Characterization of isoniazid resistance and genetic mutations in isoniazid-resistant and rifampicin-susceptible Mycobacterium tuberculosis in China.

Background: Patients with tuberculosis resistant to isoniazid but susceptible to rifampicin (Hr-Rs TB) remain a neglected demographic, despite a high disease burden and poor outcomes of these patients. The aim of this study was to investigate the characteristics of isoniazid-resistance-related mutations in Mycobacterium tuberculosis and resistance rates to drugs included in WHO-recommended regimens for Hr-Rs patients. Methods: Mycobacterium tuberculosis isolates (n = 4922) obtained from national tuberculosis drug-resistance surveillance were subjected to whole-genome sequencing to identify Hr-Rs strains. The minimal inhibitory concentrations (MICs) were established for the Hr-Rs strains to determine the isoniazid resistance levels. We also identified drug-resistance-associated mutations for five drugs (fluoroquinolones, ethambutol, pyrazinamide, streptomycin, and amikacin) in the Hr-Rs strains. Results: Of the 4922 strains, 384 (7.8 %) were Hr-Rs. The subculture of seven strains failed, so 377 (98.2 %) strains underwent phenotypic MIC testing. Among the 384 genotypic Hr-Rs strains, 242 (63.0 %) contained the katG Ser315Thr substitution; 115 (29.9 %) contained the -15C>T in the promoter region of the fabG1 gene; and 16 (4.2 %) contained Ser315Asn in the katG gene. Of the 239 strains with the Ser315Thr substitution, 229 (95.8 %) had MIC ≥ 2 µg/mL, and of the 114 strains with the -15C>T mutation, 103 (90.4 %) had 0.25 µg/mL ≤ MIC ≤ 1 µg/mL. The genotypic resistance rates were 0.8 % (3/384) for pyrazinamide, 2.3 % (9/384) for ethambutol and fluoroquinolones; 39.6 % (152/384) of the strains were resistant to streptomycin, but only 0.5 % (2/384) of the strains were resistant to amikacin. Conclusion: Ser315Thr in katG was the predominant mutation conferring the Hr-Rs phenotype, followed by the fabG1 -15C>T mutation. The combination of rifampicin, pyrazinamide, ethambutol, and levofloxacin should be effective in the treatment of patients with Hr-Rs tuberculosis because the resistance rates for these drugs in China are low.

Tuberculosis in kidney transplant candidates and recipients.

Tuberculosis (TB) is the leading cause of infectious mortality and morbidity in the world, second only to coronavirus disease 2019. Patients with chronic kidney disease and kidney transplant recipients are at a higher risk of developing TB than the general population. Active TB is difficult to diagnose in this population due to close mimics. All transplant candidates should be screened for latent TB infection and given TB prophylaxis. Patients who develop active TB pre- or post-transplantation should receive multidrug combination therapy of antitubercular therapy for the recommended duration with optimal dose modification as per glomerular filtration rate.

Polymyxin B adjuvants against polymyxin B- and carbapenem-resistant Gram-negative bacteria.

Aim: Polymyxin B (PMB) is one of the few therapeutic options for treating infections caused by carbapenem-resistant Gram-negative bacteria (CR-GNB). However, the emergence of PMB-resistant CR-GNB strains has prompted the exploration of antibiotic adjuvants as potential therapeutic avenues. Thus, this study evaluates the potential of 3,5-dinitrobenzoic acid derivatives (DNH01, DNH11, DNH13 and DNH20) and isoniazid-N-acylhydrazones (INZ1-7, INZ9 and INZ11) as adjuvants to enhance PMB efficacy against CR-GNB.Materials & methods: MIC, MBC and drug combination assays were conducted using multidrug-resistant clinical isolates of Enterobacterales and Acinetobacter baumannii. In addition, the effects of PMB and PMB + DNH derivatives were assessed through flow cytometry and scanning electron microscopy (SEM).Results: DNH01, DNH11 and DNH20, unlike the INH-acylhydrazones, significantly restored PMB activity (MIC ≤ 2 µg/ml) in 80% of the tested isolates. Flow cytometry and SEM assays confirmed that DNH derivatives rescued the activity of PMB, yielding results comparable to those expected for PMB alone but at 256-fold lower concentrations.Conclusion: These findings suggest DNH derivatives hold substantial promise as PMB adjuvants to combat PMB-resistant CR-GNB infections.

