儿童耐甲氧西林金黄色葡萄球菌感染分离株毒力特征研究  

Comparative analysis of the virulence characteristics of epidemic methicillin-resistant Staphylococcus aureus strains isolated from Chinese children

作　　者：董燕红[1] 李士朋[1] 乔艳红[1] 宁雪[1] 曾婷[1] 俞桑洁[1] 姚开虎[1] 高薇[1] 袁琳[1] 杨永弘[1] 沈叙庄[1] 

机构地区：[1]首都医科大学附属北京儿童医院,北京市儿科研究所,儿科学国家重点学科,省部共建儿科重大疾病研究重点实验室,100045

出　　处：《中华实用儿科临床杂志》2015年第10期733-737,共5页Chinese Journal of Applied Clinical Pediatrics

基　　金：国家自然科学基金（81061160509,81171648）

摘　　要：目的 探讨儿童耐甲氧西林金黄色葡萄球菌（MRSA）感染分离株的毒力特征.方法 收集2004年6月至2012年7月4家儿童医院分离的243株MRSA,采用PCR法对MRSA进行多位点序列分型（MLST）;按随机分层抽样法对136株菌进行42种毒力基因及4种重要毒力基因hla、psmα、RNAⅢ和pvl的表达水平检测.结果 MRSA分离株大多数来源于肺炎和皮肤软组织感染（SSTIs）,占88.1％（214/243株）.243株菌检测到22种MLST,6种主要流行克隆是ST59、ST239、ST1、ST910、ST88和ST338.131株菌（96.3％）至少含有1种超抗原基因.所有菌株均携带黏附基因中的fnbA、clfA和spa.所有菌株均携带hla,psmα和RNAⅢ,pvl的携带率为39％.pvl在ST59、ST910、ST338分离株中的携带率较ST239、ST1、ST88高（P均＜0.05）.hla、smα、RNAⅢ在ST59中的表达水平较其他分型高（P均＜0.05）.社区获得性MRSA （CA-MRSA）分离株pvl的携带率高于医院获得性MRSA（HA-MRSA）分离株（48.8％比24.1％,x2 =8.356,P=0.004）,但pvl表达水平比较差异无统计学意义（t=-0.777,P=0.441）.CA-MRSA分离株hla、smα和RNAⅢ的表达水平较HA-MRSA分离株高（P均＜0.05）.肺炎分离株fnbB的携带率明显高于SSTIs分离株（27.5％比12.7％,x2 =4.050,P=0.044）,而SSTIs分离株pvl的携带率明显高于肺炎分离株（52.7％比27.5％,x22=8.186,P=0.004）.侵袭性感染分离株的hla表达水平较非侵袭性感染高（=2.433,P=0.0163）.结论 儿童MRSA感染分离株的主要流行克隆间部分毒力基因携带存在差异.CA-MRSA较HA-MRSA高表达hla、psmα、RNAⅢ,尤其是ST59型,提示该型菌株可能具有较强的致病性.fnbB与肺炎、pvl与SSTIs可能有关.菌株高表达hla可能与侵袭性感染有关.Obgective To investigate the virulence characteristics of methicillin-resistant Staphylococcus aureus（MRSA） isolates from Chinese children.Methods A total of 243 MRSA isolates were collected from 4 hospitals from June of 2004 to July of 2012.Multilocus sequence typing was analyzed by PCR.A total of 136 strains were selected from 6 major STs of 243 isolates based on stratified sampling.The carriages of 42 virulence genes were tested.Expression levels of hla,psmα and RNA Ⅲ genes were also detected,as well as pvl.Results Most of MRSA isolates were from pneumonia and skin and soft tissue infections （SSTIs）,accounting for 88.1% （214/243 strains）.Twenty-two sequence types were obtained,and 6 epidemic clones were ST59,ST239,ST1,ST910,ST88 and ST338.It was found that 96.3% strains（131/136 strains） contained at least one superantigen gene.All isolates were presented with fnbA,clfA and spa genes.All these 136 isolates all had hla,psmα and RNAⅢ.The percentage ofpvlgene was 39%.The pvl gene was more frequent in ST59,ST910,ST338 than in ST239,ST1,ST88（all P 〈0.05）.The expression levels of hla,psmα and RNA Ⅲ were higher in ST59 than in other STs（all P 〈0.05）.Thepvl gene was more associated with community acquired MRSA（CA-MRSA） than with hospital acquired MRSA（HA-MRSA） （48.8% vs 24.1%,x2 =8.356,P =0.004）,but there was no statistically significant difference in their expression levels （t =-0.777,P =0.441）.CA MRSA expressed hla,psma,and RNA Ⅲ in much higher levels （P 〈 0.05）.The fnbB gene was more associated with pneumonia than with SSTIs （27.5% vs 12.7%,x2 =4.050,P =0.044）,while the pvl gene was more associated with SSTIs than with pneumonia （52.7 % vs 27.5 %,x2 =8.186,P =0.004）.Expression of hla in isolates from invasive infections was higher than that in isolates from non-invasive infections（t =2.433,P =0.0163）.Conclusions The distribution of virulence genes among epidemic MRSA strains isolated from children was different.CA-MRSA expressed hla,psmα,and R

关 键 词：耐甲氧西林金黄色葡萄球菌 儿童 毒力 基因 表达 

分 类 号：R446.5[医药卫生—诊断学]