[Efficacy and safety of first-line anti-tuberculosis drugs combined with Linezolid for the treatment of pediatric tuberculous meningitis in real-word practice].

Objective: To evaluate the efficacy and safety of first-line anti-tuberculosis (TB) drugs combined with linezolid in treatment of children with tuberculous meningitis (TBM). Methods: A retrospective cohort study design was performed. Eight-nine Children diagnosed as TBM during January 1st 2016 and December 31st 2023 in Department of Infectious Disease, Children's Hospital of Chongqing Medical University were enrolled in the study. According to different treatment regimens, children were divided into a group of first-line anti-tuberculous drugs (isoniazid, rifampicin, pyrazinamide, ethambutol (HRZE)) and a group of HRZE and linezolid combination (HRZEL). The efficacy and safety of the 2 regimens were compared and the relationship between linezolid drug concentration and adverse reactions were analyzed. Comparisons between groups were performed using χ2 test and Mann-Whitney U test. Results: The 89 children with TBM included 53 males and 36 females with an onset age of 4.6 (1.4, 9.6) years. There were 27 cases in the HZREL group and 62 cases in the HRZE group. Before treatment, positive rate of interferon-gamma release assays (IGRA) in HRZEL group was lower than that in HRZE group (64% (16/25) vs.92% (55/60), χ2=9.82, P<0.05), but protein level of cerebrospinal fluid (CSF) was higher than that in HRZE group (1.2 (1.0, 2.0) vs.0.8 (0.4,1.4) g/L, Z=0.32, P<0.05). By the end of the intensive phase, there were no significant differences of rates of CSF improvement and etiology negativity between HRZEL group and HRZE group (both P>0.05).The 44 TBM children with high CSF protein (>1 g/L) included 25 males and 19 females with an onset age of 6.7 (3.0, 11.8) years. There were 21 cases in the HZREL group and 23 cases in the HRZE group accordingly. Before treatment, there were no significant differences of positive rate of IGRA test and CSF protein level between the 2 groups (62% (13/21) vs. 87% (20/23), 1.7 (1.1, 2.2) vs. 1.5 (1.2, 1.9) g/L, χ2=3.67, Z=0.23, both P>0.05). There were no significant differences in CSF indicators, etiology negativity or imaging remission between the two groups by the end of intensive phase (all P>0.05). Higher frequencies of granulocytopenia, gastrointestinal symptoms as well as withdrawal or change of drugs were found in HRZEL group when compared to those in HRZE group (44% (12/27) vs. 19% (12/62), 7% (2/27) vs. 0, 33% (9/27) vs. 3% (2/62), χ2=6.01, 4.70, 15.74, all P<0.05). Conclusions: The efficacy of HRZEL regimen is similar to conventional HRZE regimen in children with TBM, but with higher adverse effect. Prudentially evaluating the pros and cons of linezolid in the usage of drug-susceptible TB and carefully monitoring of linezolid associated adverse effects is suggested.

Pyrazinamide-induced Toxic Epidermal Necrolysis.

The antitubercular drugs are associated with different cutaneous adverse drug reactions. Toxic epidermal necrolysis (TEN) is a severe form of cutaneous reaction. Although it is rare, it carries a high mortality rate. We report a case of a 75-year-old man with abdominal tuberculosis, who developed pyrazinamide-induced TEN.

RésuméLes médicaments antituberculeux sont associés à différents effets indésirables cutanés. La nécrolyse épidermique toxique (TEN) est une forme sévère de réaction cutanée. Bien qu'elle soit rare, elle entraîne un taux de mortalité élevé. Nous rapportons le cas d'un homme de 75 ans atteint de tuberculose abdominale, qui ont développé un TEN induit par le pyrazinamide.

Drug resistance patterns and treatment outcomes in DR-TB patients at a tertiary care centre in Mumbai.

