Adjunctive N-Acetylcysteine and Lung Function in Pulmonary Tuberculosis.

BACKGROUND: Tuberculosis remains a global health concern, and half of cured patients have permanent lung injury. N-acetylcysteine (NAC) has shown beneficial antimicrobial, antioxidant, and immunomodulatory effects in preclinical tuberculosis models. We examined its effects on tuberculosis treatment outcomes. METHODS: This prospective, randomized, controlled trial nested within the TB SEQUEL cohort study enrolled 140 adults with moderate or far-advanced tuberculosis. Participants were randomly assigned 1:1 to standard therapy with or without 1200 mg of oral NAC twice daily for days 1 to 112. Clinical evaluations, sputum culture, and spirometry were performed at specified intervals through day 168, after which participants returned to the TB SEQUEL cohort. The primary outcome was culture conversion. Secondary outcomes included whole-blood glutathione levels and lung function. RESULTS: Participants were predominantly young, male, and human immunodeficiency virus 1-negative and had heavy sputum Mycobacterium tuberculosis (MTB) infection burdens. NAC increased glutathione levels (NAC × day interaction, 8.48; 95% confidence interval [CI], 1.93 to 15.02) but did not increase stable culture conversion (hazard ratio, 0.84; 95% CI, 0.59 to 1.20; P=0.33). NAC treatment was associated with improved recovery of lung function (NAC × month, 0.49 [95% CI, 0.02 to 0.95] and 0.42 [95% CI, -0.06 to 0.91] for forced vital capacity and forced expiratory volume in the first second, respectively, as percentages of predicted values). The effects of NAC on lung function were greatest in participants with severe baseline lung impairment and appeared to persist beyond the period of NAC administration. Rates of serious or grade 3 to 4 nonserious adverse events did not differ between the groups. CONCLUSIONS: Despite increasing whole-blood glutathione levels, NAC did not affect eradication of MTB infection in adults with pulmonary tuberculosis that was moderate to far advanced. Secondary outcomes of lung function showed changes that merit further investigation. (Funded by TB SEQUEL grant 01KA1613 of the German Ministry for Education and Research, the Health Africa Project, and the German Center for Infection Research; ClinicalTrials.gov number, NCT03702738.).

Expanding Xpert MTB/RIF Ultra® and LF-LAM testing for diagnosis of tuberculosis among HIV-positive adults admitted to hospitals in Tanzania and Mozambique: a randomized controlled trial (the EXULTANT trial).

INTRODUCTION: Tuberculosis (TB) is an important cause of morbidity and mortality among people living with HIV (PLHIV). Current WHO-recommended strategies for diagnosing TB among hospitalized PLHIV rely on symptom screening and disease severity to assess eligibility for urine lipoarabinomannan lateral flow (LF-LAM) and molecular testing. Despite these recommendations, autopsy studies show a large burden of undiagnosed TB among admitted PLHIV. The EXULTANT trial aims to assess the impact of an expanded screening strategy using three specimens (sputum, stool, and urine) for TB diagnosis among PLHIV admitted to hospitals in two high HIV and TB burden African countries. METHODS: This is a multicenter, pragmatic, individually randomized controlled trial conducted across eleven hospitals in Tanzania and Mozambique. Participants in the intervention arm will be tested with Xpert MTB/RIF Ultra® from expectorated sputum, stool, and urine samples, with additional urine LF-LAM testing in the first 24 h after hospital admission, irrespective of the presence of the symptoms. The control arm will implement the WHO standard of care recommendations. Hospitalized adults (≥ 18 years) with a confirmed HIV-diagnosis, irrespective of antiretroviral (ART) therapy status or presence of TB symptoms will be assessed for eligibility at admission. Patients with a pre-existing TB diagnosis, those receiving anti-tuberculosis therapy or tuberculosis preventive treatment in the 6 months prior to enrolment, and those transferred from other hospitals will not be eligible. Also, participants admitted for traumatic reasons such as acute abdomen, maternal conditions, scheduled surgery, having a positive SARS-CoV2 test will be ineligible. The primary endpoint is the proportion of participants with microbiologically confirmed TB starting treatment within 3 days of enrolment. DISCUSSION: The EXULTANT trial investigates rapid implementation after admission of a new diagnostic algorithm using Xpert MTB/RIF Ultra® in several non-invasive specimens, in addition to LF-LAM, in hospitalized PLHIV regardless of TB symptoms. This enhanced strategy is anticipated to detect frequently missed TB cases in this population and is being evaluated as an implementable and scalable intervention. TRIAL REGISTRATION: Trial reference number: NCT04568967 (ClinicalTrials.gov) registered on 2020-09-29.

