scholarly journals Identification of Potential Binders of Mtb Universal Stress Protein (Rv1636) Through an in silico Approach and Insights Into Compound Selection for Experimental Validation

2021 ◽  
Vol 8 ◽  
Author(s):  
Sohini Chakraborti ◽  
Moubani Chakraborty ◽  
Avipsa Bose ◽  
Narayanaswamy Srinivasan ◽  
Sandhya S. Visweswariah

Millions of deaths caused by Mycobacterium tuberculosis (Mtb) are reported worldwide every year. Treatment of tuberculosis (TB) involves the use of multiple antibiotics over a prolonged period. However, the emergence of resistance leading to multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) is the most challenging aspect of TB treatment. Therefore, there is a constant need to search for novel therapeutic strategies that could tackle the growing problem of drug resistance. One such strategy could be perturbing the functions of novel targets in Mtb, such as universal stress protein (USP, Rv1636), which binds to cAMP with a higher affinity than ATP. Orthologs of these proteins are conserved in all mycobacteria and act as “sink” for cAMP, facilitating the availability of this second messenger for signaling when required. Here, we have used the cAMP-bound crystal structure of USP from Mycobacterium smegmatis, a closely related homolog of Mtb, to conduct a structure-guided hunt for potential binders of Rv1636, primarily employing molecular docking approach. A library of 1.9 million compounds was subjected to virtual screening to obtain an initial set of ~2,000 hits. An integrative strategy that uses the available experimental data and consensus indications from other computational analyses has been employed to prioritize 22 potential binders of Rv1636 for experimental validations. Binding affinities of a few compounds among the 22 prioritized compounds were tested through microscale thermophoresis assays, and two compounds of natural origin showed promising binding affinities with Rv1636. We believe that this study provides an important initial guidance to medicinal chemists and biochemists to synthesize and test an enriched set of compounds that have the potential to inhibit Mtb USP (Rv1636), thereby aiding the development of novel antitubercular lead candidates.

2021 ◽  
Author(s):  
Rika Yuliwulandari ◽  
Kinasih Prayuni ◽  
Intan Razari ◽  
Retno W Susilowati ◽  
Yenni Zulhamidah ◽  
...  

Background: Owing to the high resistance rate of tuberculosis (TB) to isoniazid, which is metabolized by N-acetyltransferase 2 (NAT2), we investigated the associations between NAT2 variants and multidrug-resistant (MDR)-TB. Materials & methods: The acetylator status based on NAT2 haplotypes of 128 patients with MDR-TB in Indonesia were compared with our published data from patients with anti-TB drug-induced liver injury (AT-DILI), TB and the general population. Results: NAT2*4 was more frequent in the MDR-TB group than in the AT-DILI group, TB controls and general controls. NAT2*4/*4 was significantly more frequent in patients with MDR-TB than in those with AT-DILI. NAT2*5B/7B, *6A/6A and *7B/*7B were detected at lower frequencies in patients with AT-DILI. Rapid acetylators were significantly more frequent in patients with MDR-TB than in those with AT-DILI. Conclusion: These results provide an initial data for optimizing TB treatment in the Indonesian population, and suggest that NAT2 genotyping may help to select appropriate treatment by predicting TB-treatment effect.


2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Y. Hu ◽  
L. Xu ◽  
Y. L. He ◽  
Y. Pang ◽  
N. Lu ◽  
...  

This study aimed to investigate the prevalence of multidrug-resistant tuberculosis (MDR-TB) isolates resistant to the second-line antituberculosis drugs (SLDs) and its association with resistant-related gene mutations inMycobacterium tuberculosis(M.tb) isolates from Southwest of China. There were 81 isolates resistant to at least one of the SLDs among 156 MDR-TB isolates (81/156, 51.9%). The rates of general resistance to each of the drugs were as follows: OFX (66/156, 42.3%), KAN (26/156, 16.7%), CAP (13/156, 8.3%), PTO (11/156, 7.1%), PAS (22/156, 14.1%), and AMK (20/156, 12.8%). Therefore, the most predominant pattern was resistant to OFX compared with other SLDs (P<0.001). The results of sequencing showed that 80.2% OFX-resistant MDR-TB isolates containedgyrAmutation and 88.5% KAN-resistant isolates hadrrsmutations with the most frequent mutation being A1401G. These results suggest that improper use of SLDs especially OFX is a real threat to effective MDR-TB treatment not only in China but also in the whole world. Furthermore the tuberculosis control agencies should carry out SLDs susceptibility testing and rapid screening in a broader population of TB patients immediately and the SLDs should be strictly regulated by the administration in order to maintain their efficacy to treat MDR-TB.


