Epidemiology of HIV-associated tuberculosis

Stool Sampling as a Non-invasive Method to Confirm Miliary Tuberculosis in a Patient With a History of HIV Infection

Tuberculosis (TB), caused by Mycobacterium tuberculosis, remains a major global health challenge despite medical advancements. We present here a case of a 44-year-old male with a history of HIV infection and inconsistent treatment adherence. The patient exhibited weight loss and miliary lesions on a computed tomography (CT) scan, prompting suspicion of pulmonary TB. Due to his inability to expectorate sputum, stool samples were used for the acid-fast bacilli (AFB) smear and culture. His miliary TB diagnosis was confirmed through lung CT imaging and positive AFB smears from stool samples. This case underscores the utility of stool samples in diagnosing TB when sputum production is compromised, offering a minimally invasive diagnostic approach. It also underscores the importance of collaborative healthcare approaches in managing complex cases, ensuring comprehensive care tailored to individual patient needs.

C-reactive protein-based tuberculosis triage testing: a multi-country diagnostic accuracy study

Rationale

C-reactive protein (CRP)-based tuberculosis (TB) screening is recommended for people with HIV (PWH). However, its performance among people without HIV and in diverse settings is unknown.

Objectives

In a multi-country study, we aimed to determine whether CRP meets the minimum accuracy targets (sensitivity ≥90%, specificity ≥70%) for an effective TB triage test.

Methods/Measurements

Consecutive outpatient adults with cough ≥2 weeks from five TB endemic countries in Africa and Asia had baseline blood collected for point-of-care CRP testing and HIV and diabetes screening. Sputum samples were collected for Xpert MTB/RIF Ultra (Xpert) testing and culture. CRP sensitivity and specificity (5 mg/L cut-point) was determined in reference to sputum test results and compared by country, sex, and HIV and diabetes status. Variables affecting CRP performance were identified using a multivariate receiver operating characteristic (ROC) regression model.

Results

Among 2904 participants, of whom 613 (21%) had microbiologically-confirmed TB, CRP sensitivity was 84% (95% CI: 81-87%) and specificity was 61% (95% CI: 59-63%). CRP accuracy varied geographically, with higher sensitivity in African countries (≥91%) than Asian countries (64-82%). Sensitivity was higher among men than women (87% vs. 79%, difference +8%, 95% CI: 1-15%) and specificity was higher among people without HIV than PWH (64% vs. 45%, difference +19%, 95% CI: 13-25%). ROC regression identified country and measures of TB disease severity as predictors of CRP performance.

Conclusions

Overall, CRP did not achieve the minimum accuracy targets and its performance varied by setting and in some sub-groups, likely reflecting population differences in mycobacterial load.

Trifluoroacetic acid-mediated synthesis of xanthene constructs and their extensive anti-tuberculosis evaluation

A diverse range of 9-substituted 1,8-dioxohexahydroxanthenes was conceptualized and synthesized through a TFA-mediated approach in near quantitative yields without the use of column chromatography. From a series of 25 compounds, we found that compounds 14c and 14r exhibited promising anti-tuberculosis potential against avirulent and virulent strains of Mycobacterium tuberculosis with a Minimal Inhibitory Concentration (MIC) of 8 μg ml-1, achieving 99% bactericidal activity at the same concentration. This series of compounds was found to be inactive against common Gram-positive and Gram-negative pathogens, indicating that the activity is mycobacteria-specific. Since the strategies for treating tuberculosis employ a combinatorial therapy, we tested and observed that the two lead compounds displayed synergistic behavior with known anti-TB drugs (ATDs) and a significant (16-32 fold) decrease in MIC values of both leads was observed in combination with either RIF or INH. Interestingly the lead molecule 14c displayed only time-dependent kill kinetics and sterilized the whole culture of Mycobacterium tuberculosis H37Rv in just 48 hours.

Roadmap for ending TB in China by 2035: The challenges and strategies

Tuberculosis (TB) is one of the top ten causes of death worldwide, taking the lives of over a million people annually. In addition to being a serious health issue, TB is also closely linked to eradicating poverty according to the Sustainable Development Goals (SDGs) of the United Nations (UN). All UN members have committed to ending the TB epidemic by 2030. China has one of the highest TB loads worldwide, ranking third in the world on many TB burden indices. The national strategy for TB control is aimed at creating a collaborative network and integrating TB treatment into the medical system. According to the WHO's global TB report, China is expected to have 748,000 new cases of TB in 2022 and an incidence of 52 cases per 100,000 people. Ending TB remains a huge challenge and requires comprehensive control strategies in China. In this work, we have discussed the challenges of TB prevention and control in China and proposed specific measures to end TB.

Management of Tuberculosis Infection: Current Situation, Recent Developments and Operational Challenges

Tuberculosis infection (TBI) is defined as a state of infection in which individuals host live Mycobacterium tuberculosis with or without clinical signs of active TB. It is now understood as a dynamic process covering a spectrum of responses to infection resulting from the interaction between the TB bacilli and the host immune system. The global burden of TBI is about one-quarter of the world’s population, representing a reservoir of approximately 2 billion people. On average, 5–10% of people who are infected will develop TB disease over the course of their lives, but this risk is enhanced in a series of conditions, such as co-infection with HIV. The End-TB strategy promotes the programmatic management of TBI as a crucial endeavor to achieving global targets to end the TB epidemic. The current development of new diagnostic tests capable of discriminating between simple TBI and active TB, combined with novel short-course preventive treatments, will help achieve this goal. In this paper, we present the current situation and recent developments of management of TBI and the operational challenges.

Lnc-EST12, which is negatively regulated by mycobacterial EST12, suppresses antimycobacterial innate immunity through its interaction with FUBP3

Long noncoding RNAs (lncRNAs) have been implicated in the pathogenesis of intracellular pathogens. However, the role and mechanism of the important lncRNAs in Mycobacterium tuberculosis (M.tb) infection remain largely unexplored. Recently, we found that a secreted M.tb Rv1579c (an early secreted target with a molecular weight of 12 kDa, named EST12) protein activates NLRP3-gasdermin D (GSDMD)-mediated pyroptosis and plays a pivotal role in M.tb-induced immunity. In the present study, M.tb and the EST12 protein negatively regulated the expression of a key lncRNA (named lnc-EST12) in mouse macrophages by activating the JAK2-STAT5a signaling pathway. Lnc-EST12, with a size of 1583 bp, is mainly expressed in immune-related organs (liver, lung and spleen). Lnc-EST12 not only reduces the expression of the proinflammatory cytokines IL-1β, IL-6, and CCL5/8 but also suppresses the NLRP3 inflammasome and GSDMD pyroptosis-IL-1β immune pathway through its interaction with the transcription factor far upstream element-binding protein 3 (FUBP3). The KH3 and KH4 domains of FUBP3 are the critical sites for binding to lnc-EST12. Deficiency of mouse lnc-EST12 or FUBP3 in macrophages increased M.tb clearance and inflammation in mouse macrophages or mice. In conclusion, we report a new immunoregulatory mechanism in which mouse lnc-EST12 negatively regulates anti-M.tb innate immunity through FUBP3.