[Box: see text].

Experimental and theoretical structural investigation of an ionic Nd coordination polymer.

Research concerning coordination polymers has been intense due to their significant variability and structural stability. With this in mind, an ionic neodymium coordination polymer was synthesized, composed of an anionic one-dimensional polymer interconnected to a cationic three-dimensional porous polymer, poly[dodecaaquabis(µ-pyridine-4-carbohydrazide-κ2N:O)bis(µ2-4-sulfobenzoato-κ2O:O')bis(µ3-4-sulfobenzoato-κ3O:O':O'')trineodymium(III)] catena-poly[aquabis(µ-pyridine-4-carbohydrazide-κ2N:O)bis(µ2-4-sulfobenzoato-κ2O:O')neodymium(III)] 4.33-hydrate, {[Nd3(C7H4O5S)4(C6H7N3O)2(H2O)12][Nd(C7H4O5S)2(C6H7N3O)2(H2O)]·4.33H2O}n. The ligands used were 4-sulfobenzoate (PSB) and pyridine-4-carbohydrazide, popularly known as isoniazid (INH), an antibiotic drug. The compound crystallizes in the monoclinic space group C2/c, with Z = 4. Solid-state calculations suggest that the crystal structure is mainly stabilized by hydrogen bonds, i.e. O-H...O and N-H...O interactions among the polymers, and by van der Waals interactions involving the organic side chains. This net is tetragonal, 2-nodal 3,4-connected, and can be described as the dmd (sqc 528) type.

Impact of Isoniazid Preventive Therapy on Tuberculosis Incidence and Predictors of Tuberculosis Among People Living With HIV/AIDS at Debre Tabor General Hospital, Northwest Ethiopia.

Background: The World Health Organization (WHO) recommended isoniazid preventive therapy (IPT) to decrease the effects of tuberculosis (TB) on human immunodeficiency virus (HIV) patients. However, not enough research has been conducted to determine the impact of IPT on TB incidence and their predictors. Therefore, the goal of this study was to evaluate how IPT affects the incidence of TB and identify factors that are predictive of TB among HIV/AIDS patients. Methods: A total of 588 patients at Debre Tabor General Hospital (DTGH) who had taken IPT between December 2009 and January 2016 participated in the current study, which then followed them for 3 years and compared them to patients who did not receive IPT during the study period. The data were gathered from patient registries and charts. IPT users' and nonusers' TB-free survival curves were compared using log-rank testing. Predictors were identified using bivariate and multivariate Cox proportional hazards models. Results: In this study, 1656 person-years (PYs) follow-ups on 588 patients found 82 additional TB cases, with an overall incidence rate (IR) of 4.95/100 PY. When compared to individuals who were not on IPT, the TB IR among patients living with human immunodeficiency virus (PLHIV) on IPT was significantly lower (1.94/100 PY vs. 8.32/100 PY). A baseline CD4 cell count < 200 cells/uL, history of TB, Hgb level < 10 g/dL, BMI < 18.5 kg/m2, and not receiving IPT are independent predictors of TB among HIV/AIDS patients. Conclusion: The frequency of TB was high among PLHIV patients who did not receive IPT. It was discovered that a low CD4 cell count at baseline, a history of TB, IPT status, Hgb level, and BMI independently predicted the presence of TB. Therefore, addressing the independent predictors that are connected to a higher risk of TB in PLHIV as well as isoniazid (INH) prophylaxis has a significant impact on reducing the incidence of TB.

Glucomannan is a promising isoniazid's enhancer that inducing macrophage phagocytosis.

Isoniazid (INH) is a frontline antituberculosis agent effective against Mycobacterium tuberculosis (Mtb), but the increasing challenge of avoiding multidrug-resistant tuberculosis, including INH resistance, necessitates innovative approaches. This study focused on enhancing macrophage phagocytosis to overcome INH resistance. Glucomannan, an immunomodulatory polysaccharide, emerged as a potential macrophage activator. Our objective was to characterize the glucomannan-INH mixture and assess its impact on INH efficacy and macrophage activity. Detailed examination of the glucomannan from Amorphophallus muelleri (0.05%-0.2%) was performed in several methods. INH sensitivity tests were carried out with the Mtb strain H37RV on Löwenstein-Jensen medium. Murine macrophage (RAW264.7) viability and activity were evaluated through MTT and latex bead phagocytosis assays. Ultraviolet-wavelength spectrophotometry was used to analyze chemical structure changes. Glucomannan (0.05%-0.2%) significantly enhanced murine macrophage viability and activity. When glucomannan was combined with INH, the IC50 value was greater compared to INH only. Phagocytosis assays revealed heightened macrophage activity in the presence of 0.05% and 0.1% glucomannan. Importantly, glucomannan did not compromise INH efficacy or alter its chemical structure. This study underscores the potential of glucomannan, particularly with a lower molecular weight, as a promising enhancer of INH, boosting macrophage phagocytosis against INH-resistant Mtb. These findings challenge the assumptions about the impact of glucomannan on drug absorption and prompt potential reevaluation. While specific receptors for glucomannan in macrophage phagocytosis require further exploration, the complement receptors are proposed to be potential mediators.