2019 ◽  
Vol 12 (8) ◽  
pp. e230628 ◽  
Author(s):  
Christian Francisco ◽  
Mary Ann Lansang ◽  
Edsel Maurice Salvana ◽  
Katerina Leyritana

Tuberculosis (TB) is common among persons living with HIV. This public health concern is aggravated by infection with multidrug-resistant organisms and adverse effects of polypharmacy. There are few published cases of multidrug-resistant tuberculosis (MDR-TB) in multidrug-resistant HIV (MDR-HIV) infected patients. We report a case of a 29-year-old Filipino man with HIV on zidovudine (AZT)-containing antiretroviral therapy (ART) but was eventually shifted to tenofovir due to anaemia. He presented with left flank tenderness, which was found to be due to an MDR-TB psoas abscess, and for which second-line anti-TB treatment was started. HIV genotyping showed MDR-HIV infection susceptible only to AZT, protease inhibitors and integrase inhibitors. Subsequently, he developed neck abscess that grew Mycobacterium avium complex and was treated with ethambutol and azithromycin. ART regimen was revised to AZT plus lamivudine and lopinavir/ritonavir. Erythropoietin was administered for recurrent AZT-induced anaemia. Both abscesses resolved and no recurrence of anaemia was noted.


2019 ◽  
Vol 23 (10) ◽  
pp. 1050-1054
Author(s):  
L. Guglielmetti ◽  
J. Jaffré ◽  
C. Bernard ◽  
F. Brossier ◽  
N. El Helali ◽  
...  

SETTING: The World Health Organization (WHO) recommends that multidrug-resistant tuberculosis (MDR-TB) treatment should be managed in collaboration with multidisciplinary advisory committees (consilia). A formal national Consilium has been established in France since 2005 to provide a centralised advisory service for clinicians managing MDR-TB and extensively drug-resistant (XDR-TB) cases.OBJECTIVE: Review the activity of the French TB Consilium since its establishment.DESIGN: Retrospective description and analysis of the activity of the French TB Consilium.RESULTS: Between 2005 and 2016, 786 TB cases or contacts of TB cases were presented at the French TB Consilium, including respectively 42% and 79% of all the MDR-TB and XDR-TB cases notified in France during this period. Treatment regimens including bedaquiline and/or delamanid were recommended for 42% of the cases presented at the French TB Consilium since 2009. Patients were more likely to be presented at the French TB Consilium if they were born in the WHO Europe Region, had XDR-TB, were diagnosed in the Paris region, or had resistance to additional drugs than those defining XDR-TB.CONCLUSION: The French TB Consilium helped supervise appropriate management of MDR/XDR-TB cases and facilitated implementation of new drugs for MDR/XDR-TB treatment.


2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Ernest Peresu ◽  
J. Christo Heunis ◽  
N. Gladys Kigozi ◽  
Diana De Graeve

Abstract Background Eswatini is facing a critical shortage of human resources for health (HRH) and limited access to multidrug-resistant tuberculosis (MDR-TB) treatment in rural areas. This study assessed multiple stakeholders’ perceptions of task-shifting directly observed treatment (DOT) supervision and administration of intramuscular MDR-TB injections to lay health workers (LHWs). Methods A mixed methods study comprising a cross-sectional survey using a semi-structured questionnaire with community treatment supporters (CTSs) and a focus group discussion with key stakeholders including representatives from the Eswatini Ministry of Health (MOH), donor organisations, professional regulatory institutions, nursing academia, civil society and healthcare providers was conducted in May 2017. Descriptive statistics, thematic content analysis and data triangulation aided in the interpretation of results. Results A large majority of CTSs (n = 78; 95.1%) were female and 33 (40.2%) were older than 50 years. Most (n = 7; 70.0%) key stakeholders had over 10 years of work experience in policy-making, advocacy in the fields of HRH or day-to-day practice in MDR-TB management. Task-shifting of MDR-TB injection administration was implemented without national policy guidance and regulation. Stakeholders viewed the strategy to be driven by the prevailing shortage of professional frontline HRH and limited access to MDR-TB treatment. Task-shifting was perceived to improve medication adherence, and reduce stigma and transport-related MDR-TB treatment access barriers. Frontline healthcare workers and implementing donor partners fully supported task-shifting. Policy-makers and other stakeholders accepted task-shifting conditionally due to fears of poor standards of care related to perceived incompetence of CTSs. Appropriate compensation, adequate training and supervision, and non-financial incentives were suggested to retain CTSs. A holistic task-shifting policy and collaboration between the MOH, academia and nursing council in regulating the practice were recommended. Conclusions Stakeholders generally accepted the delegation of DOT supervision and administration of intramuscular MDR-TB injections to LHWs as a strategy to increase access to treatment, albeit with some apprehension. Findings from this study stress that task-shifting is not a panacea for HRH shortages, but a short-term solution that must form part of an overall simultaneous strategy to train, attract and retain adequate numbers of professional healthcare workers in Eswatini. To address some of the apprehension and ambivalence about expanding access to MDR-TB services through task-shifting, attention should be paid to important aspects such as competence-based training, certification and accreditation, adequate supportive on-the-job supervision, recognition, compensation, and expediting policy and regulatory support for LHWs.