Tuberculosis challenges: Resistance, co-infection, diagnosis, and treatment

Early diagnosis of tuberculosis (TB), followed by effective treatment, is the cornerstone of global TB control efforts. An estimated 3 million cases of TB remain undetected each year. Early detection and effective management of TB can prevent severe disease and reduce mortality and transmission. Intrinsic and acquired drug resistance of Mycobacterium tuberculosis (MTB) severely restricted the anti-TB therapeutic options, and public health policies are required to preserve the new medications to treat TB. In addition, TB and HIV frequently accelerate the progression of each other, and one disease can enhance the other effect. Overall, TB-HIV co-infections show an adverse bidirectional interaction. For HIV-infected patients, the risk of developing TB disease is approximately 22 times higher than for persons with a protective immune response. Analysis of the current TB challenges is critical to meet the goals of the end TB strategy and can go a long way in eradicating the disease. It provides opportunities for global TB control and demonstrates the efforts required to accelerate eliminating TB. This review will discuss the main challenges of the TB era, including resistance, co-infection, diagnosis, and treatment.

Fatal SARS-CoV-2 and Mycobacterium tuberculosis coinfection in an infant: insights from Botswana

We report a fatal case of SARS-CoV-2 and Mycobacterium tuberculosis coinfection in an infant, Botswana’s first paediatric COVID-19-associated fatality. The patient, a 3-month-old HIV-unexposed boy, presented with fever and respiratory distress in the setting of failure to thrive. Both the patient and his mother tested positive for rifampin-sensitive M. tuberculosis (Xpert MTB/Rif) and SARS-CoV-2 (real time-PCR). Initially stable on supplemental oxygen and antitubercular therapy, the patient experienced precipitous clinical decline 5 days after presentation and subsequently died. Autopsy identified evidence of disseminated tuberculosis (TB) as well as histopathological findings similar to those described in recent reports of SARS-CoV-2 infections, including diffuse microthrombosis. TB remains a serious public health threat in hyperendemic regions like sub-Saharan Africa, and is often diagnosed late in infants. In addition to raising the question of additive/synergistic pathophysiology and/or immune reconstitution, this case of coinfection also highlights the importance of leveraging the COVID-19 pandemic response to strengthen efforts for TB prevention, screening and detection.

Trend analysis and longitudinal clustering of tuberculosis mortality in Asian and North African countries: Results from the global burden of disease 2017 study

Background: Tuberculosis (TB) is still a serious health problem with a remarkable global burden. In this study, we aimed to assess the trend of TB mortality in Asian and North African countries in the period 1990-2017 and provide a new classification according to TB mortality trend.

Methods: TB mortality rates from 1990 to 2017 were extracted from the Global Burden of Disease website for 55 Asian and North African countries. Trend analysis of TB mortality rates for males, females, and the total population was performed using the marginal modeling approach. Moreover, the latent growth mixture modeling (LGMM) framework was applied to classify these 55 countries based on their trend of TB mortality rate.

Results: In the period between 1990 and 2017, South Asia and High Income Asia-Pacific regions had the highest and lowest death rates due to TB, respectively. The marginal modeling results showed that the Asian and North African countries had experienced a downward trend with an intercept of 28.79 (95%CI: 19.64, 37.94) and a slope (mean annual reduction) of -0.67 (95%CI: -0.91, -0.43) per 100,000 the study period. Finally, the LGMM analysis classified these 55 countries into four distinct classes.

Conclusion: In general, our findings revealed that although the countries in Asia and North Africa super region experienced a descending TB mortality trend in the past decades, the slope of this reduction is quite small. Also, our new classification may be better suited for combating TB through future healthcare planning in lieu of the commonly used geographic classifications.

Chest X-ray interpretation does not complement Xpert MTB/RIF in diagnosis of smear-negative pulmonary tuberculosis among TB-HIV co-infected adults in a resource-limited setting

Background

Chest X-ray (CXR) interpretation remains a central component of the current World Health Organization recommendations as an adjuvant test in diagnosis of smear-negative tuberculosis (TB). With its low specificity, high maintenance and operational costs, utility of CXR in diagnosis of smear-negative TB in high HIV/TB burden settings in the Xpert MTB/RIF era remains unpredictable. We evaluated accuracy and additive value of CXR to Xpert MTB/RIF in the diagnosis of TB among HIV-positive smear-negative presumptive TB patients.

Methods

HIV co-infected presumptive TB patients were recruited from the Infectious Diseases Institute outpatient clinic and in-patient medical wards of Mulago Hospital, Uganda. CXR films were reviewed by two independent radiologists using a standardized evaluation form. CXR interpretation with regard to TB was either positive (consistent with TB) or negative (normal or unlikely TB). Sensitivity, specificity and predictive values of CXR and CXR combined with Xpert MTB/RIF for diagnosis of smear-negative TB in HIV-positive patients were calculated using sputum and/or blood mycobacterial culture as reference standard.

Results

Three hundred sixty-six HIV co-infected smear-negative participants (female, 63.4%; hospitalized, 68.3%) had technically interpretable CXR. Median (IQR) age was 32 (28–39) years and CD4 count 112 (23–308) cells/mm³. Overall, 22% (81/366) were positive for Mycobacterium tuberculosis (Mtb) on culture; 187/366 (51.1%) had CXR interpreted as consistent with TB, of which 55 (29.4%) had culture-confirmed TB. Sensitivity and specificity of CXR interpretation in diagnosis of culture-positive TB were 67.9% (95%CI 56.6–77.8) and 53.7% (95%CI 47.7–59.6) respectively, while Xpert MTB/RIF sensitivity and specificity were 65.4% (95%CI 54.0–75.7) and 95.8% (95%CI 92.8–97.8) respectively. Addition of CXR to Xpert MTB/RIF had overall sensitivity and specificity of 87.7% (95%CI 78.5–93.9) and 51.6% (95%CI 45.6–57.5) respectively; 86.2% (95%CI 75.3–93.5) and 48.1% (95%CI 40.7–55.6) among inpatients and 93.8% (95%CI 69.8–99.8) and 58.0% (95%CI 47.7–67.8) among outpatients respectively.

Conclusion

In this high prevalence TB/HIV setting, CXR interpretation added sensitivity to Xpert MTB/RIF test at the expense of specificity in the diagnosis of culture-positive TB in HIV-positive individuals presenting with TB symptoms and negative smear. CXR interpretation may not add diagnostic value in settings where Xpert MTB/RIF is available as a TB diagnostic tool.

Prevalence of human immunodeficiency virus among pulmonary tuberculosis patients: A cross-sectional study

Tuberculosis (TB) is caused by Mycobacterium tuberculosis and is an endemic disease in Sudan, where it has rapidly become the major complication of human immunodeficiency virus (HIV) infection. Thus, this study aimed to determine the prevalence of HIV among TB patients and evaluate the co-infection rate. The association of HIV prevalence with gender, age, and duration of treatment as risk factors was also determined. A descriptive cross-sectional study was performed in Omdurman Abu Anga Hospital, Khartoum, Sudan, from October 2018 to March 2019. A total of 281 blood samples were obtained randomly from pulmonary TB patients. The plasma was examined for the presence of HIV antibodies using sandwich ELISA. A structured questionnaire was used during data collection. A noticeable marker for HIV immunoglobulin M/immunoglobulin G was found in 12 patients (4.3%), of which five patients (41.7%) were diagnosed as new TB cases. Moreover, the relationship between age, sex, and duration of TB treatment and the prevalence of HIV was not significantly different (P > 0.05). In conclusion, the prevalence of HIV antibodies among TB pulmonary patients is high. Therefore, all TB patients should be examined for HIV risk factors and advised to undergo HIV testing. Further studies are essential to provide more insights into the epidemiology of the co-infection to better report the double burden of HIV and TB among TB patients in Sudan.

