Detection and Characterization of Salmonella Serotypes in the Production Chain of Two Pig Farms in Buenos Aires Province, Argentina

Abstract

The aim of the present study was to determine the prevalence of <i>Salmonella</i> in the pork production chain and to characterize <i>Salmonella</i> isolates. From 764 samples, 35 (4.6%) were positive for <i>Salmonella</i> spp., as determined by biochemical tests and the presence of the <i>invA</i> gene. From these, 2.6, 2.0, 8.8, and 8.0% corresponded to samples collected from farms, slaughterhouses, boning rooms and retail markets, respectively. <i>Salmonella</i> strains were classified into five serotypes and distributed as follows: <i>S.</i> Typhimurium in the pork production chain, <i>S</i>. Kentucky in farms and slaughterhouses, <i>S</i>. Brandenburg in slaughterhouses<i>, S</i>. Livingstone in farms and <i>S</i>. Agona in boning rooms and retail markets. Interestingly, the antimicrobial susceptibility testing indicated that all 35 <i>Salmonella</i> spp.-positive isolates were resistant to at least one antimicrobial agent, and 30 were multidrug-resistant (MDR) and resistant to different classes of antibiotics. The enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) analysis showed clonal relatedness among strains isolated from farms, boning rooms and retail markets. The presence of antibiotic-resistant <i>Salmonella</i> in food poses a potential health hazard to consumers.