Current trends and intricacies in the management of HIV-associated pulmonary tuberculosis

Paradoxical tuberculosis-associated immune reconstitution inflammatory syndrome in initiating ART among HIV-Infected patients in China-risk factors and management

BACKGROUND

China is a country burdened with a high incidence of both tuberculosis (TB) and HIV, Paradoxical tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) is an important early complication in TB and HIV co-infected patients, but data from China are limited. Additionally, as an integrase strand transfer inhibitor (INSTI)-based antiretroviral therapy (ART) regimen becomes the first-line treatment, concerns have arisen regarding the potential increase in the incidence of paradoxical TB-IRIS. Nevertheless, the existing data are inconclusive and contradictory.

METHODS

We conducted a retrospective study at Chongqing Public Health Clinical Center from January 2018 to December 2021. We collected demographic and clinical data of HIV/TB co-infected patients who initiated ART. We described the patient characteristics, identified predictors for TB-IRIS, and determined clinical outcomes. The Statistical Package for Social Science (SPSS 25) was used to analyse the data. Continuous variables were compared using Student's t-test or rank sum test. Counting data were compared using the chi-square test or Fisher's exact test. The variables with statistical significance in the univariate analysis were added to the binary logistic regression. A p-value less than 0.05 was considered statistically significant.

RESULTS

A total of 384 patients co-infected with naive HIV and pulmonary TB (PTB) who were given ATT and ART combination were included. 72 patients (18.8%) developed paradoxical TB-IRIS with a median of 15 (12, 21) days after initiating ART. Baseline age ≤ 40years, CD4 + T-cell counts ≤ 50cells/µL, HIV viral load ≥ 500,000 copies/mL were found to be significantly associated with development of paradoxical TB-IRIS. Mortality rates were similar in the TB-IRIS (n = 5, 6.9%) group and non-TB-IRIS (n = 13, 4.2%) group. Interestingly, CD4+ T-cell counts recovery post-ART was significant higher in the TB-IRIS group when compared to the non-TB-IRIS group at the end of 24 weeks (P = 0.004), as well as at 48 weeks (P = 0.015). In addition, we consider that INSTI- based ART regimen do not increased the risk of Paradoxical TB-IRIS.

CONCLUSION

Paradoxical TB-IRIS, while often leading to clinical deterioration and hospitalization, is generally manageable. It appears to have a positive impact on the recovery of CD4 + T-cell counts over time. Importantly, our data suggest that INSTI-based ART regimens do not elevate the risk of TB-IRIS. Thus, paradoxical TB-IRIS should not be considered an impediment to initiating ART in adults with advanced immunodeficiency, except in the case of tuberculous meningitis (TBM).

Designing New Magic Bullets to Penetrate the Mycobacterial Shield: An Arduous Quest for Promising Therapeutic Candidates

Mycobacterium spp. intimidated mankind since time immemorial. The triumph over this organism was anticipated with the introduction of potent antimicrobials in the mid-20th century. However, the emergence of drug resistance in mycobacteria, Mycobacterium tuberculosis, in particular, caused great concern for the treatment. With the enemy growing stronger, there is an immediate need to equip the therapeutic arsenal with novel and potent chemotherapeutic agents. The task seems intricating as our understanding of the dynamic nature of the mycobacteria requires intense experimentation and research. Targeting the mycobacterial cell envelope appears promising, but its versatility allows it to escape the lethal effect of the molecules acting on it. The unique ability of hiding (inactivity during latency) also assists the bacterium to survive in a drug-rich environment. The drug delivery systems also require upgradation to allow better bioavailability and tolerance in patients. Although the resistance to the novel drugs is inevitable, our commitment to the research in this area will ensure the discovery of effective weapons against this formidable opponent.

