辽宁省2021—2022年餐饮食品蜡样芽胞杆菌毒力基因和耐药特征检测

Detection of virulence genes and drug resistance characteristics of Bacillus cereus in catering food in Liaoning Province,2021-2022

目的了解辽宁省2021—2022年食品中蜡样芽胞杆菌(Bacillus cereus)污染状况、携带的毒力因子及药物敏感性的特征。方法对辽宁省2021—2022年分离自15个监测点4大样品种类共620份样品,应用GB4789.14—2014进行分离鉴定蜡样芽胞杆菌,并用PCR方法进行菌群特异性基因groEL和gyrB及11种毒力基因检测;采用微量肉汤稀释法检测菌株对抗生素的敏感性。结果79株蜡样芽胞杆菌都检出了蜡样芽胞杆菌毒力基因,占比较大的分别是非溶血性的肠毒素nheC、nheA和nheB,检出率分别是100.0%(79/79)、93.3%(74/79)和83.5%(66/79),肠毒素entFM基因检出率98.7%(78/79)。79株餐饮食品中蜡样芽胞杆菌携带19种毒力基因模式,基因模式中IX和XVII比例最多占到16.5%(13/79)。79株蜡样芽胞杆菌对氨苄西林、青霉素耐药率均为100.0%,对氯霉素、庆大霉素耐药率均为0;对其他6种抗菌药物的耐药率分别为:复方磺胺甲恶唑65.8%(52/79)、亚胺培南10.1%(8/79)、红霉素73.4%(58/79)、克林霉素60.8%(48/79)、环丙沙星75.9%(60/79)、四环素耐药率70.9%(56/79)。结论辽宁省餐饮食品存在蜡样芽胞杆菌污染,分离株至少携带4种以上毒力基因,约100%的菌株对氨苄西林、青霉素具有耐药性,对氯霉素、庆大霉素抗菌药物敏感性高,应加强主动监测,及时针对性的防控干预,为日后的溯源研究提供理论依据。

Objective To investigate the contamination status of Bacillus cereus in food,the profile of virulence factors carried,and drug sensitivity characteristics in Liaoning Province.Methods A total of 620 samples were isolated from 15 monitoring sites,covering four major sample types of food products in Liaoning Province between 2021 and 2022.Bacillus cereus was isolated and identified by GB4789.14—2014,and its virulence was assessed using PCR detection of the groEL and gyrB genes specific to the bacterial group,as well as 11 other virulence genes.Broth microdilution method was used to detect the antibiotic sensitivity of the strain.Results All 79 Bacillus cereus strains were found to carry virulence genes.The detection rates of non-hemolytic enterotoxin genes nheC,nheA,and nheB were 100%(79/79),93.3%(74/79),and 83.5%(66/79),respectively.The detection rate of enterotoxin entFM gene was 98.7%(78/79).The 79 strains of Bacillus cereus carried 19 types of virulence gene patterns,with IX and XVII gene patterns being the most prevalent,each accounted for 16.5%(13/79).The resistance rates of 79 strains of Bacillus cereus to 10 antibacterial drugs were 100%for both ampicillin and penicillin.The resistance rates to cotrimoxazole,imipenem,erythromycin,clindamycin,ciprofloxacin,and tetracycline 65.8%(52/79),10.1%(8/79),73.4%(58/79),60.8%(48/79),75.9%(60/79),and 70.9%(56/79)respectively.The resistance rates to chloramphenicol and gentamicin were both 0%.Conclusion Food from catering services in Liaoning Province shows contamination by Bacillus cereus,with isolated strains carrying at least four kinds of virulence genes.About 100%of the isolates were resistant to ampicillin and penicillin,whereas high sensitivity was observed to chloramphenicol and gentamicin.Active monitoring,timely targeted prevention and control interventions should be strengthened to provide a theoretical basis for future traceability studies.