Efficacy and safety of an innovative short-course regimen containing clofazimine for treatment of drug-susceptible tuberculosis: a clinical trial.

In preclinical studies, a new antituberculosis drug regimen markedly reduced the time required to achieve relapse-free cure. This study aimed to preliminarily evaluate the efficacy and safety of this four-month regimen, consisting of clofazimine, prothionamide, pyrazinamide and ethambutol, with a standard six-month regimen in patients with drug-susceptible tuberculosis. An open-label pilot randomized clinical trial was conducted among the patients with newly diagnosed bacteriologically-confirmed pulmonary tuberculosis. The primary efficacy end-point was sputum culture negative conversion. Totally, 93 patients were included in the modified intention-to-treat population. The rates of sputum culture conversion were 65.2% (30/46) and 87.2% (41/47) for short-course and standard regimen group, respectively. There was no difference on two-month culture conversion rates, time to culture conversion, nor early bactericidal activity (P > 0.05). However, patients on short-course regimen were observed with lower rates of radiological improvement or recovery and sustained treatment success, which was mainly attributed to higher percent of patients permanently changed assigned regimen (32.1% vs. 12.3%, P = 0.012). The main cause for it was drug-induced hepatitis (16/17). Although lowering the dose of prothionamide was approved, the alternative option of changing assigned regimen was chosen in this study. While in per-protocol population, sputum culture conversion rates were 87.0% (20/23) and 94.4% (34/36) for the respective groups. Overall, the short-course regimen appeared to have inferior efficacy and higher incidence of hepatitis but desired efficacy in per-protocol population. It provides the first proof-of-concept in humans of the capacity of the short-course approach to identify drug regimens that can shorten the treatment time for tuberculosis.

Intracellular Activity of Poly (DL-Lactide-co-Glycolide) Nanoparticles Encapsulated with Prothionamide, Pyrazinamide, Levofloxacin, Linezolid, or Ethambutol on Multidrug-Resistant Mycobacterium tuberculosis.

BACKGROUND: Multidrug-resistant Mycobacterium tuberculosis (MDR-TB) is a major cause of death amongst tuberculosis patients. Nanomedicine avoids some limitations of conventional drug treatment and increases therapeutic efficacy against bacterial infections. However, the effect of anti-TB drug nanoparticle (NP) compounds in anti-TB regimens against MDR-TB remains unclear. OBJECTIVE: The objective of this article is to prepare levofloxacin, linezolid, ethambutol, prothionamide, and pyrazinamide encapsulated NPs and to evaluate their therapeutic efficacy against MDR-TB in macrophages. METHODS: Drug-loaded PLGA NPs were prepared by the multiple emulsion method. The colocalization, intracellular release, and anti-TB activity of these NPs were investigated on cultured macrophages. The immune phenotype of the macrophages, including their mitochondrial membrane potential, reactive oxygen species (ROS), and nitric oxide (NO) production, was evaluated following treatment with NPs or free drug compounds. RESULTS: All drug-loaded PLGA NPs were spherical in shape, 150 to 210 nm in size, and showed 14.22% to 43.51% encapsulation efficiencies and long-duration release. Drug-loaded PLGA NPs were mainly distributed in the cytoplasm of macrophages, showed high cellular compatibility, and maintained their concentration for at least 13 days. Compared with the free drug compounds, the number of colonies after exposure to PLGA NP compounds was significantly less. The enhanced antibacterial activity of the NP compounds may be due to the enhanced levels of ROS and NO and the increased early apoptosis stress within M. tuberculosis-infected macrophages additionally. CONCLUSION: The application of PLGA NP compounds not only enhances drug efficacy but also induces innate bactericidal events in macrophages, confirming this as a promising approach for MDR-TB therapy.

Prothionamide Dose Optimization Using Population Pharmacokinetics for Multidrug-Resistant Tuberculosis Patients.

