葡萄球菌属诱导型克林霉素耐药及基因型分析

Inducible resistance of erythromycin to clindamcycin and resistance genes in Staphylococci

目的测定葡萄球菌属对红霉素及克林霉素的耐药性,分析红霉素诱导克林霉素耐药的发生率以及耐药基因的类型。方法用K-B法检测葡萄球菌属对红霉素及克林霉素的耐药性,依据CLSI2011年推荐的D试验方法,测定红霉素对克林霉素的诱导耐药表型,并采用聚合酶链反应PCR技术检测耐药基因型。结果2009~2011年红霉素和克林霉素同时耐药（cMLSB）菌株占葡萄球菌的比例分别是48.9%、52.0%、61.2%,随着时间的增长有升高的趋势。而D试验阳性（iMLSB）菌株占所检测葡萄球菌属的比例随着时间的增长有下降的趋势,分别是19.6%、18.5%、11.9%。这两种趋势在金黄色葡萄球中表现尤为明显。D试验阳性（iMLSB）菌株在对红霉素耐药而克林霉素敏感的葡萄球菌株所占的比例在三个不同时间段分别是58.2%、56.6%、56.5%。耐药基因分析表明：红霉素核糖体甲基化酶基因ermC是诱导耐药的主要基因。结论临床微生物实验室应开展D试验,检测葡萄球菌属中红霉素对克林霉素的诱导耐药,指导临床医生更合理使用抗菌药物。

Objective To detect the resistance of Staphylococci to erythromycin＂ and Clindamycin, and analyze the prevalence and resistance gene for inducilb resistance in Staphylococci.Methods The susceptibilities to erythromycin and clindamycin for Staphylococci were examined by Kirby-Bauer disc agar diffusion test and the inducible resistance of erythromycin to clindamycin was checked by D-test according to the standards of CLSI 2011,erm genes were detected by using PCR technology.Results Co-resistance strains to erythromycin and clindamycin accounted for 48.9%, 56.6% and 56.5% in the years-2009, 2010 and 2011 respectively, showing a yearly increasing trend. The rate of D-test positive exhibited a downward trend with the passage of time, registering 19.6%, 18.5% and 11.9% in the corresponding years respectively.Both trends were especially remarkable in Staphylococcus aureus.The rate of D-test positive Staphylococcus strains which were erythromycin resistant and clindamycin sensitive was 58.2%,56.6% and 56.5% respectively in the examined three years. The ermC gene was the major factor of erythromycin＇ s inducible resistance to clindamycino Conclusions The inducible resistance of erythromycin to clindamycin in Staphylococci should be detected by D-test in clinical microbiology laboratory in order to guide physicians to select reasonable antibiotics for Staphylococcal infections.