Antituberculosis drugs: reducing efflux=increasing activity.

In mycobacteria, it was assumed that efflux pumps only had a marginal role in drug resistance. In recent years, owing to the need to find novel drugs against multidrug-resistant tuberculosis, it has become clear that efflux should not be ignored. Although efflux inhibitors have been very useful for characterizing in vitro the properties of efflux pumps, their usefulness in vivo is limited because of their toxicity.

Design and synthesis of triazolopyrimidine acylsulfonamides as novel anti-mycobacterial leads acting through inhibition of acetohydroxyacid synthase.

Novel triazolopyrimidine acylsulfonamides class of antimycobacterial agents, which are mycobacterial acetohydroxyacid synthase (AHAS) inhibitors were designed by hybridization of known AHAS inhibitors such as sulfonyl urea and triazolopyrimidine sulfonamides. This Letter describes the synthesis and SAR studies of this class of molecules by variation of two parts of the molecule, the phenyl and triazolopyrimidine rings. SAR study describes optimisation of enzyme potency, whole cell potency and evidence of mechanism of action.

Optimization of pyrrolamides as mycobacterial GyrB ATPase inhibitors: structure-activity relationship and in vivo efficacy in a mouse model of tuberculosis.

Moxifloxacin has shown excellent activity against drug-sensitive as well as drug-resistant tuberculosis (TB), thus confirming DNA gyrase as a clinically validated target for discovering novel anti-TB agents. We have identified novel inhibitors in the pyrrolamide class which kill Mycobacterium tuberculosis through inhibition of ATPase activity catalyzed by the GyrB domain of DNA gyrase. A homology model of the M.

In vitro and in vivo efficacy of β-lactams against replicating and slowly growing/nonreplicating Mycobacterium tuberculosis.

Beta-lactams, in combination with beta-lactamase inhibitors, are reported to have activity against Mycobacterium tuberculosis bacteria growing in broth, as well as inside the human macrophage. We tested representative beta-lactams belonging to 3 different classes for activity against replicating M. tuberculosis in broth and nonreplicating M.

Involvement of efflux pumps in the resistance to peptidoglycan synthesis inhibitors in Mycobacterium tuberculosis.

We evaluated the contributions of Mycobacterium tuberculosis efflux pumps towards intrinsic resistance to different classes of peptidoglycan synthesis inhibitors (PSI). Our study indicates that the efflux pump knockout strains are more susceptible to PSI than the wild type. Vancomycin and ceftriaxone exhibited up to 3 log increased kill on efflux pump mutants compared to the wild-type strain, strongly suggesting an important role for efflux pumps in the intrinsic resistance of M.

Efflux pumps of Mycobacterium tuberculosis play a significant role in antituberculosis activity of potential drug candidates.

Active efflux of drugs mediated by efflux pumps that confer drug resistance is one of the mechanisms developed by bacteria to counter the adverse effects of antibiotics and chemicals. To understand these efflux mechanisms in Mycobacterium tuberculosis, we generated knockout (KO) mutants of four efflux pumps of the pathogen belonging to different classes. We measured the MICs and kill values of two different compound classes on the wild type (WT) and the efflux pump (EP) KO mutants in the presence and absence of the efflux inhibitors verapamil and l-phenylalanyl-l-arginyl-β-naphthylamide (PAβN).

Rv1218c, an ABC transporter of Mycobacterium tuberculosis with implications in drug discovery.

Efflux systems are important in determining the efficacy of antibiotics used in the treatment of bacterial infections. In the last decade much attention has been paid to studying the efflux pumps of mycobacteria. New classes of compounds are under investigation for development into potential candidate drugs for the treatment of tuberculosis.

Evaluation of killing kinetics of anti-tuberculosis drugs on Mycobacterium tuberculosis using a bacteriophage-based assay.

Background: Killing kinetics studies on Mycobacterium tuberculosis are labour intensive and time consuming since it takes nearly 6-7 weeks to get the data from an experiment. A modified protocol is required to increase the throughput and expedite the results.

Methods: The killing kinetics of frontline drugs used for the treatment of tuberculosis was studied using 24-well plates and 2 methods of enumeration of survivors of M.