BACKGROUND: Drug-resistant tuberculosis (DR-TB) is a major health problem and threatens Tuberculosis (TB) control and outcomes globally. India holds one-fourth of global DR-TB burden.1 AIMS: 1- To study drug resistance patterns and outcomes in DR-TB patients under National Tuberculosis Elimination Programme (NTEP) at a tertiary care-centre. 2- To correlate outcome of DR-TB with drug resistance patterns. METHODS: It is a retrospective study of 302 Drug Resistant Tuberculosis patients from Jan 2020 to May 2022. Common mutations of drug resistance, pyrazinamide resistance in DR-TB patients, correlation of High dose Moxifloxacin sensitivity by Line Probe Assay (LPA) and drug sensitivity test (DST), outcome of DR-TB patients with drug resistance patterns and correlation of outcome of DR-TB patients with their initial body-weight were studied. RESULTS: Kat G was the most common mutation in Isoniazid (96%) resistance for MDR TB as well as Isoniazid Mono-resistance TB (p = 0.001). 91% cases with MDR-TB were resistant to pyrazinamide. 51.2% cases had low dose Fluroquinolone resistance. 18.8% cases had low and high dose Fluroquinolone resistance. 8.5% cases had resistance to injectables. 21.7% of cases who were resistant to High dose Moxifloxacin on second line LPA were found to be sensitive on DST. Outcomes were not dependent on the LPA resistance patterns. Body-weight greater than 45 Kg at the time of initiation of treatment was associated with better outcomes (p = 0.007). CONCLUSION: DR-TB patients are resistant to pyrazinamide in nearly all cases; hence pyrazinamide is not suitable for initial replacement sequence. Second line resistance doesn't impact outcome in DR-TB patients.

In-silico transcriptome analysis of antibiotic-treated Mycobacterium tuberculosis identifies novel antibiotic resistance factors.

The emergence of drug resistant Mycobacterium tuberculosis strains increases the burden on the treatment of tuberculosis. In this study, through in-silico transcriptome analysis of drug-treated M. tuberculosis samples, novel drug targets for the treatment of drug resistance in tuberculosis were identified. Gene expression datasets of tuberculosis patients samples treated with different antibiotics (Isoniazid, Rifampicin, Pyrazinamide, Bedaquiline and Linezolid) were considered in this study. DESeq2 was used to identify the differentially regulated genes. Novel genes which were up-regulated during antibiotic treatment were identified which could be antibiotic resistance factors. Further, to understand the resistance mechanism of the novel genes, we performed gene ontology and gene network analysis for the differentially up-regulated genes. Thus, the in-silico transcriptome analysis paves way for a deeper understanding of the antibiotic resistance in M. tuberculosis.

Pyrazinamide resistance due to pncA gene mutation and its association with treatment outcome among tuberculosis patients of South India- A longitudinal observational study.

INTRODUCTION: Mycobacterium tuberculosis has been extensively studied for mutations leading to drug resistance. Pyrazinamide is a drug acting on the semi-dormant bacteria that is responsible for relapse of tuberculosis. This drug helped reduce the treatment duration of tuberculosis from nine to six months. However, this drug is not being screened for resistance along with Rifampicin and Isoniazid. AIMS AND OBJECTIVES: This study aimed to estimate the proportion of pncA gene mutation among tuberculosis patients and its association between treatment outcomes, clinical characteristics, and phenotypic drug resistance. METHOD: ology: A total of 154 samples included 73 drug-resistant and 81 drug-susceptible isolates. The isolates were subjected to DNA extraction and amplification using conventional PCR. The PCR product was sequenced by the Sanger sequencing method, and phenotypic drug susceptibility testing was done using the broth dilution method. The association of this gene with the treatment outcome was done by following up with the patients till the end of the regimen. RESULTS: None of the drug susceptible tuberculosis patients showed significant non-synonymous mutations. Among the drug-resistant TB patients, seven unique significant mutations out of 73 isolates (9.6%) were distributed among Isoniazid-resistant tuberculosis and Multi-Drug Resistant Tuberculosis isolates. No association was found between the mutations and the clinical characteristics of the subjects harboring these isolates. CONCLUSION: This study estimated seven unique mutations in drug-resistant tuberculosis and none in drug-sensitive tuberculosis. Isolates harboring was not significantly associated with the participant's treatment outcome and other clinical characteristics. The pyrazinamide resistance testing by the phenotypic and genotypic methods was found to be in concordance.

A Microtiter Plate Assay at Acidic pH to Identify Potentiators that Enhance Pyrazinamide Activity Against Mycobacterium tuberculosis.

