广州市市售食品中部分沙门菌耐药性及分子分型特征

Antimicrobial resistance and molecular typing characteristics of part of Salmonellae isolated from market-sold food in Guangzhou City

目的分析近年来广州市市售食品中部分沙门菌的耐药情况和分子分型特征,为广州市沙门菌疾病的防控提供实验室数据。方法对分离到的沙门菌进行血清分型,药物敏感性试验和脉冲场凝胶电泳(pulsed-field gel electrophoresis,PFGE),并用BioNumerics软件分析菌株间的同源性。结果2016—2018年期间从食品中共检出沙门菌16株,有6株是德尔卑血清型为优势型别;通过耐药性试验发现所分离到的菌株对青霉素类药物耐药率较高,其中对氨苄西林耐药率最高(56.3%),其次为头孢替坦(25.0%);经PFGE实验分析可以把菌株分成10个基因型,菌株的总体相似度为41.5%~100.0%,2个基因型分别与同时期获得的800多株病人分离株中的2株的基因型相似度较高,同源性最高的食源性菌株和人源性菌株之间相似度为93.3%。结论在食品中检出的沙门菌血清型以德尔卑型为优势型别,耐药性和基因型都呈现多态性,发现有食源性菌株与人源性菌株基因相似度较高,提示某些类型的沙门菌有更易使人致病的风险。

Objective To analyze the drug resistance status and molecular typing features of part of Salmonellae isolated from market-sold food in Guangzhou City,and to provide experimental data for prevention and control of diseases caused by Salmonella.Methods Salmonella strains isolated from food samples were serotyped,antibiotic susceptibility test was carried out,pulsed-field gel electrophoresis(PFGE)was used to conduct genotyping,and BioNumerics software was used for analyzing the homology.Results From 2016 to 2018,a total of 16 strains of Salmonella were isolated from food,of which 6 strains serotype Derby were dominant.Antibiotic resistance test showed that the Salmonella strains isolated were highly resistant to penicillins,of which drug resistance rate of the Salmonella strains to ampicillin was the highest(56.3%),followed by cefotetan(25.0%).PFGE analysis revealed that 16 strains of Salmonella were divided into 10 PFGE genotypes,and the overall similarity ranged between 41.5%and 100.0%.2 genotypes of the food-borne strains had high similarity with 2 of more than 800 strains isolated from patients and obtained during the same period.The highest similarity between food-borne and human-derived strains was 93.3%.Conclusion Salmonella Derby was dominant serotype of the Salmonellae detected from food in Guangzhou.Antimicrobial resistance and genotypes of the Salmonellae were diversified.It is found that there is a high similarity between some food-borne strains and human-derived strains,suggesting that some genotypes of Salmonellae have high risk of causing disease.