广东省潮州市2022年非伤寒沙门菌病原学特征

Pathogenetic characterization of non-typhoidal Salmonella in Chaozhou City, Guangdong Province in 2022

目的分析2022年潮州市非伤寒沙门菌血清型、耐药性及分子流行病学特征,为有效防控食源性疾病的发生提供病原学支持。方法2022年通过广东省潮州市哨点监测和食品风险监测,分离人源非伤寒沙门菌和食品来源非伤寒沙门菌,并对菌株开展血清学分型、药敏试验和全基因组测序分析。结果2022年潮州市腹泻监测粪便标本共采集1257份,检出非伤寒沙门菌58株,分离率4.61%;116份食品标本中检出非伤寒沙门菌2株,分离率1.72%。幼儿期为感染的主要年龄段(14/144,9.72%)。6月份检出率最高(12/123,9.76%)。58株人源非伤寒沙门菌可分成12种血清型,其中鼠伤寒沙门菌检出率最高(44/58,75.86%)。药敏结果示,55株存在耐药,耐药率91.67%,其中氨苄西林、四环素、氯霉素和链霉素的耐药率较高,分别为76.67%、70.00%、67.67%和60.00%;49株具有多重耐药性,多重耐药率占81.67%。分子特征示,通过多位点序列分型(multilocus sequence typing,MLST)60株沙门菌菌株可分成14个序列分型(sequence typing,ST),鼠伤寒沙门菌ST34占主导优势,全基因组单核苷酸多态性(whole genome single nucleotide polymorphism,wg-SNP)进化分析示,本研究菌株间表现为较高的遗传异质性,鼠伤寒沙门菌聚类分布,临床样本肠炎沙门菌进化关系较为接近。结论2022年潮州市人源非伤寒沙门菌血清型多样,其中鼠伤寒沙门菌占优势,多重耐药情况严重,分子分型呈现进化多样性特点。

Objective To analyze the serotypes,drug resistance,and molecular epidemiological characteristics of non-typhoidal Salmonella in Chaozhou City,Guangdong Province in 2022,providing pathogenic support for the effective prevention and control of foodborne diseases.Methods In 2022,human-derived non-typhoidal Salmonella strains and food-derived strains were isolated through sentinel surveillance and food risk monitoring in Chaozhou City,Guangdong Province.The strains were subjected to serotyping,drug susceptibility testing,and whole-genome sequencing analysis.Results A total of 1257 fecal specimens were collected for diarrhea surveillance in Chaozhou City in 2022,and 58 strains of non-typhoidal Salmonella were detected,with an isolation rate of 4.61%.Among 116 foodstuffs,2 strains of non-typhoidal Salmonella were detected,with an isolation rate of 1.72%.Early childhood was the main age group for infection(14/144,9.72%).The highest detection rate was in June(12/123,9.76%).The 58 human-derived non-typhoidal Salmonella strains were classified into 12 serotypes,with Salmonella typhimurium being the most prevalent(44/58,75.86%).In terms of drug resistance,55 strains showed resistance,with a resistance rate of 91.67%,among which ampicillin,tetracycline,chloramphenicol,and streptomycin had the highest resistance rates,76.67%,70.00%,67.67%,and 60.00%,respectively.Forty-nine strains were multi-resistant,accounting for 81.67%.From the molecular characteristics standpoint,multilocus sequence typing(MLST)divided the strains into 14 sequence typing(ST),with Salmonella typhimurium ST34 being the dominant type.Whole-genome single nucleotide polymorphism(wg-SNP)evolutionary analysis revealed high genetic heterogeneity among the studied strains,with Salmonella typhimurium clustering together and showing close evolutionary relationships to clinical samples of Salmonella enteritidis.Conclusions In 2022,the non-typhoidal Salmonella strains from Chaozhou showed a diversity of serotypes,with Salmonella typhimurium being predominant and exhibiting severe multidrug resistance.Molecular typing revealed diverse evolutionary characteristics.