福建省宁德地区沙门菌感染的流行病学特征、耐药性及毒力基因分析

Analysis of epidemiological characteristics,drug resistance and virulence genes of Salmonella in Ningde area of Fujian Province

为分析福建省宁德地区沙门菌感染的流行病学特征、耐药性及毒力基因,本研究选取2015—2020年从该地区分离获得的364株沙门菌,分析其流行病学资料,对菌株培养后进行分离鉴定,并采用脉冲场凝胶电泳进行分子分型,K-B纸片扩散法进行耐药性分析,常规聚合酶链反应进行毒力基因检测。结果显示,男性沙门菌感染率显著高于女性(P<0.05),0~10岁组人群感染率显著高于其他年龄组(P<0.05)。共分离出22个血清分型,其中鼠伤寒沙门菌、肠炎沙门菌、斯坦利沙门菌为主要血清型,分别占57.42%、16.21%、6.87%。耐药性分析结果显示:鼠伤寒沙门菌对氨苄西林、磺胺异噁唑、四环素、链霉素的耐药率较高;肠炎沙门菌对氨苄西林、磺胺异噁唑、四环素、链霉素、甲氧苄啶的耐药率较高;斯坦利沙门菌对头孢他啶、环丙沙星、头孢噻肟、头孢吡肟未表现出耐药性。364株沙门菌共212种带型,带型相似度为44.52%~100.00%,其中优势带型为B53,共23株。毒力基因avrA、ssaQ、sodC1、mgtC、gipA的携带率均为100.00%,ssiD、sopE、sopB的携带率分别为90.66%、94.23%、92.03%,spvC的携带率为63.74%。结果提示,福建省宁德地区沙门菌感染人群集中在10岁以下儿童,男性高发,具有一定的遗传多样性,且毒力基因的携带率较高,主要血清型对第3、4代头孢菌素类较为敏感。

In order to analyze the epidemiological characteristics,drug resistance and virulence genes of Salmonella in Ningde area of Fujian Province,364 Salmonella strains were isolated in Ningde area from 2015 to 2020.The epidemiological data were collected for statistical analysis.The isolated stains were identified after culture.Pulse-field gel electrophoresis(PFGE)was used for molecular typing analysis,K-B slip diffusion method was used to carry out the drug susceptibility testing,and routine polymerase chain reaction(PCR)was used to detect virulence genes.The epidemiological analysis showed that the infection rate of Salmonella in males was significantly higher than that in females(P<0.05),and the infection rate in 0-10 years old group was significantly higher than that in other age groups(P<0.05).A total of 22 serotypes were isolated.Among them,Salmonella typhimurium(S.typhimurium),S.enteritidis,S.stanley were the top three main serotypes,accounting for 57.42%,16.21%,6.87%,respectively.Drug resistance analysis showed that S.typhimurium had high resistance to ampicillin,sulfafurazole,tetracycline and streptomycin;S.enteritis had high resistance to ampicillin,sulfafurazole,tetracycline,streptomycin and trimethoprim;S.stanley was not resistant to ceftazidime,ciprofloxacin,cefotaxime and cefepime.The results of PFGE typing showed that 364 Salmonella strains had 212 bands,and the similarity of bands was from 44.52%to 100.00%.The dominant band was B53(23 strains).The results of virulence gene test showed that the carrying rates of avrA,ssaQ,sodC1,mgtC,gipA were 100.00%,those of ssiD,sopE,sopB were 90.66%,94.23%and 92.03%,respectively,and that of spvC was 63.74%.It is suggested that Salmonella infection in Ningde area is mostly concentrated in the children under 10 years old,and males are with a high incidence.Salmonella infection has a certain genetic diversity and high carrying rates of virulence genes.The main serotypes are more sensitive to the third-and fourth-generation cephalosporins.