title: Elimination of antibiotic-resistant plasmids by quinolone antibiotics.
abstract: Of 7 plasmids we tested, the plasmid pORF2 was eliminated in vitro with the most efficiency by treatment with subinhibitory concentrations of novobiocin, coumermycin and 10 quinolones. It showed a cure rate of 43% by enoxacin; 12% by novobiocin, pefloxacin, ciprofloxacin and CI-934; 7% by coumermycin and ofloxacin; 9% by amifloxacin; and 4% by AM-833. On the other hand, pSC194, pBR322 and pMH612 were poorly cured in vitro by quinolones, except pSC194 which was cured 33% by enoxacin. R1, pP1603, and pUB110 were unaffected by the treatment. Mice were challenged intraperitoneally with a 2XLD50 of Escherichia coli carrying the ORF2 plasmid and were treated per os with 1 X or 1/2 X ED50 of either enoxacin or CI-934. The frequency of loss of ampicillin resistance determined 3 h after treatment shows curing effects of 92% for CI-934, 89% for enoxacin and 20% for untreated control.
mesh_terms: D042462:4-Quinolones; D049933:Aminocoumarins; D000668:Ampicillin Resistance / Q000235:genetics; D000818:Animals; D000890:Anti-Infective Agents / Q000008:administration & dosage / Q000494:pharmacology*; D001412:Bacillus subtilis / Q000187:drug effects / Q000235:genetics; D003374:Coumarins / Q000008:administration & dosage / Q000494:pharmacology; D004269:DNA, Bacterial / Q000032:analysis / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics; D005260:Female; D051379:Mice; D008815:Mice, Inbred Strains; D009675:Novobiocin / Q000008:administration & dosage / Q000494:pharmacology; D011815:R Factors / Q000187:drug effects* / Q000235:genetics; D013211:Staphylococcus aureus / Q000187:drug effects / Q000235:genetics
chemical_list: D042462:4-Quinolones; D049933:Aminocoumarins; D000890:Anti-Infective Agents; D003374:Coumarins; D004269:DNA, Bacterial; D009675:Novobiocin; C004628:coumermycin