2020 ◽  
Vol 24 (5) ◽  
pp. 485-491
Author(s):  
D. Butov ◽  
C. Lange ◽  
J. Heyckendorf ◽  
I. Kalmykova ◽  
T. Butova ◽  
...  

OBJECTIVE: To document the level of drug resistance in MDR-TB patients and to characterize management capacities for their medical care and MDR-TB treatment outcomes in the Kharkiv region of Ukraine. This area has one of the highest frequencies of MDR-TB worldwide.METHODS: A retrospective observational cohort study was performed on registry data from the regional anti-TB dispensary in Kharkiv. All microbiologically confirmed MDR-TB patients registered in 2014 were included. Diagnostic, treatment and post-treatment follow-up data were analysed.RESULTS: Of 169 patients with MDR-TB, 55.0% had pre-extensively drug-resistant (pre-XDR) or XDR resistant patterns. Rapid molecular diagnosis by GeneXpert and liquid M. tuberculosis cultures were only available for 66.9% and 56.8% of patients, respectively. Phenotypic drug-susceptibility testing (DST) for high priority TB drugs (bedaquiline, linezolid, clofazimine) were not available. DST for later generation fluroquinolones was available only in 53.2% of patients. 50.9% of patients had less than 4 drugs in the treatment regimen proven to be effective by DST. More than 23.1% of patients with MDR-TB failed their treatment and only 45.0% achieved a cure.CONCLUSION: The high prevalence of MDR-TB and poor MDR-TB treatment outcomes in the Kharkiv region, is associated with substantial shortages in rapid molecular and phenotypic DST, a lack of high priority MDR-TB drugs, poor treatment monitoring and follow-up capacities.


2020 ◽  
Vol 148 ◽  
Author(s):  
F. Iqbal ◽  
M. K. Defer ◽  
A. Latif ◽  
H. Hadi

Tuberculosis (TB) is one of the top 10 leading causes of morbidity and mortality worldwide [1]. In 2017, approximately 10 million people were infected with TB and 1.3 million patients faced mortality [1]. Patients with active TB can infect up to 10–15 people over a year. There is a greater risk of transmission in overcrowded areas with limited air ventilation including large family units, prisons and slums [1, 2]. Without proper diagnosis and treatment, roughly 45% of non-HIV positive TB patients face mortality [1]. With the help of global organizations and national TB treatment and control programmes, the global incidence of TB is declining by approximately 2% each year [1]. The World Health Organization (WHO) TB-strategy aims to end the TB epidemic and encourages partners to fund national TB programmes to improve diagnosis and treatment of TB. The goal is to ultimately decrease death rates by 90% and decrease incidence rates by 80% [1]. To achieve these goals, the decline in TB incidence needs to reach approximately 4–5% per year [1]. The WHO 2018 TB report identified multidrug resistant TB (MDR-TB) as the leading factor hindering that goal [1]. The incidence and spread of MDR-TB has drastically increased, where approximately 558 000 new cases of MDR-TB were diagnosed in 2017 causing more than 230 000 deaths globally [1]. MDR-TB is identified by resistance to the two most powerful anti-TB treatment drugs including isoniazid and rifampicin [3]. Patients with MDR-TB are required to start second-line anti-TB drugs (SLDs), which are limited, expensive, less effective and more toxic [1,2]. Therapy duration is one of the major limitations of second-line treatments, which may require up to two years of consistent use. Since TB affects mostly developing countries, long treatment durations and associated costs become a major challenge. In 2015, 15% of new TB cases were reported as MDR-TB, which drastically increased to 24% by 2017 [1]. Even with significant improvements in molecular tests and diagnostic methods, MDR-TB is still on the rise where the success rate of treatments is between 50 and 60% [1]. Additional characteristics including socioeconomic and sociocultural factors need to be considered when targeting and treating patients with MDR-TB.


