Transferable antibiotic resistance in Escherichia coli isolated from urinary-tract infections: hospital v. community patients.

In order to study the prevalence of plasmid-mediated antibiotic resistance in E. coli causing urinary-tract infections (UTI) specimens of urine were obtained, from a total of 125 hospital and community patients, and examined bacteriologically and analysed. Thirty-nine (80%) of forty-nine, and thirty-three (65%) of fifty-one hospital and community patients respectively were infected by multiple resistant E. coli. Of these multiple-resistant strains more than three-quarters carried transferable R-plasmids. Antibiotic resistance was transferred en bloc or singly to known sensitive recipient mainly by conjugation by a technique that ensured cell-to-cell contact. Resistance markers in both the donor and the transcipient strains were eliminated by treatment with aminoacridine dyes and ethidium bromide. The result emphasises the need for bacteriological diagnosis of UTI and sensitivity testing prior to antibiotic therapy.