Prevalence, antimicrobial resistance, virulence gene, and class 1 integrons of Enterococcus faecium and Enterococcus faecalis from pigs, pork and humans in Thai-Laos border provinces

J Glob Antimicrob Resist. 2019 Sep:18:130-138. doi: 10.1016/j.jgar.2019.05.032. Epub 2019 Jun 8.

Abstract

Objectives: This study aimed to determine prevalence, antimicrobial resistance, virulence genes, and Class 1 integrons of Enterococcus faecium (E. faecium) and Enterococcus faecalis (E. faecalis) from pigs, pork and humans in Thailand-Laos border provinces.

Methods: Six hundred and forty-eight rectal and carcass swab samples from border provinces of Thailand (n=359) and Lao PDR (n=289) were collected and examined from September 2013 to October 2014.

Results: The overall prevalence of Enterococcus species was 483 of 648 (75%), comprising E. faecium (359 of 483, 74.3%) and E. faecalis (124 of 483, 25.7%). The occurrence of E. faecium in pigs, pig carcasses, retail pork, and humans in Thailand was 80.6%, 73.8%, 77.6%, and 67%, respectively. The prevalence of E. faecium was higher in Laos (65.7%) than Thailand (47.1%) (P<0.001). Conversely, E. faecalis was more common in Thailand (24.2%) than Laos (12.8%) (P<0.001). The E. faecium and E. faecalis isolates were resistant to all antimicrobials except vancomycin. High resistance was first observed to tetracycline, erythromycin and streptomycin, followed by gentamicin, ampicillin and chloramphenicol. Both E. faecium (7%) and E. faecalis (0.8%) carried empty Class 1 integrons: E. faecium carried gel (6.4%) and esp (0.8%), while E. faecalis carried agg (41.9%), cylA (36.3%), gel (60.5%), and esp (42.7%).

Conclusions: This study revealed a variable distribution of antimicrobial resistance and virulence genes among E. faecium and E. faecalis from pigs, pig products and humans in Thai-Laos border provinces. These pathogens may serve as potential reservoirs for the maintenance and widespread dissemination of antimicrobial resistance and virulence determinants from animals to humans via the food chain.

Keywords: Antimicrobial resistance; Enterococcus; Laos; Occurrence; Thailand; Virulence.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Bacterial Agents / pharmacology*
  • Drug Resistance, Multiple, Bacterial / genetics*
  • Enterococcus faecalis / genetics*
  • Enterococcus faecalis / isolation & purification
  • Enterococcus faecium / genetics*
  • Enterococcus faecium / isolation & purification
  • Genes, Bacterial / genetics*
  • Humans
  • Integrons / genetics
  • Laos
  • Microbial Sensitivity Tests
  • Molecular Epidemiology*
  • Prevalence
  • Swine
  • Thailand
  • Virulence / drug effects
  • Virulence / genetics
  • Virulence Factors / genetics*

Substances

  • Anti-Bacterial Agents
  • Virulence Factors