Antimicrobial Resistance Analysis of 5 Lactic Acid Bacteria Isolated from Fermented Foods

Lactobacillus plantarum S isolated from mixed fruit and vegetable juice,L. plantarum WD isolated from raspberry enzyme,L. bulgaricus LB-DR,L. rhamnosus Lr-05-281 and L. casei D-400 isolated from different dairy products were used as research objects. The antimicrobial resistance of strains were analyzed by phenotypic,genotype and gene expression using plate susceptibility paper diffusion method,PCR and RT-PCR. The results showed that 5 strains were resistant to aminoglycosides,quinolones,glycopeptide antibiotics,polymyxin B,and sensitive to macrolides,tetracyclines,sulfonamides,and nitrofurantoin. They had similar drug resistance spectrum and different sensitivities to different β-lactam antibiotics. 5 strains contained plasmids. Among the 12 resistance genes tested,four resistance genes of erm,aph,van Ⅰ and aac Ⅰ were detected on the plasmid,and six resistant genes of aph,erm,van Ⅰ,bla Ⅱ,aac Ⅰ and aac Ⅱ were detected on the genomic DNA. Some of the resistance genes were expressed in MRS and MRS cultured with antibiotics,and the resistance genes that were not expressed were still not expressed under the conditions induced by the corresponding antibiotic. The plasmid of L. plantarum WD strain contained only one kind of vanⅠ resistance gene,so its application safety was better.