A practical approach to render tuberculosis samples safe for application of tuberculosis molecular bacterial load assay in clinical settings without a biosafety level 3 laboratory.

BACKGROUND: Mycobacterium tuberculosis is a category B infectious pathogen requiring level-3-containment laboratories for handling. We assessed the efficacy of heat and Guanidine thiocyanate (GTC) to inactivate M. tuberculosis prior to performance of tuberculosis Molecular Bacterial Load Assay (TB-MBLA). METHOD: We performed in vitro experiments using M.tb, H37Rv reference strain and replicated in sputum specimens. A 0.5 MacFarland standard of M. tuberculosis was serially diluted to 1x101 CFU/mL and pooled sputum was homogenised prior to serial dilutions and Xpert MTB/RIF Ultra. Three replicates for each containing 1 mL for M. tuberculosis and sputum were inactivated at 80 °C for 20 min and with GTC for 15 min. Inactivated samples were processed for culture and TB-MBLA. RESULTS: No M. tuberculosis growth was observed in MGIT for GTC or heat treated H37Rv cultures. All untreated H37Rv dilutions were MGIT positive except the most diluted specimens. Heat and GTC treatment of H37Rv reduced TB-MBLA load by 2.1log10 (P = 0.7) and 1.8log10 (P = 0.7) respectively, compared to controls. In contrast, heat treated sputum had TB-MBLA bacterial load of 3.47 ± 3.53 log10 compared to 5.4 ± 3.1 log10 eCFU/mL for GTC (p = 0.57). All heat and GTC treated sputum were culture negative. CONCLUSION: Heat or GTC renders M. tuberculosis non-viable and eliminates the need for BSL3 laboratory for performing TB-MBLA in routine healthcare settings.

Impact of N-Acetyl Cysteine (NAC) on Tuberculosis (TB) Patients-A Systematic Review.

Sustained TB infection overproduces reactive oxygen species (ROS) as a host defense mechanism. Research shows ROS is destructive to lung tissue. Glutathione (GSH) neutralizes ROS, although it is consumed. NAC is a precursor of GSH synthesis, and administering an appropriate dose of NAC to patients with respiratory conditions may enhance lung recovery and replenish GSH. The present review searched for articles reporting on the effects of NAC in TB treatment from 1960 to 31 May 2022. The PICO search strategy was used in Google Scholar, PubMed, SciFinder, and Wiley online library databases. The COVIDENCE tool was used to delete inappropriate content. We eventually discovered five clinical trials, one case report, seven reviews, in vitro research, and four experimental animal studies from the twenty-four accepted articles. The use of NAC resulted in increased GSH levels, decreased treatment time, and was safe with minimal adverse events. However, the evidence is currently insufficient to estimate the overall effects of NAC, thus the study warrants more NAC clinical trials to demonstrate its effects in TB treatment.

Clinical-demographic markers for improving diabetes mellitus diagnosis in people with tuberculosis in Tanzania.

BACKGROUND: Tuberculosis (TB) control is threatened by an increasing prevalence of diabetes mellitus (DM), particularly in endemic countries. Screening for DM is not routinely implemented in Tanzania; therefore, we aimed to screen for DM at TB diagnosis using clinical-demographic markers. METHODS: Our cross-sectional study recruited TB patients who received anti-TB treatment between October 2019 and September 2020 at health care facilities in three regions from Tanzania. Patients were screened for DM using DM symptoms (polydipsia, polyphagia and polyuria) and random blood glucose (RBG) testing. Patients with a history of DM and those with no history of DM but an RBG ≥ 7.8 mmol/L had point-of-care glycated haemoglobin (HbA1c) testing, and were considered to have DM if HbA1c was ≥ 48 mmol/mol. RESULTS: Of 1344 TB patients, the mean age was 41.0 (± 17.0) years, and 64.7% were male. A total of 1011 (75.2%) had pulmonary TB, and 133 (10.4%) had at least one DM symptom. Overall, the prevalence of DM was 7.8%, of which 36 (2.8%) TB patients with no history of DM were newly diagnosed with DM by RBG testing. TB/DM patients were older than those with only TB (50.0 ± 14.0 years vs 40.0 ± 17.0 years, p < 0.001). Patients with RBG ≥ 7.8 mmol/L were more likely to have pulmonary TB (p = 0.003), age ≥ 35 years (p = 0.018), and have at least one DM symptom (p < 0.001). There was a substantial agreement (Kappa = 0.74) between the on-site glucometer and point-of-care HbA1c tests in detecting DM range of hyperglycemia. CONCLUSION: The implementation of clinical-demographic markers and blood glucose screening identified the overall prevalence of DM and those at risk of DM in TB patients. Clinical-demographic markers are independent predictors for DM range hyperglycemia and highlight the importance of further diagnostic testing and early co-management of TB and DM.

