新生儿科医务人员鼻拭子与临床分离MRSA的分子分型

Molecular clasification of methicillin resistant Staphylococcus aureus strains isolated from nose swabs of medical staff in neonatal department and clinic

目的了解深圳市儿童医院新生儿临床分离株和该科医务人员鼻拭子耐甲氧西林金黄色葡萄球菌(MRSA)的分子生物学特征及耐药性。方法收集新生儿科临床分离的MRSA以及新生儿科医务人员鼻拭子分离的MRSA 26株,对其进行多位点基因分型(MLST分型)、spa分型、SCCmec分型及脉冲场凝胶电泳(PFGE),同时检测pvl基因,并进行14种抗菌药物药敏试验。结果在26株MRSA中,痰占53.8%,医务人员鼻拭子筛查检出2株。MLST分型共5种,其中ST59占76.9%。spa分型有8种,t437占65.4%。SCCmec分型只有2种,SCCmecⅣ型20株(76.9%)、SCCmecV 4株(15.4%)。PVL基因检测,pvl阳性率15.4%。通过PFGE分析,从新生儿科护理人员的鼻拭子分离的一株MRSA与一株从患者分离的菌株100%同源。药敏试验结果显示所有MRSA对呋喃妥因、奎奴普丁/达福普汀、万古霉素、喹诺酮类抗菌药物100%敏感,而对红霉素、克林霉素和四环素耐药率较高,均在50%以上。结论本研究新生儿科临床分离的MRSA中,最常见的克隆是MRSA-ST59-SCCmecⅣ-t437,在新生儿MRSA的经验性治疗中不宜首选红霉素和克林霉素。

Objective To understand the biological characteristicsand drug resistance of methicillin-resistant staphylococcus aureus（MRSA）isolated from neonatal clinic and the nose swabs of medical staff in the neonatal department.Methods Twenty-six strains of MRSA clinically isolated from the neonatal department and the nose swabs of medical staff in this department were collected and performed the multilocus sequence typing（MLST）,spa typing,staphylococcus cassette chromosome mec（SCCmec）typing and pulsed-field gel electrophoresis（PFGE）typing.The Panton-Valentine leukocidin（PVL）gene was simultaneously detected.The antimicrobial susceptibility test of 14 antibacterial dugs was performed.Results Among 26 strains of MRSA,53.8% was isolated from sputum,2strains were detected from the nase swab of medical staff.The MLST type had 5types,ST59 accounted for76.9%.The spa type had 8types,t437 acoounted for 65.4%.the SCCmec type had only 2types,20 strains were SCCmecⅣ（76.9%,20/26）and 4strains（15.4%）were SCCmecV.In the PLV gene detection,the PVL positive rate was 15.4%.One strain of MRSA from the nose swabs of medical staff in the neonatal department was100% homologous with 1strain from the patient by PFGE analysis.The drug susceptibility test results showed that all MRSA strains were 100% sensitive to antibacterial drugs of nitrofurantoin,quinupristin/dalfopristin,vancomycin and quinolone,while had higher resistance rates to tetracycline,erythromycin and clindamycin,which were above 50%.Conclusion In MRSA strains isolated from the neonatal department in this study,the most common clones were MRSA-ST59-SCCmecⅣ-t437.Erythromycin and clindamycin should not be preferred in the empiric treatment of newborn MRSA.