Priorities among HIV-positive individuals for tuberculosis preventive therapies

BACKGROUND: There has been slow uptake of isoniazid preventive therapy (IPT) among people living with HIV (PLWH).METHODS: We surveyed adults recently diagnosed with HIV in 14 South African primary health clinics. Based on the literature and qualitative interviews, sixteen potential barriers and facilitators related to preventive therapy among PLWH were selected. Best-worst scaling (BWS) was used to quantify the relative importance of the attributes. BWS scores were calculated based on the frequency of participants' selecting each attribute as the best or worst among six options (across multiple choice sets) and rescaled from 0 (always selected as worst) to 100 (always selected as best) and compared by currently receiving IPT or not.RESULTS: Among 342 patients surveyed, 33% (n = 114) were currently taking IPT. Having the same standard of life as someone without HIV was most highly prioritized (BWS score = 67.3, SE = 0.6), followed by trust in healthcare providers (score, 66.3 ± 0.6). Poor standard of care in public clinics (score, 30.6 ± 0.6) and side effects of medications (score, 33.7 ± 0.6) were least prioritized. BWS scores differed by IPT status for few attributes, but overall ranking was similar (spearman's rho = 0.9).CONCLUSION: Perceived benefits of preventive therapy were high among PLWH. IPT prescription by healthcare providers should be encouraged to enhance IPT uptake among PLWH.

Developmental Changes in the Philippine Health System: Accomplishments, Successes and Challenges

The Philippine health system has undergone various changes which addressed the needs of the time. These changes were reflected in the benchmarks and indicators of performance of the whole health system. To understand how these changes affected the health system (HS), this study determined the changes in the Philippine health system in relation to different health domains (health determinants, financing, and management/development). Two HS periods were identified, namely, health system period 1 (HS 1) from 1997–2007 and health system period 2 (HS 2) from 2008–2017. Each HS period was assessed based on three domains. The first two domains were quantitatively assessed based on an interrupted time-series method, while the third one underwent a comparative analysis using two Health Systems in Transition reports (2011 and 2018). This study was able to assess the developmental changes in the Philippine health system. Specifically, the (health determinant) maternal mortality rate (MMR) significantly decreased by three maternal deaths per 100,000 live births, the (health financing) tobacco excise tax increased by 13,855 (in Million PhP) in HS 2, and there was (health management/development) an improvement in access to health facilities. However, there was an indication of retrogressive progress with some challenges in HS 1 which remained unaddressed in HS 2. While it seems promising that the health system has progressed with improvements apparent in both health outcomes (e.g., MMR) and health financing (e.g., tobacco excise tax), such improvements were overshadowed by the inefficiencies, which were not addressed by the current health system (HS 2), thus making it more retrogressive than progressive.

Cost-effectiveness of universal isoniazid preventive therapy among HIV-infected pregnant women in South Africa

OBJECTIVE

To estimate the incremental cost-effectiveness of universal vs. test-directed treatment of latent tuberculous infection (LTBI) among human immunodeficiency virus (HIV) positive pregnant women in South Africa.

METHODS

We compared tuberculin skin test (TST) directed isoniazid preventive therapy (IPT) (TST placement with delivery of IPT to women with positive results) against QuantiFERON^®-TB Gold In-Tube (QGIT) directed IPT and universal IPT using decision analysis. Costs were measured empirically in six primary care public health clinics in Matlosana, South Africa. The primary outcome was the incremental cost-effectiveness ratio, expressed in 2016 US$ per disability-adjusted life-year (DALY) averted.

RESULTS

We estimated that 29.2 of every 1000 pregnant women would develop TB over the course of 1 year in the absence of IPT. TST-directed IPT reduced this number to 24.5 vs. 22.6 with QGIT-directed IPT and 21.0 with universal IPT. Universal IPT was estimated to cost $640/DALY averted (95% uncertainty range $44-$3146) relative to TST-directed IPT and was less costly and more effective (i.e., dominant) than QGIT-directed IPT. Cost-effectiveness was most sensitive to the probability of developing TB and LTBI prevalence.

CONCLUSION

Providing IPT to all eligible women can be a cost-effective strategy to prevent TB among HIV-positive pregnant women in South Africa.

Transforming Growth Factor-β Suppresses Interleukin (IL)-2 and IL-1β Production in HIV-Tuberculosis Co-Infection

Interleukin (IL)-1β and IL-2 play important roles in protective immune responses against Mycobacterium tuberculosis (Mtb) infection. Information on the factors that regulate the production of these cytokines in the context of human immunodeficiency virus and latent tuberculosis infection (LTBI) or active tuberculosis (TB) disease is limited. In this study, we compared the production of these cytokines by peripheral blood mononuclear cells (PBMCs) from HIV^- and HIV⁺ individuals with latent and active Tuberculosis infection in response to Mtb Antigen 85A. PBMCs from HIV⁺ LTBI⁺ and HIV⁺ active TB patients produced low IL-1β, IL-2 but high transforming growth factor beta (TGF-β) compared to healthy controls. CD4⁺ T cells from HIV patients expressed low retinoic acid-related orphan receptor gamma (RORγ), and high suppressors of cytokine signaling-3 (SOCS-3). Active TB infection in HIV⁺ individuals further inhibited antigen-specific IL-1β and IL-2 production compared with those with LTBI. Neutralization of TGF-β restored IL-1β and IL-2 levels and lowered SOCS-3 production by CD4⁺ T cells. We hypothesize that high TGF-β in HIV patients could be a reason for defective Mtb-specific IL-1β, IL-2 production and activation of latent TB in HIV. Coupling anti-TGF-β antibodies with antiretroviral therapy treatment might increase T cell function to boost the immune system for effective clearance of Mtb.

Drug targets exploited in Mycobacterium tuberculosis: Pitfalls and promises on the horizon

Tuberculosis is an ever evolving infectious disease that still claims about 1.8 million human lives each year around the globe. Although modern chemotherapy has played a pivotal role in combating TB, the increasing emergence of drug-resistant TB aligned with HIV pandemic threaten its control. This highlights both the need to understand how our current drugs work and the need to develop new and more effective drugs. TB drug discovery is revisiting the clinically validated drug targets in Mycobacterium tuberculosis using whole-cell phenotypic assays in search of better therapeutic scaffolds. Herein, we review the promises of current TB drug regimens, major pitfalls faced, key drug targets exploited so far in M. tuberculosis along with the status of newly discovered drugs against drug resistant forms of TB. New antituberculosis regimens that use lesser number of drugs, require shorter duration of treatment, are equally effective against susceptible and resistant forms of disease, have acceptable toxicity profiles and behave friendly with anti-HIV regimens remains top most priority in TB drug discovery.

Time to death and risk factors among tuberculosis patients in Northern Ethiopia

OBJECTIVE

The main objective of this study was to assess time to death and associated risk factors among tuberculosis (TB) patients.

RESULTS

A total of 769 TB patients were studied and of those, 87 (11.3%) patients died. All of the deaths occurred within 7 months of anti-tuberculosis therapy. Extra-pulmonary TB (AHR = 17.376, 95% CI; 3.88-77.86, p < 0.001) as compared to pulmonary TB and cotrimoxazole prophylaxis therapy (CPT) (AHR = 0.15, 95% CI; 0.03-0.74, p = 0.02) were found to be the predictors of mortality. We noticed higher rates of mortality. Extra-pulmonary TB patients have high risk and TB-HIV co-infected patients who received CPT have low risk of death. Improving early diagnosis of extra-pulmonary TB and early CPT initiation of TB-HIV co-infected patients could minimize patient's mortality.