2020 ◽  
Vol 24 (11) ◽  
pp. 1151-1155
Author(s):  
M. F. Franke ◽  
C. D. Mitnick

Randomized clinical trials represent the gold standard in therapeutic research. Nevertheless, observational cohorts of patients treated for multidrug-resistant TB (MDR-TB) or rifampin-resistant TB (RR-TB) also play an important role in generating evidence to guide drug-resistant TB care. Generally, summary exposure classifications (e.g., ‘ever vs. never´, ‘exposed at baseline´) have been used to characterize drug exposure in the absence of detailed longitudinal data on MDR-TB regimen changes. These summary classifications, along with an absence of data on covariates that change throughout the course of treatment, constrain researchers´ ability to answer the most relevant questions while accounting for known biases. In this paper, we highlight the importance of regimen changes in improving inference from observational studies of longer MDR-TB treatment regimens, and offer an overview of the data and analytic strategies required to do so.


2012 ◽  
Vol 56 (5) ◽  
pp. 2612-2618 ◽  
Author(s):  
L. Garcia-Contreras ◽  
Pavan Muttil ◽  
John K. Fallon ◽  
Mohan Kabadi ◽  
Robert Gerety ◽  
...  

ABSTRACTThe global control of tuberculosis (TB) is at risk by the spread of multidrug-resistant TB (MDR TB). Treatment of MDR TB is lengthy and involves injected drugs, such as capreomycin, that have severe side effects. It was previously reported that a single daily dose of inhaled capreomycin had a positive effect on the bacterial burden of TB-infected guinea pigs. The modest effect observed was possibly due to a dose that resulted in insufficient time of exposure to therapeutic systemic and local levels of the drug. In order to determine the length of time that systemic and local drug concentrations are above therapeutic levels during the treatment period, the present study investigated the disposition of capreomycin powders after sequential pulmonary administration of doses of 20 mg/kg of body weight. Capreomycin concentrations in bronchoalveolar lavage fluid and lung tissue of animals receiving a series of one, two, or three doses of capreomycin inhalable powder were significantly higher (50- to 100-fold) at all time points than plasma concentrations at the same time points or those observed in animals receiving capreomycin solution by intramuscular (i.m.) injection (10- to 100-fold higher). Notably, at the end of each dosing period, capreomycin concentrations in the lungs were approximately 100-fold higher than those in plasma and severalfold higher than the MIC, suggesting that sufficient capreomycin remains in the lung environment to killMycobacterium tuberculosis. No accumulation of capreomycin powder was detected in the lungs after 3 pulmonary doses. These results indicate that the systemic disposition of capreomycin after inhalation is the same as when injected i.m. with the advantage that higher drug concentrations are present at all times in the lungs, the primary site of infection.


2019 ◽  
Author(s):  
Le Hong Van ◽  
Phan Trieu Phu ◽  
Dao Nguyen Vinh ◽  
Vo Thanh Son ◽  
Nguyen Thi Hanh ◽  
...  

Abstract Background: Multidrug resistant tuberculosis (MDR-TB) remains a serious public health problem with poor treatment outcome. Predictors of poor outcomes vary in different regions. Vietnam is among the 30 countries with high burden of MDR-TB. We aim to describe demographic characteristics and identify risk factors for poor outcome of MDR-TB in Ho Chi Minh City (HCMC), the most populous city in Vietnam. Methods: This retrospective study included 2,266 patients who initiated MDR-TB treatment from 2011 to 2015 in HCMC. Treatment outcomes were available in 2,240 patients. Data was collected from standardized paper-based treatment cards and electronic records. Kruskal Wallis test was used to diagnose the change of median of age and body mass index (BMI) over 5 years, and Wilcoxon test to compare median BMI of patients with and without diabetes mellitus. Chi squared test was used to compare categorical variables. Multivariate logistic regression on multiple imputation was used to identify risk factors for poor outcomes. Statistical analysis was performed using R program. Results: Among 2,266 eligible cases, 60.2% were failure of category I or II regimen, 57.7% were underweight, 30.2% had diabetes mellitus and 9.6% were HIV positive. Notification rate increased 24.7% from 2011 to 2015.Treatment success rate was 73.3%. Risk factors for poor treatment outcome included HIV co-infection (adjusted odds ratio (aOR): 2.94), advanced age (aOR: 1.45 for every increase of 5 years for patients 60 years or older), having history of MDR-TB treatment (aOR: 5.53), sputum smear grade scanty and 1+ (aOR: 1.47), smear grade 2+ or 3+ (aOR: 2.06), low BMI (aOR: 0.83 for every increase of 1kg/m2 of BMI for patients with BMI<21). Conclusion: Our study describes the increasing cases of MDR-TB in HCMC during 2011 to 2015. Patients with HIV, high smear grade, malnutrition and history of previous MDR-TB treatment should receive additional care. Keywords: multidrug resistant tuberculosis; retrospective; treatment outcome; risk factors; Vietnam


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