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Bioorganic Chemistry Oct 2021Enoyl acyl carrier protein reductase (InhA) is a key enzyme involved in fatty acid synthesis mainly mycolic acid biosynthesis that is a part of NADH dependent acyl... (Review)
Review
Enoyl acyl carrier protein reductase (InhA) is a key enzyme involved in fatty acid synthesis mainly mycolic acid biosynthesis that is a part of NADH dependent acyl carrier protein reductase family. The aim of the present literature is to underline the different scaffolds or enzyme inhibitors that inhibit mycolic acid biosynthesis mainly cell wall synthesis by inhibiting enzyme InhA. Various scaffolds were identified based on the screening technologies like high throughput screening, encoded library technology, fragment-based screening. The compounds studied include indirect inhibitors (Isoniazid, Ethionamide, Prothionamide) and direct inhibitors (Triclosan/Diphenyl ethers, Pyrrolidine Carboxamides, Pyrroles, Acetamides, Thiadiazoles, Triazoles) with better efficacy against drug resistance. Out of the several scaffolds studied, pyrrolidine carboxamides were found to be the best molecules targeting InhA having good bioavailability properties and better MIC. This review provides with a detailed information, analysis, structure activity relationship and useful insight on various scaffolds as InhA inhibitors.
Topics: Antitubercular Agents; Dose-Response Relationship, Drug; Drug Discovery; Humans; Inhibins; Microbial Sensitivity Tests; Molecular Structure; Mycobacterium tuberculosis; Structure-Activity Relationship
PubMed: 34392175
DOI: 10.1016/j.bioorg.2021.105242 -
Infection and Drug Resistance 2021The emergence of MDR-TB is a global public health problem. Hypothyroidism is one of the severe adverse drug reactions (ADRs) in MDR-TB patients on treatment....
Thyroid Profile and Factors Associated with Hypothyroidism Among Multidrug-Resistant Tuberculosis Patients Attending Saint Peter's Specialized Hospital Addis Ababa, Ethiopia.
BACKGROUND
The emergence of MDR-TB is a global public health problem. Hypothyroidism is one of the severe adverse drug reactions (ADRs) in MDR-TB patients on treatment. Representative data on hypothyroidism and its associated factors among MDR-TB patients are lacking.
OBJECTIVE
To determine thyroid profiles and associated risk factors among multidrug-resistant TB patients during therapy with anti-MDR-TB regimen in Saint Peter Specialized Hospital Addis Ababa, Ethiopia from January to November 2020.
METHODS
A cross-sectional study was conducted in MDR-TB patients in Addis Ababa, Ethiopia. A total of 162 patients, who were older than 18 years, had bacteriologically confirmed MDR-TB and on treatment for more than one month were enrolled consecutively from the TB registration book. However, critically sick patients and those who were receiving additional drugs known to cause severe ADRs were excluded. Simple descriptive statistics were used to present the socio-demographic and clinical characteristics of the patients. A logistic regression model was used to assess the association between independent and dependent variables. A -value <0.05 was considered as statistically significant in all analyses.
RESULTS
Mean age of the study participant was 35.9 ± 13.6 years. The prevalence of hypothyroidism was 32 (19.8%). The presence of co-morbidity, being underweight, and prothionamide use were significantly associated with hypothyroidism in MDR-TB patients on treatment.
CONCLUSION
Hypothyroidism occurs commonly among MDR-TB patients. Presence of co-morbidity, being underweight, and prothionamide drug use are the factors associated with hypothyroidism. Monitoring of thyroid function test during MDR-TB treatment and factors associated with hypothyroidism require attention to prevent complication.
PubMed: 34285520
DOI: 10.2147/IDR.S310404 -
Infection and Drug Resistance 2021Appropriate treatment is the key element in eliminating tuberculosis (TB), and requires prompt diagnosis. We presented a case of a household contact of...
