健康儿童鼻携带MRSA SCCmec分型及耐药性分析

SCCmec Types and Drug Resistance of MRSA Nasal Carried by Healthy Children

目的:了解健康儿童耐甲氧西林金黄色葡萄球菌(MRSA)染色体mec基因盒(SCCmec)基因分型及其对抗生素的耐药性。方法:自2011年3-5月收集广州荔湾区463名幼儿园儿童及1 012名小学生鼻拭子进行金黄色葡萄球菌分离鉴定,用头孢西丁药敏纸片鉴定MRSA,并对阳性菌株进行药敏检测;采用多重聚合酶链反应(M-PCR)对MRSA进行SCCmec基因分型。结果:1 475名儿童中共检出28株MRSA,SCCmecⅢ型1株(3.6%)、SCCmecⅣa型24株(85.7%)、SCCmecⅤ型3株(10.7%)。39.3%的MRSA菌株(11株)呈多药耐药状态,最常见的耐药模式是青霉素-红霉素-克林霉素-四环素。28株MRSA对利福平、复方磺胺甲唑、利奈唑胺及万古霉素均敏感。结论:在健康儿童鼻前庭中既携带有社区相关MRSA(CA-MRSA)菌株,亦携带医院相关MRSA(HA-MRSA)。MRSA呈多药耐药状态,青霉素、红霉素、克林霉素、四环素不宜作为经验用药之首选。

OBJECTIVE： To explore Staphylococcal cassette chromosome mec （SCCmec） type and antibiotic susceptibility of methicillin-resistant Staphylococcus aureus （MRSA） nasal carried by healthy children in the school. METHODS： Nasal swabs were collected from 463 children in kindergarten and 1 012 primary scholar from Guangzhou Liwan district during Mar.--May in 2011. S. aureus were isolated and identified, and MRSA was identified with cefoxitin disk test. The antibiotic susceptibility test was con- ducted among positive strains. The SCCmec types were analyzed by multiplex polymerase chain reaction （M-PCR）. RESULTS： 28 MRSA isolates were detected among 1 475 samples, including 1 strain of SCCmec Ⅲ type （3.6%）, 24 strains of SCCmec IVa type （85.7%）, 3 strains of SCCmecV （10.7%）. 39.3% MRSA isolates （11 strains） had the characteristic of multidrug resistance, and the most common resistant pattern was penicillin-erythromycin-clindamycin-tetracycline. All of the MRSA isolates were sensi- tive to rifampcin, Compound sulphamethoxazole, linezolid and vancomycin. CONCLUSIONS： The investigation reveals that not only community-associated MRSA （CA-MRSA） but also healthcare-associated MRSA （HA-MRSA）have been detected in nasal fos- sae among healthy children. MRSA has the characteristic of multidrug resistance. Penicillin, erythromycin, clindamycin and tetracy- cline should not be used as the empirical therapy for MRSA community infections any more.