title: Prevalence and antimicrobial resistance in Salmonella enterica isolated from broiler chickens, pigs and meat products in Thailand-Cambodia border provinces.
abstract: This study aimed to examine the prevalence and antimicrobial resistance (AMR) of Salmonella isolates from broiler chickens, pigs and their associated meat products in the Thailand-Cambodia border provinces. A total of 941 samples were collected from pigs and broiler chickens at slaughter houses and from carcasses at local fresh markets in Sa Kaeo, Thailand (n = 554) and Banteay Meanchey, Cambodia (n = 387) in 2014 and 2015. From these samples, 345 Salmonella isolates were collected from Sa Keao (n = 145; 23%) and Banteay Meanchey (n = 200; 47%) and assayed for antimicrobial susceptibility, class 1 integrons and extended-spectrum β-lactamase (ESBL) genes. Serovars Typhimurium (29%) and Rissen (29%) were the most common serotypes found in Thai and Cambodian isolates, respectively. Multidrug resistance was detected in 34% and 52% of isolates from Sa Keao and Banteay Meanchey, respectively. The majority of the Thai isolates were resistant to ampicillin (72.4%), whereas most Cambodian isolates were resistant to sulfamethoxazole (71%). Eleven isolates from Sa Keao and 44 from Banteay Meanchey carried class 1 integrons comprising resistance gene cassettes. The most common gene cassette array was dfrA12-aadA2 (61.1%). Six isolates were ESBL producers. The β-lactamase genes found included blaTEM-1, blaCTX-M-55and blaCMY-2. Some of these class 1 integrons and ESBL genes were located on conjugative plasmid. In conclusion, multidrug-resistant Salmonella are common in pigs, chickens and their products in the Thailand-Cambodia border provinces. Our findings indicate that class 1 integrons play a role in spread of AMR in the strains in this study.
authors.affiliation: Research Unit in Microbial Food Safety and Antimicrobial Resistance, Department of Veterinary Public Health, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330.
authors.forename: Suthathip
authors.initials: S
authors.lastname: Trongjit
authors.affiliation: Research Group for Prevention Technology in Livestock, Faculty of Veterinary Medicine, Khon Kaen University, Khon Khan 40000 Thailand.
authors.forename: Sunpetch
authors.initials: S
authors.lastname: Angkititrakul
authors.affiliation: Division of Global Health Protection, Thailand Ministry of Public Health-US Centers for Disease Control and Prevention Collaboration, Nonthaburi 11000 Thailand.
authors.forename: R Emerson
authors.initials: RE
authors.lastname: Tuttle
authors.affiliation: Research Unit in Microbial Food Safety and Antimicrobial Resistance, Department of Veterinary Public Health, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330.
authors.forename: Jiratchaya
authors.initials: J
authors.lastname: Poungseree
authors.affiliation: Division of Global Health Protection, Thailand Ministry of Public Health-US Centers for Disease Control and Prevention Collaboration, Nonthaburi 11000 Thailand.
authors.forename: Pawin
authors.initials: P
authors.lastname: Padungtod
authors.affiliation: Research Unit in Microbial Food Safety and Antimicrobial Resistance, Department of Veterinary Public Health, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330.
authors.forename: Rungtip
authors.initials: R
authors.lastname: Chuanchuen
mesh_terms: D000667:Ampicillin / Q000494:pharmacology; D000818:Animals; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D002160:Cambodia / Q000453:epidemiology; D002645:Chickens; D004269:DNA, Bacterial / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial; D005516:Food Microbiology; D008461:Meat Products / Q000382:microbiology*; D011201:Poultry Diseases / Q000453:epidemiology / Q000382:microbiology; D015995:Prevalence; D012481:Salmonella Infections, Animal / Q000453:epidemiology* / Q000382:microbiology*; D019779:Salmonella enterica / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D013420:Sulfamethoxazole / Q000494:pharmacology; D013552:Swine; D013553:Swine Diseases / Q000453:epidemiology / Q000382:microbiology; D013785:Thailand / Q000453:epidemiology
chemical_list: D000890:Anti-Infective Agents; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D000667:Ampicillin; D013420:Sulfamethoxazole
keywords:  Cambodia;  Salmonella enterica;  Thailand; antimicrobial resistance