新生儿侵袭性社区获得性耐甲氧西林金黄色葡萄球菌的临床及分子特点研究

Clinical and molecular characteristics of invasive community-acquired methicillin-resistant Staphylo- coccus aureus infection in Chinese neonates

目的研究新生儿侵袭性社区获得性耐甲氧西林金黄色葡萄球菌（communityacquired methicillin-resistant Staphylococcus aureus．CA。MRSA）感染的临床特征、分离株耐药性及分子特点。方法2014年1月—_2014年12月从国内6家儿童专科医院共收集到35例新生儿侵袭性CA．MRSA感染菌株，对其分离株进行多位点序列分型（MLST）、葡萄球菌染色体盒（SCCmec）、spa分型，采用琼脂稀释法对15种抗生素进行体外药物敏感试验。结果35例侵袭性CA．MRSA感染的新生儿中，88．6％的患儿是晚期新生儿，败血症（24，68．5％）是最主要的感染，16例（45．7％）患儿有并发症。ST59-MRSA。SCCmecIVa．t437（14，40％）是最主要的克隆，其次是ST59-MRSA．SCCmecV．t437（13，37．1％）。ST59．MRSA-SCCmecV-t437引起严重并发症的比例高于ST59-MRSA-SCCmecIVa-t437（P〈0．05），菌株多重耐药率高。结论新生儿侵袭性CA-MRSA感染以败血症为主，常为多脏器受累，伴有严重并发症，CA-MRSA多重耐药率高，ST59．MRSA-SCCmecⅣa-t437是新生儿CA．MRSA感染的主要克隆。

Objective To analyze the clinical and molecular features of community-acquired me- thicillin-resistant Staphylococcus attreus （CA-MRSA） infection in neonates and to investigate their antibiotic resistance profiles. Methods A total of 35 invasive CA-MRSA strains were collected from six hospitals in 2014. Multilocus sequence typing （MLST） , staphylococcal cassette chromosome mee （SCCmec） typing and spa typing were used to analyze these isolated CA-MRSA strains. In vitro antibiotic susceptibilities of those strains to 15 antibiotics were analyzed by using agar dilution method. Results Up to 88.6% patients were late-onset infection and septicemia （24, 68.5% ） was the most common infection among the 35 cases. A to- tal of 16 patients （45.7%） suffered from complications. Caesarean section and premature birth were risk factors for invasive CA-MRSA infection. ST59-MRSA-SCCmecIVa-t437 （14, 40% ） was the most predomi- nant CA-MRSA clone, followed hy ST59-MRSA-SCCmec V-t437 （13, 37.1% ）. The incidence of severe complications caused by ST59-MRSA-SCCmec V-t437 was higher than that caused by ST59-MRSA-SCCmec 1Va-t437 （P〈0.05）. Up to 85.7% of the isolated CA-MRSA strains were multidrug-resistant strains. Con- elusion This study shows that neonatal invasive CA-MRSA infections mainly result in septicemia and are often accompanied by complications and involve multiple organs. Muhidrug-resistant CA-MRSA strains are prevalent in neonates. ST59-MRSA-SCCmec IVa-t437 is the predominant clone causing neonatal invasive CA- MRSA infection.