Analysis Of Genetic Diversity And Drug Resistant Spectrum Of Lactic Acid Bacteria Isolated From Yogurt Produced Kazak Nationality Of Tacheng Area,Xinjiang

Backgroud: Lactic acid bacteria have great application potential and prospects in food processing and preservation,health care,and animal husbandry.However,most of the food fermentation industries in China still rely on imported strains from abroad.Xinjiang traditional fermented dairy products contain abundant indigenous dominant species resources,which are rarely developed and applied.Methods: 15 samples of traditional Koumiss and Shubat were diluted and plated by five different media,and the initial screening was carried out according to the colony,cell morphology,contact enzyme-negative and Gram-positive characteristics of lactic acid bacteria.Genus and specifics-specific PCR amplification,physiological and biochemical and 16 S rRNA gene amplification and sequencing are used to identify lactic acid bacteria.The genetic difference of lactic acid bacteria was analyzed using a PCR amplification method.On this basis,the ability of lactic acid bacteria to use 11 kinds of sugars for representative strains qualitative analysis,while using KB paper to analyze the drug resistance spectrum of the strains.Results,Conclusion: 1.A total of 683 pure cultures were isolated from 15 samples of traditional acid horse and camel milk,311 pure cultures were from 7 parts of sour milk and 372 were isolated from 8 parts of camel milk.Among them,583 strains were negative for contact enzyme test and 502 strains were positive for Gram stain.2.By species and genus-specific PCR amplification,the dominant strains of 502 suspected lactic acid bacteria were Enterococcus and Lactobacillus,208 and 172,respectively.Combined with Rep-PCR and 16 S rRNA gene sequencing,502 suspected lactic acid bacteria include Lactobacillus,Enterococcus,Lactococcus,Leuconostoc,Streptococcus,and one non-lactic acid bacterium(Bacillus).Among them,Lactobacillus is composed of five species: L.plantarum,L.fermentum,L.acidophilus,L.casei,and L.paracasei.Enterococcus includes E.durans,E.faecalis,E.faecium,and E.hirae.Only one strain of Lactococcus is isolated,which is Lc.garvieae.3.K-B paper test results showed that the 84% of the strains were resistant to3-7 antibiotics,3 resistant to 2 antibiotics,1 strain resistant to only one antibiotic;25 strains were susceptible to rifampicin,and 2 strains were resistant to erythrocin,76% of the strains were resistant to gentamicin.All representative strains can metabolize glucose,lactose,and fructose.Only one strain can utilize 10 carbon sources,and 12% of the strains can utilize 9 carbon sources.