Changes in tuberculosis in human immunodeficiency virus infected patients in a Spanish tertiary hospital (1995-2013)

OBJECTIVE

Although the incidence of human immunodeficiency virus (HIV)-associated tuberculosis (TB) has decreased, changes in other characteristics of the disease are largely unknown. To describe the trends in TB in patients infected with HIV from 1995 to 2013.

METHODS

We review all cases of TB in a tertiary hospital in Madrid, Spain.

RESULTS

Among 1,284 patients diagnosed of TB, 298 (23%) were coinfected with HIV. The prevalence of HIV infection during the period of study has decreased from 40% to 14% (p for the trend < 0.001). Clinical presentation has also changed. Although pulmonary and extrapulmonary TB has remained unchanged, miliary presentation has significantly decreased (from 36% to 22%, p = 0.005). The 4-drug regimen was the preferable scheme, with higher implementation at the end of the study period (82% from 1995-1999 to 95% in 2010-2013, p = 0.43). Factors such as treatment failure (OR: 11.7; CI 95%: 3.12-44.1) and miliary form (OR: 2.8; CI 95%; 1.09-7.3) were independently associated with TB related mortality, while the longer duration of treatment was as a protective factor (OR 0.7; CI 95%: 0.6-0.8).

CONCLUSIONS

HIV has decreased very significantly as a risk factor for the development of TB. Despite improvement in the treatment of both TB and HIV, and in overall mortality, deaths attributable to the disease in this population remain high mostly in miliary and relapsing forms.

The occurrence and frequency of genomic mutations that mediate Isoniazid and Rifampicin resistance in Mycobacterium tuberculosis isolates from untreated pulmonary Tuberculosis cases in urban Blantyre, Malawi

Background

The emergence and spread of drug-resistant Tuberculosis (TB) is a major public health threat. TB resistance originates in the course of treatment due to genomic mutations in Mycobacterium tuberculosis (MTB). An increase in new cases with drug-resistant TB could be an indicator of high levels of circulating resistant strains. This study was conducted to determine the occurrence and frequency of genomic mutations that mediate Isoniazid (INH) and Rifampicin (RIF) resistance among isolates from untreated TB cases in urban Blantyre, Malawi.

Methods

A cross-sectional retrospective study was conducted on a panel of 141(n=141) MTB clinical isolates recovered between June 2010 and January 2012 from >2+ Ziehl-Neelsen smear positive new pulmonary-TB patients with no history of treatment. Frozen isolates were revived using the BACTEC MGIT detection system. DNA was extracted using GenoLyse DNA extraction kit and detection of genomic mutations was carried out using the GenoType MTBDRplus Ver 2.0 assay.

Results

Out of the 141 isolates studied, 3 (2.1%) were found carrying mutations in the katG gene that confer resistance to Isoniazid (INH). No mutations were detected in the inhA promoter region gene that confer weak INH resistance or in the rpoB gene that confer Rifampicin resistance. All katG mutant genes had a S315T1 single point mutation, a genomic alteration that mediates high INH resistance.

Conclusion

The katG mutant gene conferring resistance to INH was the only genomic mutation observed among the isolates studied and the frequency of occurrence was low. Our findings suggest low levels of circulating drug-resistant MTB strains in urban Blantyre, Malawi.

Two diseases, same person: moving toward a combined HIV and tuberculosis continuum of care

The human immunodeficiency virus (HIV) and Mycobacterium tuberculosis syndemic remains a global public health threat. Separate HIV and tuberculosis (TB) global targets have been set; however, success will depend on achieving combined disease control objectives and care continua. The objective of this study was to review available policy, budgets, and data to reconceptualize TB and HIV disease control objectives by combining HIV and TB care continua. For 22 World Health Organization (WHO) TB and TB/HIV priority countries, we used 2015 data from the HIV90-90-90watch website, UNAIDS AIDSinfo, and WHO 2016 and 2017 Global TB Reports. Global resources available in TB and HIV/TB activities for 2003-2017 were collected from publicly available sources. In 22 high-burden countries, people living with HIV on antiretroviral therapy ranged from 9 to 70%; viral suppression was 38-63%. TB treatment success ranged from 71 to 94% with 14 (81% HIV/TB burden) countries above 80% TB treatment success. From 2003 to 2017, reported global international and domestic resources for HIV-associated TB and TB averaged $2.85 billion per year; the total for 2003-2017 was 43 billion dollars. Reviewing combined HIV and TB targets demonstrate disease control progress and challenges. Using an integrated HIV and TB continuum supports HIV and TB disease control efforts focused on improving both individual and public health.

Mycobacterium tuberculosis thymidylate kinase antigen assays for designating incipient, high-risk latent M.tb infection

BACKGROUND

Precise designation of high risk forms of latent Mycobacterium tuberculosis-M.tb infections (LTBI) is impossible. Delineation of high-risk LTBI can, however, allow for chemoprophylaxis and curtail majority cases of active tuberculosis (ATB). There is epidemiological evidence to support the view that LTBI in context of HIV-1 co-infection is high-risk for progression to ATB relative to LTBI among HIV-ve persons. We recently showed that assays of M.tb thymidylate kinase (TMKmt) antigen and host specific IgG can differentiate ATB from LTBI and or no TB (NTB, or healthy controls). In this study, we aimed to expose the differential levels of TMKmt Ag among HIV+ve co-infected LTBI relative to HIV-ve LTBI as a strategy to advance these assays for designating incipient LTBI.

METHODS

TMKmt host specific IgM and IgG detection Enzyme Immuno-Assays (EIA) were conducted on 40 TB exposed house-hold contacts (22 LTBI vs. 18 no TB (NTB) by QunatiFERON-TB GOLD®); and TMKmt Ag detection EIA done on 82 LTBI (46 HIV+ve vs 36 HIV-ve) and 9 NTB (American donors). Purified recombinant TMKmt protein was used as positive control for the Ag assays.

RESULTS

IgM levels were found to be equally low across QuantiFERON-TB GOLD® prequalified NTB and TB exposed house-hold contacts. Higher TMKmt host specific IgG trends were found among TB house-hold contacts relative to NTB controls. TMKmt Ag levels among HIV+ve LTBI were 0.2676 ± 0.0197 (95% CI: 0.2279 to 0.3073) relative to 0.1069 ± 0.01628 (95% CI: 0.07385 to 0.14) for HIV-ve LTBI (supporting incipient nature of LTBI in context of HIV-1 co-infection). NTB had TMKmt Ag levels of 0.1013 ± 0.02505 (5% CI: 0.0421 to 0.1606) (intimating that some were indeed LTBI).

CONCLUSIONS

TMKmt Ag levels represent a novel surrogate biomarker for high-risk LTBI, while host-specific IgG can be used to designate NTB from LTBI.

Routinely detected indicators in plasma have a predictive effect on the identification of HIV-infected patients with non-tuberculous mycobacterial and tuberculous infections

BACKGROUND

It is difficult to quickly distinguish non-tuberculous mycobacterial (NTM) infection from tuberculosis (TB) infection in human immunodeficiency virus (HIV)-infected patients because of many similarities between these diseases. A simple and effective way to determine the differences using routine blood tests is necessary in developing countries.

METHODS

A retrospective cohort study was conducted to recruit HIV-infected patients with either NTM infection or TB infection diagnosed for the first time according to mycobacterial culture and microscopic identification from May 2010 to March 2016. These data included the analysis of blood cells, liver function, renal function, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR), and were compared between the HIV/TB and HIV/NTM groups.