Prothionamide, a second-line drug for multidrug-resistant tuberculosis (MDR-TB), has been in use for a few decades. However, its pharmacokinetic (PK) profile remains unclear. This study aimed to develop a population PK model for prothionamide and then apply the model to determine the optimal dosing regimen for MDR-TB patients. Multiple plasma samples were collected from 27 MDR-TB patients who had been treated with prothionamide at 2 different study hospitals. Prothionamide was administered according to the weight-band dose regimen (500 mg/day for weight <50 kg and 750 mg/day for weight >50 kg) recommended by the World Health Organization. The population PK model was developed using nonlinear mixed-effects modeling. The probability of target attainment, based on systemic exposure and MIC, was used as a response target. Fixed-dose regimens (500 or 750 mg/day) were simulated to compare the efficacies of various dosing regimens. PK profiles adequately described the two-compartment model with first-order elimination and the transit absorption compartment model with allometric scaling on clearance. All dosing regimens had effectiveness >90% for MIC values <0.4 µg/mL in 1.0-log kill target. However, a fixed dose of 750 mg/day was the only regimen that achieved the target resistance suppression of ≥90% for MIC values of <0.2 µg/mL. In conclusion, fixed-dose prothionamide (750 mg/day), regardless of weight-band, was appropriate for adult MDR-TB patients with weights of 40 to 67 kg.

Temporal trends of pharmacologic treatments for tuberculosis and multidrug resistant tuberculosis following dissemination of treatment guidelines in South Korea.

BACKGROUND/PURPOSE(S): The World Health Organization (WHO) released treatment guidelines for multidrug resistant tuberculosis (MDR-TB) in 2008, with subsequent revisions in 2011; Korea disseminated corresponding guidelines in 2011 and 2014, respectively. Thus, we aimed to investigate the temporal trends of and the updated guideline's impact on the prescription patterns of anti-TB drugs. METHODS: We conducted a time-series study using Korea's nationwide healthcare database (2007-2015), where patients with TB or MDR-TB were included. Only anti-TB drugs prescribed during the intensive phase of treatment for TB (two months) or MDR-TB (eight months) were assessed. We estimated the annual utilization of TB treatment regimens and the relative difference (RD) in the proportion of MDR-TB treatment medications between the following periods: before the first Korean guideline (June 2008 to March 2011); between the first and revised guidelines (April 2011 to July 2014); after the revised guideline (August 2014 to December 2015). RESULTS: Of 3523 TB (mean age 54.1 years; male 56.8%) patients, treatment regimens for TB complied with guideline recommendations as >80% of patients received either quadruple (mean 66.8%) or triple (14.5%) therapy of first-line anti-TB drugs. Following the WHO's guideline update, prescription patterns changed accordingly among 111 MDR-TB (mean age 46.0 years; male 67.6%) patients, as use of pyrazinamide (RD +20.3%) and prothionamide (+11.5%) increased (recommended to be compulsory), and streptomycin (-43.1%) decreased (ototoxicity risks). CONCLUSIONS: Anti-TB drug prescription patterns for both TB and MDR-TB well reflected WHO's treatment guideline as well as corresponding domestic guidelines of South Korea.

A recombinant selective drug-resistant M. bovis BCG enhances the bactericidal activity of a second-line anti-tuberculosis regimen.

Drug-resistant tuberculosis (DR-TB) poses a new threat to global health; to improve the treatment outcome, therapeutic vaccines are considered the best chemotherapy adjuvants. Unfortunately, there is no therapeutic vaccine approved against DR-TB. Our study assessed the therapeutic efficacy of a recombinant drug-resistant BCG (RdrBCG) vaccine in DR-TB. We constructed the RdrBCG overexpressing Ag85B and Rv2628 by selecting drug-resistant BCG strains and transformed them with plasmid pEBCG or pIBCG to create RdrBCG-E and RdrBCG-I respectively. Following successful stability testing, we tested the vaccine's safety in severe combined immune deficient (SCID) mice that lack both T and B lymphocytes plus immunoglobulins. Finally, we evaluated the RdrBCG's therapeutic efficacy in BALB/c mice infected with rifampin-resistant M. tuberculosis and treated with a second-line anti-TB regimen. We obtained M. bovis strains which were resistant to several second-line drugs and M. tuberculosis resistant to rifampin. Notably, the exogenously inserted genes were lost in RdrBCG-E but remained stable in the RdrBCG-I both in vitro and in vivo. When administered adjunct to a second-line anti-TB regimen in a murine model of DR-TB, the RdrBCG-I lowered lung M. tuberculosis burden by 1 log10. Furthermore, vaccination with RdrBCG-I adjunct to chemotherapy minimized lung tissue pathology in mice. Most importantly, the RdrBCG-I showed almost the same virulence as its parent BCG Tice strain in SCID mice. Our findings suggested that the RdrBCG-I was stable, safe and effective as a therapeutic vaccine. Hence, the "recombinant" plus "drug-resistant" BCG strategy could be a useful concept for developing therapeutic vaccines against DR-TB.

