Antimicrobial resistance and molecular genotyping of Salmonella enterica serovar Enteritidis clinical isolates from Guizhou province of Southwestern China

PLoS One. 2019 Sep 23;14(9):e0221492. doi: 10.1371/journal.pone.0221492. eCollection 2019.

Abstract

Salmonella enterica serovar Enteritidis (S. Enteritidis) is the most common and essential serotype that causes salmonellosis in Guizhou province. This study aimed to investigate the antimicrobial resistance (AMR) and molecular genotyping of 79 S. Enteritidis clinical isolates from 2011 to 2016 in Guizhou, China. Antimicrobial resistance and minimum inhibitory concentrations (MICs) of S. Enteritidis clinical isolates were detected by micro broth dilution method against ten classes 16 antimicrobial agents, and molecular genotyping were examined by pulsed-field gel electrophoresis (PFGE) and multiple-locus variable-number tandem repeat analysis (MLVA). All (100%) isolates showed resistance to at least one antimicrobial. Resistance to nalidixic acid (98.7%) was the highest, followed by sulfamethoxazole (87.3%) and ampicillin (77.2%). The majority of isolates (92.4%) showed decreased susceptibility to ciprofloxacin. Resistance to the third and fourth-generation cephalosporins was observed. Twenty-six AMR profiles were observed, and the predominant AMR profile was ampicillin-streptomycin-sulfamethoxazole-amoxicillin/clavulanic acid-nalidixic acid. A high burden of multidrug resistance (MDR) (81.0%) was found. Seventy-nine S. Enteritidis isolates were divided into 33 different pulsotypes (PTs), and the most frequent PT was PT18. Twenty-six different MLVA types (MTs) were generated with seven VNTR loci analysis of these isolates. The dominant PTs and MTs were persistent during 2011-2016. S. Enteritidis clinical isolates showed higher genetic diversity using PFGE combined with MLVA grouped into 60 PT-MT genotypes. No correlation was observed between genotypes, AMR profiles and geographic location. These data revealed the characteristics of AMR and molecular genotyping of S. Enteritidis clinical isolates in Guizhou province. These results highlight that strengthening the AMR and molecular genotyping surveillance is essential to prevent and control salmonellosis in Guizhou. PFGE combined with MLVA should be powerful tools for the molecular genotyping of S. Enteritidis isolates.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • China / epidemiology
  • Drug Resistance, Bacterial / genetics
  • Electrophoresis, Gel, Pulsed-Field
  • Genotype
  • Humans
  • Microbial Sensitivity Tests
  • Minisatellite Repeats
  • Molecular Epidemiology
  • Multilocus Sequence Typing
  • Salmonella Infections / drug therapy
  • Salmonella Infections / epidemiology
  • Salmonella Infections / microbiology
  • Salmonella enteritidis / drug effects*
  • Salmonella enteritidis / genetics*
  • Salmonella enteritidis / isolation & purification

Grants and funding

This work was funded by (to XYW) the Science and Technology Foundation Planning Project of Guizhou Province of China (Qian Ke He Basis [2017]1094), (to XYW) The Science and Technology Foundation of the Health Department of Guizhou Province of China (gzwjkj2016-1-003), and (to SJL) the Program of Scientific and Technological Innovation Team of Guizhou Province (Qian Ke He Platform Talent [2018]5606). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.