目的 了解广州地区儿童患者分离的社区获得性耐甲氧西林金黄色葡萄球菌(CA-MRSA)临床分离株的分子特征。方法 收集2009年—2014年我院分离获得的65株CA-MRSA临床分离株,PCR法检测杀白细胞素(PVL)基因阳性菌株,多位点基因序列类型(MLST)测定MRSA菌株的序列类型,多重PCR法对MRSA菌株进行葡萄球菌mec盒式染色体(SCCmec)分型。结果 65株CA-MRSA分离株中PVL基因阳性31株,阳性率47.69%;MLST分型表明以ST5933.84%(22/65)及ST8823.07%(15/65)为主;SCCmec分型中发现3种类型,分别为SCCmecⅡ 32.30%(21/65)、SCCmecⅣ 49.23%(32/65)及SCCmecⅤ 18.46%(12/65),未存在未能分型菌株。结论 广州地区儿童患者分离的CA-MRSA临床分离株的PVL基因阳性率相对较高,SCCmecIV型、V型可形成小范围内的流行,其基因表型存在多种ST分型。

Objective To investigate the molecular characteristic of Community-acquired Methicillin-resistant Staphylococcus aureus(CA-MRSA) isolates from pediatric patients in Guangzhou. Methods 65 non-duplicate strains of Community-acquired Methicillin-susceptible Staphylococcus aureus(CA-MSSA) isolated from our hospital in 2009-2014 were investigated. Panton-valentine leukocidin(PVL) gene was detected by polymerase chain reaction(PCR). The sequence type (ST) of each strain was determined by muhilocus sequence typing (MLST). The genotypes of staphylococcal cassette chromosome mec(SCCmec) of the CA-MRSA isolates were confirmed by multiplex PCR. Results Among 65 isolates of CA-MRSA, the positive rate of PVL genes was 47.69%(31／65). The most common MLST type was ST59 (n=22, 33.84%), followed by ST88 (n=15, 23.07%). Three SCCmec types were found. The most common type was SCCmecIV (49.23%, 32/65), followed by SCCmecⅡ (32.30%, 21/65) and SCCmecV (8.46%, 12/65). Conclusion The PVL gene-positive rate of CA-MRSA isolates in our hospitals is at a relatively high level. SCCmec type IV and SCCmec type V could spread among hospitals and cause a small scale epidemic. Their phenotypes have a variety of ST types.