侵入性感染B族链球菌对红霉素及四环素的耐药基因检测

Detection of Erythromycin and Tetracycline Resistance-related Genes in Invasive Infections due to Group B Streptococci

目的了解侵入性感染B族链球菌(GBS)的耐药性及耐药基因谱特点。方法分别采用K-B法、D试验法检测204株GBS对抗菌药物的耐药性和克林霉素诱导型(MLSB)耐药表型,并同时采用聚合酶链反应(PCR)方法检测红霉素及四环素耐药基因ermA、ermB、ermC、ermM、ermTR、mefA、mefE、tetM、tetO、tetK、tetL与红霉素及四环素耐药性的关系。结果红霉素、克林霉素、四环素、氯霉素耐药率分别为44.1%、42.7%、83.7%、18.1%;青霉素、万古霉素未发现耐药菌株;红霉素耐药基因以ermB为主,占71.1%,检出国内未见报道的ermC基因11株及少报道的ermTR基因阳性13株;含≥2种erm基因阳性的GBS占27.8%,有1株GBS不含上述红霉素耐药基因的任何一种基因,但仍对红霉素耐药;四环素耐药基因以tetM和tetO为主,分别为70.5%、56.8%,含≥2种tet基因占72.7%;GBS在围生期以外的感染率不断上升。结论 GBS对红霉素、四环素具有较高的耐药率;ermB是GBS对红霉素耐药的重要基因,在GBS中检出国内未见报道的ermC,GBS对红霉素耐药还存在其他的耐药机制。

OBJECTIVE To examine antibiotic resistance phenotype,and the erythromycin and tetracycline resistance-related genes in group B streptococci（GBS）isolates from the First Municipal People＇s Hospital of Guangzhou.METHODS Antibiotic sensitivity test in GBS was done according to Kirby-Bauer method of NCCLS 2007.The D test for detecting phenotypic resistance in macrolide-lincosamine-streptogramin B antibiotics.Simultaneously,eleven genes encoding ermA,ermB,ermC,ermM,ermTR,mefA,mefE,tetM,tetO,tetK,and tetL antibiotic resistance-related genes were detected by PCR.RESULTS All GBS were susceptible to penicillin and vancomycin.Resistance to erythromycin（44.1%）,clindamycin（42.7%）,tetracycline（83.7%）and chloramphenicol（18.1%）was observed.ermB was determined in 71.1 % of the strains.Eleven strains contained ermC.There was 1 strain showed resistance without any of the seven erythromycin resistance-related genes.tetM and tetO were determined in 70.4% and 56.8% of the strains.CONCLUSIONS There are a high erythromycin and tetracycline resistance rate and the cross resistance to macrolide-lincosamide-streptogramin Bantibiotics.The ermB is an important erythromycin resistance determinant in GBS.