Taking forward the Stop TB Partnership and World Health Organization Joint Theme for World TB Day March 24th 2018 - "Wanted: Leaders for a TB-Free World. You can make history. End TB"

In silico identification of phytochemical inhibitors for multidrug-resistant tuberculosis based on novel pharmacophore generation and molecular dynamics simulation studies

BACKGROUND

Multidrug-resistant tuberculosis (particularly resistant to pyrazinoic acid) is a life-threatening chronic pulmonary disease. Running a marketed regime specifically targets the ribosomal protein subunit-1 (RpsA) and stops trans-translation in the non-mutant bacterium, responsible for the lysis of bacterial cells. However, in the strains of mutant bacteria, this regime has failed in curing TB and killing pathogens, which may only because of the ala438 deletion, which inhibit the binding of pyrazinoic acid to the RpsA active site. Therefore, such cases of tuberculosis need an immediate and effective regime.

OBJECTIVE

This study has tried to determine and design such chemotypes that are able to bind to the mutant RpsA protein.

METHODS

For these purposes, two phytochemical databases, i.e., NPASS and SANCDB, were virtually screened by a pharmacophore model using an online virtual screening server Pharmit.

RESULTS

The model of pharmacophore was developed using the potential inhibitor (zr115) for the mutant of RpsA. Pharmacophore-based virtual screening results into 154 hits from the NPASS database, and 22 hits from the SANCDB database. All the predicted hits were docked in the binding pocket of the mutant RpsA protein. Top-ranked five and two compounds were selected from the NPASS and SANCDB databases respectively. On the basis of binding energies and binding affinities of the compounds, three compounds were selected from the NPASS database and one from the SANCDB database. All compounds were found to be non-toxic and highly active against the mutant pathogen. To further validate the docking results and check the stability of hits, molecular dynamic simulation of three compounds were performed. The MD simulation results showed that all these finally selected compounds have stronger binding interactions, lesser deviation or fluctuations, with greater compactness compared to the reference compound.

CONCLUSION

These findings indicate that these compounds could be effective inhibitors for mutant RpsA.

Non-adherence to anti-tuberculosis treatment and associated factors among TB patients in public health facilities of Hossana town, Southern Ethiopia, 2022

Background

Non-adherence to anti-tuberculosis treatment is one of the crucial challenges to improving TB treatment outcomes and reducing healthcare costs. The prevalence of non-adherence to anti-tuberculosis treatment is not well documented in the study context. Therefore, this study was aimed at estimating the prevalence of non-adherence to anti-tuberculosis treatment and associated factors among TB patients attending TB clinics in Hosanna town, Southern Ethiopia, in 2022.

Methods

An institution-based cross-sectional study was conducted from April to May 2022. A systematic random sampling technique was employed to select a sample of 233 study subjects from all four public health facilities. According to the order of arrival, every second person was interviewed. Data were collected using a structured questionnaire that was created using several works of literature. A multivariable binary logistic regression analysis was used to identify factors associated with non-adherence to anti-TB drugs. The adjusted odds ratio (AOR) with a 95% confidence interval (CI) was estimated.

Results

The study included 233 tuberculosis (TB) patients with a response rate of 100%. The prevalence of non-adherence was 18% (95% CI: 15.39, 21.82). Being in the continuation phase (AOR = 3.09, 95% CI: 1.16, 8.23), not attending formal education (AOR = 2.47, 95% CI: 1.12, 5.42), not disclosing TB status to their family (AOR = 2.36, 95% CI: 0.11, 5.04) and having poor TB knowledge (AOR = 3.09, 95% CI: 1.48, 6.48) were significantly associated with non-adherence to TB treatment.

Conclusion

Among TB patients, there was a significant prevalence of non-adherence to anti-TB medications. Interventions that target patients with low education status, are in the continuation phase, and do not disclose their TB status to their families are required to improve TB treatment adherence. In addition, improving health education is important to enhance TB knowledge, which has an impact on TB treatment adherence. The need for good drug adherence should be emphasized while counseling TB patients.

The emerging threat of fluroquinolone-, bedaquiline-, and linezolid-resistant Mycobacterium tuberculosis in China: Observations on surveillance data

BACKGROUND

Drug-resistant tuberculosis (TB), especially multidrug-resistant tuberculosis (MDR-TB), constitutes a major obstacle to fulfill end TB strategy globally. Although fluoroquinolones (FQs), linezolid (LZD) and bedaquiline (BDQ) were classified as Group A drugs for MDR-TB treatment, our knowledge of the prevalence of TB which were resistant to Group A drugs in China is quite limited.

METHODS

In this study, we conducted a prospective multicenter surveillance study in China to determine the proportion of TB patients that were resistant to Group A drugs. A total of 1877 TB patients were enrolled from 2022 at four TB specialized hospitals. The drug susceptibility of isolated strains was conducted using the MGIT 960 system and the molecular mechanisms conferring drug resistance were investigated by Sanger sequencing.