Acquired Resistance to Isoniazid During Isoniazid Monotherapy in a Subject with Latent Infection Following Household Rifampicin-Resistant Tuberculosis Contact: A Case Report.
Appropriate treatment is the key element in eliminating tuberculosis (TB), and requires prompt diagnosis. We presented a case of a household contact of rifampicin-resistant TB revealing reactive IFN-gamma release assay with unsuspicious clinical and radiologic examinations. She was diagnosed with latent tuberculosis infection (LTBI) and treated with isoniazid monotherapy. On the ninth month, she developed a progressive cough and was found to harbor active TB disease with added resistance to isoniazid. An individualized anti-TB regimen consisting of moxifloxacin, kanamycin, prothionamide, ethambutol, and pyrazinamide was prescribed for 20 months, leading to sputum culture conversion and improvement of the reported symptom. No recurrence was observed on one-year follow-up. Assuming high compliance to therapy, we propose that the patient may have been underdiagnosed and received sub-optimal treatment leading to acquired-drug resistance. Conventional diagnosis methods based on immunological assay and radiographical findings may be insufficient to distinguish the incipient and subclinical states of TB from LTBI.
PubMed: 33907428
DOI: 10.2147/IDR.S304799 -
Antimicrobial Agents and Chemotherapy Jun 2021Preexisting and newly emerging resistant pathogen subpopulations (heteroresistance) are potential risk factors for treatment failure of multi/extensively drug resistant...
Preexisting and newly emerging resistant pathogen subpopulations (heteroresistance) are potential risk factors for treatment failure of multi/extensively drug resistant (MDR/XDR) tuberculosis (TB). Intrapatient evolutionary dynamics of Mycobacterium tuberculosis complex (Mtbc) strains and their implications on treatment outcomes are still not completely understood. To elucidate how Mtbc strains escape therapy, we analyzed 13 serial isolates from a German patient by whole-genome sequencing. Sequencing data were compared with phenotypic drug susceptibility profiles and the patient's collective 27-year treatment history to further elucidate factors fostering intrapatient resistance evolution. The patient endured five distinct TB episodes, ending in resistance to 16 drugs and a nearly untreatable XDR-TB infection. The first isolate obtained, during the patient's 5th TB episode, presented fixed resistance mutations to 7 anti-TB drugs, including isoniazid, rifampin, streptomycin, pyrazinamide, prothionamide, para-aminosalicylic acid, and cycloserine-terizidone. Over the next 13 years, a dynamic evolution with coexisting, heterogeneous subpopulations was observed in 6 out of 13 sequential bacterial isolates. The emergence of drug-resistant subpopulations coincided with frequent changes in treatment regimens, which often included two or fewer active compounds. This evolutionary arms race between competing subpopulations ultimately resulted in the fixation of a single XDR variant. Our data demonstrate the complex intrapatient microevolution of Mtbc subpopulations during failing MDR/XDR-TB treatment. Designing effective treatment regimens based on rapid detection of (hetero) resistance is key to avoid resistance development and treatment failure.
Topics: Antitubercular Agents; Drug Resistance, Multiple, Bacterial; Germany; Humans; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Tuberculosis; Tuberculosis, Multidrug-Resistant
PubMed: 33903103
DOI: 10.1128/AAC.02520-20 -
Journal of Separation Science May 2021Stability-indicating and liquid chromatography-mass spectrometry compatible ultra high performance liquid chromatography method was developed for the degradation and...
Identification and characterization of Prothionamide degradation impurities by mass spectrometry, NMR spectroscopy, and ultra high performance liquid chromatography method development.