Characteristics of isoniazid-induced psychosis: a systematic review of case reports and case series.

PURPOSE: Isoniazid, a first-line antitubercular drug, is associated with nervous system adverse drug reactions such as seizures, peripheral neuropathy, and psychosis. This systematic review of case reports and case series aimed to characterize the demographic, social, and clinical factors associated with isoniazid-induced psychosis in patients with active tuberculosis (TB) and those who received isoniazid for latent TB infection (LTBI). METHODS: We comprehensively searched the Embase, PubMed, and Scopus databases to identify relevant studies published between the date of inception of the database and June 2024. RESULTS: A total of 28 studies, including 21 case reports and 7 case series involved 37 patients who developed isoniazid-induced psychosis. A higher frequency of isoniazid-induced psychosis was observed during the first 2 months of treatment, with a relatively early onset observed among patients aged 18 years or less. Delusions and/or hallucinations are the common symptoms of isoniazid-induced psychosis. Psychomotor disturbances, disorganized speech or formal thought disorder, disorganized or abnormal behaviour, and neuropsychiatric symptoms (sleep disturbances, hostility or aggression, confusion, affective symptoms, anxiety symptoms, and cognitive difficulties) were the other symptoms observed in the included studies. More than 80% of cases rechallenged with isoniazid resulted in the recurrence of psychotic symptoms. CONCLUSION: Patients with TB and LTBI should be assessed for psychotic and neuropsychiatric symptoms during isoniazid therapy, mainly in the first 2 months. Further research is required to understand the impact of underlying risk factors, such as genetic predisposition and isoniazid pharmacokinetics, as well as the clinical utility and dosage recommendations of pyridoxine for managing isoniazid-induced psychosis.

Facile synthesis of copper carbonate analog with peroxidase-like activity for colorimetric detection of isoniazid.

In this article, copper carbonate analog with good peroxidase-like activity was successfully synthesized for the first time via a simple co-precipitation of CuSO4▪5H2O and Na2CO3. The obtained copper carbonate analog exhibited excellent intrinsic peroxidase-like activity towards a classical peroxidase substrate of 3, 3', 5, 5' -tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2) under an acidic environment. The study of the catalytic mechanism confirmed that the hydroxyl radical produced from the decomposition of H2O2 is the main reactive oxygen species responsible for the catalytic oxidation of TMB to oxTMB. Moreover, results from kinetic parameter analysis indicated that H2O2 was more easily and/or likely to attach to the copper carbonate analog than TMB. Subsequently, the effects of experimental conditions (buffer pH, temperature, and incubation time) on the catalytic activity of the copper carbonate analog were also optimized. Finally, a copper carbonate analog-based colorimetric sensor was developed to determine isoniazid. Under the optimal conditions, the linear range for isoniazid was as broad as 0-178.6 µM, and the detection limit was as low as 8.47 µM. The spiked recoveries of isoniazid in normal human serum has been observed in the range of 94.8%-105.5 %. This strategy focuses on the development of a green, cost-efficient peroxidase mimic with high activity, good biocompatibility, and a simple synthesis process.

Natural deep eutectic solvent for the simultaneous derivatization and microextraction of isoniazid from human plasma.