Incidence and Predictors of Pulmonary Tuberculosis among Children Who Received Antiretroviral Therapy (ART), Northwest Ethiopia: A Multicenter Historical Cohorts Study 2009–2019

The human immune deficiency virus (HIV) is the strongest risk factor for endogenous reactivation of pulmonary tuberculosis (PTB) through target reduction of CD4, T-lymphocytes, and cellular immune function. Almost one-third of deaths among people living with HIV are attributed to tuberculosis. Despite this evidence, in Ethiopia, information is scarce and meager regarding PTB incidence after ART initiated for seropositive children. Methods. Facility-based multicenter historical cohort was conducted among 721 seropositive children after initiating ART from January 1, 2009, to December 31, 2019. Data from the records of children were extracted using a standardized checklist. The collected data were entered using Epi-Data version 4.2 and exported to STATA (SE) R-14 version statistical soft wares for further analysis. Bivariable and multivariable Cox regression analyses were conducted to identify predictors of PTB incidence. Results. Seven hundred twenty-one (N = 721) seropositive children were included with a mean (±SD) age of 118.4 ± 38.24 months. During the follow-up periods, 63 (15.2%) participants developed new cases of TB; majority (61/63, 96.8%) of them were PTB. The overall incidence rate and the median (±IQR) time of PTB reported were determined as 5.86 per 100 child years (95% CI: 4.58, 7.5) and 17.8 (±11) months, respectively. At baseline, children being severely stunted (AHR = 2.9 : 95% CI, 1.2–7.8, P=0.03), with Hgb ≤10 mg/dl (AHR = 4.0; 95% CI, 2.1–8.1, P=0.001), and not given isoniazid and cotrimoxazole preventive therapy (AHR = 2.4; 95% CI: 1.2; 5.1, P=0.001) (AHR = 2.5; 95% CI, 1.4–4.7, P=0.021) were significantly associated with PTB incidence. Conclusion. A high incidence rate of PTB was observed in our study as compared with the previous finding in Ethiopia. Cases at baseline not taking IPT and CPT, being severely stunted, and having low hemoglobin (≤10 mg/dl) levels were found to be at higher risk of developing PTB.

Pretomanid for tuberculosis treatment: an update for clinical purposes

Coronavirus disease (COVID-19) pandemic determined a 10 years-set back in tuberculosis (TB) control programs. Recent advances in available therapies may help recover the time lost. While Linezolid (LZD) and Bedaquiline (BDQ), previously Group D second line drugs (SLDs) for TB, have been relocated to Group A, other drugs are currently being studied in regimens for drug resistant TB (DR-TB). Among these, Pretomanid (PA), a recently introduced antimycobacterial drug derived from nitroimidazole with both solid bactericidal and bacteriostatic effect, and with an excellent effectiveness and tolerability profile, is in the spotlight. Following promising data obtained from recently published and ongoing randomized controlled trials (RCTs), the World Health Organization (WHO) determined to include PA in its guidelines for the treatment of rifampicin-resistant (RR), multi drug resistant (MDR) and pre-extensively drug resistant TB (pre-XDR-TB) with BDQ, LZD and Moxifloxacine (MFX) in a 6-month regimen. Although further studies on the subject are needed, PA may also represent a treatment option for drug-susceptible TB (DS-TB), latent TB infection (LTBI) and non tuberculous mycobacteria (NTM). This narrative review aims to examine current implementation options and future possibilities for PA in the never-ending fight against TB.

Time to Develop and Predictors for Incidence of Tuberculosis among Children Receiving Antiretroviral Therapy

