利奈唑胺耐药金黄色葡萄球菌耐药机制分析  

Analysis on the resistance mechanism of linezolid-resistant Staphylococcus aureus

作　　者：高硕[1] 周万青[1] 朱宏[1] 周辉[1] 张燕[1] 张之烽[1] 曹小利[1] 沈瀚[1] GAO Shuo;ZHOU Wanqing;ZHU Hong;ZHOU Hui;ZHANG Yan;ZHANG Zhifeng;CAO Xiaoli;SHEN Han(Department of Laboratory Medicine,Nanjing Drum Tower Hospital,the Affiliated Hospital of Nanjing University Medical School,Nanjing 210008,Jiangsu,China)

机构地区：[1]南京大学医学院附属鼓楼医院检验科,南京210008

出　　处：《临床检验杂志》2020年第8期613-616,共4页Chinese Journal of Clinical Laboratory Science

基　　金：南京市医学科技发展资金(ZKX18016,QRX17143,YKK18091)。

摘　　要：目的调查临床分离金黄色葡萄球菌对利奈唑胺的耐药情况及耐药机制。方法用Vitek 2系统GP67卡对2019年1月至12月南京鼓楼医院临床分离905株金黄色葡萄球菌进行药敏试验,对检出的利奈唑胺耐药菌株用E-test法复测利奈唑胺最低抑菌浓度(MIC);用PCR扩增及测序技术分析利奈唑胺耐药决定基因cfr、optr A及23S rRNA基因V区;对菌株基因组DNA进行全基因组测序分析,对耐药基因、毒力基因进行生物信息学分析;用多位点序列分型(MLST)技术获得菌株ST分型。结果 905株金黄色葡萄球菌检出1株(0.1%)利奈唑胺耐药株(MIC为16 mg/L),该菌株除对万古霉素和复方磺胺甲噁唑敏感外,对其余常用抗菌药物均耐药。PCR及测序技术显示该菌株携带cfr基因,23S rRNA V区存在T2337G和C2370G核苷酸突变位点;全基因组序列分析显示基因组包含碱基数为2 949 411 bp,总基因数为3 023个,包含59个tRNA编码基因以及7个完整的rRNA基因编码操纵子,获得Gen Bank登录号JAANYO000000000,且该菌株携带包括cfr在内的多种耐药决定基因和毒力基因;MLST分型为新型ST5985。结论利奈唑胺耐药金黄色葡萄球菌临床分离率较低。检出由cfr基因和23S rRNA V区突变介导的新ST型利奈唑胺耐药株。Objective To investigate the resistance of Staphylococcus aureus isolated from clinical samples to linezolid and its mechanism. Methods A total of 905 strains of Staphylococcus aureus isolated from Nanjing Drum Tower Hospital during January 2019 and December 2019 were performed the antibiotic sensitivity test by the GP67 cards of Vitek 2 system,and the screened linezolid-resistant strains were further detected the minimal inhibitory concentration( MIC) of linezolid by the E-test. Resistance determining genes of linezolid such as cfr,optr A and the fifth functional region of 23 S rRNA were identified by PCR amplification and sequencing analysis. The genomic DNA of the isolated strains were analyzed by the whole genome sequencing,and the bioinformatic analysis of resistance genes and virulence genes were performed. The multilocus sequence typing( MLST) was used to obtain the sequence typing( ST) of the isolated strains. Results Only one( 0.1%) linezolid-resistant strain with 16 mg/L of MIC was detected in 905 strains of Staphylococcus aureus. The strain was susceptible to vancomycin and SMZ-TMP but resistant to other antibiotics used commonly. PCR and sequencing analysis showed that the strain carried cfr gene,and that there were nucleotide mutations of T2337 G and C2370 G in the fifth functional region of 23 S rRNA. The whole genome sequence analysis showed that the genome DNA of the strain consisted of 2 949 411 bp,and contained 3 023 genes,including 59 tRNA-encoding genes and 7 complete rRNA-encoding operons. This genome sequence was deposited in Gen Bank,and the accession number JAANYO000000000 was obtained. The strain carried multiple resistance determining genes such as cfr gene and virulence genes. MLST identified the strain as a new type of ST5985. Conclusion The clinical isolation rate of linezolid-resistant Staphylococcus aureus is low,and a new ST type strain of linezolid-resistant Staphylococcus aureus mediated by cfr gene and the mutation of the fifth functional region of 23 S rRNA is found.

关 键 词：金黄色葡萄球菌 利奈唑胺耐药 cfr基因 23S rRNA突变 全基因组测序 

分 类 号：R446.5[医药卫生—诊断学]