RESULTS

12.9% of isolates were resistant to levofloxacin (LFX), 13.2% were resistant to moxifloxacin (MOX), 0.2% were resistant to bedaquiline (BDQ), and 0.8% were resistant to linezolid (LZD). Totally, 14.0% and 0.4% were classified as multidrug resistant- (MDR-) and extensively drug resistant- (XDR-) TB. The drug resistance was more common in retreated TB cases compared to new cases. In addition, 70.0% of fluoroquinolone (FQ)-resistant isolates harbored mutations in the gyrA and gyrB gene. By contrast, the common drug-resistant mutations were only found in 50% BDQ-resistant and 20% LZD-resistant isolates.

CONCLUSIONS

Our data demonstrate that approximate half of MDR -TB patients are resistant to fluoroquinolones, with extremely low prevalence of initial BDQ and LZD resistance. Findings from this study provide important implications for the current management of MDR-TB patients.

Associated risk factor of tuberculosis infection among adult patients in Gedeo Zone, Southern Ethiopia

Background

Tuberculosis remains a major global health problem causing death among millions of people each year. Even though many of the World Health Organization recommended tuberculosis control strategies were implemented, there is still a major gap in tuberculosis case detection and treatment which resulted in rapid transmission of the cases in high burden countries. This study aimed to provide updated information on the contributing factors for the development of tuberculosis.

Methods

A case-control study was carried out in Gedeo Zone from February to July 2021 to assess the risk factors of tuberculosis. Cases were confirmed pulmonary tuberculosis patients with age ⩾18 years, while controls were participants who were confirmed to be pulmonary tuberculosis negative with the same age. Multivariate logistic regression models were used to assess the associated risk factor.

Results

A total of 368 individuals (173 cases and 173 controls) were included in this study. Based on the multivariable logistic regression analysis, we identified six variables as independent risk factors for the development of tuberculosis after controlling possible confounders. Those were patients with income <1500 Ethiopian birr per month (adjusted odds ratio = 2.35; 95% confidence interval: 1.22-3.97), patients with no educational background (illiterate) (adjusted odds ratio = 2.10; 95% confidence interval: 1.17-2.51), patients smoking cigarette (adjusted odds ratio = 2.89; 95% confidence interval: 2.10-3.82), patients chewing khat (adjusted odds ratio = 2.86; 95% confidence interval: 1.28-3.79), patients in close contact with known tuberculosis cases (adjusted odds ratio = 3.63; 95% confidence interval: 2.24-4.46), and patients being positive for HIV (adjusted odds ratio = 3.01; 95% confidence interval: 1.07-3.52) who were found to be significantly associated with tuberculosis development, while Bacille Calmette-Guérin vaccination had a protective effect against the development of tuberculosis (adjusted odds ratio = 0.52; 95% confidence interval: 0.21-0.88).

Conclusion

The priority should be given to the identified contributing factors through application of coordinated efforts on screening of patients suspected for pulmonary tuberculosis and all contacts of pulmonary tuberculosis patients and treatment of known tuberculosis cases, and appropriate control methods to reduce Mycobacterium tuberculosis cases.

The prevalence of Mycobacterium tuberculosis using Gene Xpert among tuberculosis suspected patients in Gedeo Zone, Southern Ethiopia

Background

Tuberculosis (TB) is a communicable disease remains a major global health problem and the leading cause of death from a single infectious agent. Even though many of the WHO recommended TB control strategies were implemented; there is still a major gap in TB case detection and treatment. This study aimed to determine the prevalence of Mycobacterium tuberculosis among presumptive TB patients in Gedeo Zone, Southern Ethiopia.

Methods

A cross-sectional study was conducted on 384 TB suspected patients in Gedeo Zone from February to July 2021. Data were collected using a pretested structured questionnaire. Laboratory examination was processed using Xpert-MTB/RIF assay. Data entry was made using Epi info version 7 and analyzed by SPSS version 24. Logistic regression models were used to determine the risk factors.

Results

Out of 384 study participants suspected with TB, M. tuberculosis was isolated from 103 giving an overall prevalence of 26.8%. Males (AOR) = 1.95; 95% CI 1.56–2.65, P = 0.01) were more likely to develop TB than females. Study participants who were illiterate (AOR 2.10; 95% CI 1.17–2.51, P = 0.014) were more likely to develop TB than the educated ones. Cigarette smokers (AOR 2.89; 95% CI 2.10–3.84, P = 0.01), khat chewers (AOR 2.86; 95% CI 1.28–3.79, P = 0.01), vaccination (AOR 0.52; 95% CI 0.21–0.88, P = 0.02), close contact (AOR 3.42; 95% CI 2.24–4.50, P = 0.01) and being positive for HIV (AOR 2.01; 95% CI 1.07–3.52, 0.01) were more likely to develop TB.