Infection by the human immune deficiency virus (HIV) is the strongest risk factor for latent or new infection of tuberculosis (TB) through reduction of CD4 T-lymphocytes and cellular immune function. Almost one-third of deaths among people living with HIV are attributed to tuberculosis. Despite this evidence, in Ethiopia, there is a scarcity of information regarding the incidence of tuberculosis for children living with HIV. Thus, this study assessed time to develop and predictors for incidence of tuberculosis in children attending HIV/AIDS care in public hospitals: North West Ethiopia 2021. Methods. A facility-based retrospective cohort study was conducted among 421 seropositive children on antiretroviral therapy in two hospitals between January 1, 2011 and December 31, 2020. EPI-DATA version 3.2 and STATA/14 software were used for data entry and analysis, respectively. Tuberculosis-free survival time was estimated using the Kaplan-Meier survival curve. Bivariate and multivariable Cox regression model was fitted to identify predictors at a P value <0.05 within 95% CI. Results. In the final analysis, a total of 421 seropositive children were included, of whom, 64 (15.2%) developed tuberculosis at the time of follow-up. The mean (±SD) age of the children was 10.62 ± 3.32 years, with a median (IQR) time to develop TB that was 23.5 (IQR = ±19) months. This study found that the incidence of tuberculosis was 5.9 (95% CI: 4.7; 7.6) per 100 person-years (PY) risk of observation. Cases at baseline not taking cotrimoxazol preventive therapy (CPT) (AHR = 2.5; 95% CI, 1.4-4.7, P < 0.021), being severely stunted (AHR = 2.9: 95% CI, 1.2-7.8, P < 0.03), and having low hemoglobin level (AHR = 4.0; 95% CI, 2.1-8.1, P < 0.001) were found to be predictors of tuberculosis. Conclusion. A higher rate of tuberculosis incidence was reported in our study as compared with previous studies in Ethiopia. Cases at baseline not taking cotrimoxazol preventive therapy (CPT), being severely stunted, and having low hemoglobin (≤10 mg/dl) levels were found to be at higher risk to developed TB incidence.

Association of Urinary Interferon Gamma Protein-10 Levels and Low Levels of Cluster of Differentiation 4 Serum in Patients with Tuberculosis-Human Immunodeficiency Virus Coinfection

BACKGROUND: Tuberculosis (TB) infection caused by Mycobacterium tuberculosis was the most frequent opportunistic infection in human immunodeficiency virus (HIV) patients that lead to increasing of morbidity and mortality. Very low cluster of differentiation 4 (CD4) levels causing problem in TB/HIV diagnostic because unspecific clinical manifestation. Urine interferon gamma protein-10 (IP10) examination is a method that is relatively easier and safer to do, so it can be used as an alternative method in establishing the diagnosis TB/HIV. AIM: The aim of this study was to investigate the association between urinary IP-10 and level of CD4 serum in patients with TB/HIV coinfection. MATERIALS AND METHODS: This study was conducted at the Department of Internal Medicine, Faculty of Medicine, Dr. M. Djamil Hospital, Padang, Indonesia, involved 30 patients with active TB/HIV coinfection whose urine and blood serum were collected to evaluate IP-10 and CD4 level. RESULTS: There is a significant relationship between urine IP10 levels as a biomarker for the diagnosis of active pulmonary TB in HIV patients and serum CD4 levels in TB-HIV coinfected patients with moderate correlation strength. CONCLUSION: Further research is needed with a larger sample size to see the effect of low serum CD4 levels on the sensitivity of urine IP10 diagnosis.

Effect of Isoniazid Preventive Therapy on the Incidence of Tuberculosis among Seropositive Children Attending HIV/AIDS Care in Two General Hospitals, Northwest Ethiopia, 2021

The human immune deficiency virus (HIV) is the strongest risk factor for the incidence of tuberculosis (TB) by way of reactivation of latent or new infection. The provision of isoniazid preventive therapy (IPT) is one of the public health interventions for the prevention of TB. To date, there have been limited clinical data regarding the effectiveness of isoniazid preventive therapy (IPT) on TB incidence. This study aimed to assess the effect of isoniazid preventive therapy on the incidence of tuberculosis for seropositive children in Northwest Ethiopia. Methods. A facility-based retrospective follow-up was employed for reviewing 421 files from 1 January 2015 up to 30 December 2019. EpiData version 3.2 and Stata/14 software were used for data entry and analysis, respectively. Categorical variables at bivariable Cox regression were assessed for candidates transferred at P value <0.25 for multivariable Cox regression to claiming predictors associated with TB incidence rate at 95% CI at P < 0.005. Result. The overall incidence of TB was found to be 4.99 cases per 100 person-years at 95% CI (3.89-6.53). Missed IPT (AHR = 7.45, 95% CI: 2.96, 18.74, P < 0.001), missed cotrimoxazole preventive therapy (CPT) (AHR = 2.4, 95% CI: 1.84-4.74, P < 0.022), age ≥ 11 years (AHR = 4.2, 95% CI: 1.04-7.03, P < 0.048), MUAC ≤ 11.5 cm (AHR = 4.36, 95% CI: 1.97-9.97, P < 0.001), WHO stages III and IV (AHR = 2.04, 95% CI: 1.12-3.74, P < 0.022), and CD4 count ≤100 cells/μl (AHR = 3.96, 95% CI: 1.52-10.34, P < 0.005) were significantly associated with TB incidence. Conclusion. Concomitant administration of ART with IPT had demoted more than ninety-six percent of new TB incidences for this report. Undertaking in-depth TB screening and frequent follow-up among all these children is critical in order to prevent and control tuberculosis.

