我国部分地区即食食品和蔬菜中金黄色葡萄球菌污染分布及耐药和基因分型情况

目的 了解2017年中国食源性金黄色葡萄球菌（金葡菌）耐药和肠毒素特征。 方法 2017年收集全国29个省市食源性金葡菌397株，并测定其抗生素耐药性、肠毒素基因和产肠毒素情况。 结果 96.5 %（383/397）金葡菌对受试的13种抗生素呈不同程度耐药，其中青霉素（PEN）耐药率最高（94.7 %）；30.2 %（120/397）金葡菌为多重耐药，米面制品和面包来源金葡菌多重耐药率最高，分别为37.4 %和37.3 %；共存在72种耐药谱。284株金葡菌检出了20种肠毒素基因，其中sea、seb、sec和sed等常见肠毒素基因检出82株（20.7 %，82/397），其中sea（14.9 %）基因检出率明显高于seb～sed基因（χ² = 74.534，P < 0.05），90 %以上的菌株均能产生SE-A～SE-D肠毒素。 结论 2017年中国29个省市食源性金葡菌耐药水平较高，多重耐药现象严重，且同时携带多种肠毒素基因并能产肠毒素。

Complete genome sequence of USA300, an epidemic clone of community-acquired methicillin-resistant Staphylococcus aureus

Objective To examine antimicrobial resistance and enterotoxigenicity of foodborne Staphylococcus aureus (S. aureus) isolates in 29 provincial regions of China in 2017. Methods Totally, 397 foodborne S. aureus isolates were collected in 29 provincial regions of China in 2017 and antimicrobial susceptibility, enterotoxin genes, and toxigenic capability of all isolates were tested. Results In total, 96.5% (383/397) of the S. aureus isolates exhibited different resistant level to 13 antimicrobials tested. The resistance rate to penicillin (PEN) was the highest (94.7%). Moreover, 30.2% (120/397) were identified as multi-drug resistant (MDR) strains. Isolates from rice and flour products showed the most MDR, and the MDR rates were 7.4% (34/91) and 37.3% (19/51), respectively. A total of 72 drug resistant spectrums were identified from all 397 isolates. Furthermore, 20 virulence genes were detected in 284 isolates. The typical SEs genes of sea, seb, sec and sed were detected in 82 strains (20.7%, 82/397) with sea (14.9%) and sec (5.0%) as the most frequently detected. More than 90% of the sea to sed carrying isolates were confirmed with the capacity to produce enterotoxins. Conclusion An overall high level antimicrobial resistance was found among foodborne S. aureus isolates in China in 2017, so was the MDR condition, especially for strains recovered from some foods. Virulence genes could be frequently detected in foodborne S. aureus isolates, most of which could produce enterotoxins.