RESULTS

A total of 240 patients were enrolled. The number of HIV/TB and HIV/NTM patients was 113 and 127, respectively. There were no significant differences in the CD4 T-cell count, age, sex, percentage of patients initiating antiretroviral therapy (ART) before the explicit diagnosis of TB or NTM infection. NTM infection was more likely to be restricted in the pulmonary while TB infection also involves extra-pulmonary sites. Both the leukocyte count(5.60 × 109/L) and the proportion of neutrophils in the leukocyte count (76.70%) in the HIV/TB group were significantly higher than those in the HIV/NTM group (4.40 × 109/L [P = 0.0014] and 69.30% [P < 0.001]. The analysis of liver function markers indicated that the concentration of albumin but not ALT and AST was significantly lower in the HIV/TB group than in the HIV/NTM group (P < 0.001). The creatinine and urea levels were not significantly different between the two groups. The ESR (84.00 mm/h) and the concentration of CRP (59.60 mg/L) were significantly higher in the HIV/TB group than in the HIV/NTM group (52.00 mm/h and 19.60 mg/L, respectively) (P < 0.001). To distinguish TB infection from NTM infection, the best cut-off value was 69.5 mm/h for ESR, with a positive predictive value (PPV) of 0.740 and negative predictive value (NPV) of 0.721, and 48.8 mg/L for CRP, with a PPV of 0.676 and NPV of 0.697.

CONCLUSION

The dissemination character as well as stronger immune response characterized by higher inflammation markers (e.g. WBC, ESR, CRP) can help distinguish TB from NTM infection in HIV-infected patients who need empirical therapy or diagnostic therapy immediately in low-income areas.

α-pyrones and their hydroxylated analogs as promising scaffolds against Mycobacterium tuberculosis

Tuberculosis ranks as the leading cause of global human mortality from a single infectious agent. To address the uprising issues of drug resistance, intense research efforts have been directed towards drug discovery. However, it is a long and economically challenging process that is often associated with high failure rates. Therefore, it seems prudent to take forward the core scaffolds that have already acclaimed clinical relevance. In this direction, hydroxylated α-pyrone scaffold has received US FDA approval for human use against HIV. Interestingly, literature review reveals the potential applicability of α-pyrones in TB drug discovery. On one hand, α-pyrones play a vital role in the cell wall of Mycobacterium tuberculosis and on the other hand natural α-pyrones display appreciable anti-TB activity. This review aims to rekindle the interest of researchers toward α-pyrone as a new anti-TB drug that may possibly tackle drug resistance and open a dual frontier in TB and HIV drug discovery.

Cell wall: A versatile fountain of drug targets in Mycobacterium tuberculosis

Tuberculosis is the leading infectious disease responsible for an estimated one and a half million human deaths each year around the globe. HIV-TB coinfection and rapid increase in the emergence of drug resistant forms of TB is a dangerous scenario. This underlines the urgent need for new drugs with novel mechanism of action. A plethora of literature exist that highlight the importance of enzymes involved in the biosynthesis of mycobacterial cell wall responsible for its survival, growth, permeability, virulence and resistance to antibiotics. Therefore, assembly of cell wall components is an attractive target for the development of chemotherapeutics against Mycobacterium tuberculosis. The aim of this review is to highlight novel sets of enzyme inhibitors that disrupt its cell wall biosynthetic pathway. These include the currently approved first and second line drugs, candidates in clinical trials and current structure activity guided endeavors of scientific community to identify new potent inhibitors with least cytotoxicity and better efficacy against emergence of drug resistance till date.

Profile of Respiratory and Extra-Respiratory Tuberculosis in Patients Living with HIV in Dolj County between 2005-2015

Introduction: Tuberculosis (TB) is the commonest and the deadliest opportunistic infection in patients living with HIV/ AIDS. Purpose: The paper aims to assess patients with and without TB-HIV coinfection in Dolj county registered in Regional and National database in order to identify risk factors for progression to active TB for immunodepresive patients. Material and method: We performed a retrospective descriptive study using records of 336 patients infected with HIV (PIH)-data from medical charts between 2005-2015 and we compared with the data for 1120 patients without HIV between 2005-2012. Results: 64,1% were females and 35,89% were males. Most cases were from rural areas (61,54%) most of them graduating primary (17,94%) and secondary school (48,71%). Most of them don’t have a job (87%) and are supported by state with a monthly miminum income. Majority is born between 1980-1990 (64,1%), with predominance of Romanians (92.31%) compared to the Roma. Regarding all TB diagnoses (pulmonary and extrapulmonary) 117 had at least one episode of active TB. TB and HIV have been diagnosed almost at the same time in 25,64% cases. At the time of TB diagnosis 87% of patients had CD4+lymphocytes count <200cel/ml. We also noticed the absence of prophylaxis for TB in PIH, high incidence of hepatitis B among those with HIV/TB coinfection (34%). Conclusions: Active TB in patients with HIV infection is correlated with severe immunosuppression, poor education, and atypical clinical expression and radiological findings and more cases of extrapulmonary TB.

Diagnostic Outcomes After Chest Radiograph Interpretation in Patients With Suspected Tuberculosis and Negative Sputum Smears in a High-Burden Human Immunodeficiency Virus and Tuberculosis Setting

BACKGROUND

Evaluation of patients with suspected tuberculosis and negative sputum smears for acid-fast bacilli (AFB) is challenging, especially in high human immunodeficiency virus coinfection settings where sputum smears have lower sensitivity for detecting AFB.

METHODS

We examined the utility of chest radiographs for detecting smear-negative pulmonary tuberculosis. Three hundred sixty sputum smear-negative patients who were referred from primary care clinics in the KwaZulu-Natal province of South Africa were evaluated. Chest radiographs were read by experienced pulmonologists using a previously validated Chest X-Ray Reading and Recording System (CRRS).

RESULTS

Agreement between observers using CRRS was high at 91% with a Cohen's kappa of 0.64 (95% confidence interval [CI] = 0.52-0.76). Against a reference standard of sputum culture, sensitivity was 93% (95% CI = 86%-97%), whereas specificity was 14% (95% CI = 10%-19%). Performance against clinical diagnosis (following World Health Organization guidelines) was similar with sensitivity of 92% (95% CI = 88%-95%) and specificity of 20% (95% CI = 13%-28%).

CONCLUSION

The low specificity of CRRS in this setting indicates poor diagnostic utility for detecting pulmonary tuberculosis.

TB-IRIS: Proteomic analysis of in vitro PBMC responses to Mycobacterium tuberculosis and response modulation by dexamethasone

Paradoxical tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) occurs in 8-54% of South African patients undergoing treatment for tuberculosis/human immunodeficiency virus co-infection. Improved TB-IRIS molecular pathogenesis understanding would enhance risk stratification, diagnosis, prognostication, and treatment. We assessed how TB-IRIS status and dexamethasone influence leukocyte proteomic responses to Mycobacterium tuberculosis (Mtb). Patient blood was obtained three weeks post-anti-retroviral therapy initiation. Isolated mononuclear cells were stimulated ex vivo with heat-killed Mtb in the presence/absence of dexamethasone. Mass spectrometry-based proteomic comparison of TB-IRIS and non-IRIS patient-derived cells facilitated generation of hypotheses regarding pathogenesis. Few represented TB-IRIS-group immune-related pathways achieved significant activation, with relative under-utilisation of "inter-cellular interaction" and "Fcγ receptor-mediated phagocytosis" (but a tendency towards apoptosis-related) pathways. Dexamethasone facilitated significant activation of innate-related pathways. Differentially-expressed non-IRIS-group proteins suggest focused and co-ordinated immunological pathways, regardless of dexamethasone status. Findings suggest a relative deficit in TB-IRIS-group responses to and clearance of Mtb antigens, ameliorated by dexamethasone.