Gender difference in mortality among pulmonary tuberculosis HIV co-infected adults aged 15-49 years in Kenya

Setting

Kenya, 2012–2015

Objective

To explore whether there is a gender difference in all-cause mortality among smear positive pulmonary tuberculosis (PTB)/ HIV co-infected patients treated for tuberculosis (TB) between 2012 and 2015 in Kenya.

Design

Retrospective cohort of 9,026 smear-positive patients aged 15–49 years. All-cause mortality during TB treatment was the outcome of interest. Time to start of antiretroviral therapy (ART) initiation was considered as a proxy for CD4 cell count. Those who took long to start of ART were assumed to have high CD4 cell count.

Results

Of the 9,026 observations analysed, 4,567(51%) and 4,459(49%) were women and men, respectively. Overall, out of the 9,026 patients, 8,154 (90%) had their treatment outcome as cured, the mean age in years (SD) was 33.3(7.5) and the mean body mass index (SD) was 18.2(3.4). Men were older (30% men’ vs 17% women in those ≥40 years, p = <0.001) and had a lower BMI <18.5 (55.3% men vs 50.6% women, p = <0.001). Men tested later for HIV: 29% (1,317/4,567) of women HIV tested more than 3 months prior to TB treatment, as compared to 20% (912/4,459) men (p<0.001). Mortality was higher in men 11% (471/4,459) compared to women 9% (401/4,567, p = 0.004). There was a 17% reduction in the risk of death among women (adjusted HR 0.83; 95% CI 0.72–0.96; p = 0.013). Survival varied by age-groups, with women having significantly better survival than men, in the age-groups 40 years and over (log-rank p = 0.006).

Conclusion

Women with sputum positive PTB/HIV co-infection have a significantly lower risk of all-cause mortality during TB treatment compared to men. Men were older, had lower BMI and tested later for HIV than women.

Ocular Tuberculosis in HIV-infected Individuals

Aim: To review the current literature and publications to assess the clinical features, recommended investigations and treatment for ocular tuberculosis in HIV infected patients. Methods: Literature review. Results: The human immunodeficiency virus (HIV) epidemic affects as many as 37.9 million people. Mycobacterium tuberculosis infection is common in HIV infection and is a leading cause of death and morbidity. Common clinical presentations include anterior uveitis (granulomatous or otherwise), choroidal granulomas/tubercles, chorioretinitis, subretinal abscess, panophthalmitis, retinal detachment and vasculitis. The majority of clinical findings were in the posterior segment, appeared primarily infective (tubercles/chorioretinitis/abscess) and were largely seen in the context of pulmonary tuberculosis or disseminated disease. Current investigational patterns include corroborative tests such as tuberculin skin test or Interferon-γ release assay. Systemic testing includes Computed Tomography, MRI or PET/CT scans. Newer Molecular techniques such as GeneXpert MTB/RIF assay and Line Probe assays (LPA) are increasingly important. Apart from standard ocular anti-inflammatory protocols, anti-tubercular treatment as per the clinical staging (latent or active) needs to be initiated. Initiation of anti-retroviral therapy (ART) is important and can be started soon after ATT. Conclusions: Ocular manifestations within this group are distinct and unique investigational and therapeutic approaches are needed.

