title: Erythromycin and azithromycin transport into Haemophilus influenzae ATCC 19418 under conditions of depressed proton motive force (delta mu H).
abstract: The effect of collapsing the electrochemical proton gradient (delta mu H) on [3H]erythromycin and [14C]azithromycin transport in Haemophilus influenzae ATCC 19418 was studied. The proton gradient and membrane potential were determined from the distribution of [2-14C]dimethadione and rubidium-86, respectively. delta mu H was reduced from 124 to 3 mV in EDTA-valinomycin-treated cells at 22 degrees C with 150 mM KCl and 0.1 mM carbonyl cyanide m-chlorophenylhydrazone. During the collapse of delta mu H, macrolide uptake increased. Erythromycin efflux studies strongly suggested that this increase was not due to an energy-dependent efflux pump but was likely due to increased outer membrane permeability. These data indicated that macrolide entry was not a delta mu H-driven active transport process but rather a passive diffusion process.
authors.affiliation: Anti-Infective Research Division, Abbott Laboratories, Illinois 60064-3500.
authors.forename: J O
authors.initials: JO
authors.lastname: Capobianco
authors.forename: R C
authors.initials: RC
authors.lastname: Goldman
mesh_terms: D017963:Azithromycin; D001426:Bacterial Proteins / Q000096:biosynthesis; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D004492:Edetic Acid / Q000494:pharmacology; D004917:Erythromycin / Q000031:analogs & derivatives* / Q000493:pharmacokinetics*; D006193:Haemophilus influenzae / Q000378:metabolism* / Q000648:ultrastructure; D008564:Membrane Potentials / Q000502:physiology; D011522:Protons; D014634:Valinomycin / Q000494:pharmacology
chemical_list: D001426:Bacterial Proteins; D011522:Protons; D014634:Valinomycin; D004917:Erythromycin; D017963:Azithromycin; D004492:Edetic Acid