Phenoxyalkylimidazoles with an oxadiazole moiety are subject to efflux in Mycobacterium tuberculosis

Carbonyl Cyanide

The phenoxyalkylimidazoles (PAI) are an attractive chemical series with potent anti-tubercular activity targeting Mycobacterium tuberculosis respiration. Our aim was to determine if the PAI compounds are subject to efflux. Two analogs containing an oxadiazole had improved potency in the presence of the efflux inhibitors reserpine and carbonyl cyanide m-chlorophenylhydrazine, whereas the potency of analogs with a diazole was not affected.

mmpL7 Gene of Mycobacterium tuberculosis Is Responsible for Isoniazid Efflux in Mycobacterium smegmatis

10.1128/aac.49.11.4775-4777.2005 ◽

2005 ◽

Vol 49 (11) ◽

pp. 4775-4777 ◽

Cited By ~ 78

Author(s):

Maria R. Pasca ◽

Paola Guglierame ◽

Edda De Rossi ◽

Francesca Zara ◽

Giovanna Riccardi

Keyword(s):

High Resistance ◽

Mycobacterium Smegmatis ◽

Efflux Pump ◽

Gene Encoding ◽

Resistance Level ◽

Carbonyl Cyanide ◽

Resistance Nodulation Division ◽

Efflux Pump Inhibitors ◽

Energy Dependent

ABSTRACT The Mycobacterium tuberculosis mmpL7 gene, encoding a hypothetical resistance nodulation division transporter, confers a high resistance level to isoniazid when overexpressed in Mycobacterium smegmatis. The resistance level decreased in the presence of the efflux pump inhibitors reserpine and CCCP (carbonyl cyanide m-chlorophenylhydrazone). Energy-dependent efflux of isoniazid from M. smegmatis cells expressing the mmpL7 gene was observed.

Characterization of P55, a Multidrug Efflux Pump inMycobacterium bovis and Mycobacterium tuberculosis

10.1128/aac.45.3.800-804.2001 ◽

2001 ◽

Vol 45 (3) ◽

pp. 800-804 ◽

Cited By ~ 82

Author(s):

Pedro E. A. Silva ◽

Fabiana Bigi ◽

Marı́a de la Paz Santangelo ◽

Maria Isabel Romano ◽

Carlos Martı́n ◽

...

Keyword(s):

Mycobacterium Smegmatis ◽

Efflux Pump ◽

Tetracycline Resistance ◽

Drug Efflux ◽

Multidrug Efflux ◽

Multidrug Efflux Pump ◽

Reading Frame ◽

Carbonyl Cyanide

ABSTRACT The Mycobacterium bovis P55 gene, located downstream from the gene that encodes the immunogenic lipoprotein P27, has been characterized. The gene was identical to the open reading frame of the Rv1410c gene in the genome of Mycobacterium tuberculosisH37Rv, annotated as a probable drug efflux protein. Genes similar toP55 were present in all species of the M. tuberculosis complex and other mycobacteria such asMycobacterium leprae and Mycobacterium avium. By Western blotting, P55 was located in the membrane fraction ofM. bovis. When transformed into Mycobacterium smegmatis after cloning, P55 conferred aminoglycoside and tetracycline resistance. The levels of resistance to streptomycin and tetracycline conferred by P55 were decreased in the presence of the protonophore carbonyl cyanide m-chlorophenylhydrazone and the pump inhibitors verapamil and reserpine. M. smegmatiscells expressing the plasmid-encoded P55 accumulated less tetracycline than the control cells. We conclude that P55 is a membrane protein implicated in aminoglycoside and tetracycline efflux in mycobacteria.

Uncoupling Environmental pH and Intrabacterial Acidification from Pyrazinamide Susceptibility in Mycobacterium tuberculosis

10.1128/aac.00967-15 ◽

2015 ◽

Vol 59 (12) ◽

pp. 7320-7326 ◽

Cited By ~ 36

Author(s):

Nicholas D. Peterson ◽

Brandon C. Rosen ◽

Nicholas A. Dillon ◽

Anthony D. Baughn

Keyword(s):

Fluorescent Protein ◽

Active Form ◽

Growth Conditions ◽

Alkaline Media ◽

Content Type ◽

Carbonyl Cyanide ◽

Cytoplasmic Acidification ◽

Bona Fide ◽

Green Fluorescent

ABSTRACTPyrazinamide (PZA) is a first-line antitubercular drug for which the mode of action remains unresolved.Mycobacterium tuberculosislacks measurable susceptibility to PZA under standard laboratory growth conditions. However, susceptibility to this drug can be induced by cultivation of the bacilli in an acidified growth medium. Previous reports suggested that the active form of PZA, pyrazinoic acid (POA), operates as a proton ionophore that confers cytoplasmic acidification whenM. tuberculosisis exposed to an acidic environment. In this study, we demonstrate that overexpression of the PZA-activating enzyme PncA can confer PZA susceptibility toM. tuberculosisunder neutral and even alkaline growth conditions. Furthermore, we find that wild-typeM. tuberculosisdisplays increased susceptibility to POA relative to PZA in neutral and alkaline media. Utilizing a strain ofM. tuberculosisthat expresses a pH-sensitive green fluorescent protein (GFP), we find that unlike the bona fide ionophores monensin and carbonyl cyanide 3-chlorophenylhydrazone, PZA and POA do not induce rapid uncoupling or cytoplasmic acidification under conditions that promote susceptibility. Thus, based on these observations, we conclude that the antitubercular action of POA is independent of environmental pH and intrabacterial acidification.

Rv2686c-Rv2687c-Rv2688c, an ABC Fluoroquinolone Efflux Pump in Mycobacterium tuberculosis

10.1128/aac.48.8.3175-3178.2004 ◽

2004 ◽

Vol 48 (8) ◽

pp. 3175-3178 ◽

Cited By ~ 108

Author(s):

Maria Rosalia Pasca ◽

Paola Guglierame ◽

Fabio Arcesi ◽

Marco Bellinzoni ◽

Edda De Rossi ◽

...

Keyword(s):

Abc Transporter ◽

Mycobacterium Smegmatis ◽

Efflux Pump ◽

Resistance Level ◽

Carbonyl Cyanide ◽

Efflux Pump Inhibitors ◽

Energy Dependent

ABSTRACT The Mycobacterium tuberculosis Rv2686c-Rv2687c-Rv2688c operon, encoding an ABC transporter, conferred resistance to ciprofloxacin and, to a lesser extent, norfloxacin, moxifloxacin, and sparfloxacin to Mycobacterium smegmatis. The resistance level decreased in the presence of the efflux pump inhibitors reserpine, carbonyl cyanide m-chlorophenylhydrazone, and verapamil. Energy-dependent efflux of ciprofloxacin from M. smegmatis cells containing the Rv2686c-Rv2687c-Rv2688c operon was observed.