fragilis extract containing capsular polysaccharide A; Preferably, the content of lipid in the capsular polysaccharide A is less than 0.02 wt%, the residual protein is less than 1%, and the residual nucleic acid is less than 0.05%; Preferably, the structure of the capsular polysaccharide A is as follows: Preferably, the weight average molecular weight of the capsular polysaccharide A is 80-90 kD, and the ratio of weight average molecular weight to number average molecular weight (Mw / Mn) is 1.0-1.

2.

6. The use according to any one of claims 1 to 5, characterized in that: The composition can be any one of a pharmaceutical composition, a food, a health product or a food additive.

7. The use according to claim 6, characterized in that: The pharmaceutical composition contains a pharmaceutically effective dose of the inactivated Bacteroides fragilis powder according to claim 4.

8. The use according to claim 6, characterized in that: The pharmaceutical composition comprises one or more of the Bacteroides fragilis and the zwitterionic capsular polysaccharide A of the Bacteroides fragilis or a Bacteroides fragilis extract containing capsular polysaccharide A, and pharmaceutically acceptable excipients; Preferably, the excipients include one or more of diluents, wetting agents, adhesives, disintegrants, lubricants, color and flavor regulators, solvents, solubilizers, cosolvents, emulsifiers, antioxidants, metal complexing agents, inert gases, preservatives, local analgesics, pH regulators, and isotonic or isotonic regulators.

9. The use according to any one of claims 6 to 8, characterized in that: The dosage form of the pharmaceutical composition is pills, tablets, granules, capsules, powders, suspensions, gels, oral solutions or enema; Preferably, the pharmaceutical composition is administered orally, or by application or enema; Preferably, the administration cycle of the pharmaceutical composition is intermittent administration, periodic administration, continuous administration or long-term administration.

10. The use according to any one of claims 1 to 9, characterized in that: The skin and soft tissue infection is one or more of carbuncle, ecthyma, folliculitis, furuncle, impetigo, and smaller skin abscess.

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