BACKGROUND: Personalized medicine is a rapidly revolving field that offers new opportunities for tailoring disease treatment to individual patients. The main idea behind this approach is to carefully select safe and effective medications and treatment plant based on each patient's unique pharmacokinetic profile. Isoniazid is a first-line anti-tuberculosis drug that has interindividual variability in its metabolic processing, leading to significant differences in plasma concentrations among patients receiving equivalent doses. This variability necessitates the creation of individualized treatment regimens as part of personalized medicine to achieve more effective therapy. RESULTS: In this work, a deep eutectic solvent-based liquid-liquid microextraction approach for the separation and determination of isoniazid in human plasma by high-performance liquid chromatography with UV-Vis detection was developed for the first time. A new natural deep eutectic solvent based on thymol as a hydrogen bond donor and 4-methoxybenzaldehyde as a hydrogen bond acceptor was proposed as the extraction solvent. The developed microextraction procedure assumed two simultaneous processes during the mixing of the sample and extraction solvent: the derivatization of the polar analyte in the presence of 4-methoxybenzaldehyde (component of the natural deep eutectic solvent) with the formation of a hydrophobic Schiff base (1); mass transfer of the Schiff base from the sample phase to the extraction solvent phase (2). Under optimal conditions, the limits of detection and quantification were 20 and 60 µg L-1, respectively. The RSD value was <10 %, the extraction recovery was 95 %. SIGNIFICANCE: In this work, the possibility of isoniazid derivatization in the natural deep eutectic solvent phase with the formation of the Schiff base was presented for the first time. The approach provided the separation and preconcentration of polar isoniazid without the use of expensive derivatization agents and solid-phase extraction cartridges. The formation of the Schiff base was confirmed by mass spectrometry.

Factors associated with uptake of isoniazid preventive therapy among children living with HIV in Mwanza region, Tanzania: a cross-sectional study.

BACKGROUND: Tuberculosis (TB) is a leading cause of death among children living with HIV (CLHIV). Isoniazid preventive therapy (IPT) reduces the incidence of TB by 70% and mortality by 50% among CLHIV. However, in most developing countries including Tanzania, the uptake of IPT is suboptimal, below the 90% WHO-global uptake target. We assessed the factors associated with IPT uptake among CLHIV in Mwanza region, Tanzania. METHODS: This was a multicenter facility-based cross-sectional study among CLHIV aged 1 to 10 years in seven districts of Mwanza region, Tanzania from 1st November 2021 to 20th January 2022. Data were collected using a structured interview-administered questionnaire including information on children and caregivers' demographics, caregivers' health related information and children's clinical information. Our outcome variable was uptake of IPT, defined as initiation on IPT either during the time of the study or within past three years before this study We conducted modified Poisson regression to assess the association between IPT uptake and selected exposures in Stata version 15.0. RESULTS: A total of 415 CLHIV were enrolled, the median age of the children was 7 years (Interquartile range: 5-8). The uptake of IPT was 91% (n = 377). The majority of children's caregivers were HIV positive (86%, n = 387) and were aware about IPT (63.6%, n = 264). Factors associated with IPT uptake included; having an employed caregiver [Adjusted Prevalence Ratio (aPR): 1.06 95% Confidence Interval (CI): 1.00-1.13] and attending the ART clinic every month [aPR: 1.00; 95% CI: 0.87-1.00] . CONCLUSIONS: The uptake of IPT uptake among CLHIV in Mwanza, Tanzania exceeds the global WHO-target of ≥ 90%. Monthly ART clinic visits could be essential in promoting IPT uptake among CLHIV.

Factors associated with tuberculosis drug resistance among presumptive multidrug resistance tuberculosis patients identified in a DRTB surveillance study in western Kenya.

Multidrug-resistant tuberculosis (MDR-TB) is caused by M. tuberculosis (Mtb) with resistance to the first-line anti-TB medicines isoniazid (INH) and rifampicin (RIF). In Western Kenya, there is reported low prevalence of drug resistant strains among HIV tuberculosis patients, creating a need to determine factors associated with drug resistance patterns among presumptive MDR-TB patients. To determine factors associated with drug resistance patterns among presumptive MDR-TB patients in western Kenya. Three hundred and ninety (3 9 0) sputum sample isolates from among presumptive multidrug TB patients, were analyzed for TB drug resistance as per Ministry of Health (MoH) TB program diagnostic algorithm. Frequency and percentages were used to summarize categorical data while median and interquartile range (IQR) were used for continuous data. Multivariable logistic regression was carried out to identify factors associated with TB drug resistance. Out of 390 participants enrolled, 302/390 (77.4 %) were males, with a median age of 34 years. The HIV-infected were 118/390 (30.3 %). Samples included 322 (82.6 %) from presumptive patients, while 68/390 (17.4 %) were either lost to follow-up patients, failures to first-line treatment or newly diagnosed cases. A total of 64/390 (16.4 %) of the isolates had at least some form of drug resistance. Out of 390, 14/390 (3.6 %) had MDR, 12 (3.1 %) were RIF mono-resistance, 34 (8.7 %) had INH, while 4 (1 %) had ethambutol resistance. The category of previously treated patients (those who received or are currently on TB treatment) had a 70 % reduced likelihood of resistance (aOR: 0.30; 95 % CI: 0.13-0.70). In contrast, older age was associated with an increased likelihood of resistance to INH and RIF, with an adjusted odds ratio of 1.04 per year (95 % CI: 1.00-1.08). Prompt MDR-TB diagnosis is essential for appropriate patient care, management, and disease prevention and control. We recommend active surveillance on drug resistant TB in these regions to detect drug resistance patterns for rapid disease management.