Pathogenesis of Human Immunodeficiency Virus-Mycobacterium tuberculosis Co-Infection

Given that infection with Mycobacterium tuberculosis (Mtb) is the leading cause of death amongst individuals living with HIV, understanding the complex mechanisms by which Mtb exacerbates HIV infection may lead to improved treatment options or adjuvant therapies. While it is well-understood how HIV compromises the immune system and leaves the host vulnerable to opportunistic infections such as Mtb, less is known about the interplay of disease once active Mtb is established. This review explores how glutathione (GSH) depletion, T cell exhaustion, granuloma formation, and TNF-α upregulation, as a result of Mtb infection, leads to an increase in HIV disease severity. This review also examines the difficulties of treating coinfected patients and suggests further research on the clinical use of GSH supplementation.

Tuberculosis IRIS: Pathogenesis, Presentation, and Management across the Spectrum of Disease

Antiretroviral therapy (ART), while essential in combatting tuberculosis (TB) and HIV coinfection, is often complicated by the TB-associated immune reconstitution inflammatory syndrome (TB-IRIS). Depending on the TB disease site and treatment status at ART initiation, this immune-mediated worsening of TB pathology can take the form of paradoxical TB-IRIS, unmasking TB-IRIS, or CNS TB-IRIS. Each form of TB-IRIS has unique implications for diagnosis and treatment. Recently published studies have emphasized the importance of neutrophils and T cell subtypes in TB-IRIS pathogenesis, alongside the recognized role of CD4 T cells and macrophages. Research has also refined our prognostic understanding, revealing how the disease can impact lung function. While corticosteroids remain the only trial-supported therapy for prevention and management of TB-IRIS, increasing interest has been given to biologic therapies directly targeting the immune pathology. TB-IRIS, especially its unmasking form, remains incompletely described and more data is needed to validate biomarkers for diagnosis. Management strategies remain suboptimal, especially in the highly morbid central nervous system (CNS) form of the disease, and further trials are necessary to refine treatment. In this review we will summarize the current understanding of the immunopathogenesis, the presentation of TB-IRIS and the evidence for management recommendations.

Two-drug vs. three-drug combinations for HIV-1: Do we have enough data to make the switch?

Three-drug combination antiretroviral therapy (ART) became available in 1996, dramatically improving the prognosis of people living with HIV. The clinical benefits of ART are due to the sustained viral load suppression and CD4 T cell gains. Major drawbacks of the first ART regimens were adverse events, and high pill burden, which led to the reduction of drug adherence resulting in frequent treatment discontinuations and the development of drug resistance. Due to increased viral potency of new antiretroviral drugs consideration of a two-drug combination therapy repositioning occurred in an effort to reduce adverse events, drug-drug interactions and cost, while maintaining a sustained antiviral effect. Various combinations of two-drug regimens have been studied, and non-inferiority compared to a three-drug regimen has been shown only for some of them. In addition, a two-drug combination regimen may not be suitable for every patient, especially those who are pregnant, those with tuberculosis or coexisting HBV infection. Furthermore no information has been generated concerning the secondary transmission of HIV from patients who have undetectable plasma viral load on two-drug regimens. Additional studies of two-drug combinations are also necessary to evaluate the debated existence of low viral replication in tissues and on immune activation. While there is no urgent need to routinely switch patients to two-drug combination therapy, due to the availability of drug combinations without significant toxicities, dual regimens represent a suitable option that deserve long-term evaluation before being introduced to clinical practice.

Clustering and spatial heterogeneity of bovine tuberculosis at the livestock/wildlife interface areas in Namwala District of Zambia

BACKGROUND AND AIM

Bovine tuberculosis (bTB) remains a major public health issue in Zambia and has been exacerbated by human immunodeficiency virus prevalence and consumption of unpasteurized milk in the Southern Province of the country. The prevalence of bTB has been established to be linked to Kafue Lechwe, which act as reservoir hosts and share grazing fields with domestic cattle. No studies have so far used geographic information system (GIS) to investigate the relationship between the reservoir hosts (Kafue Lechwe) and domestic animals. This study, therefore, aimed to apply GIS to investigate the spatial distribution of bTB in Namwala District of the Southern Province of the country.

