CpxRA双组分系统对小肠结肠炎耶尔森菌环境耐受性和抗生素耐药性的影响

Role of CpxRA in environmental stress tolerance and antibiotic resistance in Yersinia enterocolitica

目的探究CpxRA双组分系统对小肠结肠炎耶尔森菌环境耐受性和抗生素耐药性的影响。方法本研究选用Cat-SacB无标记基因敲除系统,利用同源重组双交换原理,构建了基因敲除菌株ΔcpxA和ΔcpxR,以及相应的回补菌株ΔcpxA-cpxA和ΔcpxR-cpxR,然后分别测定了野生型、突变型和回补型在酸性、碱性、高氧和高渗环境中的存活率,以及红霉素、罗红霉素、卡那霉素、链霉素的最小抑菌浓度值。结果cpxA和cpxR基因的缺失使小肠结肠炎耶尔森菌的在酸性环境下的存活率由55.1%分别降为45.9%和42.8%;使该菌在碱性环境下的存活率由43.4%分别降为38.9%和37.2%;在高渗环境下的存活率由44.1%分别降为36.3%和33.7%;在高氧环境下的存活率由20.8%分别降为15.1%和15.8%。cpxA基因的缺失增强了该菌对于氨基糖苷类抗生素:卡那霉素、链霉素的耐药性,而cpxR基因的缺失减弱了该菌对于大环内酯类抗生素:红霉素、罗红霉素的耐药性。结论CpxRA双组分系统参与调控小肠结肠炎耶尔森菌在不良环境中的存活能力以及抗生素耐药性。

Objective To investigate the effects of CpxRA two-component system on environmental tolerance and antibiotic resistance of Yersinia enterocolitica.Methods In this study,the Cat-SacB label-free knockout system was selected and the knockout strainsΔcpxA andΔcpxR were constructed,as well as the complemented strainsΔcpxA-cpxA andΔcpxR-cpxR by utilizing the principle of double-swapping by homologous recombination,and then the survival rates of the wild-type,mutant,and complemented strains were determined in acidic,alkaline,hyper-oxygenic,and hyperosmotic environments,respectively;as well as determined in ythromycin,roxithromycin,kanamycin,and streptomycin’s minimal inhibitory concentration values.Results Deletion of the cpxA and cpxR genes reduced the survival of Yersinia enterocolitica from 55.1%to 45.9%and 42.8%,respectively.The survival rate under alkaline environment decreased from 43.4%to 38.9%and 37.2%,respectively.The survival rate in hypertonic environment decreased from 44.1%to 36.3%and 33.7%,respectively.The survival rate in high oxygen environment decreased from 20.8%to 15.1%and 15.8%respectively.Deletion of the cpxA gene enhanced the Yersinia enterocolitica’s resistance to aminoglycoside antibiotics:Kanamycin,streptomycin,whereas deletion of the cpxR gene attenuated the Yersinia enterocolitica’s resistance to macrolide antibiotics:Erythromycin,roxithromycin.Conclusion The CpxRA two-component system is involved in regulating the ability of Yersinia enterocolitica to survive in adverse environments as well as antibiotic resistance.