Caregiver perspectives on TB case-finding and HIV clinical services for children diagnosed with TB in Tanzania.

Caregivers of children with tuberculosis (TB) and HIV play a critical role in seeking healthcare for their children. To assess the perspectives of caregivers of pediatric TB patients, we conducted 76 in-depth interviews at 10 TB clinics in 5 districts of Tanzania in March 2016. We assessed how the child received their TB diagnosis, the decision-making process around testing the child for HIV, and the process of linking the child to HIV treatment in the event of an HIV diagnosis. Caregivers suspected TB due to cases in their family, or the child being ill and not improving. Most caregivers noted delays before confirmation of a TB diagnosis and having to visit multiple facilities before a diagnosis. Once diagnosed, some caregivers reported challenges administering TB medications due to lack of pediatric formulations. Reasons for accepting HIV testing included recurrent illness and HIV symptoms, history of HIV in the family, and recommendation of the clinical provider. Caregivers described a relatively seamless process for linking their child to HIV treatment, highlighting the success of TB/HIV integration efforts. The multiple clinic visits required prior to TB diagnosis suggests the need for additional training and sensitization of healthcare workers and better TB diagnostic tools.

Molecular Bacterial Load Assay Concurs with Culture on NaOH-Induced Loss of Mycobacterium tuberculosis Viability.

Effective methods to detect viable Mycobacterium tuberculosis, the main causative agent of tuberculosis (TB), are urgently needed. To date, cultivation of M. tuberculosis is the gold standard, which depends on initial sample processing with N-acetyl-l-cysteine-sodium hydroxide (NALC-NaOH), chemicals that compromise M. tuberculosis viability and, consequently, the performance of downstream tests. We applied culture and the novel molecular bacterial load assay (MBLA) to measure the loss of M. tuberculosis viability following NALC-NaOH treatment of M. tuberculosis H37Rv pure culture and clinical sputum samples from pulmonary TB patients. Compared to the bacterial loads of untreated controls, NALC-NaOH treatment of M. tuberculosis reduced the MBLA-detectable bacillary load (estimated number of CFU [eCFU] per milliliter) by 0.66 ± 0.21 log10 at 23°C (P = 0.018) and 0.72 ± 0.08 log10 at 30°C (P = 0.013). Likewise, NALC-NaOH treatment reduced the viable count on solid culture by 0.84 ± 0.02 log10 CFU/ml at 23°C (P < 0.001) and 0.85 ± 0.01 log10 CFU/ml at 30°C (P < 0.001), respectively. The reduction in the viable count was reflected by a corresponding increase in the time to positivity of the mycobacterial growth indicator tube (MGIT) liquid culture: 1.2 days at 23°C (P < 0.001) and 1.1 days at 30°C (P < 0.001). This NaOH-induced M. tuberculosis viability loss was replicated in clinical sputum samples, with the bacterial load dropping by 0.65 ± 0.17 log10 from 5.36 ± 0.24 log10 eCFU/ml to 4.71 ± 0.16 log10 eCFU/ml for untreated and treated sputa, respectively. Applying the model of Bowness et al. (R. Bowness, M. J. Boeree, R. Aarnoutse, R. Dawson, et al., J Antimicrob Chemother 70:448-455, 2015, https://doi.org/10.1093/jac/dku415) revealed that the treated MGIT time to culture positivity of 142 ± 7.02 h was equivalent to 4.86 ± 0.28 log10 CFU, consistent with the MBLA-measured bacterial load. Our study confirms the contribution of NALC-NaOH treatment to the loss of viable bacterial counts. Tests that obviate the need for decontamination may offer an alternative option for the accurate detection of viable M. tuberculosis and treatment response monitoring.

