儿童医院相关性耐甲氧西林金黄色葡萄球菌感染的临床特征和分离株分子特征

Clinical and molecular characteristics of hospital-associated infection caused by methicillin-resistant Staphylococcus aureus in children

目的探讨儿童医院相关性耐甲氧西林金黄色葡萄球菌(MRSA)感染的临床特征和分离株的分子特征。方法收集2010至2016年首都医科大学附属北京儿童医院符合医院相关感染MRSA感染的病例资料和致病分离株。分析其临床特点,采用PCR和测序对分离株进行多序列分型(MLST)和spa分型,采用多重PCR进行SCCmec分型,同时检测毒力基因携带,并对菌株的药物敏感性进行分析。结果共纳入150例,中位年龄为18个月。肺炎(55.3%)为最常见的疾病,其次为皮肤软组织感染(46.0%)。所有菌株共获得16种ST分型,其中ST239(46%)和ST59(28%)为最常见的克隆,共获得3种SCCmec分型,其中SCCmecⅢ最常见,占52. 7%;获得32种spa分型,最常见的是t030 (22. 0%)和t437(23.4%)。所有菌株、MRSA-ST59和MRSA-ST239分离株的多重耐药率分别为84.0%、78.6%和81.2%。结论医院相关性MRSA感染常见于1岁以内婴儿,菌株的遗传背景复杂,最常见的流行克隆是ST239-SCCmecⅢ-t030和ST59-SCCmecⅣ-t437,菌株的多重耐药率高。

Objective To investigate the clinical and molecular characteristics of hospital-associated(HA)infections caused by methicillin-resistant Staphylococcus aureus(MRSA)in pediatric patients.Methods We collected clinical S.aurues isolates from the patients(<14 years old)with HA-MRSA infections from 2010 to 2016 at Beijing Children's Hospital.The medical records were retrospectively reviewed and collected.Isolates as HA-MRSA were further characterized by MLST,SCCmec and spa typing methods.Carriage of pvl genes were also detected.Antibiotic susceptibility test was performed to detect drug resistance to antibiotics.Results A total of 150 cases were collected,with a median age of 18 months.Pneumonia(55.3%)was the most common disease,followed by skin and soft tissue infections(46.0%).A total of 16 ST genotypes were obtained with common clones of ST239(46%)and ST59(28%).Three SCCmec types were detected and SCCmecⅢ was the predominant one,accounting for 52.7%.Thirty-two spa types were detected and t030(22.0%)and t437(23.4%)were the top two clones.The multidrug resistance rate for all isolates,MRSA-ST59 and MRSA-ST239 were 84.0%,78.6% and 81.2% respectively.Conclusion Hospital-associated MRSA infections were common in young children,and the genetic background was diverse.The most common clones were ST239-SCCmecⅢ-t030 and ST59-SCCmecⅣ-t437.The rate of multiple drug resistance was high in the isolates.