Stability-indicating and liquid chromatography-mass spectrometry compatible ultra high performance liquid chromatography method was developed for the degradation and drug substances related impurities of Prothionamide. Forced degradation of Prothionamide was carried out under acidic, basic, thermal, oxidative, and photolytic stress conditions. The impurities separation was achieved on Acquity UPLC BEH-C18 (50 mm × 2.1 mm, 1.7 μm) with the mobile phase of 10 mm ammonium acetate pH 6.0 and Acetonitrile in a time gradient mode. Related substances by ultra-performance liquid chromatography method was validated according to ICH tripartite guidelines. Degradation products were isolated by Column chromatography and characterized by liquid chromatography-mass spectrometry, H, and C nuclear magnetic resonance spectroscopy. The developed related substances method showed adequate specificity, sensitivity, accuracy, linearity (0.4-1.5 μg/mL), precision, and robustness in line with ICH tripartite guidelines for validation of analytical procedures. Limits of detection and quantitation were 0.1 and 0.4 μg/mL, respectively, for Prothionamide and all the impurities. The method was found to be linear with a correlation coefficient > 0.99, precise (%RSD < 5.0), robust and accurate (%recovery 85-115%).
Topics: Chromatography, High Pressure Liquid; Drug Stability; Hot Temperature; Limit of Detection; Magnetic Resonance Spectroscopy; Mass Spectrometry; Prothionamide
PubMed: 33733566
DOI: 10.1002/jssc.202100050 -
Infection and Drug Resistance 2021This study aims to analyze the correlation between gene mutations by melting curve technology and phenotypic drug susceptibility (DST) results of ethionamide (ETH), and...
OBJECTIVE
This study aims to analyze the correlation between gene mutations by melting curve technology and phenotypic drug susceptibility (DST) results of ethionamide (ETH), and evaluate whether gene mutations detection can serve as a molecular marker in predicting ETH resistance.
METHODS
A retrospective analysis was conducted on 382 strains of (MTB) with the anti-tuberculosis drugs isoniazid (INH), rifampicin (RIF), ETH, and others. Phenotypic drug susceptibility and the results of and katG genotypes (mutation and no mutation) were obtained using the melting curve technology MeltPro TB assay.
RESULTS
Of the 382 clinical strains of MTB tested, 118 (30.9%) were resistant to INH, and 28 (7.3%) were resistant to ETH. Among the 28 phenotypically ETH-resistant strains, mutations accounted for 42.9% (12/28). These ETH-resistant strains comprise 35.3% (12/34) of the 34 mutant strains. Of 8 single mutation strains (without or mutation), 4(50%) were resistant to INH; however, all of these 8 strains were sensitive to ETH.
CONCLUSION
The mutation test may not be a reliable predictor of ETH resistance. Mutant strains are not necessarily resistant to ETH. The strains with single inhA mutation (without or mutation) may be effective for ETH treatment. The use of ETH in clinical medicine should be guided by gene (other than alone) detection and phenotypic drug susceptibility testing.
PubMed: 33551644
DOI: 10.2147/IDR.S268799 -
BMC Infectious Diseases Jan 2021Treatment monitoring of drug-resistant tuberculosis (DR-TB) in resource-limited settings is challenging. We developed a multi-analyte assay for eleven anti-TB drugs in...
Diagnostic accuracy of a liquid chromatography-tandem mass spectrometry assay in small hair samples for rifampin-resistant tuberculosis drug concentrations in a routine care setting.
BACKGROUND
Treatment monitoring of drug-resistant tuberculosis (DR-TB) in resource-limited settings is challenging. We developed a multi-analyte assay for eleven anti-TB drugs in small hair samples as an objective metric of drug exposure.
METHODS
Small hair samples were collected from participants at various timepoints during directly observed RR-TB treatment at an inpatient tertiary referral facility in South Africa (DR-TB cohort). We assessed qualitative determination (i.e., detection above limit of detection) of bedaquiline, linezolid, clofazimine, pretomanid, levofloxacin, moxifloxacin, pyrazinamide, isoniazid, ethambutol, ethionamide, and prothionamide in an LC-MS/MS index panel assay against a reference standard of inpatient treatment records. Because treatment regimens prior to hospitalization were not available, we also analyzed specificity (for all drugs except isoniazid) using an external cohort of HIV-positive patients treated for latent TB infection with daily isoniazid (HIV/LTBI cohort) in Uganda.
RESULTS
Among the 57 DR-TB patients (58% with pre-XDR/XDR-TB; 70% HIV-positive) contributing analyzable hair samples, the sensitivity of the investigational assay was 94% or higher for all drugs except ethionamide (58.5, 95% confidence interval [CI], 40.7-99.9). Assay specificity was low across all tested analytes within the DR-TB cohort; conversely, assay specificity was 100% for all drugs in the HIV/LTBI cohort.
CONCLUSIONS
Hair drug concentrations reflect long-term exposure, and multiple successive regimens commonly employed in DR-TB treatment may result in apparent false-positive qualitative and falsely elevated quantitative hair drug levels when prior treatment histories within the hair growth window are not known.
Topics: Adult; Antitubercular Agents; Chromatography, Liquid; Drug Monitoring; Female; Hair; Humans; Male; Middle Aged; Mycobacterium tuberculosis; Rifampin; Sensitivity and Specificity; Tandem Mass Spectrometry; Tuberculosis; Tuberculosis, Multidrug-Resistant
PubMed: 33482745
DOI: 10.1186/s12879-020-05738-5 -
Journal of Chromatography. B,... Nov 2020Treatment of multidrug-resistant tuberculosis (MDR-TB) is challenging due to high treatment failure rate and adverse drug events. This study aimed to develop and...
Development and validation of a simple LC-MS/MS method for simultaneous determination of moxifloxacin, levofloxacin, prothionamide, pyrazinamide and ethambutol in human plasma.
Treatment of multidrug-resistant tuberculosis (MDR-TB) is challenging due to high treatment failure rate and adverse drug events. This study aimed to develop and validate a simple LC-MS/MS method for simultaneous measurement of five TB drugs in human plasma and to facilitate therapeutic drug monitoring (TDM) in MDR-TB treatment to increase efficacy and reduce toxicity. Moxifloxacin, levofloxacin, prothionamide, pyrazinamide and ethambutol were prepared in blank plasma from healthy volunteers and extracted using protein precipitation reagent containing trichloroacetic acid. Separation was achieved on an Atlantis T3 column with gradient of 0.1% formic acid in water and acetonitrile. Drug concentrations were determined by dynamic multiple reaction monitoring in positive ion mode on a LC-MS/MS system. The method was validated according to the United States' Food and Drug Administration (FDA) guideline for bioanalytical method validation. The calibration curves for moxifloxacin, levofloxacin, prothionamide, pyrazinamide and ethambutol were linear, with the correlation coefficient values above 0.993, over a range of 0.1-5, 0.4-40, 0.2-10, 2-100 and 0.2-10 mg/L, respectively. Validation showed the method to be accurate and precise with bias from 6.5% to 18.3% for lower limit of quantification and -5.8% to 14.6% for LOW, medium (MED) and HIGH drug levels, and with coefficient of variations within 11.4% for all levels. Regarding dilution integrity, the bias was within 7.2% and the coefficient of variation was within 14.9%. Matrix effect (95.7%-112.5%) and recovery (91.4%-109.7%) for all drugs could be well compensated by their isotope-labelled internal standards. A benchtop stability test showed that the degradation of prothionamide was over 15% after placement at room temperature for 72 h. Clinical samples (n = 224) from a cohort study were analyzed and all concentrations were within the analytical range. The signal of prothionamide was suppressed in samples with hemolysis which was solved by sample dilution. As the method is robust and sample preparation is simple, it can easily be implemented to facilitate TDM in programmatic MDR-TB treatment.
Topics: Adult; Chromatography, Liquid; Drug Monitoring; Ethambutol; Female; Fluoroquinolones; Humans; Limit of Detection; Linear Models; Male; Prothionamide; Pyrazinamide; Reproducibility of Results; Tandem Mass Spectrometry
PubMed: 33091676
DOI: 10.1016/j.jchromb.2020.122397 -
Antibiotics (Basel, Switzerland) Oct 2020Perchlozone ([PCZ] 4-thioureido-iminomethylpyridinium perchlorate) is a new thiosemicarbazone approved for the treatment of multidrug-resistant tuberculosis (MDR-TB) in...