MATERIALS AND METHODS

To investigate the spatial distribution of bTB, geographical positioning system (GPS) coordinates representing 96 cattle herds across 20 independent villages were captured alongside risk factor data. The 96 herds were based on abattoir reports of condemned carcasses and a trace back. Positive herds were confirmed by cross-reference to purified protein derivative tests conducted by the District Veterinary Office. The GPS coordinates were transferred into ArcView 3.2 and laid on the map of Namwala District alongside physical features, including national parks, game management areas, and flood plains. Questionnaires were administered across 96 independent households to assess risk factors of bTB transmission.

RESULTS

The results revealed a "clustered" spatial distribution of the disease in cattle in Namwala District of Zambia, particularly significant in the eastern interface areas of the district (p=0.006 using Moran's I). Abattoir to production area trace back revealed a herd-level prevalence of 36.4% (95% CI=26.7-46.3%) among cattle herds in Namwala District, whereas individual animal prevalence ranged from 0% to 14% (95% CI=2.4-26.2%). Further, GPS data indicated that the majority of the positive herds were located at the livestock/wildlife interface area. Contacts with wildlife, coupled with sharing grazing, and watering points were found to be significant risk factors for bTB transmission.

CONCLUSION

This study demonstrated the presence of bTB in cattle and associated spatial risk factors. In particular, bTB was observed to be a function of animal location within the livestock/wildlife interface area. GIS is thus an applicable and important tool in studying disease distribution.

Laboratory tools for tuberculosis control in a setting with a high burden of HIV/AIDS

Introduction. Nosocomial transmission of Mycobacterium tuberculosis is an important health issue and the detection of tuberculosis (TB) cases is the main tool for controlling this disease.Aim. We aimed to assess the possible occurrence of nosocomial transmission of M. tuberculosis in a reference hospital for HIV/AIDS patients and evaluate both the performance of the Xpert MTB/RIF (Xpert) platform and drug resistance profiles.Methodology. We evaluated the performance of the Xpert platform. Samples that tested positive on the BACTEC MGIT 320 (MGIT320) platform were submitted for genotyping and drug susceptibility testing.Results. In this study, pulmonary and extrapulmonary samples from 407 patients were evaluated, and among these, 15.5 % were diagnosed with TB by the MGIT320 platform, with a TB/HIV coinfection rate of 52.4 %. The Xpert platform gave positive results for TB for 11 samples with negative results on the MGIT320 platform. In the genotyping results, 53.3 % of the strains clustered; of these strains, half were in two of the four clusters formed, and the patients had visited the hospital on the same day. Drug resistance was observed in 11.7 % of the strains.Conclusion. Putative nosocomial transmission of M. tuberculosis was detected, showing that genotyping is a powerful approach for understanding the dynamics of M. tuberculosis transmission, especially in a high-burden TB and HIV landscape.

Drug susceptibility testing and mortality in patients treated for tuberculosis in high-burden countries: a multicentre cohort study

BACKGROUND

Drug resistance is a challenge for the global control of tuberculosis. We examined mortality in patients with tuberculosis from high-burden countries, according to concordance or discordance of results from drug susceptibility testing done locally and in a reference laboratory.

METHODS

This multicentre cohort study was done in Côte d'Ivoire, Democratic Republic of the Congo, Kenya, Nigeria, South Africa, Peru, and Thailand. We collected Mycobacterium tuberculosis isolates and clinical data from adult patients aged 16 years or older. Patients were stratified by HIV status and tuberculosis drug resistance. Molecular or phenotypic drug susceptibility testing was done locally and at the Swiss National Center for Mycobacteria, Zurich, Switzerland. We examined mortality during treatment according to drug susceptibility test results and treatment adequacy in multivariable logistic regression models adjusting for sex, age, sputum microscopy, and HIV status.

