Salmonella is a common pathogen causing food-borne diseases in humans when contaminated food is consumed. As a food commonly consumed in Northern Thailand, raw pork consumption is a common source of contamination. However, there is limited information of the extent and prevalence of Salmonella contamination in this region. This current study was a preliminary investigation of the prevalence of Salmonella in minced pork from retail shops around the University of Phayao, Thailand, and an analysis of the antimicrobial resistance of the Salmonella. A total of 35 minced pork samples were randomly collected from retail shops in the area, and Salmonella isolation and identification were performed following ISO 6579. Serogrouping was examined by slide agglutination, and antimicrobial susceptibility testing was performed by the disk diffusion method, based on recommendations of Clinical and Laboratory Standard Institute (CLSI), 2017. Our findings were that a total of 42 Salmonella isolates were isolated from 35 samples. The most frequently isolated serogroup was Group C (54.8%), followed by Group B (16.7%) and Group E (14.3%). Antimicrobial susceptibility results revealed that most isolates were resistant to ampicillin (64.3%) and tetracycline (61.9%). Eighteen isolates (43.9%) exhibited multidrug resistant (MDR). The most frequent pattern of MDR was AMP-TE-SXT (19.1%). In summary, 100% of the minced pork samples from food retail outlets around the University of Phayao were contaminated with Salmonella, and 43.9% of the isolates were characterized to have a multidrug resistant phenotype.
Keywords: Salmonella, Minced pork, Serogrouping, Antimicrobial resistance
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