Occurrence of plasmid-mediated quinolone resistance determinants and rmtB gene in Salmonella enterica serovar enteritidis and Typhimurium isolated from food-animal products in Tunisia

Foodborne Pathog Dis. 2013 Sep;10(9):813-9. doi: 10.1089/fpd.2012.1466. Epub 2013 Jun 15.

Abstract

Four hundred and thirty Salmonella isolates, recovered from various food-animal products, were tested for nalidixic acid resistance, plasmid-mediated quinolone resistance, and genetic relationship. One hundred fifteen isolates (113 Salmonella serovar Enteritidis and two Salmonella serovar Typhimurium isolates) of 430 (26.7%) Salmonella isolates exhibited nalidixic acid resistance. Polymerase chain reaction screening for qnrA, qnrB, qnrS, qepA (encoding fluoroquinolones resistance) and rmtB (encoding aminoglycosides resistance) showed that 5 (1.16%) isolates were positive for qnr- and qepA-type genes, and the aac(6')-Ib-cr gene was observed in two (1.7%) Enteritidis isolates concomitantly with qnrA or qnrB. The co-occurrence of qepA and rmtB in one Typhimurium isolate is noteworthy. Pulsed-field gel electrophoresis revealed a high genetic homogeneity of nalidixic-resistant isolates and the persistence of clonal clusters over 4 years in different regions in Tunisia and from various food-animal products. To the best of our knowledge, this is the first report of co-occurrence of qepA and rmtB in a Salmonella strain.

MeSH terms

  • Aminoglycosides / pharmacology
  • Animals
  • Anti-Bacterial Agents / pharmacology
  • DNA, Bacterial / genetics
  • Drug Resistance, Multiple, Bacterial / genetics*
  • Electrophoresis, Gel, Pulsed-Field
  • Fluoroquinolones / pharmacology*
  • Food Contamination*
  • Food Microbiology
  • Genes, Bacterial
  • Meat / microbiology
  • Microbial Sensitivity Tests
  • Milk / microbiology
  • Retrospective Studies
  • Salmonella enteritidis / drug effects
  • Salmonella enteritidis / genetics*
  • Salmonella enteritidis / isolation & purification
  • Salmonella typhimurium / drug effects
  • Salmonella typhimurium / genetics*
  • Salmonella typhimurium / isolation & purification
  • Tunisia

Substances

  • Aminoglycosides
  • Anti-Bacterial Agents
  • DNA, Bacterial
  • Fluoroquinolones