中文摘要：

目的：比较伤寒沙门菌virK和mig-14基因在拮抗多黏菌素B杀伤作用中的差异,探讨两者在拮抗多黏菌素B杀伤作用中的关系。方法：用自杀质粒介导的同源重组方法制备伤寒沙门菌virK缺陷变异株和virK/mig-14双缺陷变异株,在弱酸性环境下对缺陷菌株做多黏菌素B杀伤试验,比较mig-14缺陷株、virK缺陷株和virK/mig-14双缺陷株对多黏菌素B的耐受情况。结果：成功制备伤寒沙门菌virK缺陷变异株和virK/mig-14双缺陷变异株,在弱酸性环境下mig-14缺陷株、virK缺陷株和virK/mig-14双缺陷株对多黏菌素B的耐受情况基本一致。结论：virK在伤寒沙门菌GIFU10007中也发挥对多黏菌素B的拮抗作用,与mig-14对多黏菌素B的拮抗作用有相似效果。

英文摘要：

Objective： To compare the effect and study the association in resistance to polymyxin B between virK and mig-14 gene of Salmonella enterica serovar Typhi.Methods： Prepared the virK deleted mutant and virK/ mig-14 double deleted mutant of S.enterica serovar Typhi by homologous recombination mediated by suicide plasmid;performed the polymyxin B sensitivity assay for wild strain,mig-14 deleted mutant,virK deleted mutant,virK/ mig-14 double deleted mutant and phoP deleted mutant,then compared their resistance to polymyxin B.Results： Successfully prepared a virK mutant and virK/mig-14 double mutant.The effect of polymyxin B on mig-14 mutant,virK mutant and virK/mig-14 double mutant were nearly similar at poor acid environment from the polymyxin B sensitivity assay.Conclusion： VirK participated in the regulations of resistance to polymyxin B.The resistance to polymyxin B of virK mutant was nearly consistent with mig-14 mutant.