Conclusion

Despite implementation of national and international TB control strategies, TB still remains one of the major public health problems in the country especially in the study area. The high prevalence of MTB was reported different risk groups. Early case detection and management of TB should be given special attention to strengthen and an appropriate control and prevention methods to reduce the emergence and increasing of MTB cases.

In Silico Drug Designing for ala438 Deleted Ribosomal Protein S1 (RpsA) on the Basis of the Active Compound Zrl15

Pyrazinoic acid-resistant tuberculosis is a severe chronic disorder. First-line drugs specifically target the ribosomal protein subunit-1 (RpsA) and stop trans-translation in the wild-type bacterium, causing bacterial cell death. In mutant bacterial strain, the deletion of ala438 does not let the pyrazinoic acid to bind to the active site of RpsA and ensures that the bacterium survives. Hence, such tuberculosis cases require an immediate and successful regime. The current study was designed to identify inhibitors that could bind to the mutant state of the RpsA protein. Initially, a pharmacophore model was generated based on the recently published most potent inhibitor for the mutant state of RpsA, i.e., zrl15. The validated pharmacophore model was further used for virtual screening of two chemical libraries, i.e., ZINC and ChemBridge. After applying the Lipinski rule of five (Ro5), a total of 260 and 749 hits from the ChemBridge and ZINC libraries, respectively, were identified using pharmacophore mapping. These hits were then docked into the active site of the mutant state of the RpsA protein, and later, the top 150 compounds from each library were chosen based on the docking score. A total of 21 compounds were shortlisted from each library based on the best protein-ligand interactions. Finally, a total of 05 compounds were subjected to molecular dynamics study to examine the dynamic behavior of each compound in the active site of the mutant state of the RpsA protein. The results revealed that all compounds had good chemical properties such as absorption, distribution, metabolism, excretion, and toxicity (ADMET), and there was no Pan Assay Interference (PAINS) or deviation from Ro5, indicating that these compounds could be useful antagonists for the mutant state of the RpsA protein.

A Saudi Arabian Public Health Perspective of Tuberculosis

Tuberculosis is a global health challenge due to its spreading potential. The Kingdom of Saudi Arabia (KSA) faces a challenge in the spread of tuberculosis from migrant workers, but the foremost threat is the huge number of pilgrims who travel to visit sacred sites of the Islamic world located in the holy cities of Makkah and Al Madina. Pilgrims visit throughout the year but especially in the months of Ramadan and Zul-Hijah. The rise of resistance in Mycobacterium tuberculosis is an established global phenomenon that makes such large congregations likely hotspots in the dissemination and spread of disease at a global level. Although very stringent and effective measures exist, the threat remains due to the ever-changing dynamics of this highly pathogenic disease. This overview primarily highlights the current public health challenges posed by this disease to the Saudi health system, which needs to be highlighted not only to the concerned authorities of KSA, but also to the concerned global quarters since the pilgrims and migrants come from all parts of the world with a majority coming from high tuberculosis-burdened countries.

Exploration of barriers and facilitators to household contact tracing of index tuberculosis cases in Anlemo district, Hadiya zone, Southern Ethiopia: Qualitative study

BACKGROUND

Tuberculosis [TB] is the second leading cause of death from an infectious disease in the world. Intensifying tuberculosis screening and contact investigation strategy is recommended to ensure early diagnosis among household contacts of TB patients. Studies showed that there is low TB contact tracing. There was limited evidence on barriers and facilitators of household contact tracing. Therefore, this study was aimed at exploring barriers and facilitators for household contact tracing of index TB cases.

METHODS

A descriptive qualitative study was conducted at Anlemo district, Hadiya zone, Ethiopia from March 12-April 9, 2019. Purposive sampling technique was used to recruit study participants. A total of 16 participants were involved in the study which included health extension workers [HEWs], index TB patients, household contacts of TB patients, health center TB focal and district TB coordinator. Data were collected through in-depth interviews using a semi-structured guide, transcribed verbatim and translated into English. Inductive thematic analysis was employed using ATLAS.ti7.1 software and the findings were presented on major themes, categories, and quotations.

RESULTS

This study found low TB contact tracing and investigation, and explored barriers and facilitators such as monitoring and supervision, training of health workers, logistics and infrastructure, waiting time and institutional readiness, referral, feedback and linkage, human resource, charge for some laboratory, transportation, budget, knowledge, commitment and motivation, workload, distance, social support, economic constrain, and stigma and discrimination for household contact tracing of index TB cases under four themes.

CONCLUSIONS

From this study, it was understood that there was a gap in addressing all household contacts. Also, the study explored a wide range of possible barriers and facilitators for it. Explored barriers outweigh the facilitators which might have an implication facilitating the dissemination of TB silently within the community. This underscores the importance of taking action to avert those barriers by developing different strategies to increase TB contact tracing. Therefore, health care providers should have to improve the implementation of contact tracing by designing and developing appropriate strategies that should fit the local context.