Drug resistance and colicin production among various serotypes of Escherichia coli of animal origin.

One hundred and twenty two strains of E. coli isolated from clinical conditions of animals were studied for the production of colicins and their sensitivity behaviour towards 16 antibiotics and trimethoprim-sulphamethoxazole. Out of 122 strains, 27 (22.1%) were found colicinogenic and 25 (93%) of these colicinogenic strains were found resistant to one or more of drugs in various combinations. All the 27 colicinogenic strains could be typed into 15 serogroups. Serogroup 084 was found predominant. Transfer of R-plasmids and Col-plasmids were observed in 5 (18.5%) strains individually. In one strain both drug resistance and colicin production determinants were transferred enblock. Such transconjugants will be more invasive and virulent and will create serious chemotherapeutic problems.