临床分离金黄色葡萄球菌ST22克隆毒力及耐药基因分析

Analysis of antimicrobial resistance and virulence genes profiling of staphylococcus aureus lineage ST22 isolates

目的了解金黄色葡萄球菌ST22克隆临床分离株的毒力及耐药特征,为防控其感染提供依据。方法收集临床分离的经鉴定为ST22克隆的104株金黄色葡萄球菌,以及1株病房空气中分离到ST22菌株,应用SCCmec分型、spa分型等分子分型方法对菌株进行分子分型,检测pvl等18种毒力基因的携带率,检测erm基因的携带率,检测菌株对苯唑西林、红霉素、四环素等13种临床常用抗生素的耐药性,分析菌株的耐药情况。结果 104株ST22菌株中,76株为CA-SA,28株为HA-SA;其中6株为MRSA,98株为MSSA。6株MRSA均为ST22-MRSA-IV-t309。98株MSSA分为12种spa型,主要型别为t309型(87.8%,86/98)。ST22克隆的pvl毒力基因检出率为79.8%(83/104),ST22主要携带有seg,sei,sem,sen及seo 5种肠毒素基因,75%(78/104)的ST22菌株携带有这5种基因。药敏结果显示ST22主要对青霉素耐药,对红霉素也有较高的耐药率,erm耐药基因检出率较低。结论乌鲁木齐地区流行的ST22克隆能够引起社区及医院内感染,携带有较多的致病基因,并且有MRSA菌株的出现。

Objective To understand the virulence and drug resistance of Staphylococcus aureus lineage ST22.Methods A total of 104 S.aureus ST22 isolates were collected,and one ST22 strain was isolated from the air of a ward was also analysed.The molecular typing methods,including staphylococcal cassette chromosome mec(SCCmec)typing and staphylococcal protein A(spa)gene typing were applied for the strains.The antimicrobials susceptibility,antibiotic resistant genes and virulence profiles were also performed among the isolates.Results In the 104 S.aureus isolates,76 were CA SA and 28 were HA SA.Six isolates were MRSA strains and 98 were MSSA.All MRSA strains were ST22-MRSA-IV-t309.The MSSA strains were divided into 12 spa types,t309 was the most prevalent clone(87.8%,86/98).The frequency of pvl carriage was 79.8%(83/104)in ST22 clones,V irulence factors profiling showed that most of ST22 isolates carried the enterotoxin gene of seg,sei,sem,sen and seo.The antimicrobials susceptibility results showed that ST22 was resistant to penicillin,and had a high resistance rate to erythromycin,and 6 isolates carried the ermC genes.Conclusion The S.aureus ST22 clones as the major lineage epidemic in Urumqi can cause communitie and hospital infections,carry more virulence genes,and emergence MRSA strains.