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There is urgent need for new drug regimens that more rapidly cure tuberculosis (TB). Existing TB drugs and regimens vary in treatment-shortening activity, but the molecular basis of these differences is unclear, and no existing assay directly quantifies the ability of a drug or regimen to shorten treatment. Here, we show that drugs historically classified as sterilizing and non-sterilizing have distinct impacts on a fundamental aspect of Mycobacterium tuberculosis physiology: ribosomal RNA (rRNA) synthesis. In culture, in mice, and in human studies, measurement of precursor rRNA reveals that sterilizing drugs and highly effective drug regimens profoundly suppress M. tuberculosis rRNA synthesis, whereas non-sterilizing drugs and weaker regimens do not. The rRNA synthesis ratio provides a readout of drug effect that is orthogonal to traditional measures of bacterial burden. We propose that this metric of drug activity may accelerate the development of shorter TB regimens.

Diagnosing Buruli ulcer (BU) is complicated by limited access to the sensitive IS2404 qPCR. Experienced clinicians report a distinct odour of Buruli ulcers. We explored the potential of headspace analysis by thermal desorption-gas chromatography-mass spectrometry to detect volatile organic compounds (VOCs) from Mycobacterium ulcerans both in vitro and clinically. This study was conducted in two phases: a discovery and validation phase. During the discovery phase, VOCs that enable identification of M. ulcerans cultures were determined. During the validation phase, these VOCs were evaluated in clinical samples for which we used gauzes from patients with skin ulcerations in the Democratic Republic of Congo. Seven M. ulcerans headspace samples were compared with four from sterile growth medium and laboratory environmental air. The univariate analysis resulted in the selection of 24 retained VOC fragments and a perfect differentiation between cultures and controls. Sixteen of 24 fragments were identified, resulting in eleven unique compounds, mainly alkanes. Methylcyclohexane was the best performing compound. Based on these 24 fragments, headspace samples originating from gauzes of 50 open skin lesions (12 qPCR positive and 38 negative) were analysed and an AUC of 0.740 (95%-CI 0.583–0.897) was obtained. As this is an experimental study, future research has to confirm whether the identified compounds can serve as novel biomarkers. Author summary: In this study the odour of bacteria that cause Buruli ulcer was examined. First, the air of bacteria cultured in the lab was analysed and compared with controls. Next, air was sampled from gauzes worn by people in the Kongo Central province, the Democratic Republic of Congo. Their lesions were compatible with Buruli ulcer disease but only 12 out of 50 were infected with the Buruli bacterium. In the odour of the Buruli bacteria and in gauzes from people with Buruli ulcer, several chemicals were present more abundantly than in gauzes from people with wounds caused by other diseases. Future research has to determine whether these chemicals can become part of a new test for Buruli ulcer disease. [ABSTRACT FROM AUTHOR]

Some anti‐mycobacterial drugs are known to cause QT interval prolongation, potentially leading to life‐threatening ventricular arrhythmia. However, the highest leprosy and tuberculosis burden occurs in settings where electrocardiographic monitoring is challenging. The feasibility and accuracy of alternative strategies, such as the use of automated measurements or a mobile electrocardiogram (mECG) device, have not been evaluated in this context. As part of the phase II randomized controlled BE‐PEOPLE trial evaluating the safety of bedaquiline‐enhanced post‐exposure prophylaxis (bedaquiline and rifampicin, BE‐PEP, versus rifampicin, SDR‐PEP) for leprosy, all participants had corrected QT intervals (QTc) measured at baseline and on the day after receiving post‐exposure prophylaxis. The accuracy of mECG measurements as well as automated 12L‐ECG measurements was evaluated. In total, 635 mECGs from 323 participants were recorded, of which 616 (97%) were of sufficient quality for QTc measurement. Mean manually read QTc on 12L‐ECG and mECG were 394 ± 19 and 385 ± 18 ms, respectively (p < 0.001), with a strong correlation (r = 0.793). The mean absolute QTc difference between both modalities was 11 ± 10 ms. Mean manual and automated 12L‐ECG QTc were 394 ± 19 and 409 ± 19 ms, respectively (n = 636; p < 0.001), corresponding to moderate agreement (r = 0.655). The use of a mECG device for QT interval monitoring was feasible and yielded a median absolute QTc error of 8 ms. Automated QTc measurements were less accurate, yielding longer QTc intervals. [ABSTRACT FROM AUTHOR]

