In vitro susceptibility of salmonellae to eight antimicrobial agents.

The Bauer-Kirby disk diffusion method was used to determine the susceptibility of 333 strains of Salmonella isolated in Saudi Arabia to eight antimicrobial agents. The following susceptibilities were observed: Cephalothin 99.40%, furadoine 99.10%, chloramphenicol 98.80%, ampicillin 98.20%, polymyxin 96.70%, kanamycin 95.80%, streptomycin 90.99%. Only 50.45% of the strains were susceptible to tetracycline, whereas 44.14% and 5.41% were respectively intermediate and resistant to this drug. The antibiograms displayed many resistant patterns. Some of the salmonellae were singly resistant while others were resistant to 2 or more drugs in various combinations. In view of the potential for salmonellae to have inherent or acquired resistance to certain commonly used antimicrobial agents, susceptibility of all isolates of salmonellae, particularly of all clinically significant strains should be determined periodically.