Mycobacterium tuberculosis from chronic murine infections that grows in liquid but not on solid medium

Dhillon, Jasvir; Lowrie, Douglas B.; Mitchison, D.A.

doi:10.1186/1471-2334-4-51

Cited by 53 publications

(42 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, RLUs have been used to monitor transcriptional changes and to estimate the total numbers of viable cells in such cultures. However, to date, the enumeration of nonreplicating populations in liquid culture or the organs of mice is still conducted by determination of the numbers of CFU (14,22). In the present study, changes in the colony-forming rate were observed over time in the fermentor culture, with a progressive decrease in the population able to form colonies within 2 weeks, consistent with slow or nonreplicating populations resulting from the self-depletion of oxygen (37,38).…”

Section: Discussionsupporting

confidence: 49%

Low-Oxygen-Recovery Assay for High-Throughput Screening of Compounds against Nonreplicating Mycobacterium tuberculosis

Cho

Warit

Wan

et al. 2007

Antimicrob Agents Chemother

288

370

View full text Add to dashboard Cite

Screening for new antimicrobial agents is routinely conducted only against actively replicating bacteria. However, it is now widely accepted that a physiological state of nonreplicating persistence (NRP) is responsible for antimicrobial tolerance in many bacterial infections. In tuberculosis, the key to shortening the 6-month regimen lies in targeting this NRP subpopulation. Therefore, a high-throughput, luminescence-based lowoxygen-recovery assay (LORA) was developed to screen antimicrobial agents against NRP Mycobacterium tuberculosis. M. tuberculosis H 37 Rv containing a plasmid with an acetamidase promoter driving a bacterial luciferase gene was adapted to low oxygen conditions by extended culture in a fermentor with a 0.5 headspace ratio. The MICs of 31 established antimicrobial agents were determined in microplate cultures maintained under anaerobic conditions for 10 days and, for comparative purposes, under aerobic conditions for 7 days. Cultures exposed to drugs under anaerobic conditions followed by 28 h of "recovery" under ambient oxygen produced a luminescent signal that was, for most compounds, proportional to the number of CFU determined prior to the recovery phase. No agents targeting the cell wall were active against NRP M. tuberculosis, whereas drugs hitting other cellular targets had a range of activities. The calculated Z factor was in the range of 0.58 to 0.84, indicating the suitability of the use of LORA for high-throughput assays. This LORA is sufficiently robust for use for primary high-throughput screening of compounds against NRP M. tuberculosis.It is now widely accepted that a physiological state of nonreplicating persistence (NRP) is responsible for antimicrobial tolerance in many bacterial infections (11). In tuberculosis, a subpopulation of Mycobacterium tuberculosis isolates in NRP is considered an important contributing factor to the long treatment duration required, and the key to shortening the currently recommended 6-month regimen (the primary goal of new anti-M. tuberculosis chemotherapy) lies in effective targeting of this phenotype (2, 6). Standard drug susceptibility assays for detection of the activities of drugs against rapidly growing bacteria may not identify such compounds (8,11). In vitro models of M. tuberculosis isolates in NRP exist (4,30,(37)(38)(39), and there are several reports of studies that have assessed drug activity against NRP or stationary-phase cells (20,(34)(35)(36)42); however, these have relied upon the enumeration of CFU, thus precluding high-throughput screening (HTS) applications and requiring a minimum of 3 to 4 weeks for the completion of testing. In addition, the culture and preparation of NRP M. tuberculosis cells (5,17,29,30,38) have used batch cultures, which are not optimal for monitoring and for comparative studies. In contrast, a chemostat or a fermentor with a continuous-oxygen-monitoring culture system allows bacteria to be grown in a controlled and defined environment; there are two reports of the successful cultivation of M. tuberculos...

show abstract

Section: Discussionsupporting

confidence: 49%

Low-Oxygen-Recovery Assay for High-Throughput Screening of Compounds against Nonreplicating Mycobacterium tuberculosis

Cho

Warit

Wan

et al. 2007

Antimicrob Agents Chemother

288

370

View full text Add to dashboard Cite

show abstract

“…These bacteria could be resuscitated by addition of Rpf (resuscitation promoting factor of Micrococcus luteus) to the media. However, whether these mycobacteria regain identical growth capacities to M. tuberculosis isolated from sputum specimens remains to be clarified [56]. Tufariello et al showed that rpf-deficient M. tuberculosis strains remain viable and that rpf genes are expressed during latent stages of M. tuberculosis in mouse lungs [57].…”

Section: Resuscitation Of M Tuberculosis In Granulomatous Lesionsmentioning

confidence: 99%

New insights into the function of granulomas in human tuberculosis

Ulrichs

Kaufmann

2005

The Journal of Pathology

353

337

View full text Add to dashboard Cite

The human tuberculous granuloma provides the morphological framework for local immune processes central to the outcome of tuberculosis. This review article describes investigations on human lung granulomas aimed at better understanding the regional host response and counter-measures to Mycobacterium tuberculosis. These findings lead to a revised view of the regional immune response in human tuberculosis. Novel insights into this dynamic cross-talk form the basis of novel intervention strategies.

show abstract

“…The primary efficacy endpoint was the EBA over 14 days [EBA(0-14)] calculated for each individual with the formula EBA(0-14) ϭ [mean log 10 CFU(day 0) Ϫ log 10 CFU(day 14)]/14, averaged per treatment group. Secondary efficacy endpoints were EBA(0-2) and EBA (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14), calculated in analogous fashion, and the mycobacterial metabolic activity was measured by change in TTP calculated in the same manner as that for EBA. EBA and TTP were also described with linear, bilinear, or nonlinear regression over time, depending on which method best fitted the data.…”

Section: Methodsmentioning

confidence: 99%

Early Bactericidal Activity and Pharmacokinetics of PA-824 in Smear-Positive Tuberculosis Patients

Diacon

Dawson

Hanekom

et al. 2010

Antimicrob Agents Chemother

165

110

View full text Add to dashboard Cite

show abstract

Mycobacterium tuberculosis from chronic murine infections that grows in liquid but not on solid medium

Cited by 53 publications

References 5 publications

Low-Oxygen-Recovery Assay for High-Throughput Screening of Compounds against Nonreplicating Mycobacterium tuberculosis

Low-Oxygen-Recovery Assay for High-Throughput Screening of Compounds against Nonreplicating Mycobacterium tuberculosis

New insights into the function of granulomas in human tuberculosis

Early Bactericidal Activity and Pharmacokinetics of PA-824 in Smear-Positive Tuberculosis Patients

Contact Info

Product

Resources

About