南方医科大学学报

南方医科大学学报 ›› 2017, Vol. 37 ›› Issue (07): 861-.

• •    下一篇

医院获得性感染中出现携带SCCmec Ⅳ/Ⅴ的耐甲氧西林金黄色葡萄球菌

钟一鸣，袁瑞，丁健生，杨芳，刘文恩   

  • 出版日期:2017-07-20 发布日期:2017-07-20

Emergence of methicillin-resistant Staphylococcus aureus SCCmec type IV/V epidemic clones in a large teaching hospital in China

  • Online:2017-07-20 Published:2017-07-20

HTML

PDF

648

摘要： 目的研究某院临床分离的医院获得性耐甲氧西林金黄色葡萄球菌（HA-MRSA）的葡萄球菌染色体mec盒（SCCmec）分型 及分子流行病学特征。方法收集中南大学湘雅医院2012年1月~2012年12月临床分离的71株HA-MRSA，采用多重PCR进 行SCCmec 分型，PCR 检测PVL 毒素基因，并用脉冲场凝胶电泳（PFGE）分析菌株间的同源性。结果71 株HA-MRSA 以 SCCmec Ⅲ型为主，占69.0%（49/71），其次为SCCmec Ⅳ型、SCCmec Ⅴ型和SCCmecⅡ型，分别占14.1%（10/71）、4.2%（3/71）和 4.2%（3/71），另有6株（8.5%）菌株未能分型。HA-SCCmec Ⅳ/Ⅴ MRSA感染者年龄显著低于HA-SCCmec Ⅰ/Ⅱ/Ⅲ MRSA感染 者，携带PVL基因阳性率显著高于HA-SCCmecⅠ/Ⅱ/Ⅲ MRSA感染者，而两者入院至检出菌株的时间及住院天数均未见明显 差异。HA-SCCmec Ⅳ/Ⅴ MRSA对左旋氧氟沙星、环丙沙星、利福平、庆大霉素、四环素等的耐药率均显著低于HA-SCCmecⅠ/ Ⅱ/Ⅲ MRSA（P<0.05）。13株HA-SCCmec Ⅳ/Ⅴ MRSA菌株在55%的相似度水平形成一个大的组群。按照≥85%的相似度，这 些菌株共形成3 个PFGE 簇以及4 个单一菌株的PFGE 型。结论在国内首次发现携带SCCmec Ⅴ型的HA-MRSA 菌株， HA-SCCmec Ⅳ/Ⅴ MRSA已有在医疗机构传播的趋势，并成为医院内感染的重要来源。

Abstract: Objective To investigate the staphylococcal cassette chromosome mec (SCCmec) genotype and molecular epidemiological characteristics of healthcare-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) in a large teaching hospital in China. Methods From January 2012 to December 2012, a total of 71 nonduplicate HA-MRSA were collected in a teaching hospital in Changsha, China. SCCmec types were determined by multiplex PCR, and Panton-Valentine leukocidin (PVL) gene was detected by PCR. The homology among the tested isolates was determined using pulsed-field gel electrophoresis (PFGE). Results Of the 71 HA-MRSA isolates, 49 (69.0%) carried SCCmec III, 10 (14.1%) carried SCCmec IV, 3 (4.2%) carried SCCmec V and 3 (4.2%) carried SCCmec II; the remaining 6 isolates were not typeable by PCR. Compared with patients having SCCmec I/II/III MRSA infections, those with SCCmec IV/V MRSA infections had a significantly younger age and a similar duration of hospital stay before the first MRSA-positive culture and total hospital stay. PVL genes were strongly associated with SCCmec type IV/V MRSA infections. HA-SCCmec IV/V MRSA strains showed a greater susceptibility to rifampicin, gentamicin, levofloxacin, ciprofloxacin, and tetracycline than HA-SCCmec I/II/III MRSA strains. The 13 HA-SCCmec IV/V MRSA isolates formed one large group at the 55% similarity level. Three PFGE clusters with a similarity index of 85% or more were identified, and unique PFGE profiles were observed in 4 isolates. Conclusions This is the first report of HA-MRSA isolates carrying SCCmec V in Chinese hospitals. SCCmec types IV and V MRSA clones have emerged in Chinese hospitals, which urges more rigorous surveillance of their spread in healthcare facilities in China.