表皮葡萄球菌对大环内酯-林可酰胺-链阳菌素B的耐药基因型及同源性分析  

Analysis on genotypes and their epidemiology of MLS_B resistant Staphylococcus epidermidis isoloates causing nosocomial infections

作　　者：贾宁[1] 徐志凯[2] 白立彦[3] 索继江[1] 邢玉斌[1] 

机构地区：[1]解放军总医院感染管理与疾病控制科,北京100853 [2]第四军医大学微生物学教研室,北京100853 [3]解放军总医院微生物科,北京100853

出　　处：《中华检验医学杂志》2007年第4期399-402,共4页Chinese Journal of Laboratory Medicine

基　　金：国家自然科学基金(30300296)

摘　　要：目的深入了解引发医院感染的表皮葡萄球菌(简称"表葡菌")对大环内酯-林可酰胺一链阳菌素 B(MLS_B)类抗生素的耐药机制。方法收集2003—2004年北京3家综合医院126株引发医院感染的表葡菌,检测其在红霉素(ERY)、克林霉素(CLI)、喹努普丁/达福普丁中的 MIC;用 D试验区分诱导型(iMLS_B)和泵出型(MS)耐药菌株。采用 PCR 检测 ermA、ermB、ermC、msrA 和 mecA耐药基因,并用脉冲场凝胶电泳(PFGE)进行同源性分析。结果 126株菌株对 ERY 和 CLI 耐药率高(分别为92.8%和84.1%);在结构型(cMLS_B)中,耐甲氧西林表葡菌(MRSE)占78.5%,而 iMLS_B中甲氧西林敏感株(MSSE)较多,占69.2%;ermC 不仅在 MRSE 和 MSSE 中是最常见的耐药基因(70.8%和56.8%),而且在 iMLS_B 型和 cMLS_B 型中也占多数(76.9%和90.3%);所有 MS 型菌株均检测出 msrA;在 ERY 敏感菌株中未检测出相关耐药基因。PFGE 分析显示,无特异的流行株;99.2%MLS_B耐药表型相同的菌株分布于 A～F型中,且无显著集中趋势。结论导致医院感染的126株菌株对MLS_B 类抗生素耐药率高,ermC 是其常见耐药基因,对 MLS_B 抗生素使用需谨慎、合理。Objective To determine the genotypes and their epidermiology of microlide, lincosamide and streptogramin B （MLSB ） resistant S. epidermidis isolates causing nosocomial infection. Method 126 isolates were collected from inpatients in three hospitals in Beijing from 2003 - 2004 for testing the antibiotic susceptibility to the macrolide erythromycin, the lincosamide clindamycin. The resistance phenotypes of erythromycin-resistant isolates were determined by the double-disc test with erythromycin and clindamycin. The presence of the relative genes （ ermA, ermB, ermC and msrA） to MLSB resistance was identified by PCR and the similarity of the isolates was analyzed by PFGE. Result The isolates were mostly resistant to macrolide and lincosamide. In the constitutive phenotype cMLSB isolates, the methieillin resistant S. epidermidis （MRSE） proportion appeared high（78.5% ） , whereas high methieiliin susceptible S. epidermidis （MSSE） proportion was found in the inducible MLSB phenotype （iMLSB ） （69. 2% ）. ermC was shown as the most frequent determinant to the resistance,not only in MRSE and MSSE （70. 8% and 6. 8% ） ,but also in iMLSB and cMLSs（76. 9% and 90. 3% ）. No specific endemic strain was found by PFGE analysis. The same resistance phenotype pattern was not clustered together and distributed into type A - F at the similarity of 60%. Among the phenotypes （ cMLSB, iMLSB and MS phenotype）, no significant difference was shown in the PFGE genotype distribution. Conclusion Our results indicate that the MLSB resistance in S. epidermidis causing nosocomial infection is prevalent in the hospital and MLSB antibiotics should be used judiciously, ermC was shown as the most frequent determinant to the resistance.

关 键 词：交叉感染 葡萄球菌 表皮 电泳 凝胶 脉冲场 

分 类 号：R450[医药卫生—治疗学]