title: Proton motive force-dependent efflux of tetracycline in clinical isolates of Helicobacter pylori.
abstract: The aim of this study was to evaluate the role of proton motive force (PMF)-dependent efflux in resistance of Helicobacter pylori to tetracycline (Tet). Tet MIC was determined by agar dilution in the presence and absence of carbonyl cyanide m-chlorophenylhydrazone (CCCP), an inhibitor of PMF. Antibiotic accumulation was conducted in the presence or absence of CCCP and the fluorescence of the accumulated antibiotic was measured by spectrofluorometry. In the presence of CCCP, antibiotic accumulation was increased by 2-17-fold in 17/20 Tet(r) isolates and by 3-10-fold in four of five high-level-resistant mutants. Correlation was observed between this increase and diminution of MIC with CCCP. PMF-dependent efflux mechanisms therefore appear to play an important role in the resistance of clinical isolates of H. pylori to Tet.
authors: Department of Biology, Alzahra University, Tehran, Iran.
authors: Mona
authors: M
authors: Anoushiravani
authors: Department of Biology, Alzahra University, Tehran, Iran.
authors: Tahereh
authors: T
authors: Falsafi
authors: Department of Biology, Tehran University, Tehran, Iran.
authors: Vahid
authors: V
authors: Niknam
mesh_terms: D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002648:Child; D005798:Genes, Bacterial; D016481:Helicobacter Infections / Q000188:drug therapy / Q000382:microbiology; D016480:Helicobacter pylori / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D008826:Microbial Sensitivity Tests; D009154:Mutation; D018892:Proton-Motive Force / Q000187:drug effects / Q000502:physiology*; D013050:Spectrometry, Fluorescence; D013752:Tetracycline / Q000493:pharmacokinetics* / Q000494:pharmacology; D013753:Tetracycline Resistance / Q000235:genetics / Q000502:physiology; D014475:Uncoupling Agents / Q000494:pharmacology
chemical_list: D014475:Uncoupling Agents; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D013752:Tetracycline