Phenotypic Changes on Mycobacterium Tuberculosis-Specific CD4 T Cells as Surrogate Markers for Tuberculosis Treatment Efficacy.

Background: The analysis of phenotypic characteristics on Mycobacterium tuberculosis (MTB)-specific T cells is a promising approach for the diagnosis of active tuberculosis (aTB) and for monitoring treatment success. We therefore studied phenotypic changes on MTB-specific CD4 T cells upon anti-tuberculosis treatment initiation in relation to the treatment response as determined by sputum culture. Methods: Peripheral blood mononuclear cells from subjects with latent MTB infection (n = 16) and aTB (n = 39) at baseline, weeks 9, 12, and 26 (end of treatment) were analyzed after intracellular interferon gamma staining and overnight stimulation with tuberculin. Liquid sputum cultures were performed weekly until week 12 and during 4 visits until week 26. Results: T cell activation marker expression on MTB-specific CD4 T cells differed significantly between subjects with aTB and latent MTB infection with no overlap for the frequencies of CD38pos and Ki67pos cells (both p < 0.0001). At 9 weeks after anti-TB treatment initiation the frequencies of activation marker (CD38, HLA-DR, Ki67) positive MTB-specific, but not total CD4 T cells, were significantly reduced (p < 0.0001). Treatment induced phenotypic changes from baseline until week 9 and until week 12 differed substantially between individual aTB patients and correlated with an individual's time to stable sputum culture conversion for expression of CD38 and HLA-DR (both p < 0.05). In contrast, the frequencies of maturation marker CD27 positive MTB-specific CD4 T cells remained largely unchanged until week 26 and significantly differed between subjects with treated TB disease and latent MTB infection (p = 0.0003). Discussion: Phenotypic changes of MTB-specific T cells are potential surrogate markers for tuberculosis treatment efficacy and can help to discriminate between aTB (profile: CD38pos, CD27low), treated TB (CD38neg, CD27low), and latent MTB infection (CD38neg, CD27high).

The impact of repeated NALC/NaOH- decontamination on the performance of Xpert MTB/RIF assay.

The Xpert MTB/RIF assay detects Mycobacterium tuberculosis in unprocessed or NALC/NaOH- decontaminated sputum. The effect of repeated NALC/NaOH-decontamination on several Xpert performance parameters was assessed in this study. A second NALC/NaOH-decontamination had no effect on the binary Xpert-outcome but increased the value for the quantitative readout (CTmin). Repeated decontamination was not associated with PCR-inhibition or invalid results. The CTmin of M.tb positive samples was higher in inhibited Xpert runs. Our data indicate that NALC/NaOH-decontamination has an effect on the performance of the Xpert assay, and that CTmin readouts of decontaminated sputum samples should be interpreted with caution.

Maturation and Mip-1ß Production of Cytomegalovirus-Specific T Cell Responses in Tanzanian Children, Adolescents and Adults: Impact by HIV and Mycobacterium tuberculosis Co-Infections.

It is well accepted that aging and HIV infection are associated with quantitative and functional changes of CMV-specific T cell responses. We studied here the expression of Mip-1ß and the T cell maturation marker CD27 within CMVpp65-specific CD4(+) and CD8(+) T cells in relation to age, HIV and active Tuberculosis (TB) co-infection in a cohort of Tanzanian volunteers (≤ 16 years of age, n = 108 and ≥ 18 years, n = 79). Independent of HIV co-infection, IFNγ(+) CMVpp65-specific CD4(+) T cell frequencies increased with age. In adults, HIV co-infection further increased the frequencies of these cells. A high capacity for Mip-1ß production together with a CD27(low) phenotype was characteristic for these cells in children and adults. Interestingly, in addition to HIV co-infection active TB disease was linked to further down regulation of CD27 and increased capacity of Mip-1ß production in CMVpp65-specific CD4+ T cells. These phenotypic and functional changes of CMVpp65-specific CD4 T cells observed during HIV infection and active TB could be associated with increased CMV reactivation rates.