副干酪乳杆菌的基因多样性及其抗生素耐受性分析

Genetic diversity and antibiotic resistance of Lactobacillus paracasei

探究不同因素对副干酪乳杆菌系统进化的影响,并对其抗生素耐受性的基因型和表型进行关联分析。以分离自不同地区人或动物粪便样品及泡菜样品的33株副干酪乳杆菌为研究对象,利用比较基因组学对其基因组进行特征分析,同时测定12种抗生素对菌株的最低抑制浓度(minimum inhabitory conceutration,MIC)。部分菌株在进化树上以分离地区为主因素聚集;部分粪便源菌株对克林霉素、阿莫西林、环丙沙星、红霉素和四环素均存在抗性,而泡菜源菌株普遍对抗生素较为敏感;抗生素抗性基因与表型有一定的匹配性,个别菌株的高抗性是抗性基因ErmB与tetM调控所导致。因此,分析副干酪乳杆菌的基因多样性和表型,可为其在发酵食品中的应用提供理论指导。

The purpose of this study was to explore the effects of different factors on Lactobacillus paracasei evolution and to correlate the genotypes and phenotypes of antibiotic resistance of L.paracasei.There were 33 strains of L.paracasei isolated from pickles and human or animal faeces from different regions,and they were characterized by comparative genomics.Their minimum inhibitory concentrations for 12 antibiotics were determined.The results showed that some strains from the same regions clustered together in the phylogenetic tree.Partial strains isolated from faeces were resistant to clindamycin,amoxicillin,ciprofloxacin,erythromycin,and tetracycline,while strains isolated from pickles were generally sensitive to all antibiotics.Antibiotic resistance genes matched with phenotypes to some extent and high antibiotic resistance of few strains was regulated by resistance genes ErmB and tetM.Therefore,analysis of genetic diversity and phenotypes of L.paracasei provides a theoretical guidance for their applications in fermented foods.