Pyrazinamide (PZA) is a key component of chemotherapy for the treatment of drug-susceptible tuberculosis (TB) and is likely to continue to be included in new drug combinations. Potentiation of PZA could be used to reduce the emergence of resistance, shorten treatment times, and lead to a reduction in the quantity of PZA consumed by patients, thereby reducing the toxic effects. Acidified medium is required for the activity of PZA against Mycobacterium tuberculosis. In vitro assessments of pyrazinamide activity are often avoided because of the lack of standardization, which has led to a lack of effective in vitro tools for assessing and/or enhancing PZA activity.We have developed and optimized a novel, robust, and reproducible, microtiter plate assay, that centers around acidity levels that are low enough for PZA activity. The assay can be applied to the evaluation of novel compounds for the identification of potentiators that enhance PZA activity. In this assay, potentiation of PZA is demonstrated to be statistically significant with the addition of rifampicin (RIF), which can, therefore, be used as a positive control. Conversely, norfloxacin demonstrates no potentiating activity with PZA and can be used as a negative control. The method, and the associated considerations, described here, can be adapted in the search for potentiators of other antimicrobials.

Efficacy and tolerability of a 4-month ofloxacin-containing regimen compared to a 6-month regimen in the treatment of patients with superficial lymph node tuberculosis: a randomized trial.

BACKGROUND: Tuberculosis (TB) lymphadenitis is the most common form of extra-pulmonary TB, and the treatment duration is six months. This non-inferiority based randomized clinical trial in South India evaluated the efficacy and safety of a four-month ofloxacin containing regimen in tuberculosis lymphadenitis (TBL) patients. METHODS: New, adult, HIV-negative, microbiologically and or histopathologically confirmed superficial lymph node TB patients were randomized to either four-month oflaxacin containing test regimen [ofloxacin (O), isoniazid (H), rifampicin (R), pyrazinamide (Z) -2RHZO daily/ 2RHO thrice-weekly] or a six-month thrice-weekly control regimen (2HRZ, ethambutol/4RH). The treatment was directly observed. Clinical progress was monitored monthly during and up to 12 months post-treatment, and thereafter every three months up to 24 months. The primary outcome was determined by response at the end of treatment and TB recurrence during the 24 months post-treatment. RESULTS: Of the 302 patients randomized, 298 (98.7%) were eligible for modified intention-to-treat (ITT) analysis and 294 (97%) for per-protocol (PP) analysis. The TB recurrence-free favourable response in the PP analysis was 94.0% (95% CI: 90.1-97.8) and 94.5% (95% CI: 90.8-98.2) in the test and control regimen respectively, while in the ITT analysis, it was 92.7% and 93.2%. The TB recurrence-free favourable response in the test regimen was non-inferior to the control regimen 0.5% (95% CI: -4.8-5.9) in the PP analysis based on the 6% non-inferiority margin. Treatment was modified for drug toxicity in two patients in the test regimen, while one patient had a paradoxical reaction. CONCLUSION: The 4-month ofloxacin containing regimen was found to be non-inferior and as safe as the 6-month thrice-weekly control regimen.

The impact of alcohol and illicit substance use on the pharmacokinetics of first-line TB drugs.

BACKGROUND: In South Africa, an estimated 11% of the population have high alcohol use, a major risk factor for TB. Alcohol and other substance use are also associated with poor treatment response, with a potential mechanism being altered TB drug pharmacokinetics. OBJECTIVES: To investigate the impact of alcohol and illicit substance use on the pharmacokinetics of first-line TB drugs in participants with pulmonary TB. METHODS: We prospectively enrolled participants ≥15 years old, without HIV, and initiating drug-susceptible TB treatment in Worcester, South Africa. Alcohol use was measured via self-report and blood biomarkers. Other illicit substances were captured through a urine drug test. Plasma samples were drawn 1 month into treatment pre-dose, and 1.5, 3, 5 and 8 h post-dose. Non-linear mixed-effects modelling was used to describe the pharmacokinetics of rifampicin, isoniazid, pyrazinamide and ethambutol. Alcohol and drug use were tested as covariates. RESULTS: The study included 104 participants, of whom 70% were male, with a median age of 37 years (IQR 27-48). Alcohol use was high, with 42% and 28% of participants having moderate and high alcohol use, respectively. Rifampicin and isoniazid had slightly lower pharmacokinetics compared with previous reports, whereas pyrazinamide and ethambutol were consistent. No significant alcohol use effect was detected, other than 13% higher ethambutol clearance in participants with high alcohol use. Methaqualone use reduced rifampicin bioavailability by 19%. CONCLUSION: No clinically relevant effect of alcohol use was observed on the pharmacokinetics of first-line TB drugs, suggesting that poor treatment outcome is unlikely due to pharmacokinetic alterations. That methaqualone reduced rifampicin means dose adjustment may be beneficial.

