糕点店从业人员带菌者引起沙门菌食源性疾病暴发的溯源与药敏调查

Source tracing and drug resistance analysis of a food-borne salmonella disease event caused by the pastry shop bacilli-carrier

目的找到引起2020-09重庆市长寿区一起疑似食源性疾病暴发的病原;对分离到13株肠炎沙门氏菌进行分子流行病学调查溯源分析;同时进行抗生素敏感试验以了解菌株耐药状况。方法对2020-09重庆市长寿区一起疑似食源性疾病患者100余份肛拭(粪便)样本按国标进行微生物检测,同时使用MALDI-TOF(基质辅助激光解吸电离飞行时间质谱)对可疑菌株进行了快速鉴定;对分离到的13株肠炎沙门菌使用PFGE技术结合Bionumerics 7.6软件进行分子溯源分析,观察患者、从业人员、食品分离株之间的相关性;使用微量肉汤稀释法对13株肠炎沙门菌进行耐药检测。结果用MALDI-TOF对2020-09重庆市长寿区一起疑似食源性疾病患者肛拭(粪便)样本中可疑菌株进行快速鉴定,检测结果与国标方法检测结果一致;从患者分离到的6株、食品分离到的2株、从业人员分离到的5株肠炎沙门菌经PFGE后得到了完全相同的指纹图谱,聚类分析相似度为100%;13株肠炎沙门菌经抗生素敏感试验后得到了一致的耐药谱,对氨苄西林(青霉素类)、氨苄西林/舒巴坦(β-内酰胺复合类)、头孢唑啉(1代头孢类)、萘啶酸(喹诺酮类)、多粘菌素(乳菌肽脂肽类)表现为耐药,对环丙沙星(氟喹诺酮类)表现为中度敏感。结论引起本次食源性疾病的病原为肠炎沙门氏菌;患者菌株、食品分离株、食品加工人员带菌者分离株为同一克隆,结合流行病学调查结果判断为糕点受到糕点加工人员带菌污染引起的本次食源性疾病暴发,且该菌株对三种以上不同种类抗生素耐药,存在多重耐药现象。

Objective To find the pathogen that caused the suspected food-borne outbreak in Changshou District, Chongqing, in September 2020;to conduct a molecular epidemiological investigation and traceability analysis of the 13 strains of isolated Salmonella enteritidis;and to understand the drug resistance of these stains by antimicrobial susceptibility test. Methods More than 100 anal swab(fecal) samples from the suspected food-borne event in Changshou District, Chongqing, in September 2020, were tested for microorganism according to national standards. MALDI-TOF(matrix assisted laser desorption ionization time of flight mass spectrometry) was used for rapid identification of suspicious isolates. PFGE(pulse field gel electrophoresis) and software Bionumerics7.6 were carried out for molecular traceability analysis of the 13 Salmonella isolates.The correlation of the isolates from food, patients and practitioners was observed. The drug resistance of these isolates was measured by broth microdilution method. Results The result of the rapid identification by MALDI-TOF was consistent with that of the national standards. The PFGE finger-prints of the 6 isolates from patients, 2 from food and 5 from practitioners were exactly the same, and the similarity was 100% by cluster analysis. Consistent drug resistance profiles were obtained after the antimicrobial susceptibility test of the 13 Salmonella enteritidis isolates,which were all resistant to ampicillin(belonging to penicillin), ampicillin/sulbactam (β-lactam compound),cefazoline(first-generation cephalosporins),nalidixic acid(quinolones) and polymyxin(lactopeptides,lipopeptides),and moderately sensitive to ciprofloxacin(fluoroquinolones).Conclusions Salmonella enteritidis was the origin of this food-borne disease event. The isolates from patients, food, practitioner bacilli-carriers were the same clone. Combined with the results of the epidemiological investigation, it confirmed this food-borne Salmonella disease event was caused by contaminated pastry by bacilli-carriers in the manufacturing process. The isolate was resistant to more than three different kinds of antibiotics, and a phenomenon of multiple drug resistance was presented.