Tuberculosis preventive treatment in newborns.

OBJECTIVE: To describe the reported cases of newborns subjected to tuberculosis preventive treatment (TPT) in the state of Paraná, Brazil, and to evaluate the safety and effectiveness in preventing the progression of TB disease in this population. METHOD: Observational, descriptive case series, with secondary data. The characteristics of the participants were analyzed from the information systems of preventive treatment of TB (of Paraná), between 2009 and 2016. To evaluate which children had developed tuberculosis later or died, we used the data from the information systems of TB (in Brazil), and mortality (in Paraná), covering the years 2009 to 2018. RESULTS: A total of 24 children underwent TPT with the age at treatment onset ranging from 0 to 87 days (median: 23 days). In 95.8 %, the exposure occurred at home, and in 33.3 % of cases, the mother was the source of the infection. A total of 20.8 % of the children tested positive for tuberculosis test at 3 months of age, 83.3 % completed treatment, and 2 experienced adverse events (gastrointestinal issues). No children developed TB or died during the minimum of a 2-year evaluation period through the official databases. CONCLUSIONS: In this case series, the adherence to the plan was high, with few adverse events and 100 % protection against infection.

Additive Manufacturing of SmartEx QD 100 Designed Oral Three-Dimensional Printlets Containing Isoniazid for Immediate Gastric Release by Selective Laser Sintering.

The selection of appropriate materials and compatibility of selected materials with drugs and formulations are limiting steps in three-dimensional printing technology. In this study, SmartEx QD 100 (SM QD 100) was introduced as a novel, coprocessed, unexplored excipient that can be used in SLS-mediated 3D printing. The current study aimed to evaluate the feasibility of fabricating SM QD 100 containing INH-embedded SLS-mediated immediate gastric release tablets. The prepared physical mixtures were subjected to the fabrication of 3D printlets by using SLS-mediated 3D printing. The fabricated 3D printlets were subjected to physicochemical characterization by using various analytical techniques. After oral administration of sintered 3D printlets to rabbits, samples were collected and pharmacokinetic parameters were analyzed using the developed LC-APCI-MS/MS method. The optimized batch was able to release 100% INH within 15 min, which confirmed the immediate gastric release. Similarly, sintered 3D printlets were stable under accelerated stability conditions for three months. Finally, the pharmacokinetic parameters revealed the rate and extent of absorption of INH from sintered 3D printlets. As evidenced by in vitro and in vivo analyses, SM QD 100 was able to sinter SLS-mediated INH-embedded stable immediate gastric release tablets. SM QD 100 is a novel material for SLS-mediated 3D printing in pharmaceutical applications.

Risk assessment and transmission of fluoroquinolone resistance in drug-resistant pulmonary tuberculosis: a retrospective genomic epidemiology study.

