Variability in Antimicrobial Resistance amongSalmonella entericaStrains from Fattening Pigs and Sows

Abstract

The aim of this study was to determine the prevalence of antibiotic resistance and different resistance patterns for Salmonella isolates collected from Belgian sows and fattening pigs at different ages and at slaughter. The most frequently isolated serotypes were S. Typhimurium (42.3%), S. Derby (25.1%), S. Goldcoast (7.3%), and S. Infantis (4.8%). All 901 isolates were submitted to antimicrobial susceptibility testing for 14 compounds using the disc agar diffusion test. The highest percentage of resistance was found to oxytetracycline (34.2%), streptomycin (32.5%), sulfamethizole (27.6%), and ampicillin (24.9%). Three of the isolates showed resistance to cephalosporins and none to second-generation fluoroquinolones. Multiresistance (resistance to > or =2 antimicrobials) was observed in 33.2% of the strains. Differences in resistance patterns were observed between and within serotypes as well as genotypes. A significant lower proportion (p < 0.01) of resistant strains was recovered in fecal samples from sows (23/56) than from fattening pigs during the weaning (30/30), growing (79/85), and finishing periods (45/52). The proportion of resistant strains recovered from fecal samples taken at the herd (154/167) was higher than in the samples collected at the slaughterhouse (75/140). When designing antimicrobial resistance surveillance programs for Salmonella in pigs, it is important to take multiple samples within each herd from both sows and fattening pigs at different time points.

Non-typhoidal Salmonella infections in pigs: A closer look at epidemiology, pathogenesis and control

“…A thorough knowledge of how these serotypes During the 1950s and 1960s, Salmonella Choleraesuis, including variant Kunzendorf, was the predominant serotype isolated from pigs worldwide (Fedorka-Cray et al, 2000). At the present time, Salmonella Choleraesuis is still highly prevalent in North America and Asia, but is found rarely in Australia and Western European countries (Wilcock and Schwartz, 1992;Fedorka-Cray et al, 2000;Chiu et al, 2004;Davies et al, 2004;Chang et al, 2005;Nollet et al, 2006). Pigs can be infected by several Salmonella serotypes and the occurrence of these serotypes is also partly geographically determined (Fedorka-Cray et al, 2000;Loynachan et al, 2004).…”

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The Importance of Sample Size in the Determination of a Flock-Level Antimicrobial Resistance Profile forEscherichia coliin Broilers

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