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, 1 H, and 13 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%).

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.

Cytochemical Evaluation of the Toxic Effects of Combined Antituberculosis Substances on Metabolic State of Blood Lymphocytes.

Combined antituberculosis substances induced a dose-dependent changes in activity of dehydrogenases and hydrolases in rat lymphocytes. The main toxic effect of the substances was related to inhibition of mitochondrial dehydrogenases (succinate dehydrogenase and α-glycerol phosphate dehydrogenase) usually followed by suppression of activity of hydrolytic enzymes (acid phosphatase and non-specific esterase). Opposite changes in lactate dehydrogenase activity reflected specific features of intoxication.

Different macrophage polarization between drug-susceptible and multidrug-resistant pulmonary tuberculosis.

BACKGROUND: Macrophages play a key role in the infection process, and alternatively activated macrophages (M2 polarization) play important roles in persistent infection via the immune escape of pathogens. This suggests that immune escape of pathogens from host immunity is an important factor to consider in treatment failure and multidrug-resistant tuberculosis (MDR-TB)/extensively drug-resistant tuberculosis (XDR-TB). In this study, we investigated the association between macrophage polarization and MDR-TB/XDR-TB and the association between macrophage polarization and the anti-TB drugs used. METHODS: iNOS and arginase-1, a surface marker of polarized macrophages, were quantified by immunohistochemical staining and imaging analysis of lung tissues of patients who underwent surgical treatment for pulmonary TB. Drug susceptibility/resistance and the type and timing of anti-tuberculosis drugs used were investigated. RESULTS: The M2-like polarization rate and the ratio of the M2-like polarization rate to the M1-like polarization rate were significantly higher in the MDR-TB/XDR-TB group than in the DS-TB group. The association between a high M2-like polarization rate and MDR-TB/XDR-TB was more pronounced in patients with a low M1-like polarization rate. Younger age and a higher M2-like polarization rate were independent associated factors for MDR-TB/XDR-TB. The M2-like polarization rate was significantly higher in patients who received anti-TB drugs containing pyrazinamide continuously for 4 or 6 weeks than in those who received anti-TB drugs not containing pyrazinamide. CONCLUSIONS: The M2-like polarization of macrophages is associated with MDR-TB/XDR-TB and anti-TB drug regimens including pyrazinamide or a combination of pyrazinamide, prothionamide and cycloserine.

Rifampin Induces Expression of P-glycoprotein on the THP1 Cell-Derived Macrophages, Causing Decrease Intramacrophage Concentration of Prothionamide.

Rifampin (RIF) has been widely used for the treatment of bacterial infections, including tuberculosis (TB). Treatment of drug-resistant TB is a global problem because of reduced drug efficacy. The present study determined the effect of RIF on MDR1 gene (P-glycoprotein, P-gp) expression in THP1 macrophages and analyzed the intracellular concentration of the anti-TB drug prothionamide in the presence of RIF. RIF treatment significantly induced MDR1 protein and mRNA levels in phorbol 12-myristate 13-acetate-stimulated THP1 macrophages (p < 0.001 and 0.01, respectively). The pregnane X receptor inhibitors resveratrol and ketoconazole significantly suppressed RIF-induced P-gp expression in THP1 macrophages (p < 0.05). RIF-treated THP1 macrophages also exhibited strong efflux of P-gp substrate, resulting in a reduced intracellular concentration of rhodamine-123 and prothionamide (p < 0.01 and 0.05, respectively). By contrast, the P-gp inhibitor cyclosporine A significantly increased intracellular concentration of rhodamine-123 and prothionamide (p < 0.001 and 0.05, respectively). The present results suggest that the usage of RIF together with P-gp-substrate drugs to treat TB may lead to deteriorated treatment efficacy because of the lower intracellular drug concentration. Further studies would be necessary to know the influence of RIF-induced P-gp induction on the treatment outcome of patients with TB.

Bacterial Genome-Wide Association Identifies Novel Factors That Contribute to Ethionamide and Prothionamide Susceptibility in Mycobacterium tuberculosis.