Latent tuberculosis infection: An overview

Latent tuberculosis infection (LTBI) is defined as a state of persistent immune response to stimulation by Mycobacterium tuberculosis antigens without evidence of clinically manifested active tuberculosis (TB) disease. Individuals with LTBI represent a reservoir for active TB cases. The detection and management of LTBI is now a key component of the World Health Organization's End TB Strategy and the Government of Canada's federal framework for action on TB prevention and control. This is because people with LTBI can progress to active TB or undergo reactivation, a risk that is greatly increased in those with immunocompromising conditions. This overview provides a summary of LTBI and reactivation risk, as well as the recent advances in the diagnosis and treatment of LTBI.

The pharmacological challenges of treating tuberculosis and HIV coinfections

INTRODUCTION

Tuberculosis (TB) is the most prevalent opportunistic infection among HIV patients, and the leading cause of death among HIV patients worldwide. Simultaneous treatment of both diseases is recommended by current guidelines, but can be challenging due to the potential for drug-drug interactions, overlapping toxicities, difficulty adhering to medications, and an increased risk for immune reconstitution inflammatory syndrome (IRIS). Clinical manifestations of TB can also vary between HIV-infected patients and uninfected patients, which can increase the risk for delayed diagnosis. Areas covered: Topics covered in this review include the following: the inter-related pathophysiology of HIV and TB; clinical manifestations and diagnosis; drug-drug interactions, particularly the rifamycins with the antiretrovirals; IRIS presentation and treatment, as well as a discussion on overlapping toxicity between the two disease states. Expert commentary: The complexity of managing these two disease states simultaneously requires a multidisciplinary approach to care and dedicated resources. If properly funded, TB/HIV co-infection will continue to decline over the coming years.

Tuberculosis and pneumonia in HIV-infected children: an overview

Pneumonia remains the most common cause of hospitalization and the most important cause of death in young children. In high human immunodeficiency virus (HIV)-burden settings, HIV-infected children carry a high burden of lower respiratory tract infection from common respiratory viruses, bacteria and Mycobacterium tuberculosis. In addition, Pneumocystis jirovecii and cytomegalovirus are important opportunistic pathogens. As the vertical transmission risk of HIV decreases and access to antiretroviral therapy increases, the epidemiology of these infections is changing, but HIV-infected infants and children still carry a disproportionate burden of these infections. There is also increasing recognition of the impact of in utero exposure to HIV on the general health of exposed but uninfected infants. The reasons for this increased risk are not limited to socioeconomic status or adverse environmental conditions—there is emerging evidence that these HIV-exposed but uninfected infants may have particular immune deficits that could increase their vulnerability to respiratory pathogens. We discuss the impact of tuberculosis and other lower respiratory tract infections on the health of HIV-infected infants and children.

Mortality among tuberculosis patients under DOTS programme: a historical cohort study

Background

In high human immunodeficiency virus (HIV) prevalence population, tuberculosis (TB) is the leading cause of morbidity and mortality. HIV is driving the TB epidemic in many countries, especially those in sub-Saharan Africa. We assessed the survival time and predictors of mortality among tuberculosis patients under directly observed treatment, short course (DOTS) strategy in Dessie Referral Hospital tuberculosis clinic, Northeast Ethiopia.

Method

A historical cohort design was utilized to assess survival time and determinants of mortality. A total of 1260 records of patients who started ant-tuberculosis treatment from January 2006 up to December 2010 were analyzed. Survival curves were estimated using Kaplan–Meier and were compared using the Log-rank test. The Cox proportional hazard model was used to assess the relationship between baseline variables and mortality.

Results

Out of the 1260 registered patients, 117 (9.3 %) died over the entire follow-up period. Among those died, 113 (18 %) were HIV positive and 4 (0.6 %) were HIV negative. The 1260 patients contributed a cumulative total of 634.25 person‑years observation.

Conclusion

The mortality of HIV positive tuberculosis patients was higher than those of HIV negative patients and the use of cotrimoxazole preventive therapy increased the survival time of patients.

Home-Based and Facility-Based Directly Observed Therapy of Tuberculosis Treatment under Programmatic Conditions in Urban Tanzania

Introduction

Decentralization of Directly Observed Treatment (DOT) for tuberculosis (TB) to the community (home-based DOT) has improved the coverage of TB treatment and reduced the burden to the health care facilities (facility-based DOT). We aimed to compare TB treatment outcomes in home-based and facility-based DOT under programmatic conditions in an urban setting with a high TB burden.

Methodology

A retrospective analysis of a cohort of adult TB patients (≥15 years) routinely notified between 2010 and 2013 in two representative TB sub-districts in the Temeke district, Dar es Salaam, Tanzania. We assessed differences in treatment outcomes by calculating Risk Ratios (RRs). We used logistic regression to assess the association between DOT and treatment outcomes.

Results

Data of 4,835 adult TB patients were analyzed, with a median age of 35 years, 2,943 (60.9%) were men and TB/HIV co-infection prevalence of 39.9%. A total of 3,593 (74.3%) patients were treated under home-based DOT. Patients on home-based DOT were more likely to die compared to patients on facility-based DOT (RR 2.04, 95% Confidence Interval [95% CI]: 1.52–2.73), and more likely to complete TB treatment (RR 1.14, 95% CI: 1.06–1.23), but less likely to have a successful treatment outcome (RR 0.94, 95% CI: 0.92–0.97). Home-based DOT was preferred by women (adjusted Odds Ratio [aOR] 1.55, 95% CI: 1.34–1.80, p<0.001), older people (aOR 1.01 for each year increase, 95% CI: 1.00–1.02, p = 0.001) and patients with extra-pulmonary TB (aOR 1.45, 95% CI: 1.16–1.81, p = 0.001), but less frequently by patients on a retreatment regimen (aOR 0.12, 95% CI: 0.08–0.19, p<0.001).

Conclusions/significance

TB patients under home-based DOT had more frequently risk factors of death such as older age, HIV infection and sputum smear-negative TB, and had higher mortality compared to patients under facility-based DOT. Further operational research is needed to monitor the implementation of DOT under programmatic conditions.

Synthesis and antitubercular activity of new 1,3,4-oxadiazoles bearing pyridyl and thiazolyl scaffolds

In search of more potent and safe new antitubercular agents, here new 2-pyridinyl substituted thiazolyl-5-aryl-1,3,4-oxadiazoles (6a-o), have been designed and synthesized using thionicotinamide as a starting, following novel multistep synthetic route. An intermediate, pyridinyl substituted thiazolyl acid hydrazide (4) when condensed with benzoic acids/nicotinic acids (5a-o) in the presence of silica supported POCl3 yielded better to excellent yields of the title compounds. All the synthesized compounds (6a-o) and intermediate acid hydrazide (4) have been screened for their in vitro antitubercular activity against Mycobacterium tuberculosis H37Ra (MTB) and Mycobacterium bovis BCG. Amongst them, 6f, 6j, 6l and 6o have revealed promising activity against M. bovis BCG at concentrations less than 3μg/mL. These compounds have shown low cytotoxicity (CC50: >100μg/mL) towards four human cancer cell lines. Molecular docking study has also been performed against mycobacterial enoyl reductase (InhA) enzyme to gain an insight into the binding modes of these molecules and recorded good binding affinity. The ADME properties the title products have also been analyzed.

