摘要
目的研究耐甲氧西林凝固酶阴性葡萄球菌（MRCoNS）临床分离株对利奈唑胺的耐药机制及分子流行病学。方法2011年3—8月我院分离到17株对利奈唑胺耐药的MRCoNS，包括10株头状葡萄球菌、4株科氏葡萄球菌、2株溶血葡萄球菌和l株松鼠葡萄球菌。用E-test法测定抗生素对细菌的最低抑菌浓度（MIC）；脉冲场凝胶电泳（PFGE）分析菌株之间的同源性；PCR扩增和序列分析研究细菌对利奈唑胺耐药的分子机制。结果9株利奈唑胺MIC值为〉256斗g／ml的头状葡萄球菌为同一克隆株，MIC值为4μg／ml的另1株头状葡萄球菌为密切相关菌株。4株利奈唑胺MIC值为〉256μg／ml的科氏葡萄球菌为同一克隆株。松鼠葡萄球菌利奈唑胺MIC值为64μg／ml，2株溶血葡萄球菌分别为4μg/ml和6μg/ml。对23SrRNA基因第5功能区和驴基因进行PCR扩增和测序发现，9株利奈唑胺MIC值为〉256μg/ml的头状葡萄球菌的23SrRNA基因第5功能区存在常见G2576T突变和一个未报道过的C2104T突变；松鼠葡萄球菌存在G2576T突变；除松鼠葡萄球菌外，其余16株菌株均携带驴基因。结论首次报道在国内分离到利奈唑胺耐药的葡萄球菌临床菌株。MRCoNS对利奈唑胺耐药与23SrRNA基因第5功能区碱基突变和携带驴基因相关。利奈唑胺耐药MRCoNS在我院有克隆传播现象。
Objective To investigate the linezolid resistance mechanisms and molecular epidemiology of clinical isolates of methicillin-resistant coagulase-negutive staphylococci （MRCoNS）. Meth- ods Seventeen MRCoNS, including 10 S. capitis, 4 S. cohnii, 2 S, haemolyticus, and 1 S. sciuri with va- rious levels of linesolid resistance were isolated from intensive care units in our hospital from March to August 2011. Minimal inhibitory concentration （MIC） was determined by E-test method. Pulsed-field gel electrophoresis was performed to analyze the molecular epidemiology. PCRs and DNA sequencing were pre- formed to investigate the mechanisms of linesolid resistance in MRCoNS. Results Nine S. capitis with lin- ezolid MIC of 〉256 p,g/ml were indistinguishable, and another S. capitis with linezolid MIC of 4 μg/ml was closely related. Four .5. cohnii with linezolid MIC of 〉256 μg/ml were belonged to the same clonal strain. MIC of linezolid for S. sciuri was 64 μg/ml, and were 4 μg/ml and 6 μg/rnl for 2 S. haemoly^icus, respec- tively. A commom G2576T mutation and a novel C2104T mutation were identified in 9 S. capitis with lin- ezolid MIC of 〉256 μg/ml by DNA sequence analysis of domain V of the 23S rRNA gene. cfi gene was de- tected in all staphylococci except a S. sciuri whose 23S rRNA gene contained the G2576T mutation. Conclu- sion It is the first report of linezolid-resistant clinical isolates of staphylococci in China. Linezolid resist- ance in MRCoNS is related to the presence of DNA mutation in domain V of the 23S rRNA gene and cfr gene. It＇s a clonally dissemination of linezolid-resistant MRCoNS in intensive care units of our hospital.
出处
《中华微生物学和免疫学杂志》
CAS
CSCD
北大核心
2012年第6期532-536,共5页
Chinese Journal of Microbiology and Immunology