FINDINGS

We obtained M tuberculosis isolates from 871 patients diagnosed between 2013 and 2016. After exclusion of 237 patients, 634 patients with tuberculosis were included in this analysis; the median age was 33·2 years (IQR 26·9-42·5), 239 (38%) were women, 272 (43%) were HIV-positive, and 69 (11%) patients died. Based on the reference laboratory drug susceptibility test, 394 (62%) strains were pan-susceptible, 45 (7%) monoresistant, 163 (26%) multidrug-resistant (MDR), and 30 (5%) had pre-extensively or extensively drug resistant (pre-XDR or XDR) tuberculosis. Results of reference and local laboratories were concordant for 513 (81%) of 634 patients and discordant for 121 (19%) of 634. Overall, sensitivity to detect any resistance was 90·8% (95% CI 86·5-94·2) and specificity 84·3% (80·3-87·7). Mortality ranged from 6% (20 of 336) in patients with pan-susceptible tuberculosis treated according to WHO guidelines to 57% (eight of 14) in patients with resistant strains who were under-treated. In logistic regression models, compared with concordant drug susceptibility test results, the adjusted odds ratio of death was 7·33 (95% CI 2·70-19·95) for patients with discordant results potentially leading to under-treatment.

INTERPRETATION

Inaccurate drug susceptibility testing by comparison with a reference standard leads to under-treatment of drug-resistant tuberculosis and increased mortality. Rapid molecular drug susceptibility test of first-line and second-line drugs at diagnosis is required to improve outcomes in patients with MDR tuberculosis and pre-XDR or XDR tuberculosis.

FUNDING

National Institutes of Allergy and Infectious Diseases, Swiss National Science Foundation, Swiss National Center for Mycobacteria.

New antituberculous drugs derived from natural products: current perspectives and issues in antituberculous drug development

Tuberculosis is one of the most common and challenging infectious diseases worldwide. Especially, the lack of effective chemotherapeutic drugs for tuberculosis/human immunodeficiency virus co-infection and prevalence of multidrug-resistant and extensively drug-resistant tuberculosis remain to be serious clinical problems. Development of new drugs is a potential solution to fight tuberculosis. In this decade, the development status of new antituberculous drugs has been greatly advanced by the leading role of international organizations such as the Global Alliance for Tuberculosis Drug Development, Stop Tuberculosis Partnership and Global Health Innovative Technology Fund. In this review, we introduce the development status of new drugs for tuberculosis, focusing on those derived from natural products.The Journal of Antibiotics advance online publication, 1 November 2017; doi:10.1038/ja.2017.126.

Single nucleotide polymorphisms of IFNγ (+874 A/T) and IFNγR1 (-56 C/T) in Iranian patients with TB

BACKGROUND

Two important genes for controlling TB are IFNγ and IFNγR1. However, little information exists regarding genetic susceptibility of the Iranian TB population.

METHODS

We investigated the single nucleotide polymorphisms (SNPs) in genes of IFNγ (+874 A/T) and IFNγR1 (-56 C/T) and serum level of IFNγ and their influence on TB in patients; 300 patients with TB and 300 healthy controls were enrolled in this study. PCR-restriction fragment length polymorphism was used to identify SNPs and serum level of IFNγ was measured by ELISA.

RESULTS

The allelic and the genotypic form of IFNγ+874 A/T SNP of the studied population were not significant (p>0.05). Allele T frequencies of IFNγR1 -56 C/T promoter region in patients with pulmonary TB (PTB) or extrapulmonary TB (EPTB) were significantly greater than allele C. The -56 TT motif of IFNγR1 is associated with both forms of TB (p<0.05). The serum level of IFNγ was significantly higher in patients with TB than in controls, but there was no significant difference between serum level of IFNγ and the studied genotypes (p>0.05).

CONCLUSIONS

The cause of active TB in the patients seems to be due to the lack of effective IFNγ function or the lack of effective signaling connection between IFNγ and its receptor in presence of -56 C/T polymorphism in promoter region of IFNγR1 gene.