食源性耐甲氧西林金黄色葡萄球菌表型及分子流行病学特征  

Phenotypic and molecular epidemiological characteristics of foodborne methicillin-resistant Staphylococcus aureus

作　　者：王君 马鑫鑫 陈晓草 胡豫杰 陈雅丽[4] 纪建军[5] 贺金明 刘新利 韩蓓 WANG Jun;MA Xinxin;CHEN Xiaocao;HU Yujie;CHEN Yali;JI Jianjun;HE Jinming;LIU Xinli;HAN Bei(School of Public Health,Health Science Center,Xi'an Jiaotong University,Xi'an,Shaanxi 710061,China;Center for Disease Control and Prevention of Tongchuan,Tongchuan,Shaanxi 727031,China;National Health Commission Key Laboratory of Food Safety Risk Assessment of Health,China National Center for Food Safety Risk Assessment,Beijing 100021,China;Center for Disease Control and Prevention of Hanzhong,Hanzhong,Shaanxi 723000,China;Center for Disease Control and Prevention of Yan'an,Yan'an,Shaanxi 716000,China)

机构地区：[1]西安交通大学医学部公共卫生学院,陕西西安710061 [2]铜川市疾病预防控制中心,陕西铜川727031 [3]国家食品安全风险评估中心国家卫生健康委员会食品安全风险评估重点实验室,北京100021 [4]汉中市疾病预防控制中心,陕西汉中723000 [5]延安市疾病预防控制中心,陕西延安716000

出　　处：《中国热带医学》2024年第11期1349-1356,共8页China Tropical Medicine

基　　金：陕西省卫生科研基金项目(No.2018E007)。

摘　　要：目的分析食源性耐甲氧西林金黄色葡萄球菌(methicillin-resistant Staphylococcus aureus,MRSA)耐药性、毒力、生物膜及分子流行病学特征,为开展食源性病原微生物风险评估提供数据支撑。方法对2019—2020年陕西省市售食品中分离的21株食源性MRSA进行药物药敏性试验,脉冲场凝胶电泳(pulsed field gel electrophoresis,PFGE)分析,多位点序列分型(multilocus sequence typing,MLST)、spa、SCCmec分型,生物膜形成能力测定,大蜡螟毒力测定;通过全基因测序分析菌株耐药基因、毒力基因、质粒及可移动遗传元件携带情况;通过SNP和cgMLST对分离株进行系统进化分析。结果21株食源性MRSA菌株在生肉及其制品检出率最高(80.95%,17/21)。分离株对青霉素、苯唑西林、红霉素、克林霉素、四环素等抗菌药物耐药。PFGE分型呈7个聚类群,带型较分散;共有7个ST型别,其中ST59为主要型别(57.14%,12/21);共有6种spa型别,其中t437为主要型别(66.67%,14/21);共有3个SCCmec型别,其中Ⅳa(2B)为主要型别(71.43%,15/21)。38.09%(8/21)的菌株具有不同程度的生物膜形成能力。编号110菌株毒力最强,菌液浓度为1×10^(6) CFU/mL时36 h对大蜡螟幼虫致死率达100.00%。全基因组测序分析结果显示,菌株携带β-内酰胺类耐药、氨基糖苷类、大环内酯类、四环素类等4~12个耐药基因不等,其中2株菌携带季铵化合物类抗性基因qacG。菌株均含有自溶酶基因aur,溶血素基因hlgA、hlgB、hlgC,大部分菌株(95.23%,20/21)含有完整的肠毒素egc基因簇基因。种系进化树分析结果显示ST59-t437-Ⅳa(2B)型为食源性MRSA主要进化分支。结论本研究中食源性MRSA具有多重耐药、较高毒力及一定程度生物膜形成能力,且携带临床感染中重要的毒力基因。菌株毒力与其耐药、生物膜形成能力及毒力基因携带情况相关。Objective To analyze the drug resistance,virulence,biofilm formation ability,and molecular epidemiological characteristics of foodborne methicillin-resistant Staphylococcus aureus(MRSA),and to provide data support for risk assessment of foodborne pathogens.Methods Antimicrobial susceptibility test,pulsed-field gel electrophoresis(PFGE)analysis,MLST,spa,SCCmec typing,biofilm formation ability determination,and virulence determination of Galleria mellonella were performed on 21 strains of foodborne MRSA isolated from commercially available food in Shaanxi Province from 2019 to 2020;The drug resistance genes,virulence genes,plasmids,and mobile genetic elements of the strains were analyzed by whole-genome sequencing.SNP and cgMLST were utilized to analyze the phylogenetic patterns of the isolates.Results The detection rate of 21 foodborne MRSA strains was highest in raw meat and meat products(80.95%,17/21).The isolates were resistant to antibiotics such as penicillin,oxacillin,erythromycin,clindamycin,and tetracycline.PFGE typing showed 7 clusters with the band patterns being dispersed.There were 7 ST types,with ST59 being the main type(57.14%,12/21);6 spa types,with t437 as the main type(66.67%,14/21);and 3 SCCmec types,withⅣa(2B)as the main type(71.43%,15/21).Biofilm formation ability varied in 38.09%(8/21)of the strains.The MRSA isolate No.110 showed the highest toxicity,achieving a 100.00%mortality rate in Galleria mellonella larvae at a bacterial concentration of 1×10^(6) CFU/mL within 36 hours.The results of wholegenome sequencing analysis showed that the strains carried 4-12 resistance genes,includingβ-lactam,aminoglycosides,macrolides,and tetracycline resistance genes,with 2 strains carrying the quaternary ammonium compound resistance gene qacG.All strains contained the autolysin gene aur and hemolysin genes hlgA,hlgB,and hlgC.The enterotoxin egc gene cluster was present in most strains(95.23%,20/21).Phylogenetic tree analysis indicated the ST59-t437-Ⅳa(2B)as the principal evolutionary branch of foodbor

关 键 词：食源性 耐甲氧西林金黄色葡萄球菌 耐药性 毒力 生物膜 分子特征 

分 类 号：R515[医药卫生—内科学]