VirAB在单核细胞增生李斯特菌耐药性及生物被膜形成中的作用

Role of VirAB in antimicrobial resistance and biofilm formation of Listeria monocytogene

摘要:

【背景】单核细胞增生李斯特菌(Listeria monocytogenes，Lm)对一些临床常用抗生素、乳酸链球菌素(Nisin)等抗菌药物的敏感性下降，然而其背后的机制仍未完全阐明。【目的】调查转运蛋白VirAB在Lm对抗菌药物的耐药性及生物被膜形成中的作用。【方法】利用同源重组技术构建Lm基因缺失突变株，比较野生株和缺失株对抗菌药物的耐药性；利用微孔板法观测突变株生物被膜形成能力的变化；利用平板泳动法研究菌株的泳动能力。【结果】与野生株相比，virAB缺失突变株对头孢类抗生素、Nisin和溴化乙锭的敏感性增加；当培养基中分别添加亚致死浓度的苯扎氯铵、卡那霉素和四环素时，突变株均表现出不同程度的生长缺陷。缺失virAB后菌株形成生物被膜的能力下降。【结论】VirAB在Lm对头孢类等抗菌药物的耐药及生物被膜形成方面具有重要作用。

Abstract:

[Background] Reduced susceptibility has been found in Listeria monocytogenes to antimicrobial agents such as several clinical commonly used antibiotics and nisin. However, mechanisms behind this are still unclear. [Objective] To study the role of VirAB transporter in resistance to antimicrobial agents and biofilm formation of L. monocytogenes. [Methods] Gene deletion mutants were constructed by homologous recombination, and resistance to antimicrobial agents was determined in the wild-type and mutant strains. The ability of biofilm formation was measured using the microplate method. Swimming motility of these strains was investigated by plate migration method. [Results] The mutant strain ΔvirAB showed increased sensitivity to cephalosporin, nisin and ethidium bromide compared to the wild-type strain; the mutant strain exhibited varying degrees of growth defects in the presence of sub-lethal concentrations of benzalkonium chloride, kanamycin and tetracyclines. Decreased ability of biofilm formation was observed in ΔvirAB. [Conclusion] VirAB plays an important role in resistance to antimicrobial agents and biofilm formation of L. monocytogenes.