Antimicrobial susceptibility of Salmonella isolated pig carriers

Abstract

Ninety-six Salmonella isolates from healthy carrier pigs were obtained from a survey in pig farms of Catalonia (Spain). Isolates were serotyped and examined for their antimicrobial susceptibility against a panel of 18 antimicrobial agents. Only isolates having different phenotypic and antimicrobial susceptibility characteristics were considered. With this restriction, we considered to have 62 different strains belonging to 17 serotypes. The most common serotype was Anatum (16.1 %) followed by Rissen (14.5 %), Typhimurium (11.3 %), Derby (9.7 %), Tilburg (8.1 %), Goldcoast (8.1 %) and Typhimurium variant 4,5,12:i:-(6.5 %). Others 10 serotypes were also isolated less than three times each. Antimicrobial susceptibility analysis showed that the highest level of resistance was against tetracycline (68.8 %). Sixty-two percent of the strains showed resistance to three or more antimicrobial agents and 46% were resistant to five or more drugs. The maximum number of compounds to which two strains were resistant was 10 (corresponding to a 4,5,12:i:-strain). None of the strains was resistant to colistin or ceftriaxone and 12 strains were susceptible to all antimicrobial agents tested