Antibiotic resistance among predominant Salmonella serovars and phagovars in Canada.

The antibiotic susceptibility of 2609 Salmonella isolates, collected during the period 1975-1976, was tested and the relationships between antibiotic-resistance pattern, source of isolation, and serovar and phagovar were determined. Of 95 serovars examined, 40 were sensitive to all of the antibiotics tested. Salmonella typhimurium was the major contributor to multiple resistance from both human and non-human sources. Multiply resistant strains were not found from animal feed sources and, in addition, S. typhimurium, one of the most predominant serovars, was found in every source but animal feeds. 90% of phagovar 10 was sensitive to all antibiotics tested whereas over 80% of phagovars 3-aerogenic, 92, and 123 were multiply resistant.