In Mycobacterium tuberculosis, recent genome-wide association studies have identified a novel constellation of mutations that are correlated with high-level drug resistances. Interpreting the functional importance of the new resistance-associated mutations has been complicated, however, by a lack of experimental validation and a poor understanding of the epistatic factors influencing these correlations, including strain background and programmatic variation in treatment regimens. Here we perform a genome-wide association analysis in a panel of Mycobacterium tuberculosis strains from China to identify variants correlated with resistance to the second-line prodrug ethionamide (ETH). Mutations in a bacterial monooxygenase, Rv0565c, are significantly associated with ETH resistance. We demonstrate that Rv0565c is a novel activator of ETH, independent of the two known activators, EthA and MymA. Clinically prevalent mutations abrogate Rv0565c function, and deletion of Rv0565c confers a consistent fitness benefit on M. tuberculosis in the presence of partially inhibitory doses of ETH. Interestingly, Rv0565c activity affects susceptibility to prothionamide (PTH), the ETH analog used in China, to a greater degree. Further, clinical isolates vary in their susceptibility to both ETH and PTH, to an extent that correlates with the total expression of ETH/PTH activators (EthA, MymA, and Rv0565c). These results suggest that clinical strains considered susceptible to ETH/PTH are not equally fit during treatment due to both Rv0565c mutations and more global variation in the expression of the prodrug activators.IMPORTANCE Phenotypic antibiotic susceptibility testing in Mycobacterium tuberculosis is slow and cumbersome. Rapid molecular diagnostics promise to help guide therapy, but such assays rely on complete knowledge of the molecular determinants of altered antibiotic susceptibility. Recent genomic studies of antibiotic-resistant M. tuberculosis have identified several candidate loci beyond those already known to contribute to antibiotic resistance; however, efforts to provide experimental validation have lagged. Our study identifies a gene (Rv0565c) that is associated with resistance to the second-line antibiotic ethionamide at a population level. We then use bacterial genetics to show that the variants found in clinical strains of M. tuberculosis improve bacterial survival after ethionamide exposure.

Simultaneous determination of the potent anti-tuberculosis regimen-Pyrazinamide, ethambutol, protionamide, clofazimine in beagle dog plasma using LC-MS/MS method coupled with 96-well format plate.

Tuberculosis is one of the top concerns in the world and acutely threatens human health. A new potent candidate regimen containing pyrazinamide (PZA), ethambutol (EMB), protionamide (PTO) and clofazimine (CFZ) was proposed by Parabolic Response Surface/Feedback System Control (FSC/PRS) system and showed excellent outcomes in vitro and vivo studies. Here, a convenient liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneously determination of four compounds in beagle dog plasma. The plasma samples, 50 µL for each, were pretreated by methanol on 96-well format plates and a further dilution step was designed to reduce predictable matrix effect and lessen the burden of subsequent analysis. The chromatographic separation was achieved on an Agilent SB-Aq column (4.6 mm × 150 mm, 5 µm) at 30 °C by a gradient elution within 6 min. The mobile phase was a mixture of 0.2% formic acid-5 mM ammonium acetate aqueous solution (phase A) and 0.2% formic acid methanol (phase B) with a total flow rate of 1 mL/min. The 30% of post-column eluant was injected into mass spectrometer, equipped with electrospray ionization (ESI) source under positive mode and multiple-reaction monitoring (MRM). This quantification method was proved to be satisfied in selectivity, accuracy, precision, linearity (r2 > 0.998), recovery, matrix effect and stability. Under the specialized conditions, the calibration curves ranged from 20 to 5000 ng/mL for PZA, 1 to 500 ng/mL for EMB, 1 to 500 ng/mL for PTO, and 1 to 200 ng/mL for CFZ. The quantitative accuracy was further assessed under different degrees of hemolyses in detail. This method was proved to be robust and efficient, and successfully applied to the pharmacokinetic study of the new regimen in Beagle dogs.

Detection of novel mutations associated with independent resistance and cross-resistance to isoniazid and prothionamide in Mycobacterium tuberculosis clinical isolates.

