2009—2020年北京市朝阳区113株食源性金黄色葡萄球菌耐甲氧西林和肠毒素/类肠毒素基因携带与分子分型分析

Diversity of methicillin-resistant Staphylococcus aureus and enterotoxins/ enterotoxin-likes and molecular typing of 113 strains Staphylococcus aureus from foodborne in Chaoyang district of Beijing from 2009 to 2020

中文关键词:  金黄色葡萄球菌  耐甲氧西林金黄色葡萄球菌  肠毒素  类肠毒素  脉冲场凝胶电泳  多位点序列分型

英文关键词:Staphylococcus aureus  methicillin-resistant Staphylococcus aureus  staphylococcal enterotoxins  enterotoxin-likes  pulsed field gel electrophoresis  multilocus sequence typing

中文摘要:

      目的 了解北京市朝阳区2009—2020年113株食源性金黄色葡萄球菌甲氧西林耐药、肠毒素/类肠毒素基因携带和分子分型情况。方法 采用纸片扩散法进行头孢西丁药物敏感性实验, 结合mecA基因扩增鉴定耐甲氧西林金黄色葡萄球菌(methicillin-resistant Staphylococcus aureus, MRSA); 实时荧光定量聚合酶链式反应(quantitative real-time polymerase chain reaction, QR-PCR)检测28种金黄色葡萄球菌肠毒素/类肠毒素(staphylococcal enterotoxins/enterotoxin-likes, SEs/SEls)基因; 采用脉冲场凝胶电泳(pulsed field gel electrophoresis, PFGE)和多位点序列分型(multilocus sequence typing, MLST)进行分子分型。结果 检出7株MRSA (6.19%、7/113) ; 所有菌株至少携带1种肠毒素/类肠毒素基因, 最多携带14种, 共检出24种肠毒素/类肠毒素基因; 经典sea~see肠毒素基因携带率为0%~33.63%。MLST共24型, ST1、ST398、ST7、ST59为优势型; 发现ST6656、ST6688、ST6709、ST6745、ST6754 5个新型别。PFGE共分25型, H型(11/113)、I型(9/113)、J型(29/113)是优势分型, 占比43.36%。结论 本地区食源性金黄色葡萄球菌MRSA菌株分离率低于临床株; PFGE分型结果中J、H、I 3种优势型占比近半, 显示本地区食源性金黄色葡萄球菌优势菌株集中; 优势ST型别主要与医院、社区感染和动物相关。新发现5个ST型别; 肠毒素/类肠毒素携带与ST型别存在一定关联性; ST1-MSSA-sea-seh-sek-seq-selw-selx是优势株; 仅检测5种经典肠毒素不能代表金黄色葡萄球菌引起食物中毒的致病因子, 应扩大肠毒素检测范围。

英文摘要:

      Objective To investigate the methicillin-resistance, enterotoxin/enterotoxin-like gene carrier and molecular typing of 113 foodborne Staphylococcus aureus strains from 2009 to 2020 in Chaoyang district, Beijing. Methods Detection of cefoxitin drug susceptibility test by disc diffusion method combined with amplification of mecA gene to identify methicillin-resistant Staphylococcus aureus (MRSA) of 113 strains of Staphylococcus aureus; 28 kinds of staphylococcal enterotoxins/enterotoxin-likes (SEs/SEls) genes were detected by quantitative real-time polymerase chain reaction (QR-PCR). Molecular typing was performed by pulsing field gel electrophoresis and multilocus sequence typing. Results Seven strains of MRSA (6.19%, 7/113) were detected, all strains carried 1?14 kinds of SEs/SEls genes, and a total of 24 kinds of SEs/SEls genes were detected, the carrying rate of sea-see enterotoxin genes was 0%-33.63%. MLST could be divided into 24 types, ST1, ST398, ST7, ST59 were the dominant type, 5 new types of ST6656, ST6688, ST6709, ST6745 and ST6754. PFGE could be divided into 25 types, H type (11/113), I type (9/113) and J type (29/113) were the dominant types, accounting for 43.36%. Conclusion The isolation rate of foodborne Staphylococcus aureus MRSA strain is lower than that of clinical strains, the 3 dominant types of J, H, and I account for nearly half of the PFGE typing results, indicating that the dominant strains of foodborne Staphylococcus aureus are concentrated in the region. The main ST types are associated with nosocomial, community infection and animal, and 5 new ST types have been found. There is a certain correlation between enterotoxins/enterotoxin-likes and ST type, ST1-MSSA-sea-seh-sek-seq-selw-selx is the dominant strain; only 5 kinds of classical enterotoxins can not represent the pathogenic factors of food poisoning caused by Staphylococcus aureus, so the detection scope of enterotoxins should be expanded.