克林霉素诱导耐药B族链球菌同源性和耐药基因分析

Homology and drug resistance genes of clindamycin-induced drug-resistant group B Streptococcus

目的探讨克林霉素诱导耐药B族链球菌(Group B streptococcus,GBS)同源性和耐药基因。方法选取2015年12月-2019年12月674名于新乡市中心医院接受产前检查孕妇为研究对象,记录孕妇年龄、产次、流产史情况;收集孕妇泌尿生殖道标本进行GBS培养鉴定,对培养分离出的GBS菌株进行药敏试验,采用多位点序列分型方法确定菌株的序列型,PCR方法检测红霉素耐药基因mefA和ermB。结果 674名孕妇GBS感染阳性率为8.90%(60/674),不同年龄、产次、流产史孕妇GBS阳性率比较差异无统计学意义;60株GBS对青霉素、万古霉素、头孢吡肟、头孢噻肟以及利奈唑胺的耐药率均为0.00%,对红霉素和克林霉素的耐药率分别为61.67%和58.33%;克林霉素诱导耐药GBS菌株包含11种ST型,其中ST12占31.7%(19/60),ST19占25.0%(15/60);60株GBS中红霉素耐药基因mefA、ermB检出率分别为26.7%(16/60)和40.0%(24/60)。结论克林霉素诱导GBS耐药性具有遗传多样性,不同基因型的耐药性亦有较大差距。

OBJECTIVE To explore the homology and drug resistance genes of clindamycin-induced drug-resistant group B Streptococcus(GBS).METHODS A total of 674 pregnant women who received prenatal care in the Xinxiang Central Hospital from Dec 2015 to Dec 2019 were recruited as the study objects,the age,number of birth and history of abortion of the pregnant women were recorded,the urogenital tract specimens were collected from the pregnant women so as to carry out the culture and identification of GBS,the drug susceptibility testing was performed for the isolated GBS strains,the sequence types of the strains were determined by using multi-locus sequence typing method,and the erythromycin resistance genes mefA and ermB were detected by means of PCR.RESULTS Of the 674 pregnant women,8.90%(60/674)were tested positive for GBS,and there was no significant difference in the positive rate of GBS among the pregnant women with different age,number of birth or history of abortion.The drug resistance rates of 60 strains of GBS to penicillin,vancomycin,cefepime,cefotaxime and linezolid were 0,and the drug resistance rates to erythromycin and clindamycin were 61.67%and 58.33%,respectively.The clindamycin-induced drug-resistant GBS strains contained 11 ST types,31.7%(19/60)of which were ST12,25.0%(15/60)were ST19.Among the 60 strains of GBS,the detection rates of erythromycin resistance genes mefA and ermB were 26.7%(16/60)and 40.0%(24/60),respectively.CONCLUSION The clindamycin-induced drug-resistant GBS strains are characterized by genetic diversity,and there is significant difference in the drug resistance among the strains of different genotypes.