2018-2021年南山区食物中毒中肠炎沙门氏菌与布利丹沙门氏菌遗传特征和耐药性分析

Biological and genetic characteristics of Salmonella enteritidis and Salmonella blegdam in food poisoning in Nanshan District,2018-2021

目的分析2018-2021年南山区食物中毒样品中分离的肠炎沙门氏菌(Salmonella Enteritidis S.Enteritidis)与布利丹沙门氏菌(Salmonella Blegdam.S.Blegdam),从遗传特征和耐药性角度了解细菌间的亲缘进化关系和耐药特征、为食源性疾病暴发溯源和临床诊治提供参考依据。方法分别对33株沙门氏菌采用脉冲场凝胶电泳(pulsed-field gel electrophoresis,PFGE)与全基因组序列方法(Whole genome sequencing,WGS)分析,同时测定30种药物的最小抑菌浓度(minimal inhibitory concentration,MIC)。结果33株菌分为8个PFGE型别,MLST型均为ST11型。全基因组k-mer系统发生树可见9簇。氨苄西林(AMP)、头孢唑啉(CFZ)、萘啶酸(NAL)、磺胺异噁唑(Sul)4种抗菌药物的检出率较高,均大于50%。20株菌对3类以上的药物耐药(60.60%),属于多重耐药,7株菌产ESBL酶。15株菌的耐药基因与耐药表型完全符合。结论2018-2021年,南山区由沙门氏菌引起的食物中毒事件中,沙门氏菌的总体遗传距离较近,但与数据库中其它肠炎沙门氏菌遗传距离较远,自成一簇。本研究中的沙门氏菌多重耐药现象严重,需加强对多重耐药株的监控及抗菌药物使用的监管。

This study analyzed Salmonella enteritidis and S.blegdam isolated from food poisoning samples in 2018-2021,to understand the genetic evolutionary relationship and drug resistance characteristics of the bacteria,and to provide a reference for food-borne disease outbreaks and clinical diagnosis.Cluster analysis and determination of the genetic relationships among 33 salmonella strains were performed through pulsed-field gel electrophoresis(PFGE)and whole genome sequencing(WGS),respectively.Antibiotic susceptibility testing was performed to determine the minimum inhibitory concentrations of 30 antibiotics.The 33 strains were divided into eight PFGE types.MLST was all ST11 types.On the basis of the S.enteritidis reference database,the K-mer phylogenetic tree had nine clusters with wide genetic distance.The detection rates of ampicillin,cefazolin,naphthalenate,and sulisoxazole exceeded 50%.Twenty strains were resistant to more than three types of drugs(60.60%),thus indicating multi-drug resistance,and seven strains produced the ESBL enzyme.The drug resistance genes of 15 strains were completely consistent with the drug resistance phenotype.The overall genetic distance was close among the Salmonella in the analyzed food poisoning cases during 2018-2021,but these Salmonella were far from the other S.enteritidis in the database,thus forming a cluster of their own.The multi-drug resistance of Salmonella in this study was quite high;therefore,monitoring of multi-drug resistant strains and supervision of antibacterial drug use must be strengthened.