OBJECTIVES: Prothionamide, a structural analogue of isoniazid, is used mainly for treating multidrug-resistant tuberculosis (MDR-TB). Both drugs have a common target InhA, so prothionamide can be ineffective against isoniazid-resistant (INHR) Mycobacterium tuberculosis. We aimed to investigate the prevalence of mutations in katG, ethA, ndh, ethR, mshA, inhA and/or its promoter associated with independent resistance and cross-resistance to INHR and/or prothionamide-resistant (PTOR) M. tuberculosis isolates. METHODS: We sequenced the above genes in 206 M. tuberculosis isolates with susceptibility testing against ten drugs. RESULTS: Of the 173 INHR PTOR isolates, 170 (98.3%) harboured mutations in katG, 111 (64.2%) in ethA, 58 (33.5%) in inhA or its promoter, 5 (2.9%) in ndh, 3 (1.7 %) in ethR and 2 (1.2%) in mshA. Among the 18 INHR PTOS isolates, mutations in katG were found in all of them; one had a mutation in the inhA promoter and another in ndh. Of the five INHS PTOR isolates, four showed mutations in ethA and two in the inhA promoter. Notably, 55 novel non-synonymous mutations were found in them and 20.2% of the PTORM. tuberculosis isolates harboured no known mutations. CONCLUSIONS: This is the first report to investigate cross-resistance between INHR and/or PTOR isolates. Among INHR (94.4% MDR-TB) M. tuberculosis isolates, the high diversity of mutations for independent resistance and cross-resistance with prothionamide highlight the importance of both phenotypic susceptibility and genotypic diagnosis when using it to treat patients with INHR-TB. The high proportion (one-fifth) of PTORM. tuberculosis isolates showed no known mutation related to PTOR genes, so uncovered resistance mechanism(s) of prothionamide exist.

Correlation between GenoType MTBDRplus Assay and Phenotypic Susceptibility Test for Prothionamide in Patients with Genotypic Isoniazid Resistance / 결핵

BACKGROUND: The purpose of this study was to analyze the relationship between the gene mutation patterns by the GenoType MTBDRplus (MTBDRplus) assay and the phenotypic drug susceptibility test (pDST) results of isoniazid (INH) and prothionamide (Pto). METHODS: A total of 206 patients whose MTBDRplus assay results revealed katG or inhA mutations were enrolled in the study. The pDST results were compared to mutation patterns on the MTBDRplus assay. RESULTS: The katG and inhA mutations were identified in 68.0% and 35.0% of patients, respectively. Among the 134 isolated katG mutations, three (2.2%), 127 (94.8%) and 11 (8.2%) were phenotypically resistant to low-level INH, high-level INH, and Pto, respectively. Among the 66 isolated inhA mutations, 34 (51.5%), 18 (27.3%) and 21 (31.8%) were phenotypically resistant to low-level INH, high-level INH, and Pto, respectively. Of the 34 phenotypic Pto resistant isolates, 21 (61.8%), 11 (32.4%), and two (5.9%) had inhA, katG, and both gene mutations. CONCLUSION: It is noted that Pto may still be selected as one of the appropriate multidrug-resistant tuberculosis regimen, although inhA mutation is detected by the MTBDRplus assay until pDST confirms a Pto resistance. The reporting of detailed mutation patterns of the MTBDRplus assay may be important for clinical practice, rather than simply presenting resistance or susceptibility test results.

Predicting the Outcomes of New Short-Course Regimens for Multidrug-Resistant Tuberculosis Using Intrahost and Pharmacokinetic-Pharmacodynamic Modeling.

Short-course regimens for multidrug-resistant tuberculosis (MDR-TB) are urgently needed. Limited data suggest that the new drug bedaquiline (BDQ) may have the potential to shorten MDR-TB treatment to less than 6 months when used in conjunction with standard anti-TB drugs. However, the feasibility of BDQ in shortening MDR-TB treatment duration remains to be established. Mathematical modeling provides a platform to investigate different treatment regimens and predict their efficacy. We developed a mathematical model to capture the immune response to TB inside a human host environment. This model was then combined with a pharmacokinetic-pharmacodynamic model to simulate various short-course BDQ-containing regimens. Our modeling suggests that BDQ could reduce MDR-TB treatment duration to just 18 weeks (4 months) while still maintaining a very high treatment success rate (100% for daily BDQ for 2 weeks, or 95% for daily BDQ for 1 week during the intensive phase). The estimated time to bacterial clearance of these regimens ranges from 27 to 33 days. Our findings provide the justification for empirical evaluation of short-course BDQ-containing regimens. If short-course BDQ-containing regimens are found to improve outcomes, then we anticipate clear cost savings and a subsequent improvement in the efficiency of national TB programs.

