低能N^(+)注入诱变耐诺氟沙星的金黄色葡萄球菌及其机制分析

Mechanism Analysis of Norfloxacin-resistant Staphylococcus aureus Via Low-energy N^(+)Implantation Mutagenesis

利用低能N^(+)注入诱变筛选耐诺氟沙星的金黄色葡萄球菌,通过基因组测序、耐药表型和生物被膜分析,探索低能N^(+)注入驱动金黄色葡萄球菌产生诺氟沙星耐药性的机制。结果表明,利用低能N^(+)注入诱变获得81株耐诺氟沙星的金黄色葡萄球菌,其中44株耐药菌16S rRNA或耐药基因出现片段缺失、插入、点突变和拷贝数变化;且基因变化高的耐药菌的药物外排蛋白、生物被膜的生物量和密度显著增加,对诺氟沙星的耐药性提高了8~16倍,并对5~8种抗菌药物产生了多重耐药。说明低能N^(+)注入可能通过介导金黄色葡萄球菌16S rRNA或相关耐药基因变异,调控细菌药物外排蛋白表达量增加和生物被膜形成能力增强,进而介导菌株产生耐药性。

The norfloxacin-resistant Staphylococcus aureus was constructed via low-energy N^(+)implantation mutagenesis.Then these strains were examined by whole-genome sequencing,drug-resistance phenotype tests and biofilm analysis methods to explore the mechanism involved in the norfloxacin-resistant S.aureus mediated by low-energy N^(+)implantation.The results showed that 81 norfloxacin-resistant S.aureus strains were screened by low-energy N^(+)implantation mutagenesis.Among which,44 strains appared deletion,insertion,point mutation and copy number change of 16S rRNA and antimicrobial resistance genes(ARGs).Further more,the strains with high genetic variety acquired multidrug resistance to different antimicrobials,whose resistance to norfloxacin increased by 8 and 16 times,and the biomass,density and matrix protein content of their biofilm were enhanced significantly.These results indicated that low-energy N^(+)implantation may cause the sequence variety or copy number changes of 16SrRNA and ARGs in S.aureus,which enhances the biofilm formation ability and the drug efflux protein content,thereby accelerates the formation of drug resistance in S.aureus.