Etiological analysis of a case of food poisoning caused by mixed infection with two rare serotypes of Vibrio parahaemolyticus

Abstract

Objective To analyze the etiology of a food poisoning caused by mixed infection with two rare serotypes of Vibrio parahaemolyticus, and we provide the basis for the pathogen examination of food poisoning. Methods According to Food Microbiology Testing for Vibrio parahaemolyticus (GB 4789.7-2013) and other standards, 9 patients with food poisoning treated in Longmen County People’s Hospital were selected as research objects, and their rectal swabs were collected for analy⁃ sis and identification. Results There were a total of 9 patients with clinical symptoms, including 2 patients aged ≤20 years old, 1 patient aged 21-<40 years old , 4 patients aged 41-<60 years old , and 2 patients aged ≥60 years old. Eight strains of Vibrio parahaemolyticus were detected in 9 rectal swabs, with ratios of the blood classification type O2:K28 was 25.00% (2/8), and O8: K21 was: 75.00%(6 / 8); The similarity of O2∶K28 serotypes (VP18171 and VP18175) was 66.7% by PFGE molecular typing. The similarity of O8∶K21 serotype (VP18172, VP18173, VP18176) was 100.0%, and the similarity of O8∶K21 serotype (VP18177, VP18174, VP18170) was 88.4%-95.2%. The results of the drug sensitivity test showed that while 1 strain was resis⁃ tant to ampicillin and cefazolin, 1 strain was resistant to ampicillin and 3 strains were resistant to cefazolin, the other strains were sensitive to all of the tested drugs, and there was no multi-drug resistance. Conclusion The food poisoning was caused by mixed infection of two different serotypes O2∶K28 and O8∶K21 of Vibrio parahaemolyticus. 摘要：目的 分析一起由两种罕见血清型混合感染引起的副溶血性弧菌食物中毒病原学的检测结果, 为食物中毒 病原学检查途径提供依据。 方法 对一起在龙门县人民医院就诊食物中毒事件的 9 例患者采集其肛拭子样本, 参照《食品微生物学检验副溶血性弧菌检验》( GB 4789.7—2013) 等标准进行病原学分析鉴定。 结果 本次事件出现临床症 状者 9 例, 其中≤20 岁 2 例, 20~<40 岁 1 例, 40~<60 岁 4 例, ≥60 岁 2 例; 9 份肛拭子样本检出 8 株副溶血性弧菌, 血清分型 O2: K28 构 成 比 占 25.00% (2 / 8); O8: K21 构 成 比 占 75.00%(6 / 8); 经 PFGE 分 子 分 型 , 2 株 O2∶K28 血 清 型 (VP18171、VP18175) 相似度为 66.7%; 3 株 O8∶K21 血清型 (VP18172、VP18173、VP18176) 相似度为 100.0%, 与另外 3 株 O8∶K21 血 清型 (VP18177、VP18174、VP18170) 相似度为 88.4%~95.2%; 药敏试验结果显示, 除有 1 株菌株对氨苄西林、头孢唑林二 重耐药、1 株菌株对氨苄西林耐药、3 株菌株对头孢唑林耐药外, 其它菌株对所有测试药物均敏感, 无多重耐药现象。 结论 此次食物中毒是由 O2:K28 和 O8:K21 这两种罕见血清型的副溶血性弧菌混合感染引起的。