Characterization of phenotypic and genotypic antibiotic resistance in <i>M</i>. <i>tuberculosis</i> H37Rv and clinical strains.

<p>Characterization of phenotypic and genotypic antibiotic resistance in <i>M</i>. <i>tuberculosis</i> H37Rv and clinical strains.</p

Exposure to pretomanid in broth cultures.

<p>The bacterial strains H37Rv and BTB 02–141 were exposed to increasing concentrations of PRT (0.032-1mg/L) or to INH (2mg/L) in broth The bacterial numbers were determined by luminometry directly after exposure (0h) and at 4h, 24h and 4 days later. Data are presented as mean bacterial survival (% of unexposed control) ± SEM (n = 4–5). Significant differences are indicated with * (p≤0.05) or ** (p≤0.01) as determined by two-way ANOVA.</p

Effect of iNOS inhibition on growth of clinical strains of <i>M</i>. <i>tuberculosis</i> in macrophages.

<p>Macrophages (RAW 264.7) were stimulated with IFN-γ/LPS and/or the iNOS inhibitor L-NMMA (1mM) or left untreated. Macrophages were infected with H37Rv (a), the INH-susceptible strains E3942 (b), CDC 1551 (c), the INH-resistant strains BTB 02–141 (d), and E1155 (e) at a MOI of 5 and bacterial numbers were determined by luminometry. Data are presented as mean fold change of the bacterial numbers on day 2 compared to day 0 (D2/D0) ± SEM, (n = 5–6). Significant differences are indicated with * (p≤0.05), ** (p≤0.01) or with *** (p≤0.001) as determined by one-way ANOVA with repeated measures.</p

Survival of <i>M</i>. <i>tuberculosis</i> exposed to DETA/NO and SIN-1.

<p>The bacterial strains were exposed to 0.1 mM DETA/NO (a) and 1 mM SIN-1 (b) and bacterial numbers were determined by luminometry after 4 days of incubation. Data are presented as mean bacterial survival (% of unexposed control) ± SEM, (n = 3). Significant differences from H37Rv are indicated with *(p≤0.05), or **(p≤0.01) as determined by one-way ANOVA with correction for multiple testing.</p

Dose- and time-dependent killing of <i>M. tuberculosis</i> exposed to NO.

<p>Survival of three clinical strains, H37Rv and BCG after exposure to 1 mM of the NO donor DETA/NO for 4 and 24 hours (A). Survival of the three clinical strains exposed to different doses of DETA/NO for 24 hours (B). Survival was determined through viable count (colony forming units, CFU) and each point represents a mean value of duplicates.</p

Characteristics for patients infected with strains of <i>M. tuberculosis</i> susceptible to NO or with reduced susceptibility to NO.

<p>Q1–Q3 (quartile 1 to quartile 3); NO (nitric oxide); BMI (body mass index); ESR (sedimentation rate); INH (isoniazid); SM (streptomycin); EMB (ethambutol); RIF (rifampin). NO-susceptible and reduced NO-susceptible strains defined as ≤10% and >10% survival respectively after exposure to 1 mM DETA/NO. All patients were smear positive at week 0. Continuous data were tested with Mann-Whitney <i>U</i>-test and discrete data with Fisher’s exact test or Pearson’s Chi-square test.</p

Multiple logistic regression analysis comparing strains of <i>M. tuberculosis</i> susceptible to NO with strains of reduced susceptibility to NO.

<p>Multiple logistic regression analysis comparing strains of <i>M. tuberculosis</i> susceptible to NO with strains of reduced susceptibility to NO.</p

Reduced NO susceptibility in spoligotype-based clusters of <i>M. tuberculosis</i>.

<p>Survival of clinical isolates 24 hours after exposure to the NO donor DETA/NO. Presence of resistance to first-line anti-TB drugs is indicated with circles; isoniazid (INH), streptomycin (SM) and rifampin (RIF). Each point represents a mean value of duplicates and the dashed line is the median survival of all 50 isolates.</p

Novel N‑Linked Aminopiperidine-Based Gyrase Inhibitors with Improved hERG and in Vivo Efficacy against Mycobacterium tuberculosis

DNA gyrase is a clinically validated target for developing drugs against Mycobacterium tuberculosis (Mtb). Despite the promise of fluoroquinolones (FQs) as anti-tuberculosis drugs, the prevalence of pre-existing resistance to FQs is likely to restrict their clinical value. We describe a novel class of N-linked aminopiperidinyl alkyl quinolones and naphthyridones that kills Mtb by inhibiting the DNA gyrase activity. The mechanism of inhibition of DNA gyrase was distinct from the fluoroquinolones, as shown by their ability to inhibit the growth of fluoroquinolone-resistant Mtb. Biochemical studies demonstrated this class to exert its action via single-strand cleavage rather than double-strand cleavage, as seen with fluoroquinolones. The compounds are highly bactericidal against extracellular as well as intracellular Mtb. Lead optimization resulted in the identification of potent compounds with improved oral bioavailability and reduced cardiac ion channel liability. Compounds from this series are efficacious in various murine models of tuberculosis