Urinary drug metabolite profiling of tuberculosis treatment failure using proton nuclear magnetic resonance.

The underlying cause of tuberculosis (TB) treatment failure is still largely unknown. A 1H NMR approach was applied to identify and quantify a subset of TB drugs and drug metabolites: ethambutol (EMB), acetyl isoniazid (AcINH), isonicotinic acid, pyrazinamide (PZA), pyrazinoic acid and 5-hydroxy-pyrazinoic acid, from the urine of TB patients. Samples were collected before, during (weeks one, two and four) and after standardised TB treatment. The median concentrations of the EMB and PZA metabolites were comparable between the samples from patients with eventually cured and failed treatment outcomes. The INH metabolites showed comparatively elevated concentrations in the treatment failure patients during and after treatment. Variation in INH metabolite concentrations couldn't be associated with the varying acetylator genotypes, and it is therefore suggested that treatment failure is influenced more so by other conditions, such as environmental factors, or individual variation in other INH metabolic pathways.

Evaluation of Whole Genome Sequencing-Based Predictions of Antimicrobial Resistance to TB First Line Agents: A Lesson from 5 Years of Data.

Phenotypic susceptibility testing of the Mycobacterium tuberculosis complex (MTBC) isolate requires culture growth, which can delay rapid detection of resistant cases. Whole genome sequencing (WGS) and data analysis pipelines can assist in predicting resistance to antimicrobials used in the treatment of tuberculosis (TB). This study compared phenotypic susceptibility testing results and WGS-based predictions of antimicrobial resistance (AMR) to four first-line antimicrobials-isoniazid, rifampin, ethambutol, and pyrazinamide-for MTBC isolates tested between the years 2018-2022. For this 5-year retrospective analysis, the WGS sensitivity for predicting resistance for isoniazid, rifampin, ethambutol, and pyrazinamide using Mykrobe was 86.7%, 100.0%, 100.0%, and 47.8%, respectively, and the specificity was 99.4%, 99.5%, 98.7%, and 99.9%, respectively. The predictive values improved slightly using Mykrobe corrections applied using TB Profiler, i.e., the WGS sensitivity for isoniazid, rifampin, ethambutol, and pyrazinamide was 92.31%, 100%, 100%, and 57.78%, respectively, and the specificity was 99.63%. 99.45%, 98.93%, and 99.93%, respectively. The utilization of WGS-based testing addresses concerns regarding test turnaround time and enables analysis for MTBC member identification, antimicrobial resistance prediction, detection of mixed cultures, and strain genotyping, all through a single laboratory test. WGS enables rapid resistance detection compared to traditional phenotypic susceptibility testing methods using the WHO TB mutation catalog, providing an insight into lesser-known mutations, which should be added to prediction databases as high-confidence mutations are recognized. The WGS-based methods can support TB elimination efforts in Canada and globally by ensuring the early start of appropriate treatment, rapidly limiting the spread of TB outbreaks.

Applying whole genome sequencing to predict phenotypic drug resistance in Mycobacterium tuberculosis: leveraging 20 years of nationwide data from Denmark.

