title: Persistence of plasmid-carrying tetracycline-resistant Escherichia coli in a married couple, one of whom was receiving antibiotics.
abstract: This paper describes an extension to an earlier account of the coliform flora carried by a married couple, one of whom was taking tetracycline for prolonged periods. The latter phase of this study was notable for the following: first, certain tetracycline-resistant Escherichia coli O antigen types persisted in one of the participants for several weeks after tetracycline was withdrawn; second, a course of ampicillin led to replacement of the tetracycline-resistant flora by one that was ampicillin resistant, but the end of the ampicillin course led to the reappearance of the tetracycline-resistant line, even though no tetracycline was being taken; and third, the tetracycline-sensitive O75 E. coli, which appeared toward the end of the survey, had not lost their plasmid but carried a derivative in which the tetracycline resistance gene(s) had been inactivated by the insertion of an extra piece of deoxyribonucleic acid with a molecular weight of about 1 megadalton.
mesh_terms: D000942:Antigens, Bacterial / Q000032:analysis; D004269:DNA, Bacterial / Q000032:analysis; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000235:genetics*; D004927:Escherichia coli Infections / Q000188:drug therapy* / Q000235:genetics; D006801:Humans; D008297:Male; D011815:R Factors; D013752:Tetracycline / Q000627:therapeutic use*
chemical_list: D000942:Antigens, Bacterial; D004269:DNA, Bacterial; D013752:Tetracycline