两起副溶血性弧菌食物中毒血清学溯源结果分析

Analysis of serologic traceability results in two cases of food poisoning caused by Vibrio parahaemolyticus

目的对两起副溶血性弧菌(VP)引起的食物中毒进行血清学溯源,分析可疑食品和病人样品中菌株血清型之间的关系。方法依据GB/T4789.7—2008方法,对检出的VP做血清分型、溶血素试验;PCR扩增VP直接耐热溶血素基因(tdh)、tdh相关溶血素基因(trh)和毒素调控基因(toxR)。结果通过增加样品中可疑菌落数量的鉴定,两起食物中毒共检出9种VP血清型,主要有O3∶K6型13株,O2∶K28型6株,O1∶K56型2株,其它各1株;两起食物中毒中分离的27株VP有17株tdh基因检测阳性,与溶血试验结果一致。结论增加可疑菌落数鉴定,有助于VP食物中毒的溯源;虽然O3∶K6血清型是引起食物中毒的主要病原菌,但不同样品来源的VP血清型呈现多样性;副溶血性弧菌tdh基因检测等同于溶血试验来鉴定VP致病性。

Objective To trace the serological source of two food poisoning cases caused by Vibrio parahaemolyticus （VP） and analyze the relationship between serotypes in the suspect food and patient samples. Methods Based on the GB/T 4789.7- 2008 method, the detected VP was serotyped, and hemolysin tests were performed. The directly heat- resistant hemolysin gene （tdh）, tdh-related hemolysin gene （trh） and toxins regulated genes （toxR） were amplified by PCR. Results 9 VP serotypes in two food poisoning cases were identified by expanding the identification of suspicious colonies in the sample. There were 13 strains of 03： K6, 6 strains of 02： K28, 2 strains of O1： K56. The results of tdh gene detection were positive in 17 strains from 27 isolated VP strains which were consistent with the hemolysin tests. Conclusion Expanding the identification of suspicious colonies contributed to the traceability of food poisoning caused by VP. Although 03：K6 was the major pathogen causing food poisoning, VP serotypes from different samples show diversity. The tdh gene detection is equivalent to the hemolysis test in detecting the VP pathogenicity.