BackgroundIt is unknown whether immunosuppression influences the physiologic state of Mycobacterium tuberculosis in vivo. We evaluated the impact of host immunity by comparing M. tuberculosis and human gene transcription in sputum between human immunodeficiency virus (HIV)-infected and uninfected patients with tuberculosis.MethodsWe collected sputum specimens before treatment from Gambians and Ugandans with pulmonary tuberculosis, revealed by positive results of acid-fast bacillus smears. We quantified expression of 2179 M. tuberculosis genes and 234 human immune genes via quantitative reverse transcription-polymerase chain reaction. We summarized genes from key functional categories with significantly increased or decreased expression.ResultsA total of 24 of 65 patients with tuberculosis were HIV infected. M. tuberculosis DosR regulon genes were less highly expressed among HIV-infected patients with tuberculosis than among HIV-uninfected patients with tuberculosis (Gambia, P < .0001; Uganda, P = .037). In profiling of human genes from the same sputa, HIV-infected patients had 3.4-fold lower expression of IFNG (P = .005), 4.9-fold higher expression of ARG1 (P = .0006), and 3.4-fold higher expression of IL10 (P = .0002) than in HIV-uninfected patients with tuberculosis.ConclusionsM. tuberculosis in HIV-infected patients had lower expression of the DosR regulon, a critical metabolic and immunomodulatory switch induced by NO, carbon monoxide, and hypoxia. Our human data suggest that decreased DosR expression may result from alternative pathway activation of macrophages, with consequent decreased NO expression and/or by poor granuloma formation with consequent decreased hypoxic stress.

BackgroundTreatment initiation rapidly kills most drug-susceptible Mycobacterium tuberculosis, but a bacterial subpopulation tolerates prolonged drug exposure. We evaluated drug-tolerant bacilli in human sputum by comparing messenger RNA (mRNA) expression of drug-tolerant bacilli that survive the early bactericidal phase with treatment-naive bacilli.MethodsM. tuberculosis gene expression was quantified via reverse-transcription polymerase chain reaction in serial sputa from 17 Ugandans treated for drug-susceptible pulmonary tuberculosis.ResultsWithin 4 days, bacterial mRNA abundance declined >98%, indicating rapid killing. Thereafter, the rate of decline slowed >94%, indicating drug tolerance. After 14 days, 16S ribosomal RNA transcripts/genome declined 96%, indicating slow growth. Drug-tolerant bacilli displayed marked downregulation of genes associated with growth, metabolism, and lipid synthesis and upregulation in stress responses and key regulatory categories-including stress-associated sigma factors, transcription factors, and toxin-antitoxin genes. Drug efflux pumps were upregulated. The isoniazid stress signature was induced by initial drug exposure, then disappeared after 4 days.ConclusionsTranscriptional patterns suggest that drug-tolerant bacilli in sputum are in a slow-growing, metabolically and synthetically downregulated state. Absence of the isoniazid stress signature in drug-tolerant bacilli indicates that physiological state influences drug responsiveness in vivo. These results identify novel drug targets that should aid in development of novel shorter tuberculosis treatment regimens.

BackgroundTuberculosis is a leading cause of death worldwide, yet the determinants of death are not well understood. We sought to determine risk factors for mortality during treatment of drug-susceptible pulmonary tuberculosis under program settings.MethodsRetrospective chart review of patients with drug-susceptible tuberculosis reported to the San Francisco Tuberculosis Control Program from 1990-2001.ResultsOf 565 patients meeting eligibility criteria, 37 (6.6%) died during the study period. Of 37 deaths, 12 (32.4%) had tuberculosis listed as a contributing factor. In multivariate analysis controlling for follow-up time, four characteristics were independently associated with mortality: HIV co-infection (HR = 2.57, p = 0.02), older age at tuberculosis diagnosis (HR = 1.52 per 10 years, p = 0.001); initial sputum smear positive for acid fast bacilli (HR = 3.07, p = 0.004); and experiencing an interruption in tuberculosis therapy (HR = 3.15, p = 0.002). The association between treatment interruption and risk of death was due to non-adherence during the intensive phase of treatment (HR = 3.20, p = 0.001). The median duration of treatment interruption did not differ significantly in either intensive or continuation phases between those who died and survived (23 versus 18 days, and 37 versus 29 days, respectively). No deaths were directly attributed to adverse drug reactions.ConclusionsIn addition to advanced age, HIV and characteristics of advanced tuberculosis, experiencing an interruption in anti-tuberculosis therapy, primarily due to non-adherence, was also independently associated with increased risk of death. Improving adherence early during treatment for tuberculosis may both improve tuberculosis outcomes as well as decrease mortality.

