title: Molecular characterization of antibiotic-resistant bacteria in contaminated chicken meat sold at supermarkets in Bangkok, Thailand.
abstract: We assessed contamination by antibiotic-resistant bacteria in chicken meat obtained from supermarkets in Bangkok, Thailand. The prevalence of Salmonella enterica and Escherichia coli was 18.7% (14/75) and 53% (106/200), respectively. Most probable number (MPN) analysis showed that 56.7% of the samples (34/60) were in violation of the limit of allowable coliform bacteria in chicken meat, for which the maximum is 46,000 MPN/g. Multidrug-resistant phenotypes of both S. enterica and E. coli were found. The presence of class 1 integrons was demonstrated by polymerase chain reaction (PCR) and dot-blot hybridization. PCR showed that class 1 integrons were present in 42.9% (6/14) and 37.7% (40/106) of S. enterica and E. coli isolates, respectively. Resistance genes identified in this study were aadA2, aadA4, aadA22, and aadA23 (for aminoglycoside resistance); dfrA5 (for trimethoprim resistance), and lnuF (for lincosamide resistance). Four S. enterica isolates underwent multilocus sequence typing and the results were sequence type (ST) 50, ST 96, ST 1543, and ST 1549, which matched well with strains from many countries and reflected an international spread. Our study revealed that class 1 integrons have spread into community sources and might play an important role in horizontal antibiotic resistance gene transfer.
authors.affiliation: Department of Microbiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.
authors.forename: Chaiyaporn
authors.initials: C
authors.lastname: Chaisatit
authors.forename: Chanwit
authors.initials: C
authors.lastname: Tribuddharat
authors.forename: Chaiwat
authors.initials: C
authors.lastname: Pulsrikarn
authors.forename: Surang
authors.initials: S
authors.lastname: Dejsirilert
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D058491:Bacterial Load; D002645:Chickens; D004269:DNA, Bacterial / Q000235:genetics; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D005798:Genes, Bacterial; D032023:Integrons; D008460:Meat / Q000382:microbiology*; D058885:Multilocus Sequence Typing; D016133:Polymerase Chain Reaction; D019779:Salmonella enterica / Q000145:classification / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D013785:Thailand
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial