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PloS One 2020Pakistan is among top five high burden countries for tuberculosis and drug resistant TB. Among rifampicin sensitive new pulmonary TB (PTB), prevalence of isoniazid...
Isoniazid resistance profile and associated levofloxacin and pyrazinamide resistance in rifampicin resistant and sensitive isolates/from pulmonary and extrapulmonary tuberculosis patients in Pakistan: A laboratory based surveillance study 2015-19.
BACKGROUND
Pakistan is among top five high burden countries for tuberculosis and drug resistant TB. Among rifampicin sensitive new pulmonary TB (PTB), prevalence of isoniazid resistance is 8.3% (95%CI: 7.0-10.7) and resistance to fluoroquinolone is higher (11·1%, 95%CI: 7·8-14·3) than isoniazid resistance.
METHOD
Five year retrospective data (2015-2019) of drug susceptibility testing (DST) for Mycobacterium tuberculosis isolates, performed using recommended phenotypic (pDST) and/or genotypic (gDST) methods was analyzed stratified by rifampicin results for isoniazid resistance profiles and associated levofloxacin and pyrazinamide resistance.
FINDINGS
DST data was analyzed from 11045 TB patients. Isolates were tested using pDST (87%), gDST (92%) and both methods (79.5%). For both rifampicin and isoniazid, a significant difference (P < .001) was noted between resistance detected by pDST and gDST. Among isolates, tested by both methods (8787), 49% were resistant to rifampicin and 51.7% to isoniazid with discordance in resistant results of 15.8% for each, with 13.2% (570) of rifampicin resistance reported sensitive by pDST and 14.2% (660) of isoniazid resistance missed by gDST. Estimated isoniazid resistance among rifampicin sensitive new PTB, extrapulmonary TB and previously treated PTB was 9.8% (95%CI: 8.7-11.1), 6.8% (95%CI: 5.4-8.5) and 14.6% (95%CI: 11.8-17.9) respectively. Significant differences were reported between the genotypic profile of isoniazid resistance associated with rifampicin-resistant and sensitive isolates including detectable mutations (87% vs 71.6%), frequency of inhA (7.6% and 30.2%) and katG mutations (76.1% vs 41.2%) respectively. Among rifampicin resistant and sensitive isolates, a significantly higher level of resistance to levofloxacin and pyrazinamide was seen associated with isoniazid resistance.
CONCLUSION
There are risks and many challenges in implementing WHO recommended treatment for isoniazid resistant tuberculosis. The laboratory based surveillance can complement random surveys in country specific planning for TB diagnostics and appropriate treatment regimens.
Topics: Adolescent; Adult; Antitubercular Agents; Child; Child, Preschool; Drug Resistance, Bacterial; Epidemiological Monitoring; Female; Genotype; Humans; Infant; Isoniazid; Laboratories; Levofloxacin; Male; Microbial Sensitivity Tests; Pakistan; Phenotype; Pyrazinamide; Retrospective Studies; Rifampin; Tuberculosis, Multidrug-Resistant; Young Adult
PubMed: 32966321
DOI: 10.1371/journal.pone.0239328 -
Journal of Clinical Microbiology Jan 2022Pyrazinamide is an important component of both drug-susceptible and drug-resistant tuberculosis treatment regimens. Although approximately 50% of rifampin-resistant...
Pyrazinamide is an important component of both drug-susceptible and drug-resistant tuberculosis treatment regimens. Although approximately 50% of rifampin-resistant isolates are also resistant to pyrazinamide, pyrazinamide susceptibility testing is not routinely performed due to the challenging nature of the assay. We investigated the diagnostic accuracy of genotypic and phenotypic methods and explored the occurrence of pyrazinamide heteroresistance. We assessed pyrazinamide susceptibility among 358 individuals enrolled in the South African EXIT-RIF cohort using Sanger and targeted deep sequencing (TDS) of the gene, whole-genome sequencing (WGS), and phenotypic drug susceptibility testing. We calculated the diagnostic accuracy of the different methods and investigated the prevalence and clinical impact of heteroresistance. True pyrazinamide susceptibility status was assigned to each isolate using the Köser classification and expert rules. We observed 100% agreement across genotypic methods for detection of fixed mutations; only TDS confidently identified three isolates (0.8%) with minor variants. For the 355 (99.2%) isolates that could be assigned true pyrazinamide status with confidence, phenotypic DST had a sensitivity of 96.5% (95% confidence interval [CI], 93.8 to 99.3%) and specificity of 100% (95% CI, 100 to 100%), both Sanger sequencing and WGS had a sensitivity of 97.1% (95% CI, 94.6 to 99.6%) and specificity of 97.8% (95% CI, 95.7 to 99.9%), and TDS had sensitivity of 98.8% (95% CI, 97.2 to 100%) and specificity of 97.8% (95% CI, 95.7 to 99.9%). We demonstrate high sensitivity and specificity for pyrazinamide susceptibility testing among all assessed genotypic methods. The prevalence of pyrazinamide heteroresistance in Mycobacterium tuberculosis isolates was lower than that identified for other first-line drugs.
Topics: Amidohydrolases; Antitubercular Agents; Genomics; Humans; Microbial Sensitivity Tests; Mutation; Mycobacterium tuberculosis; Pyrazinamide; Tuberculosis, Multidrug-Resistant
PubMed: 34757831
DOI: 10.1128/JCM.01907-21 -
ImmunoHorizons Jun 2023Mechanisms to shorten the duration of tuberculosis (TB) treatment include new drug formulations or schedules and the development of host-directed therapies (HDTs) that...
Mechanisms to shorten the duration of tuberculosis (TB) treatment include new drug formulations or schedules and the development of host-directed therapies (HDTs) that better enable the host immune system to eliminate Mycobacterium tuberculosis. Previous studies have shown that pyrazinamide, a first-line antibiotic, can also modulate immune function, making it an attractive target for combinatorial HDT/antibiotic therapy, with the goal to accelerate clearance of M. tuberculosis. In this study, we assessed the value of anti-IL-10R1 as an HDT along with pyrazinamide and show that short-term anti-IL-10R1 blockade during pyrazinamide treatment enhanced the antimycobacterial efficacy of pyrazinamide, resulting in faster clearance of M. tuberculosis in mice. Furthermore, 45 d of pyrazinamide treatment in a functionally IL-10-deficient environment resulted in sterilizing clearance of M. tuberculosis. Our data suggest that short-term IL-10 blockade with standard TB drugs has the potential to improve clinical outcome by reducing the treatment duration.
Topics: Animals; Mice; Pyrazinamide; Antitubercular Agents; Interleukin-10; Tuberculosis; Mycobacterium tuberculosis
PubMed: 37279084
DOI: 10.4049/immunohorizons.2200077 -
Infection and Drug Resistance 2020This study was designed to identify the phenotypic and genotypic characteristics of pyrazinamide (PZA) resistance among multidrug-resistant (MDR-TB) from Henan and to...
PURPOSE
This study was designed to identify the phenotypic and genotypic characteristics of pyrazinamide (PZA) resistance among multidrug-resistant (MDR-TB) from Henan and to evaluate the efficacy of , and mutations in predicting PZA resistance.
MATERIALS AND METHODS
A total of 152 MDR strains were included in this study. The Bactec MGIT system was used to determine PZA susceptibility for all strains. The , and genes were sequenced to identify any mutations, and the sequences were then aligned with the sequence of standard strain H37Rv. Moreover, the correlations between PZA-resistant phenotypes and treatment outcomes were analysed.
RESULTS
Of the152 strains, 105 had a PZA-resistant phenotype, and 102 harboured the mutation. The PZA resistance rate was higher in the strains with resistance to all four first-line drugs and those that were pre-extensively drug-resistant (pre-XDR) and extensively drug-resistant (XDR). A total of 100 different mutation patterns were identified, including 80 point mutations and 20 insertions/deletions, and 32 new mutation patterns were detected. In this study, 13 strains had multiple mutations. Of the11 PZA-resistant strains without mutations, two harboured the mutation, and one harboured the mutation. With PZA susceptibility results as the reference, single-gene sequencing had sensitivity of 89.52% and specificity of 89.36%. With the combination of and , the sensitivity increased to 92.38%, and the specificity remained the same. No significant differences were observed in the sputum smear/culture conversion rate between PZA-resistant patients and PZA-sensitive patients. However, PZA resistance was related to the time to sputum smear/culture conversion ( = 0.018).
CONCLUSION
The combination of , and was beneficial for the timely diagnosis of PZA resistance and could provide a laboratory basis for customizing treatment regimens for MDR-TB patients.
PubMed: 32903869
DOI: 10.2147/IDR.S260161 -
Acta Crystallographica Section B,... Jun 2022This article focuses on the structure and relative stability of four pyrazinamide polymorphs. New single crystal X-ray diffraction data collected for all forms at 10 K...
This article focuses on the structure and relative stability of four pyrazinamide polymorphs. New single crystal X-ray diffraction data collected for all forms at 10 K and 122 K are presented. By combining periodic ab initio DFT calculations with normal-mode refinement against X-ray diffraction data, both enthalpic and entropic contributions to the free energy of all polymorphs are calculated. On the basis of the estimated free energies, the stability order of the polymorphs as a function of temperature and the corresponding solid state phase transition temperatures are anticipated. It can be concluded that the α and γ forms have higher vibrational entropy than that of the β and δ forms and therefore they are significantly more stabilized at higher temperatures. Due to the entropy which arises from the disorder in γ form, it overcomes form α and is the most stable form at temperatures above ∼500 K. Our findings are in qualitative agreement with the experimental calorimetry results.
Topics: Crystallography, X-Ray; Entropy; Phase Transition; Pyrazinamide; Thermodynamics
PubMed: 35695115
DOI: 10.1107/S2052520622004577 -
South African Medical Journal =... Mar 2023The clinical significance of low antituberculosis (anti-TB) drug concentrations has not been fully elucidated.
BACKGROUND
The clinical significance of low antituberculosis (anti-TB) drug concentrations has not been fully elucidated.
OBJECTIVES
To investigate the clinical consequences of first-line drug concentrations in adult patients with drug-susceptible pulmonary TBin South Africa (SA).
METHOD
We conducted a pharmacokinetic study nested within the control arm of the Improving Treatment Success (IMPRESS) trial(NCT02114684) in Durban, SA. During the first 2 months of treatment, participants received weight-based dosing of first-line anti-TBdrugs (rifampicin, isoniazid, pyrazinamide and ethambutol), and had plasma drug concentrations measured at 2 and 6 hours after drugadministration during the 8th week of treatment. Intermediate (8 weeks), end-of-treatment (6 months) and follow-up TB outcomes wereassessed using World Health Organization criteria.
RESULTS
We measured plasma drug concentrations on available samples in 43 participants. Peak drug concentrations were below thetherapeutic range in 39/43 (90.7%) for rifampicin, 32/43 (74.4%) for isoniazid, 27/42 (64.3%) for pyrazinamide and 5/41 (12.2%) forethambutol. At the end of the intensive phase of treatment (week 8), 20.9% (n=9/43) of participants remained culture positive. We did notfind a relationship between the concentrations of first-line drugs and treatment outcomes at week 8. All participants were cured at the endof treatment, and there were no relapses during the 12-month follow-up period.
CONCLUSION
Treatment outcomes were favourable despite low drug concentrations as defined by current reference thresholds.
Topics: Adult; Humans; Antitubercular Agents; Isoniazid; Pyrazinamide; Rifampin; South Africa
PubMed: 36876350
DOI: 10.7196/SAMJ.2023.v113i3.16761 -
CPT: Pharmacometrics & Systems... Sep 2023Tuberculosis (TB) is a leading cause of mortality attributed to an infectious agent. TB primarily targets the lungs, but in about 16% cases can affect other organs as...
Tuberculosis (TB) is a leading cause of mortality attributed to an infectious agent. TB primarily targets the lungs, but in about 16% cases can affect other organs as well, giving rise to extrapulmonary TB (EPTB). However, an optimal regimen for EPTB treatment is not defined. Although the recommended treatment for most forms of EPTB is the same as pulmonary TB, the pharmacokinetics of EPTB therapy are not as well studied. To address this gap, we formulate a whole-body physiologically-based pharmacokinetic (PBPK) model for EPTB that for the first time includes the ability to simulate drug concentrations in the pleura and lymph node, the most commonly affected sites of EPTB. Using this model, we estimate the time-dependent concentrations, at potential EPTB infection sites, of the following four first-line anti-TB drugs: rifampicin, ethambutol, isoniazid, and pyrazinamide. We use reported plasma concentration kinetics data to estimate model parameters for each drug and validate our model using reported concentration data not used for model formulation or parameter estimation. Model predictions match the validation data, and reported pharmacokinetic parameters (maximum plasma concentration, time to reach maximum concentration) for the drugs. The model also predicts ethambutol, isoniazid, and pyrazinamide concentrations in the pleura that match reported experimental values from an independent study. For each drug, the predicted drug concentrations at EPTB sites are compared with their critical concentration. Simulations suggest that although rifampicin and isoniazid concentrations are greater than critical concentration values at most EPTB sites, the concentrations of ethambutol and pyrazinamide are lower than their critical concentrations at most EPTB sites.
Topics: Humans; Isoniazid; Pyrazinamide; Ethambutol; Rifampin; Tuberculosis; Antitubercular Agents
PubMed: 37431175
DOI: 10.1002/psp4.13008 -
Frontiers in Molecular Biosciences 2022As the first-line clinical drugs for tuberculosis (TB), isoniazid (INH), pyrazinamide (PZA), and rifampicin (RMP) are playing important roles for preventing the rapid...
A Simple and Sensitive UPLC-UV Method for Simultaneous Determination of Isoniazid, Pyrazinamide, and Rifampicin in Human Plasma and Its Application in Therapeutic Drug Monitoring.
As the first-line clinical drugs for tuberculosis (TB), isoniazid (INH), pyrazinamide (PZA), and rifampicin (RMP) are playing important roles for preventing the rapid spread of TB. Precise quantification of these drugs in biological samples is crucial to evaluate or improve the efficacy of advanced TB drug delivery systems, which are designed for reducing drug resistance, minimizing side effects, etc. Herein, a simple and sensitive method based on UPLC-UV was established and investigated for simultaneous quantification of PZA, INH, and RMP in human plasma and was applied to anti-TB drug therapeutic drug monitoring. The analytes were implemented on an HSS T3 C18 column at 40°C. The separation was performed with a gradient elution with methanol-acetonitrile-water (3:3:94) at 0.1 ml/min. The analysis only involved plasma with a small volume of 100 µL and a rapid one-step protein precipitation with methanol-acetonitrile (1:1). The results showed that the calibration curves for INH, PZA, and RMP were linear in a range of 0.5-20 μg/ml, 5-60 μg/ml, and 5-60 μg/ml, respectively. The intra- and inter-day precisions were both smaller than 15%, and the lower limit of quantitation (LLOQ) was identifiable and reproducible at 0.5 μg/ml for INH and 5 μg/ml for both PZA and RMP, respectively. The target drugs in plasma were stable after 21 days of storage at -80°C. The results indicated that our developed method is suitable for the simultaneous monitoring of INH, PZA, and RMP in human plasma.
PubMed: 35573738
DOI: 10.3389/fmolb.2022.873311 -
MBio Apr 2023Antituberculosis therapy (ATT) causes a rapid and distinct alteration in the composition of the intestinal microbiota that is long lasting in both mice and humans. This...
Antituberculosis therapy (ATT) causes a rapid and distinct alteration in the composition of the intestinal microbiota that is long lasting in both mice and humans. This observation raised the question of whether such antibiotic-induced changes in the microbiome might affect the absorption or gut metabolism of the tuberculosis (TB) drugs themselves. To address this issue, we utilized a murine model of antibiotic-induced dysbiosis to assay the bioavailability of rifampicin, moxifloxacin, pyrazinamide, and isoniazid in mouse plasma over a period of 12 h following individual oral administration. We found that 4-week pretreatment with a regimen of isoniazid, rifampicin, and pyrazinamide (HRZ), a drug combination used clinically for ATT, failed to reduce the exposure of any of the four antibiotics assayed. Nevertheless, mice that received a pretreatment cocktail of the broad-spectrum antibiotics vancomycin, ampicllin, neomycin, and metronidazole (VANM), which are known to deplete the intestinal microbiota, displayed a significant decrease in the plasma concentration of rifampicin and moxifloxacin during the assay period, an observation that was validated in germfree animals. In contrast, no major effects were observed when similarly pretreated mice were exposed to pyrazinamide or isoniazid. Thus, the data from this animal model study indicate that the dysbiosis induced by HRZ does not reduce the bioavailability of the drugs themselves. Nevertheless, our observations suggest that more extreme alterations of the microbiota, such as those occurring in patients on broad-spectrum antibiotics, could directly or indirectly affect the exposure of important TB drugs and thereby potentially influencing treatment outcome. Previous studies have shown that treatment of Mycobacterium tuberculosis infection with first-line antibiotics results in a long-lasting disruption of the host microbiota. Since the microbiome has been shown to influence the host availability of other drugs, we employed a mouse model to ask whether the dysbiosis resulting from either tuberculosis (TB) chemotherapy or a more aggressive course of broad-spectrum antibiotics might influence the pharmacokinetics of the TB antibiotics themselves. While drug exposure was not reduced in animals previously described as exhibiting the dysbiosis triggered by conventional TB chemotherapy, we found that mice with other alterations in the microbiome, such as those triggered by more intensive antibiotic treatment, displayed decreased availability of rifampicin and moxifloxacin, which in turn could impact their efficacy. The above findings are relevant not only to TB but also to other bacterial infections treated with these two broader spectrum antibiotics.
Topics: Humans; Animals; Mice; Antitubercular Agents; Rifampin; Isoniazid; Pyrazinamide; Biological Availability; Moxifloxacin; Dysbiosis; Tuberculosis
PubMed: 36877010
DOI: 10.1128/mbio.00353-23 -
Antimicrobial Agents and Chemotherapy Jun 2017Improved knowledge regarding the tissue penetration of antituberculosis drugs may help optimize drug management. Patients with drug-resistant pulmonary tuberculosis...
Improved knowledge regarding the tissue penetration of antituberculosis drugs may help optimize drug management. Patients with drug-resistant pulmonary tuberculosis undergoing adjunctive surgery were enrolled. Serial serum samples were collected, and microdialysis was performed using lung tissue to measure pyrazinamide concentrations. Among 10 patients, the median pyrazinamide dose was 24.7 mg/kg of body weight. Imaging revealed predominant lung lesions as cavitary ( = 6 patients), mass-like ( = 3 patients), or consolidative ( = 1 patient). On histopathology examination, all tissue samples had necrosis; eight had a pH of ≤5.5. Tissue samples from two patients were positive for by culture (pH 5.5 and 7.2). All 10 patients had maximal serum pyrazinamide concentrations within the recommended range of 20 to 60 μg/ml. The median lung tissue free pyrazinamide concentration was 20.96 μg/ml. The median tissue-to-serum pyrazinamide concentration ratio was 0.77 (range, 0.54 to 0.93). There was a significant inverse correlation between tissue pyrazinamide concentrations and the amounts of necrosis ( = -0.66, = 0.04) and acid-fast bacilli ( = -0.75, = 0.01) identified by histopathology. We found good penetration of pyrazinamide into lung tissue among patients with pulmonary tuberculosis with a variety of radiological lesion types. Our tissue pH results revealed that most lesions had a pH conducive to pyrazinamide activity. The tissue penetration of pyrazinamide highlights its importance in both drug-susceptible and drug-resistant antituberculosis treatment regimens.
Topics: Adolescent; Adult; Antitubercular Agents; Female; Humans; Isoniazid; Lung; Male; Middle Aged; Mycobacterium tuberculosis; Pyrazinamide; Rifampin; Tuberculosis, Multidrug-Resistant; Tuberculosis, Pulmonary; Young Adult
PubMed: 28373198
DOI: 10.1128/AAC.00226-17