Infection with Mycobacterium tuberculosis remains one of the biggest causes of death from a single microorganism worldwide, and the continuous emergence of drug resistance aggravates our ability to cure the disease. New improved resistance detection methods are needed to provide adequate treatment, such as whole genome sequencing (WGS), which has been used increasingly to identify resistance-conferring mutations over the last decade. The steadily increasing knowledge of resistance-conferring mutations increases our ability to predict resistance based on genomic data alone. This study evaluates the performance of WGS to predict M. tuberculosis complex resistance. It compares WGS predictions with the phenotypic (culture-based) drug susceptibility results based on 20 years of nationwide Danish data. Analyzing 6,230 WGS-sequenced samples, the sensitivities for isoniazid, rifampicin, ethambutol, and pyrazinamide were 82.5% [78.0%-86.5%, 95% confidence interval (CI)], 97.3% (90.6%-99.7%, 95% CI), 58.0% (43.2%-71.8%, 95% CI), and 60.5% (49.0%-71.2%, 95% CI), respectively, and specificities were 99.8% (99.7%-99.9%, 95% CI), 99.8% (99.7%-99.9%, 95% CI), 99.4% (99.2%-99.6%, 95% CI), and 99.9% (99.7%-99.9%, 95% CI), respectively. A broader range of both sensitivities and specificities was observed for second-line drugs. The results conform with previously reported values and indicate that WGS is reliable for routine resistance detection in resource-rich tuberculosis low-incidence and low-resistance settings such as Denmark.

The Unusual Adverse Effects of Antituberculosis Therapy in Kidney Patients.

BACKGROUND: Chronic kidney disease (CKD) patients are at a high risk of tuberculosis (TB), with a relative risk of developing active TB of 10%-25%. Similarly, glomerular disease increases the risk of TB due to diminished glomerular filtration rate, proteinuria, and immunosuppression use. Further, the first-line anti-TB drugs are associated with acute kidney injury (AKI) even in patients with normal kidney functions. METHODS: We retrospectively identified 10 patients hospitalized with unusual adverse effects of antituberculosis therapy (ATT) from 2013 to 2022. RESULTS: We found three cases of AKI caused by rifampicin: acute interstitial nephritis, crescentic glomerulonephritis, and heme pigment-induced acute tubular necrosis. We observed rifampicin-induced accelerated hypertension and thrombocytopenia in two patients on maintenance hemodialysis. Isoniazid caused pancreatitis and cerebellitis in two CKD patients, respectively. In a CKD patient, we detected acute gout secondary to pyrazinamide-induced reduced uric acid excretion. We also observed cases of drug rash with eosinophilia and systemic symptoms and hypercalcemia due to immune reconstitution inflammatory syndrome in patients with glomerular disease on ATT. Immediate discontinuation of the offending drug, along with specific and supportive management, led to a recovery in all cases. CONCLUSION: The adverse effects of ATT may be unusually severe and varied in kidney patients due to decreased renal elimination. Early recognition of these adverse effects and timely discontinuation of the offending drug is essential to limit morbidity and mortality.

Drug Susceptibility and Mutation Profiles in Mycobacterium tuberculosis Isolates from a Tertiary Care Hospital in Kerala, India.

The rising prevalence of drug-resistant Mycobacterium tuberculosis (MTB) strains poses a significant challenge to global tuberculosis (TB) control efforts. This study aimed to analyze drug resistance patterns and investigate the molecular characteristics of 193 MTB clinical isolates to shed light on the mechanisms of drug resistance. Of the 193 MTB clinical isolates, 28.5% (n = 53) exhibited mono-drug or multidrug resistance. Pyrazinamide mono-drug resistance (PZAr) was the most prevalent (17%, n = 33), followed by isoniazid mono-drug resistance (3.6%, n = 7). Rifampicin resistance was associated with mutations in the rpoB gene (D435Y, D435V, S450L, L452P). Isoniazid resistance mutations were found in the katG (S315T), inhA (C[-15] T), and ndh (R268H) genes, whereas ethambutol resistance mutations were observed in the embB gene (M306V, M306I, M306L, G406S, Q497R). Surprisingly, 94% of PZAr isolates (n = 31) showed no mutations in the pncA or rpsA genes. The presence of the R268H mutation in the ndh gene, not previously linked to PZAr, was detected in 15% of PZAr isolates (n = 5), suggesting its potential contribution to PZAr in specific cases but not as a predominant mechanism. The specific molecular mechanisms underlying PZAr in the majority of the isolates remain unknown, emphasizing the need for further research to uncover the contributing factors. These findings contribute to the understanding of drug resistance patterns and can guide future efforts in TB control and management.

Comparative evaluation of intensified short course regimen and standard regimen for adults TB meningitis: a protocol for an open label, multi-center, parallel arms, randomized controlled superiority trial (INSHORT trial).

BACKGROUND: Despite several incremental improvements in the management of tuberculous meningitis (TBM), the mortality rates remain high. In spite of national and international guidelines, variation in the choice, dose, and duration of drugs exist between countries and clinicians. We propose to evaluate a shorter and more effective regimen containing agents with augmented intracerebral drug exposure and anti-inflammatory approaches to improve disability-free survival among patients with TBM. Our strategy incorporates the various developments in the field of TBM over the last two decades and only few trials have evaluated a composite of these strategies in the overall outcomes of TBM. METHODS: An open label, parallel arms, randomized controlled superiority trial will be conducted among 372 participants across 6 sites in India. Eligible participants will be randomly allocated in 1:1:1 ratio into one of the three arms. The intervention arm consists of 2 months of high-dose rifampicin (25 mg/kg), moxifloxacin (400 mg), pyrazinamide, isoniazid, aspirin (150 mg), and steroids followed by rifampicin, isoniazid, and pyrazinamide for 4 months. The second intervention arm includes all the drugs as per the first arm except aspirin and the patients in the control arm will receive treatment according to the National TB Elimination Program guidelines. All participants will be followed up for 1 year after the treatment.  DISCUSSION: Current WHO regimens have agents with poor central nervous system drug exposure and is too long. It does not reflect the accumulating evidence in the field. We propose a comprehensive clinical trial incorporating the emerging evidence accrued over the last two decades to shorten the duration and improve the treatment outcomes. This multi-centric trial may generate crucial evidence with policy and practice implications in the treatment of TBM. TRIAL REGISTRATION: Clinical Trial Registry India CTRI/2023/05/053314. Registered on 31 May 2023 ( https://ctri.nic.in/Clinicaltrials/pmaindet2.php?EncHid=ODYzMzg=&Enc=&userName=CTRI/2023/05/053314 ). CLINICALTRIALS: gov NCT05917340. Registered on 6 August 2023 ( https://classic. CLINICALTRIALS: gov/ct2/show/NCT05917340 ). PROTOCOL VERSION: Version 1.3 dated 12 July 2023.

Proficiency of phenotypic drug susceptibility testing for Mycobacterium tuberculosis in China, 2008-2021.

To analyze the results of proficiency testing for anti-tuberculosis drug susceptibility testing (DST) in China. Number of laboratory participating the proficiency testing performed DST, and the sensitivity, specificity, reproducibility, and accordance rate were calculated from data of 13 rounds proficiency testing results for DST from 2008 to 2021. A total of 30 and 20 strains of Mycobacterium tuberculosis with known susceptibility results were sent to each laboratory in 2008 to 2019, 2020 and 2021, respectively. The number of participating laboratories ranged from 30 in 2009 to 546 in 2021. L-J DST was the predominant method. The specificity presented relatively higher than sensitivity. Improvement of specificity were observed for all drugs through the years, while sensitivity did not show improvement for amikacin and capreomycin. Accordance rate of pyrazinamide and kanamycin and reproducibility of capreomycin and pyrazinamide were not significantly improved through the years. Most of the participating laboratories significantly improved the quality of their DST through the consecutive rounds of proficiency testing except for second-line injectable drugs and pyrazinamide. The results highlight the importance of developing novel and/or improving existing methods for phenotypic DST for certain drugs.

A robust computational quest: Discovering potential hits to improve the treatment of pyrazinamide-resistant Mycobacterium tuberculosis.

The rise of pyrazinamide (PZA)-resistant strains of Mycobacterium tuberculosis (MTB) poses a major challenge to conventional tuberculosis (TB) treatments. PZA, a cornerstone of TB therapy, must be activated by the mycobacterial enzyme pyrazinamidase (PZase) to convert its active form, pyrazinoic acid, which targets the ribosomal protein S1. Resistance, often associated with mutations in the RpsA protein, complicates treatment and highlights a critical gap in the understanding of structural dynamics and mechanisms of resistance, particularly in the context of the G97D mutation. This study utilizes a novel integration of computational techniques, including multiscale biomolecular and molecular dynamics simulations, physicochemical and medicinal chemistry predictions, quantum computations and virtual screening from the ZINC and Chembridge databases, to elucidate the resistance mechanism and identify lead compounds that have the potential to improve treatment outcomes for PZA-resistant MTB, namely ZINC15913786, ZINC20735155, Chem10269711, Chem10279789 and Chem10295790. These computational methods offer a cost-effective, rapid alternative to traditional drug trials by bypassing the need for organic subjects while providing highly accurate insight into the binding sites and efficacy of new drug candidates. The need for rapid and appropriate drug development emphasizes the need for robust computational analysis to justify further validation through in vitro and in vivo experiments.

