5株发酵食品源乳酸菌的抗药性分析

以实验室前期分离自混合果蔬酵素的植物乳杆菌(Lactobacillus plantarum S)、分离自树莓酵素的植物乳杆菌(L. plantarum WD)和分离自不同奶制品的保加利亚乳杆菌(L. bulgaricus LB-DR)、鼠李糖乳杆菌(L. rhamnosus Lr-05-281)与干酪乳杆菌(L. casei D-400)5株乳酸菌为研究对象,采用平板药敏纸片扩散法、PCR及RT-PCR技术从表型、基因型以及基因表达几个方面分析菌株的抗药性。结果表明5株菌对氨基糖苷类、喹诺酮类、糖肽类抗生素、多粘菌素B均有抗性;对大环内酯类、四环素类、磺胺类抗生素、呋喃妥因均敏感,并有较为相似的耐药谱;而对不同的β-内酰胺类抗生素敏感性不同;5株乳酸菌均含有质粒,供试的12个抗性基因中,在质粒上检测到erm、aph、vanⅠ、aacⅠ4种抗性基因,基因组DNA上检测到aph、erm、vanⅠ、blaⅡ、aacⅠ、aacⅡ6种抗性基因。部分抗性基因在MRS和加抗生素的MRS培养下会表达,不表达的抗性基因在相应抗生素诱导的条件下其抗性基因不表达。L. plantarum WD菌株质粒上因只含一种vanⅠ抗性基因,其应用安全性较好。

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.