title: Inhibition of conjugal transfer of R plasmids by pipemidic acid and related compounds.
abstract: It was found that pipemidic acid and related compounds have the common property of inhibiting the conjugal transfer of R plasmids carried by Escherichia coli and Pseudomonas aeruginosa. This inhibition was not due to bactericidal activity of the compounds against donors, recipients, or R(+) transconjugants. However, it was correlated inversely with their minimal inhibitory concentrations, depending especially upon sensitivity of donors to the compounds. The inhibition was generally observed in mating systems using various combinations of 14 R plasmids and 9 bacterial strains. The pretreatment of a donor or a recipient strain with pipemidic acid showed only a small inhibitory effect on the transfer of an R plasmid, whereas the presence of the compound during an active mating caused a marked inhibitory effect.
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003227:Conjugation, Genetic / Q000187:drug effects*; D003864:Depression, Chemical; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D009268:Nalidixic Acid / Q000494:pharmacology; D009539:Nicotinic Acids / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D011815:R Factors; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D009539:Nicotinic Acids; D009268:Nalidixic Acid