Triple combination dry powder formulation of pretomanid, moxifloxacin, and pyrazinamide for treatment of multidrug-resistant tuberculosis.

Both latent and multidrug-resistant tuberculosis (TB) have been causing significant concern worldwide. A novel drug, pretomanid (PA-824), has shown a potent bactericidal effect against both active and latent forms of Mycobacterium tuberculosis (MTb) and a synergistic effect when combined with pyrazinamide and moxifloxacin. This study aimed to develop triple combination spray dried inhalable formulations composed of antitubercular drugs, pretomanid, moxifloxacin, and pyrazinamide (1:2:8 w/w/w), alone (PaMP) and in combination with an aerosolization enhancer, L-leucine (20 % w/w, PaMPL). The formulation PaMPL consisted of hollow, spherical, dimpled particles (<5 µm) and showed good aerosolization behaviour with a fine particle fraction of 70 %. Solid-state characterization of formulations with and without L-leucine confirmed the amorphous nature of moxifloxacin and pretomanid and the crystalline nature of pyrazinamide with polymorphic transformation after the spray drying process. Further, the X-ray photoelectron spectroscopic analysis revealed the predominant surface composition of L-leucine on PaMPL dry powder particles. The dose-response cytotoxicity results showed pyrazinamide and moxifloxacin were non-toxic in both A549 and Calu-3 cell lines up to 150 µg/mL. However, the cell viability gradually decreased to 50 % when the pretomanid concentration increased to 150 µg/mL. The in vitro efficacy studies demonstrated that the triple combination formulation had more prominent antibacterial activity with a minimum inhibitory concentration (MIC) of 1 µg/mL against the MTb H37Rv strain as compared to individual drugs. In conclusion, the triple combination of pretomanid, moxifloxacin, and pyrazinamide as an inhalable dry powder formulation will potentially improve treatment efficacy with fewer systemic side effects in patients suffering from latent and multidrug-resistant TB.

Targeted sequencing from cerebrospinal fluid for rapid identification of drug-resistant tuberculous meningitis.

Mortality from tuberculous meningitis (TBM) remains around 30%, with most deaths occurring within 2 months of starting treatment. Mortality from drug-resistant strains is higher still, making early detection of drug resistance (DR) essential. Targeted next-generation sequencing (tNGS) produces high read depths, allowing the detection of DR-associated alleles with low frequencies. We applied Deeplex Myc-TB-a tNGS assay-to cerebrospinal fluid (CSF) samples from 72 adults with microbiologically confirmed TBM and compared its genomic drug susceptibility predictions to a composite reference standard of phenotypic susceptibility testing (pDST) and whole genome sequencing, as well as to clinical outcomes. Deeplex detected Mycobacterium tuberculosis complex DNA in 24/72 (33.3%) CSF samples and generated full DR reports for 22/24 (91.7%). The read depth generated by Deeplex correlated with semi-quantitative results from MTB/RIF Xpert. Alleles with <20% frequency were seen at canonical loci associated with first-line DR. Disregarding these low-frequency alleles, Deeplex had 100% concordance with the composite reference standard for all drugs except pyrazinamide and streptomycin. Three patients had positive CSF cultures after 30 days of treatment; reference tests and Deeplex identified isoniazid resistance in two, and Deeplex alone identified low-frequency rifampin resistance alleles in one. Five patients died, of whom one had pDST-identified pyrazinamide resistance. tNGS on CSF can rapidly and accurately detect drug-resistant TBM, but its application is limited to those with higher bacterial loads. In those with lower bacterial burdens, alternative approaches need to be developed for both diagnosis and resistance detection.

Fetal protective effect of Indonesian propolis from Apis mellifera against rifampicin-pyrazinamide induced impaired pregnancy in BALB/c mice.

