Serodiversity and antimicrobial resistance profiles of detected Salmonella on swine production chain in Chiang Mai and Lamphun, Thailand

ABSTRACT

Background: Foodborne illness is growing public health problem worldwide. Salmonella is recognized as a major causeof this problem. Salmonella serotyping is a phenotypic characteristics which provided useful epidemiological markers forprimary discrimination. The emergence and spread of antimicrobial resistant of this pathogen have become a major publichealth concern. The objectives of this study were to determine Salmonella serotypes, and antimicrobial resistance profileson swine production chain (Farm-to-slaughtering process) in Chiang Mai and Lamphun, Thailand.Materials, Methods & Results: A total of 300 Salmonella strains were randomly selected from isolates recovered in2011-2013 in Chiang Mai and Lamphun, Thailand, including the isolates from fecal, lymph node, pest and environmentalsamples. Serotyping and antimicrobial susceptibility testing was performed by WHO National Salmonella and Shigella center(Thailand). Salmonella isolates were serotyped by agglutination tests with antisera (S&A Reagents Lab Ltd., Thailand) onthe basis of somatic-O, as well as phase 1 and phase 2 flagellar antigens according to the Kauffmanne-White scheme. Inaddition, all serotyping Salmonella isolates were detected for antimicrobial susceptibility testing by using the disk diffusion method of the Clinical and Laboratory Standard Institute. Ten antimicrobial agents were determined. The data werecollected and analyzed for descriptive statistical analysis by Epi Info ™7. Twenty-one Salmonella serotypes were detectedin both farms and slaughterhouses. Salmonella Rissen is the highest frequency found in both farms and slaughterhouses(30.7% and 38.0%, respectively). Thirty three antimicrobial resistance patterns were demonstrated. There were including10 common patterns isolated from pig farms and slaughterhouses. The highest frequency...