Antimicrobial resistance and incidence of R factor among Salmonella isolated from patients with enteric fever and other clinical conditions in Madras, India (1975-1976).

The incidence of transmissible drug resistance among Salmonella isolated from patients with enteric fever and other clinical conditions is reported. All of the Salmonella isolated were studied for antimicrobial resistance. Of the 336 strains, five were multiply resistant to drugs including chloramphenicol, and four of these strains transmitted resistance to Escherichia coli F-Lac+. Multiply drug resistant E. coli were isolated from 12 patients receiving chloramphenicol, and in seven cases the E. coli transmitted drug resistance to sensitive Salmonella isolated from the same patients. The occurrence of multiple drug resistance among Salmonella was not found to be restricted to a single serogroup, and multiple drug resistance in Salmonella paratyphi A in India is reported for the first time. Although the incidence of Salmonella carring R factor is negligible, the unpredictability of its occurrence poses a potential threat in a country where typhoid is endemic.