Whole Genome Sequencing, Antibiotic Resistance, and Epidemiology Features of Nontyphoidal Salmonella Isolated From Diarrheic Children: Evidence From North China

Nontyphoidal Salmonella (NTS) in children remains a growing burden on public health and often causes children to be hospitalized with diarrheic symptoms. In this work, 260 strains of human Salmonella isolated from Jilin, China were characterized by serotypes and antimicrobial resistance using whole genome sequencing (WGS). The most prevalent serotype was Salmonella enteritidis (47.3%), followed by S. I 4,[5],12:i:- (33.1%), and Salmonella Typhimurium (7.3%). Furthermore, the consistency between resistance phenotype and genotype was confirmed. Similarly, strains harbored bla(TEM-1B) and tetA genes were detected, which verified the level of resistant phenotype in beta-lactams and tetracyclines. The presence of a single mutation in parC, gyrA, and qnrS1 genes corresponding to quinolones was also observed. In our work, multilocus sequence typing (MLST) and core genome multilocus sequence typing (cgMLST) were found to have a high resolution to molecular traceability, and the combination of both was conducive to practical application in an actual situation. Taking all of this into account, we suggested that the comprehensive surveillance of Salmonella infection in children should be carried out to monitor antimicrobial-resistant trends from various sources and to alert on outbreaks of foodborne diseases to protect public health.

Automated summary

This study characterized 260 strains of human Salmonella isolated from Jilin, China through serotyping and antimicrobial resistance analysis using whole genome sequencing. The most common serotype was Salmonella enteritidis, followed by S. I 4,[5],12:i:- and Salmonella Typhimurium. The presence of resistance genes and their corresponding phenotypes were confirmed, as well as the presence of specific mutations related to quinolone resistance. The combination of multilocus sequence typing (MLST) and core genome multilocus sequence typing (cgMLST) proved to be effective in molecular traceability. Comprehensive surveillance of Salmonella infections in children was recommended to monitor antimicrobial-resistant trends and prevent outbreaks of foodborne diseases, thus protecting public health.