Fluoroquinolone resistance is a major challenge in treating Multidrug-Resistant Tuberculosis globally. The GenoType MTBDRsl Ver 2.0, endorsed by the WHO, was used to characterize fluoroquinolone resistance. The fluoroquinolone resistance rates in the MDR-TB, Rifampicin-Resistant TB, and non-MDR-TB were 33%, 16.5%, and 5.4%, respectively. The most common mutation found in fluoroquinolone-resistant isolates was D94G (49.5%) in the gyrA gene. Of the 150 MDR-TB isolates, the prevalence of Extensively Drug-Resistant Tuberculosis and pre-XDR-TB was 1.33% and 30%, respectively. Among the 139 RR-TB isolates, pre-XDR-TB prevalence was 15.8%. The fluoroquinolone resistance rates were 5.12% among the 1230 isoniazid-monoresistant isolates. The study found that MDR-TB and RR-TB have higher risk of fluoroquinolone resistance than non-MDR tuberculosis. Rifampicin-resistant isolates with a mutation at codon S450L have a higher risk (RR = 12.96; 95%CI: 8.34-20.13) of developing fluoroquinolone resistance than isolates with mutations at other codons in the rpoB gene. Isoniazid-resistant isolates with a mutation at codon S315T have a higher risk (RR = 2.09; 95%CI: 1.25-3.50) of developing fluoroquinolone resistance. The study concludes that rapid diagnosis of fluoroquinolone resistance before starting treatment is urgently needed to prevent the spread and increase of resistance and to achieve better treatment outcomes in areas where it is higher.

Diagnosis, prevention and risk-management of drug-induced liver injury due to medications used to treat mycobacterium tuberculosis.

INTRODUCTION: Many of the first line medications for the treatment of active and latent M. tuberculosis are hepatoxic and cause a spectrum of anti-tuberculosis drug induced liver injury (ATLI), including acute liver failure (ALF). Despite advances in recognition of and prevention of ATLI, isoniazid remains one of the leading causes of DILI as well as drug-induced ALF. AREAS COVERED: A literature search of the incidence, risk factors, current societal guidelines, monitoring, and prophylactic medication usage in ATLI was performed using PubMed and institutional websites. Relevant articles from 1972 to 2024 were included in this review. EXPERT OPINION: Current societal guidelines regarding ATLI monitoring are mixed, but many recommend liver enzyme testing of high-risk populations. We recommend liver test monitoring for all patients on multi-drug therapy as well as those on isoniazid therapy. Precision medicine practices, such as N-acetyltransferase-2 polymorphism genotyping, are thought to be beneficial in reducing the incidence of ATLI in high-risk populations. However, broader implementation is currently cost prohibitive. Hepatoprotective drugs are not currently recommended, although we do recognize their potential. In patients who develop ATLI but require ongoing anti-TB treatment, strategies to restart the same or less hepatotoxic regimens are currently being followed.

Molecular Epidemiology of Isoniazid-resistant M tuberculosis in Port-au-Prince, Haiti.

Background: Isoniazid-resistant, rifampin-susceptible tuberculosis (Hr-TB) is associated with poor treatment outcomes and higher rates of acquisition of further drug resistance during treatment. Due to a lack of widespread diagnostics, Hr-TB is frequently undetected and its epidemiology is incompletely understood. Methods: We studied the molecular epidemiology of Hr-TB among all patients diagnosed with culture-positive pulmonary tuberculosis between January 1 and June 30, 2017, at an urban referral tuberculosis clinic in Port-au-Prince, Haiti. Demographic and clinical data were extracted from the electronic medical record. Archived diagnostic Mycobacterium tuberculosis isolates were tested for genotypic and phenotypic isoniazid resistance using the Genotype MTBDRplus assay (Hain, Nehren, Germany) and culture-based testing, respectively. All isoniazid-resistant isolates and a randomly selected subset of isoniazid-susceptible isolates underwent whole-genome sequencing to confirm the presence of mutations associated with isoniazid resistance, to validate use of Genotype MTBDRplus in this population, and to identify potential transmission links between isoniazid-resistant isolates. Results and Conclusions: Among 845 patients with culture-positive pulmonary tuberculosis in Haiti, 65 (7.7%) had Hr-TB based on the Genotype MTBDRplus molecular assay. Age < 20 years was significantly associated with Hr-TB (odds ratio, 2.39; 95% confidence interval, 1.14, 4.70; P = .015). Thirteen (20%) isoniazid-resistant isolates were found in 5 putative transmission clusters based on a single nucleotide polymorphism distance of ≤ 5. No patients in these transmission clusters were members of the same household. Adolescents are at higher risk for Hr-TB. Strains of isoniazid-resistant M tuberculosis are actively circulating in Haiti and transmission is likely occurring in community settings.

Metabolism-dependent inhibition of CYP2E1 by isoniazid, a mediator of idiosyncratic liver injury.

