Distribution and molecular typing analysis of Salmonella detection results among employees in Qidong in 2019

JI Donghua; ZHANG Haiying; MAO Liting

doi:10.19821/j.1671-2781.2025.04.017

Abstract：Objective To understand the distribution of Salmonella infections among employees in Qidong,and to analyze their serotypes and molecular subtypes,so as to provide scientific basis for formulating the prevention and control measures.Methods 21 696 anal swab samples from employees in Qidong in 2019 were preliminarily screened for Salmonella by real-time fluorescent quantitative PCR.The pathogenic identification and serological typing were carried out according to the inspection methods of WS 271-2007 and GB 4789.4-2016.The molecular typing was performed by pulsed-field gel electrophoresis(PFGE),and the experimental results were analyzed.Results The overall positive rate of Salmonella detection among the working population was 0.24%;the positive rate among men was 0.29%,and that among women was 0.21%,with no statistically significant difference between genders(χ2=1.469,P＞0.05).The positive rates for different age groups were different,the highest positive rates was 0.42%in the 30-39 age group,and there was significantly different between the 30-39 age group and other age groups(χ2=7.817,P＜0.01).There was no statistically significant difference among the seasons(χ2=1.063,P＞0.05).The positive rates for each month of the year ranged from 0.11%to 0.38%,with no statistically significant difference among the months(χ2=3.654,P＞0.05).Twelve serotypes were detected,mainly in the B group,with Salmonella typhimurium being the predominant type.The PFGE spectrum of 51 Salmonella strains was divided into 50 band types,with significant differences among the band types,and no obvious correlation between the band type clustering and serotype.Conclusion There is a significant difference in the positive rate among the 30-39 age group employees in Qidong.The environmental factors and dietary habits contribute to the unique regional characteristics of Salmonella.The dominant groups and dominant strains are found by serotyping,and PFGE shows a polymorphic distribution of molecular typing,with no clustering infection phenomenon.