BackgroundHelicobacter pylori, a lifelong and typically asymptomatic infection of the stomach, profoundly alters gastric immune responses, and may benefit the host in protection against other pathogens. We explored the hypothesis that H. pylori contributes to the control of infection with Mycobacterium tuberculosis.Methodology/principal findingsWe first examined M. tuberculosis-specific IFN-gamma and H. pylori antibody responses in 339 healthy Northern Californians undergoing routine tuberculin skin testing. Of 97 subjects (29%) meeting criteria for latent tuberculosis (TB) infection (LTBI), 45 (46%) were H. pylori seropositive. Subjects with LTBI who were H. pylori-seropositive had 1.5-fold higher TB antigen-induced IFN-gamma responses (p = 0.04, ANOVA), and a more Th-1 like cytokine profile in peripheral blood mononuclear cells, compared to those who were H. pylori seronegative. To explore an association between H. pylori infection and clinical outcome of TB exposure, we evaluated H. pylori seroprevalence in baseline samples from two high risk TB case-contact cohorts, and from cynomolgus macaques experimentally challenged with M. tuberculosis. Compared to 513 household contacts who did not progress to active disease during a median 24 months follow-up, 120 prevalent TB cases were significantly less likely to be H. pylori infected (AOR: 0.55, 95% CI 0.0.36-0.83, p = 0.005), though seroprevalence was not significantly different from non-progressors in 37 incident TB cases (AOR: 1.35 [95% CI 0.63-2.9] p = 0.44). Cynomolgus macaques with natural H. pylori infection were significantly less likely to progress to TB 6 to 8 months after M. tuberculosis challenge (RR: 0.31 [95% CI 0.12-0.80], p = 0.04).Conclusions/significanceH. pylori infection may induce bystander effects that modify the risk of active TB in humans and non-human primates. That immunity to TB may be enhanced by exposure to other microbial agents may have important implications for vaccine development and disease control.

