Transmissible drug resistance of Escherichia coli and Salmonella from humans, animals, and their rural environments.

Isolates of Escherichia coli and Salmonella species obtained from humans, animals, and their rural environments were tested for their ability to transfer multiple drug resistance to competent recipients. In all, 125 (52.9%) of 242 isolates of E.coli transferred all or part of their resistance to E.coli CSH-2, and 103 (44.4%) of 232 isolates of E.coli transferred all or part of their resistance to Salmonella choleraesuis var. kuzendorf 214. The data suggest that the multiple drug resistance of E.coli transferred all or part of their resistance to Salmonella choleraesuis var kuzendorf 214. The data suggest that the multiple drug resistance of E. coli in the gut of humans who work with livestock may be due to the transfer of resistance determinants from animal strains to the resident flora of the human gut. Such transfer could occur during transient passage through the digestive tract. Multiple drug-resistant Salmonella were isolated from all sources. In all, 48 (80%) of 60 isolates of Salmonella transferred all or part of their resistance to E. coli CSH-2, and isolates of Salmonella transferred all or part of their resistance to E.coli CSH-2, and 42 (82.4%) of 51 isolates of Salmonella transferred all or part of their resistance to S. choleraesuis var, kuzendorf 214. Fifty-three (46.9%) of 113 antibiotic-sensitive isolates of E.coli possessed resistance transfer factor, and six (23.1%) of 26 isolates with resistance transfer factor mobilized resistance determinants in isolates unable to transfer drug resistance during conjugation experiments.