Assessment of the patient, health system, and population effects of Xpert MTB/RIF and alternative diagnostics for tuberculosis in Tanzania: an integrated modelling approach

BACKGROUND

Several promising new diagnostic methods and algorithms for tuberculosis have been endorsed by WHO. National tuberculosis programmes now face the decision on which methods to implement and where to place them in the diagnostic algorithm.

METHODS

We used an integrated model to assess the effects of different algorithms of Xpert MTB/RIF and light-emitting diode (LED) fluorescence microscopy in Tanzania. To understand the effects of new diagnostics from the patient, health system, and population perspective, the model incorporated and linked a detailed operational component and a transmission component. The model was designed to represent the operational and epidemiological context of Tanzania and was used to compare the effects and cost-effectiveness of different diagnostic options.

FINDINGS

Among the diagnostic options considered, we identified three strategies as cost effective in Tanzania. Full scale-up of Xpert would have the greatest population-level effect with the highest incremental cost: 346 000 disability-adjusted life-years (DALYs) averted with an additional cost of US$36·9 million over 10 years. The incremental cost-effectiveness ratio (ICER) of Xpert scale-up ($169 per DALY averted, 95% credible interval [CrI] 104-265) is below the willingness-to-pay threshold ($599) for Tanzania. Same-day LED fluorescence microscopy is the next most effective strategy with an ICER of $45 (95% CrI 25-74), followed by LED fluorescence microscopy with an ICER of $29 (6-59). Compared with same-day LED fluorescence microscopy and Xpert full rollout, targeted use of Xpert in presumptive tuberculosis cases with HIV infection, either as an initial diagnostic test or as a follow-on test to microscopy, would produce DALY gains at a higher incremental cost and therefore is dominated in the context of Tanzania.

INTERPRETATION

For Tanzania, this integrated modelling approach predicts that full rollout of Xpert is a cost-effective option for tuberculosis diagnosis and has the potential to substantially reduce the national tuberculosis burden. It also estimates the substantial level of funding that will need to be mobilised to translate this into clinical practice. This approach could be adapted and replicated in other developing countries to inform rational health policy formulation.

Structure activity relationships of 4-hydroxy-2-pyridones: A novel class of antituberculosis agents

Pyridone 1 was identified from a high-throughput cell-based phenotypic screen against Mycobacterium tuberculosis (Mtb) including multi-drug resistant tuberculosis (MDR-TB) as a novel anti-TB agent and subsequently optimized series using cell-based Mtb assay. Preliminary structure activity relationship on the isobutyl group with higher cycloalkyl groups at 6-position of pyridone ring has enabled us to significant improvement of potency against Mtb. The lead compound 30j, a dimethylcyclohexyl group on the 6-position of the pyridone, displayed desirable in vitro potency against both drug sensitive and multi-drug resistant TB clinical isolates. In addition, 30j displayed favorable oral pharmacokinetic properties and demonstrated in vivo efficacy in mouse model. These results emphasize the importance of 4-hydroxy-2-pyridones as a new chemotype and further optimization of properties to treat MDR-TB.

Tuberculosis retreatment 'others' in comparison with classical retreatment cases; a retrospective cohort review

BACKGROUND

Many of the countries in sub-Saharan Africa are still largely dependent on microscopy as the mainstay for diagnosis of tuberculosis (TB) including patients with previous history of TB treatment. The available guidance in management of TB retreatment cases is focused on bacteriologically confirmed TB retreatment cases leaving out those classified as retreatment 'others'. Retreatment 'others' refer to all TB cases who were previously treated but with unknown outcome of that previous treatment or who have returned to treatment with bacteriologically negative pulmonary or extra-pulmonary TB. This study was conducted in 11 regional referral hospitals (RRHs) serving high burden TB districts in Uganda to determine the profile and treatment success of TB retreatment 'others' in comparison with the classical retreatment cases.

METHODS

A retrospective cohort review of routinely collected National TB and Leprosy Program (NTLP) facility data from 1 January to 31 December 2010. This study uses the term classical retreatment cases to refer to a combined group of bacteriologically confirmed relapse, return after failure and return after loss to follow-up cases as a distinct group from retreatment 'others'. Distribution of categorical characteristics were compared using Chi-squared test for difference between proportions. The log likelihood ratio test was used to assess the independent contribution of type of retreatment, human immunodeficiency virus (HIV) status, age group and sex to the models.

RESULTS

Of the 6244 TB cases registered at the study sites, 733 (11.7%) were retreatment cases. Retreatment 'others' constituted 45.5% of retreatment cases. Co-infection with HIV was higher among retreatment 'others' (70.9%) than classical retreatment cases (53.5%). Treatment was successful in 410 (56.2%) retreatment cases. Retreatment 'others' were associated with reduced odds of success (AOR = 0.44, 95% CI 0.22,0.88) compared to classical cases. Lost to follow up was the commonest adverse outcome (38% of adverse outcomes) in all retreatment cases. Type of retreatment case, HIV status, and age were independently associated with treatment success.

CONCLUSION

TB retreatment 'others' constitute a significant proportion of retreatment cases, with higher HIV prevalence and worse treatment success. There is need to review the diagnosis and management of retreatment 'others'.

Analysis of HLA association among North Indian HIV-positive individuals co-infected with Mycobacterium tuberculosis

BACKGROUND

Genetic variation in HLA genes influence the immune response and may thus contribute to differential development of tuberculosis (TB) in HIV-infected individuals. The study was designed to determine whether HLA polymorphisms influence the development of Mycobacterium tuberculosis infection in HIV-infected individuals.

MATERIALS AND METHODS

Fifty HIV-positive individuals without TB (HIV+TB-), 50 HIV patients co-infected with TB (HIV+TB+) and 50 control subjects (HIV-TB-) were analyzed for HLA Class I and II polymorphisms.

RESULTS

In HLA Class II, frequency of occurrence of DRB1*13 (OR 3.165, CI 1.176-8.518, P value 0.019), DRB5 (OR 2.253, CI 1.011-5.019, P value 0.045) and DQB1*06 (OR 2.705, CI 1.197-6.113, P value 0.016) were increased in HIV+TB+compared to HIV+TB-. HLA DQB1*02 (OR 0.436, CI 0.185-1.029, P value 0.05) on the other hand conferred a protective role. In HLA Class I, frequency of B*15 (OR 2.705, CI 1.040-7.036, P value 0.038) was increased, whereas B*51 (OR 0.148, CI 0.031-0.706, P value 0.007) was decreased in HIV+TB+group compared to HIV+TB-. These differences however were not significant when compared with healthy controls.

CONCLUSION

HLA polymorphisms independently did not account for the susceptibility to either of the disease mostly, although they seem to play a role once the infection(s) has established in a particular individual. Further studies are needed on a larger sample size to confirm these observations.

The Effect of Early Initiation of Antiretroviral Therapy in TB/HIV-Coinfected Patients: A Systematic Review and Meta-Analysis

BACKGROUND

The importance of early initiation of antiretroviral therapy (ART) for tuberculosis (TB) and HIV-coinfected patients is controversial. We conducted a systematic review and meta-analysis to assess the effect of early initiation of ART (within 2-4 weeks of TB treatment) on several treatment outcomes among TB/HIV-coinfected patients.

