我国市售食用菌中金黄色葡萄球菌污染调查、耐药性及其肠毒素基因检测

Prevalence, Antibiotic Resistance, and Enterotoxin Gene Detection of Staphylococcus aureus Isolated from Retail Edible Mushrooms in China

摘要:

调查了2011—2016年我国市售食用菌中金黄色葡萄球菌的污染情况,并对分离到的相关菌株进行了肠毒素基因的检测和耐药性分析。收集全国39个城市699份市售食用菌,利用定性和定量检测方法,检出金黄色葡萄球菌阳性样品33份,平均污染率4.72%,污染水平9.75MPN/g。24种抗生素的药敏结果显示,分离株耐药情况严重,对利奈唑胺、利福平敏感,对氨苄西林等22种抗生素都产生不同程度的耐药。7株分离株经表型和分子鉴定确定为耐甲氧西林金黄色葡萄球菌。运用聚合酶链式反应法对分离的39株金黄色葡萄球菌进行了18种肠毒素基因检测,约60%分离株携带4~6种肠毒素基因,携带率最高的肠毒素基因是sei,其次是sem、seg、seq、sec、seb、sen。本研究反映了我国市售食用菌金黄色葡萄球菌污染的潜在风险,相关分离株具毒性潜力,且耐药性严重,应引起重视。

Abstract:

This study investigated the contamination level of Staphylococcus aureus of retail edible mushrooms in China. 699 retail edible mushroom samples were collected from 39 cities in China during 2011 to 2016,3 samples (4.72%) were positive for Staphylococcus aureus and the geometric mean was 9.75 MPN/g. A total of 39 isolates were analyzed.For antibiotics susceptibility tests, all isolated strains were resistant to 22 kinds of different antibiotics, such as ampicillin, and only sensitive to linezolid and rifampicin. Seven isolates were resistant to cefoxitin and carried mecA gene, confirmed as methicililin-resistant Staphylococcus aureus (MRSA).Polymerase chain reaction(PCR) analysis of 18 SE genes showed that 4-6 kinds of enterotoxin genes carried by 60% isolated strains, and sei gene was the most frequently detected, followed by sem,seg,seq,sec,seb,sen.This study reflects the potential risk of Staphylococcus aureus contamination of retail edible mushrooms in China and these isolate strains had virulence potential and drug tolerance, which should be drawn public attention.