摘要
目的 研究细胞壁锚定蛋白编码基因sasX在金黄色葡萄球菌中的分布及对细菌耐药性的影响.方法 随机收集上海华山医院2004、2007和2010年从金黄色葡萄球菌感染的住院患者标本中分离鉴定的金黄色葡萄球菌共300株,收集同时期社区健康人群的鼻咽拭子分离鼻腔内定植的金黄色葡萄球菌170株.按照国际通用的MLST以及葡萄球菌A蛋白序列分析（spa typing）方法进行克隆株的鉴定分析.通过苯唑西林MIC值测定方法对MRSA进行检测.采用PCR结合测序方法对金黄色葡萄球菌携带sasX基因情况进行分析,采用纸片琼脂扩散法药敏试验分析临床sasX阳性和sasX阴性金黄色葡萄球菌对抗菌药物的耐药性.结果 300株从金黄色葡萄球菌感染的住院患者标本中分离到的致病性金黄色葡萄球菌克隆分型以ST239（110株,36.7％）和ST5（122株,40.7％）为主.2004至2010年,sasX基因在致病性的金黄色葡萄球菌中的阳性率从17％上升至39％,sasX基因在健康人鼻腔内分离的金黄色葡萄球菌中阳性率平均为0.59％.ST239中sasX的阳性率从47.2％上升至83.8％.携带sasX基因的MRSA百分率从26.4％上升至50.8％,携带sasX基因的MSSA的比率只约占10％.sasX基因阳性组对部分目前临床常用的抗菌药物的耐药性高于sasX基因阴性组.结论 sasX基因主要存在于医院环境内致病性的金黄色葡萄球菌中,SasX可能是金黄色葡萄球菌在医院环境内持续感染毒力因子之一,sasX基因的存在与细菌的耐药有关.
Objective To investigate the distribution and effect on antibiotic resistance of the novel cell wall anchored protein-encoding gene sasX.Methods A total of 300 S.aureus isolates were randomly collected from inpatients with S.aureus infection in Shanghai Huashan hospital in 2004, 2007 and 2010.Meanwhile,170 S.aureus isolates from the nasal swabs of healthy people were collected as part of a population-based community prevalence study.Typing of S.aureus isolates were identified by using multilocus sequence typing （MLST） and S.aureus-specific staphylococcal protein A typing （spa typing）.Determination of oxacillin MICs was used to screen MRSA.PCR and sequencing were used to analyze sasX gene.The effect on antibiotic resistance of sasX gene was detect by disc agar diffusion drug sensitive test.Results The major clonal types of the 300 S.aureus isolates collected from inpatients with S.aureus infection were ST239 （ 110,36.7%） and ST5 （122,40.7%）.From 2004 to 2010,the percentage of isolates from inpatients with S.aureus infection was increased from 17% to 39%,but sasX was only found in 0.59% of the S.aureus isolates from the nasal swabs of healthy people.The percentage of sasX positive was increased from 47.2% to 83.8% in ST239.The percentage of sasX positive MRSA was increased from 26.4% to 50.8%,but the percentage of sasX positive MSSA was about 10%.Antibiotic resistance of sasX positive strains were higher than that of sasX negative strains.Conclusions SasX gene is mainly detected in nosocomial pathogenic S.aureus and it is a possible virulence factor of S.aureus in hosptal setting.The presence of sasX gene is related to antibiotic resistance.For better understanding the real function of this novel gene,further studies such as expression of the encoded protein should be carried out.
出处
《中华检验医学杂志》
CAS
CSCD
北大核心
2011年第12期1093-1097,共5页
Chinese Journal of Laboratory Medicine
基金
上海市浦江人才计划（A）类资助项目（09PJ1402300）
国家自然基金资助项目（30900026和81171623）