METHOD

A systematic search of clinical trials was performed in PubMed, Embase, Google Scholar, Science Direct, Medscape, and the Cochrane library. Clinical trials which were published in any language before the last date of search (March 31, 2015) were included. The qualities of the studies were assessed using criteria from the Cochrane Library. Heterogeneity test was conducted to assess the variations among study outcomes. For each study outcome, the risk ratio (RR) with 95% confidence interval (CI) was calculated as a measure of intervention effect. The Mantel-Haenszel method was used to estimate the RR using a fixed-effects model.

FINDINGS

A total of 2272 study participants from 6 trials were included in the meta-analysis. Early ART initiation during TB treatment was associated with reduced all-cause mortality (RR = 0.78; 95% CI = 0.63-0.98) and increased rate of TB-associated immune reconstitution inflammatory syndrome (TB-IRIS; RR = 2.19; 95% CI = 1.77- 2.70) and death related to TB-IRIS (RR = 6.94; 95% CI = 1.26-38.22). However, the time of ART initiation has no association with TB cure rate (RR = 0.99; 95% CI = 0.81-1.07), rate of drug toxicity (RR = 1.00; 95% CI = 0.93-1.08), death associated with drug toxicity (RR = 0.40; 95% CI = 0.14- 1.16), rate of low viral load (less than 400 copies/mL; RR = 1.00; 95% CI = 0.96-1.04), and rate of new AIDS-defining illness (RR = 0.84; 95% CI = 0.60-1.18). Immunological response in early ART arms of study participant in different trials showed a greater or equal response compared with late ART arms.

CONCLUSION

This systematic review presents conclusive evidence on the reduction of all-cause mortality as a result of early initiation of ART. However, this study also confirms the high rate of TB-IRIS and death associated with it. Operational and implementation research are required to maintain the benefit of early ART initiation and proper management of TB-IRIS. Studies on the timing of ART in extrapulmonary and multidrug-resistant TB are recommended.

Detection and management of drug-resistant tuberculosis in HIV-infected patients in lower-income countries

SETTING

Drug resistance threatens tuberculosis (TB) control, particularly among human immunodeficiency virus (HIV) infected persons.

OBJECTIVE

To describe practices in the prevention and management of drug-resistant TB under antiretroviral therapy (ART) programs in lower-income countries.

DESIGN

We used online questionnaires to collect program-level data on 47 ART programs in Southern Africa (n = 14), East Africa (n = 8), West Africa (n = 7), Central Africa (n = 5), Latin America (n = 7) and the Asia-Pacific (n = 6 programs) in 2012. Patient-level data were collected on 1002 adult TB patients seen at 40 of the participating ART programs.

RESULTS

Phenotypic drug susceptibility testing (DST) was available in 36 (77%) ART programs, but was only used for 22% of all TB patients. Molecular DST was available in 33 (70%) programs and was used in 23% of all TB patients. Twenty ART programs (43%) provided directly observed therapy (DOT) during the entire course of treatment, 16 (34%) during the intensive phase only, and 11 (23%) did not follow DOT. Fourteen (30%) ART programs reported no access to second-line anti-tuberculosis regimens; 18 (38%) reported TB drug shortages.

CONCLUSIONS

Capacity to diagnose and treat drug-resistant TB was limited across ART programs in lower-income countries. DOT was not always implemented and drug supplies were regularly interrupted, which may contribute to the global emergence of drug resistance.

Dysregulation of Apoptosis Is a Risk Factor for Tuberculosis Disease Progression

BACKGROUND

A major barrier to effective tuberculosis control is our limited understanding of risk factors for tuberculosis disease progression. This study examined the role of apoptosis in immunity to tuberculosis.

METHODS

Cell subsets from tuberculosis cases and tuberculin skin test-positive (TST(+)) and TST-negative (TST(-)) household contacts (HHCs) were analyzed for expression of annexin-V and propidium iodide by flow cytometry. RNA microarrays were used to determine differences in apoptotic gene expression levels and multiplex ligation-dependent probe amplification was used to analyze gene expression in HHCs who progressed to active tuberculosis.

RESULTS

T cells from TST(+)HHC exhibited higher levels of apoptosis than tuberculosis cases; however, tuberculosis cases had a higher proportion of late apoptotic cells within the CD3(+)PD-1(+) subset. Tuberculosis cases had reduced levels of antiapoptotic genes compared to HHCs with a significant reduction in BCL2 associated with disease progression at least 1 year prior to progression.

CONCLUSIONS

While T cells are clearly able to mount a robust immune response to Mycobacterium tuberculosis, there are increased levels of apoptosis seen in effector T cells from tuberculosis patients. Dysregulation of several apoptotic genes suggest that apoptosis is a major functional pathway that could be targeted for future host-directed therapeutics.

Modelling challenges in context: lessons from malaria, HIV, and tuberculosis

Malaria, HIV, and tuberculosis (TB) collectively account for several million deaths each year, with all three ranking among the top ten killers in low-income countries. Despite being caused by very different organisms, malaria, HIV, and TB present a suite of challenges for mathematical modellers that are particularly pronounced in these infections, but represent general problems in infectious disease modelling, and highlight many of the challenges described throughout this issue. Here, we describe some of the unifying challenges that arise in modelling malaria, HIV, and TB, including variation in dynamics within the host, diversity in the pathogen, and heterogeneity in human contact networks and behaviour. Through the lens of these three pathogens, we provide specific examples of the other challenges in this issue and discuss their implications for informing public health efforts.

Modeling tuberculosis in nonhuman primates

Nonhuman primates have emerged as an excellent model of human tuberculosis, in large part because they recapitulate the full spectrum of infection outcome and pathology seen in humans. Several variables inherent to the nonhuman primate models of tuberculosis are discussed in this review, including the monkey species, Mycobacterium tuberculosis strains, and routes of infection, all of which can influence the model to be chosen for various studies. New technologies for studying the microbiology, immunology, and pathogenesis of tuberculosis in nonhuman primates have greatly expanded the capabilities of this model for basic and translational studies, including the development and testing of new treatment and prevention strategies for tuberculosis.

Decline in overall, smear-negative and HIV-positive TB incidence while smear-positive incidence stays stable in Guinea-Bissau 2004-2011

OBJECTIVE

To calculate Tuberculosis (TB) incidence rates in Guinea-Bissau over an 8-year period.

METHODS

Since 2003, a surveillance system has registered all TB cases in six suburban districts of Bissau. In this population-based prospective follow-up study, 1205 cases of pulmonary TB were identified between January 2004 and December 2011. Incidence rates were calculated using census data from the Bandim Health and Demographic Surveillance System (HDSS).

RESULTS

The overall incidence of pulmonary TB was 279 per 100,000 person-years of observation; the male incidence being 385, and the female 191. TB incidence rates increased significantly with age in both sexes, regardless of smear or HIV status. Despite a peak with unknown cause of 352 per 100,000 in 2007, the overall incidence of pulmonary TB declined over the period. The incidence of HIV infected TB cases declined significantly from 108 to 39 per 100,000, while the incidence of smear-positive TB cases remained stable; the overall figure was 188 per 100,000.

CONCLUSIONS

Overall incidence of pulmonary TB in Guinea-Bissau has declined from 2004 to 2011. The decline was also seen in the subgroups of smear-negative and HIV-positive TB cases, probably due to antiretroviral treatment. Smear-positive TB incidence remains stable over the period.