OBJECTIVES: Anti-tuberculosis drugs rifampicin and pyrazinamide combination in pregnancy can cause morphological, visceral and skeletal damage. Several studies showed that propolis improves pregnancy outcomes. This study aims to determine the fetal protective effect of propolis in BALB/c mice given the anti-tuberculosis drug combination rifampicin and pyrazinamide. METHODS: A total of 21 pregnant mice were randomly divided into three groups: the normal group (N) was given distilled water as a vehicle, the positive control group (RP) were given rifampicin 15 mg/kg BW, pyrazinamide 35 mg/kg BW and the treatment group (IP) were given rifampicin 15 mg/kg BB, pyrazinamide 35 mg/kg BW and propolis 400 mg/kg BW. The treatment was given during the period of organogenesis, from day 6 to day 15. Laparotomy was performed on the 18th day of pregnancy. Maternal and fetal body weight, fetal length, number of fetuses, and skeletal defects of fetuses were used as parameters to identify the teratogenic effect. All data were analyzed using the ANOVA. RESULTS: All groups significantly differed between maternal and fetal body weights (p<0.05). The administration of rifampicin-pyrazinamide and propolis during pregnancy did not significantly affect the number of fetuses (p>0.05). The administration of propolis protects the fetus from skeletal abnormalities. While in the RP and IP groups, we can find resorption sites and haemorrhagic. CONCLUSIONS: This study may suggest the protective effects of propolis against rifampicin pyrazinamide-induced impaired pregnancy.

Co-resistance to isoniazid and second-line anti-tuberculosis drugs in isoniazid-resistant tuberculosis at a tertiary care hospital in Thailand.

Isoniazid-resistant tuberculosis (Hr-TB) is an important drug-resistant tuberculosis (TB). In addition to rifampicin, resistance to other medications for Hr-TB can impact the course of treatment; however, there are currently limited data in the literature. In this study, the drug susceptibility profiles of Hr-TB treatment and resistance-conferring mutations were investigated for Hr-TB clinical isolates from Thailand. Phenotypic drug susceptibility testing (pDST) and genotypic drug susceptibility testing (gDST) were retrospectively and prospectively investigated using the Mycobacterium Growth Indicator Tube (MGIT), the broth microdilution (BMD) method, and whole-genome sequencing (WGS)-based gDST. The prevalence of Hr-TB cases was 11.2% among patients with TB. Most Hr-TB cases (89.5%) were newly diagnosed patients with TB. In the pDST analysis, approximately 55.6% (60/108) of the tested Hr-TB clinical isolates exhibited high-level isoniazid resistance. In addition, the Hr-TB clinical isolates presented co-resistance to ethambutol (3/161, 1.9%), levofloxacin (2/96, 2.1%), and pyrazinamide (24/118, 20.3%). In 56 Hr-TB clinical isolates, WGS-based gDST predicted resistance to isoniazid [katG S315T (48.2%) and fabG1 c-15t (26.8%)], rifampicin [rpoB L430P and rpoB L452P (5.4%)], and fluoroquinolones [gyrA D94G (1.8%)], but no mutation for ethambutol was detected. The categorical agreement for the detection of resistance to isoniazid, rifampicin, ethambutol, and levofloxacin between WGS-based gDST and the MGIT or the BMD method ranged from 80.4% to 98.2% or 82.1% to 100%, respectively. pDST and gDST demonstrated a low co-resistance rate between isoniazid and second-line TB drugs in Hr-TB clinical isolates. IMPORTANCE: The prevalence of isoniazid-resistant tuberculosis (Hr-TB) is the highest among other types of drug-resistant tuberculosis. Currently, the World Health Organization (WHO) guidelines recommend the treatment of Hr-TB with rifampicin, ethambutol, pyrazinamide, and levofloxacin for 6 months. The susceptibility profiles of Hr-TB clinical isolates, especially when they are co-resistant to second-line drugs, are critical in the selection of the appropriate treatment regimen to prevent treatment failure. This study highlights the susceptibility profiles of the WHO-recommended treatment regimen in Hr-TB clinical isolates from a tertiary care hospital in Thailand and the concordance and importance of using the phenotypic drug susceptibility testing or genotypic drug susceptibility testing for accurate and comprehensive interpretation of results.