Liver injury is a well-known adverse effect of the anti-tuberculosis drug isoniazid (INH); however, animal models that accurately replicate this effect as seen in humans have not been constructed, and the mechanism of its pathogenesis remains unclear. Recently, an immune-mediated mechanism have been proposed based on clinical studies, suggesting the involvement of cytochrome P450-mediated formation of reactive metabolites and covalent adducts in severe cases. In the present study, we investigated the role of CYP2E1 in this mechanism. Liver microsomes from humans, rats, and mice were preincubated with INH and NADPH; thereafter, residual CYP2E1 activity was measured. The inhibition of CYP2E1 by INH was potentiated by preincubation, indicating time-dependent inhibition. There were no major species-based differences in inhibition among humans, rats, and mice. Further to our findings on the inhibition kinetics, resistance of the inhibition to glutathione and catalase indicated that the reactive metabolites of INH covalently bonded to CYP2E1 in a suicidal manner. A similar time-dependent inhibition was also observed for the known metabolites acetylhydrazine and hydrazine; however, the conditions that inhibited the hydrolysis or activated the acetylation of INH did not affect inhibition by INH, suggesting that the reactive metabolites contributing to the inhibition were generated via alternative pathways. This indicates that CYP2E1 alone generates reactive INH metabolites and that haptenized CYP2E1 may be involved in immune-mediated liver injury.

Occurrence of multidrug-resistant Mycobacterium tuberculosis in upper Southern Thailand.

Background and Aim: Mycobacterium tuberculosis causes global concern with tuberculosis (TB). Multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) pose additional challenges, as they resist to multiple first-line drugs. This study investigated the occurrence of TB, antibiotic resistance due to inhA and katG gene mutations, and multidrug resistance in M. tuberculosis during fiscal years 2020-2022. Materials and Methods: Samples were gathered from hospitals in seven provinces of upper Southern Thailand. The study investigated the correlation between inhA and katG gene mutations in M. tuberculosis and the development of antimicrobial resistance and isoniazid resistance. Results: A total of 19,186 samples were sent to the Office of Disease Prevention and Control Region 11st, Nakhon Si Thammarat, Thailand. The results showed that 51% of the samples were obtained from patients located in Nakhon Si Thammarat, followed by Surat Thani provinces. Regarding the spatial distribution of TB-infected cases, the incidence of TB was high in the province, which has a moderate to high population density. The highest average occurrence of TB in this study was found in Phuket province (9.75/100,000 risk person-year). The detected isoniazid resistance was 394, 255, and 179 cases in 2020, 2021, and 2022, respectively. A total of 99 isolates were MDR, whereas four isolates were XDR. The antimicrobial resistance associated with the inhA mutation was 192, 142, and 105 isolates, respectively, whereas the resistance associated with the katG mutation was 249, 182, and 120 cases in 2020, 2021, and 2022, respectively. Conclusion: These findings contribute to the understanding of the occurrence of antibiotic-resistant TB that could lead to use as data for preventing MDR-TB.

Enhanced detection of rifampicin and isoniazid resistance in mycobacterium tuberculosis using AuNP-qPCR: a rapid and accurate method.

OBJECTIVES: To evaluate the resistance of Mycobacterium tuberculosis to Rifampicin (RIF) and Isoniazid (INH) using enhanced qPCR methodologies. METHODS: This study compared the detection of drug-resistant mutations in the rpoB and katG genes using AuNP-qPCR and No-AuNP-qPCR. Calibration curves were constructed to correlate the amount of template with the Ct values for resistant strains. RESULTS: The AuNP-qPCR method demonstrated high efficacy in detecting RIF resistance with an area under the curve (AUC) of 0.951, sensitivity of 97.92%, specificity of 87.5%, and overall accuracy of 95.31%. Similarly, INH resistance detection by AuNP-qPCR showed an AUC of 0.981, sensitivity of 98.08%, specificity of 94.44%, and accuracy of 97.14%. Comparatively, No-AuNP-qPCR yielded lower performance metrics for RIF resistance (AUC: 0.867, sensitivity: 91.67%, specificity: 75%, accuracy: 87.5%) and INH resistance (AUC: 0.882, sensitivity: 88.46%, specificity: 83.33%, accuracy: 87.14%). CONCLUSIONS: AuNP-qPCR exhibits over traditional qPCR methods, making it a promising tool for rapid and precise detection of drug resistance in Mycobacterium tuberculosis. This method's robust performance underscores its potential to improve diagnostic protocols and contribute to more effective management of tuberculosis treatment.