title: Spread of R-plasmids among Escherichia coli causing urinary tract infections.
abstract: The incidence of multiple-antibiotic resistance among Escherichia coli isolated from urinary tract infections at Charing Cross Hospital, London, increased over the last 10 years, and its distribution was related to O-type. Among strains of the eight O-types most frequently causing such infections at this hospital, O4, O9, and O18 had a high incidence of multiple resistance (35, 22, and 19%, respectively); O2 and O6 had a intermediate incidence (14 and 11%, respectively); and O7, O1, and O75 had a low incidence (8, 6, and less than 3%, respectively). This nonrandom distribution appears to be a consequence of unequal plasmid recipient ability. After overnight mating with antibiotic-resistant donors, R-plasmid infection frequencies among antibiotic-sensitive urinary tract isolates differed by up to 10(5)-fold, and such differences were correlated with the variation in the incidence of antibiotic resistance among the O-types. The inherent differences in the ability to achieve significant R-plasmid spread, which appear to be determined by the host, not the plasmid, may be compounded in some cases by the inhibition of potential mating partners by colicin production.
mesh_terms: D000667:Ampicillin / Q000494:pharmacology; D003227:Conjugation, Genetic; D003470:Culture Media; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000382:microbiology*; D006801:Humans; D007612:Kanamycin / Q000494:pharmacology; D010403:Penicillin Resistance; D011815:R Factors; D013444:Sulfisoxazole / Q000494:pharmacology; D014552:Urinary Tract Infections / Q000382:microbiology*
chemical_list: D003470:Culture Media; D007612:Kanamycin; D013444:Sulfisoxazole; D000667:Ampicillin