ABSTRACT
The prevalence of and the antibiotic resistance shown by Salmonella isolated from pigs in Andalusia (southern Spain) is reported. Salmonella enterica was recovered from 40 (33%) of 121 sampled herds, and a total of 65 isolates were serotyped. The most common Salmonella serotypes were Typhimurium and Rissen (30.7% each); others included Derby (9.2%), Brandenburg (9.2%), Newport (7.7%), Bredeney (4.6%), Anatum (3.0%), Hadar (1.5%), and Goldcoast (1.5%). One strain (1.5%) belonging to the monophasic variant of the Typhimurium serotype (Salmonella 4,5,12:i: -) was also detected. Definitive phage type (DT) 104b was the most common Typhimurium phage type isolated. These Salmonella strains were resistant to various antimicrobial agents, including tetracycline (84.6%), streptomycin (69.2%), neomycin (63.0%), sulfonamides (61.5%), ampicillin (53.8%), and amoxicillin (53.8%). All isolates were fully susceptible to ceftriaxone, ciprofloxacin, and colistin. Thirty-nine strains (64%) resistant to four or more antimicrobial agents were defined as multidrug resistant. Multidrug resistance profiles were observed in Salmonella serotypes Typhimurium, Rissen, Brandenburg, Bredeney, a monophasic variant, Gold-coast, Hadar, and Anatum, with serotypes Typhimurium and Brandenburg showing the most complicated resistance patterns (resistant to > or = 11 drugs).
