Serotypes, antibiotic resistance, and virulence genes of Salmonella in children with diarrhea

Background Salmonellais an important foodborne pathogen that causes acute diarrhea in humans worldwide. This study analyzed the relationships of serotypes and antibiotic resistance with virulence genes ofSalmonellaisolated from children with salmonellosis. Methods Serological typing was performed using the slide-agglutination method. The Kirby-Bauer disk diffusion method was used to test antibiotic susceptibility. Twenty virulence genes were detected by PCR. Results SalmonellaTyphimurium (21 isolates, 34.43%) andS Enteritidis (12 isolates, 19.67%) were the predominant species among the 61 isolates. Ampicillin resistance was most common (63.93%), and among the cephalosporins, resistance was most often found to cefotaxime, a third-generation cephalosporin (19.67%). Among the 20 virulence genes,prgH, ssrB, andpagCwere detected in allSalmonellaisolates. InS Typhimurium, the detection rates ofhilA, sipB, marT, mgtC, sopB, pagN, nlpI, bapA, oafA, andtolCwere high. InS Enteritidis, the detection rates oficmF, spvB, spvR, andpefAwere high. Nitrofurantoin resistance was negatively correlated with the virulence genebapA(P = .005) and was positively correlated withicmF, spvB, spvR, andpefA(P = .012, .008, .002, and .005, respectively), ThePvalues between all other virulence genes and antibiotic resistance were >.05. Conclusion SalmonellaTyphimurium andS Enteritidis were the main serotypes in children with diarrhea in Hangzhou, China.Salmonellaexhibited a high level of resistance to common antibiotics, and a high rate of bacteria carrying virulence genes was observed. However, no significant correlation was found between virulence genes and resistance to common antibiotics.