Genetic Variation Putatively Associated with Resistance to Perchlozone, a New Thiosemicarbazone: Clues from Whole Genome Sequencing and Implications for Treatment of Multidrug-Resistant Tuberculosis.
Perchlozone ([PCZ] 4-thioureido-iminomethylpyridinium perchlorate) is a new thiosemicarbazone approved for the treatment of multidrug-resistant tuberculosis (MDR-TB) in Russia and some other countries. The and mutations may confer PCZ resistance. At the same time, mutations are known to mediate resistance to ethionamide (ETH) and prothionamide (PTH). We aimed to study the genetic variation underlying resistance to PCZ through whole genome sequencing (WGS) of consecutive isolates recovered during long-term treatment. This prospective study included patients admitted in 2018-2019 to the regional tuberculosis dispensary, Kaliningrad, Russia, whose treatment regimen included PCZ. Multiple isolates were recovered during PCZ treatment, and the bacterial DNA was subjected to WGS followed by bioinformatics analysis. We identified mutations in the genes putatively associated with PCZ resistance, , and The most frequent one was a frameshift 106 GA > G (seven of nine patients) and most of the other mutations were also likely present before PCZ treatment. In one patient, a frameshift mutation 702 CT > C emerged after six months of PCZ treatment. A frequent presence of cross-resistance mutations to PCZ and ETH/PTH should be taken into consideration when PCZ is included in the treatment regimen of MDR-TB patients.
PubMed: 33022959
DOI: 10.3390/antibiotics9100669 -
Journal of Visualized Experiments : JoVE May 2020Drug resistant-tuberculosis (DR-TB) is a growing public health threat, and assessment of therapeutic drug levels may have important clinical benefits. Plasma drug levels...
Drug resistant-tuberculosis (DR-TB) is a growing public health threat, and assessment of therapeutic drug levels may have important clinical benefits. Plasma drug levels are the current gold standard assessment, but require phlebotomy and a cold chain, and capture only very recent adherence. Our method uses hair, a matrix that is easily collected and reflective of long-term adherence, to test for 11 anti-TB medications. Previous work by our group shows that antiretroviral drug levels in hair are associated with HIV outcomes. Our method for DR-TB drugs uses 2 mg of hair (3 cm proximal to the root), which is pulverized and extracted in methanol. Samples are analyzed with a single LC-MS/MS method, quantifying 11 drugs in a 16 min run. Lower limits of quantification (LLOQs) for the 11 drugs range from 0.01 ng/mg to 1 ng/mg. Drug presence is confirmed by comparing ratios of two mass spectrometry transitions. Samples are quantified using the area ratio of the drug to the deuterated, N-, or C-labeled drug isotopologue. We used a calibration curve ranging from 0.001-100 ng/mg. Application of the method to a convenience sample of hair samples collected from DR-TB patients on directly observed therapy (DOT) indicated drug levels in hair within the linear dynamic range of nine of the eleven drugs (isoniazid, pyrazinamide, ethambutol, linezolid, levofloxacin, moxifloxacin, clofazimine, bedaquiline, pretomanid). No patient was on prothionamide, and the measured levels for ethionamide were close to its LLOQ (with further work instead examining the suitability of ethionamide's metabolite for monitoring exposure). In summary, we describe the development of a multi-analyte panel for DR-TB drugs in hair as a technique for therapeutic drug monitoring during drug-resistant TB treatment.
Topics: Antitubercular Agents; Calibration; Chromatography, Liquid; Directly Observed Therapy; Hair; Humans; Limit of Detection; Reference Standards; Tandem Mass Spectrometry; Tuberculosis, Multidrug-Resistant
PubMed: 32510502
DOI: 10.3791/60861