Objective To estimate the population prevalence of active pulmonary tuberculosis in Gambia. Methods Between December 2011 and January 2013, people aged ≥ 15 years participating in a nationwide, multistage cluster survey were screened for active pulmonary tuberculosis with chest radiography and for tuberculosis symptoms. For diagnostic confirmation, sputum samples were collected from those whose screening were positive and subjected to fluorescence microscopy and liquid tuberculosis cultures. Multiple imputation and inverse probability weighting were used to estimate tuberculosis prevalence. Findings Of 100678 people enumerated, 55 832 were eligible to participate and 43100 (77.2%) of those participated. A majority of participants (42942; 99.6%) were successfully screened for symptoms and by chest X-ray. Only 5948 (13.8%) were eligible for sputum examination, yielding 43 bacteriologically confirmed, 28 definite smear-positive and six probable smear-positive tuberculosis cases. Chest X- ray identified more tuberculosis cases (58/69) than did symptoms alone (43/71). The estimated prevalence of smear-positive and bacteriologically confirmed pulmonary tuberculosis were 90 (95% confidence interval, CI: 53-127) and 212 (95% CI: 152-272) per 100000 population, respectively. Tuberculosis prevalence was higher in males (333; 95% CI: 233-433) and in the 35-54 year age group (355; 95% CI: 219- 490). Conclusion The burden of tuberculosis remains high in Gambia but lower than earlier estimates of 490 per 100000 population in 2010. Less than half of all cases would have been identified based on smear microscopy results alone. Successful control efforts will require interventions targeting men, increased access to radiography and more accurate, rapid diagnostic tests. Objectif Estimer la prevalence de la tuberculose pulmonaire active dans la population de Gambie. Methodes Entre decembre 2011 et janvier 2013, dans le cadre d'une enquete nationale en grappes a plusieurs degres, un depistage de la tuberculose pulmonaire active a ete realise au moyen d'un questionnaire sur les symptomes tuberculeux et d'une radiographie pulmonaire, chez des personnes agees de 15 ans ou plus ayant consenti a participer. Pour confirmer le diagnostic, des echantillons d'expectoration ont ete collectes pourtous les participants dont les resultats de depistage s'etaient reveles positifs, en vue de realiser des examens par microscopie de fluorescence et des cultures en milieu liquide. Les techniques d'imputation multiple et de ponderation par l'inverse de la probabilite ont ete utilisees pour estlmer la prevalence de la tuberculose. Resultats Sur les 100 678 personnes recensees, 55 832 etaient eligibles pour participer a l'etude et, parmi elles, 43 100 personnes (77,2%) ont participe. La majorite des participants (42 942; 99,6%) ont effectivement repondu au questionnaire sur les symptomes et passe une radiographie pulmonaire. Seules 5 948 personnes (13,8%) ont ete eligibles pour un examen des expectorations, ce qui a entralne le depistage de 43 cas de tuberculose confirmee bacteriologiquement, de 28 cas formeis de tuberculose a frottis positif et de 6 cas probables de tuberculose a frottis positif. Les radiographies pulmonaires ont permis d'identifier plus de cas de tuberculose (58/69) que le seul questionnaire sur les symptomes (43/71). Les prevalences de la tuberculose pulmonaire a frottis positif et de la tuberculose bacteriologiquement confirmee ont respectivement ete estimees a 90 cas (Intervalle de confiance de 95%: 53-127) pour 100 OOCK habitants et 212 cas (IC 95%: 152-272) pour 100000 habitants. La prevalence de la tuberculose s'est averee plus elevee dans la population masculine (333 cas; IC 95%: 233-433) et dans la tranche des 35-54 ans (355; IC 95%: 219-490). Conclusion La charge de la tuberculose reste elevee en Gambie, merme si elle a baisse par rapport a la precedente estimation, realisee en 2010, qui faisait etat de 490 cas pour 100 000 habitants. En utilisant uniquement la microscopie des frottis, moins de la moitie des cas auraient ete identifies. Pour etre efficaces, les efforts de lutte contre la tuberculose doivent indure des campagnes ciblant les hommes, ameliorer l'accessibilite des examens radlographiques et utiliser des tests diagnostiques rapides plus precis. Objetivo Estimarla prevalencia de la tuberculosis pulmonar activa entre la poblacion en Gambia. Metodos Entre diciembre de 2011 y enero de 2013, personas de 15 anos o mas que participaron en una encuesta nacional en varias etapas y a nivel de grupos fueron examinadas en busca de tuberculosis pulmonar activa mediante una radiografia de torax y para encontrar sintomas de tuberculosis. Para confirmarei diagnostico, se recolectaron muestras de esputo de las personas cuyo examen resulto positivo y se sometieron a microscopia de fluorescencia y cultivos liquidos de tuberculosis. Para calcularla prevalencia de la tuberculosis, se utilizaron varias asignaciones y analisis de probabilidad inversa. Resultados De las 100 678 personas enumeradas, 55 832 se consideraron aptas para participar, de las cuales 43 100 (77,2%) participaron. La mayoria de los participantes (42 942; 99,6%) fueron examinados con exito para detectar sintomas, asi como por radiografia del torax. Solo 5 948 (13,8%) fueron aptos para pruebas de esputo, lo que dio lugar a 43 confirmados a nivel bacteriologico, 28 casos baciliferos de tuberculosis definitivos y 6 casos baciliferos de tuberculosis probable. Las radiografias del torax identificaron mas casos de tuberculosis (58/69) que los sintomas por si solos (43/71). La prevalence estimada de tuberculosis pulmonar bacilifera y confirmada a nivel bacteriologico fue de 90 (intervalo de confianza, 1C, del 95%: 53-127) y 212 (IC del 95%: 152-272) porcada 100 000 habitantes, respectivamente. La prevalence de la tuberculosis fue mayor en hombres (333; IC del 95%: 233-433) y en los grupos de edad entre 35 y 54 anos (355; IC del 95%: 219-490). Conclusion Los indices de tuberculosis siguen siendo altos en Gambia, pero inferiores a las estimaciones anteriores de 490 por cada 100000 habitantes en 2010. Se identificaron menos de la mitad de todos los casos segun los resultados de la microscopia de frotis por si solos. Para que los esfuerzos de control tengan exito, seran necesarias intervenciones enfocadas a los hombres, un mayor acceso a radiografias y pruebas de diagnostico mas rapidas y exactas., Introduction Tuberculosis killed 1.5 million people in 2014 and is the leading cause of death from an infectious disease worldwide. (1) Sub-Saharan Africa, with 28% (9.6 million) of all notified [...]