Prevalence and antimicrobial resistance in Salmonella enterica isolated from broiler chickens, pigs and meat products in Thailand–Cambodia border provinces. (14th February 2017) - Trongjit, Suthathip
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 bla TEM‐1, bla CTX‐M‐55 and bla CMY‐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.