In vitro antimicrobial susceptibility of Salmonellae from animals in Louisiana.

A total of 56 Salmonella isolates from animals were tested for susceptibility to 12 antimicrobial agents by the standard disk diffusion and mirodilution methods. All isolates were susceptible to gentamicin, tobramycin, amikacin, chloramphenicol, crimethoprim and sulfonamide, colistin, and nitrofurantoin. Isolates were most frequently resistant to tetracycline (50%) and kanamycin (36%). A low prevalence of resistance to ampicillin (16%), carbenicillin (16%), and cephalothin (4%) was found. The differences in susceptibility results between the two methods were minor.