B族链球菌皮肤软组织及创伤感染分离株的耐药基因检测

Detection of erythromycin and tetracycline resistant-related genes in skin and soft tissue infection due to group B streptococci

目的了解皮肤软组织及创伤感染的B族链球菌(GBS)的耐药性及耐药基因存在的特点。方法采用聚合酶链反应(PCR)方法对分离自皮肤软组织及创伤感染的132株GBS进行红霉素及四环素等11种耐药基因的检测;药物敏感试验及克林霉素诱导型(MLSB)耐药表型采用琼脂纸片扩散(K-B)法、D-试验法检测。结果皮肤软组织及创伤感染的GBS红霉素耐药基因以ermB为主,占25.0%,ermA、ermC、ermM、ermTR、mefA、mefE基因的阳性率分别为3.8%、8.3%、1.5%、9.0%、32.6%、38.6%;同时含2种或2种以上erm基因阳性的GBS占22.5%;耐药表型以结构型耐药(红霉素耐药、克林霉素耐药,cMLSB)为主(31株,占红霉素耐药GBS的50.0%);四环素耐药基因tetM、tetO、tetK、tetL阳性率分别为64.0%、47.2%、13.2%、40.0%;未发现对青霉素、氨苄青霉素、替考拉宁、万古霉素、利奈唑胺、奎诺普汀/达福普汀耐药菌株,但青霉素、氨苄青霉素的中介率分别是11.2%、6.8%;红霉素、克林霉素、四环素耐药率分别为47.0%、46.2%、86.4%。结论 ermB基因是皮肤软组织及创伤感染的GBS对红霉素耐药的重要基因,检出国内少见报道的ermC、ermM、ermTR基因。青霉素、氨苄青霉素仍可作为治疗皮肤GBS感染的首选药物;对于过敏体质的患者,红霉素和克林霉素作为预防和治疗皮肤GBS感染的药物应用价值应给予重新评价。

Objective To examine erythromycin and tetracycline resistance-related genes and phylogenetic analysis in group B streptococci 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,and streptogramin B antibiotics. Simultaneously, eleven genes encoding ermA, ermB, ermC, ermM, ermTR, mefA, merE, tetM, tetO, tetK,tetL antibiotic resistance-related genes were detected by PCR. Results ermB were determined in 25~//oo of the strains. PCR showed the positive rates o f ermA, ermC, ermM, ermTR, mefA,mefE genes were 3.8%,8. 3%, 1. g%, 9. 0%, 32. 6%, 38. 6%. TetM, tetO, tetK, tetL were determined in 64.0 %, 47.2 %, 13.2 %, 40.0 % of the strains. All GBS were susceptible to penicillin, ampicilin, linezolid, Quinipristin/Dalfo and vancomycin. Resistance to clindamycin （46. 2 %）, erythromycin （47. 0 %）, tetracycline （86.4%）was observed. Conclusion The ermB were important erythromycin resistance determinants in GBS. There is little infor- mation about ermC,ermM, ermTR, and tet genes described in GBS. The susceptibility of GBS isolates to penicillin and ampicilin suggests use of penicillin onto bene（N. B. ）as a first-line drug in prophylactic treatment regimes against early onset neonatal GBS disease. In Guangzhou, erythromycin and clindamycin should not be recommended as the second-line antmicrobial. There were a high erythromycin and tetracycline resistance rate and the cross resistance to macrolide-lincosamide-streptogramin B-resistant.