Development and evaluation of Chitosan nanoparticles based dry powder inhalation formulations of Prothionamide.

Prothionamide (PTH), a second line antitubercular drug is used to administer in conventional oral route. However, its unpredictable absorption and frequent administration limit its use. An alternate approach was thought of administering PTH through pulmonary route in a form of nanoparticles, which can sustain the release for several hours in lungs. Chitosan, a bio-degradable polymer was used to coat PTH and further freeze dried to prepare dry powder inhaler (DPI) with aerodynamic particle size of 1.76µm. In vitro release study showed initial burst release followed by sustained release up to 96.91% in 24h. In vitro release further correlated with in vivo study. Prepared DPI maintained the PTH concentration above MIC for more than 12h after single dose administration and increased the PTH residency in the lungs tissue more than 24h. Animal study also revealed the reduction of dose in pulmonary administration, which will improve the management of tuberculosis.

Case Report: Carbapenemase-Producing Enterobacteriaceae in an Asylum Seeker with Multidrug-Resistant Tuberculosis.

A Syrian asylum seeker with multidrug-resistant tuberculosis (TB) developed a bronchopleural fistula after pneumonectomy. Although screening tests were negative on admission, carbapenemase-producing Enterobacteriaceae were cultured after a few months of TB treatment. Prevalence of multidrug-resistant organisms is reported to be increased in asylum seekers compared with the general Dutch population. Arduous conditions during transit and interrupted health care delivery in our patient led to multiple-resistant microorganisms that complicated treatment.

Treatment outcomes of rifampin-sparing treatment in patients with pulmonary tuberculosis with rifampin-mono-resistance or rifampin adverse events: A retrospective cohort analysis.

BACKGROUND: Rifampin (RIF) mono-resistant tuberculosis (RMR-TB) is a rare disease. Current guidelines recommend that RMR-TB be treated as multidrug-resistant TB (MDR-TB) but the evidence is scarce. METHODS: We conducted a retrospective cohort study on pulmonary TB patients to investigate the characteristics and outcomes of RMR-TB. The characteristics of RMR-TB were compared with those with adverse events to rifampin (RAE-TB). RESULTS: Forty-four RMR-TB and 29 RAE-TB patients were enrolled. RMR-TB patients showed more alcohol use, prior history of TB, and radiologically severe disease, while RAE-TB patients were older and had more comorbidities and combined extrapulmonary TB. A fluoroquinolone (FQ) was the drug most commonly added (70.5%, RMR-TB; 82.8%, RAE-TB). Median treatment duration was 453 days in RMR-TB and 371 days in RAE-TB (p = 0.001) and treatment success rates were 87.2% (34/39) and 80.0% (20/25), respectively (p = 0.586). Subanalysis of the RMR-TB group by treatment regimen (standard regimen [n = 11], standard regimen + FQ [n = 12], MDR-TB regimen [n = 21]) revealed a higher rate of radiologically severe disease in the MDR-TB subgroup, with similar treatment success rates for the subgroups (85.7% [6/7]), 91.7% [11/12], and 85.0% [17/20], respectively) despite different durations of treatment (345, 405, and 528 days, respectively). Two recurrences (33.3% [2/6]) developed only in standard regimen subgroup, suggesting that standard regimen is not enough to treat RMR-TB patients. CONCLUSIONS: The treatment outcome of RMR-TB with 1st-line drugs + FQ was comparable to that of MDR-TB regimen. Shorter treatment duration may be considered for RMR-TB patients compared with MDR-TB patients.

Clinical predictors of aminoglycoside-induced ototoxicity in drug-resistant Tuberculosis patients on intensive therapy.

OBJECTIVE: The study objectives were to determine the incidence of aminoglycoside-induced ototoxicity in institutionalized patients on intensive phase of therapy for drug-resistant Tuberculosis (DR Tb) and also to assess clinical factors which could predict the ototoxicity. METHODS: The study was a prospective analytical study among consecutive DR Tb patients who were admitted for intensive phase of therapy (of 4 months) at the DR-Tb center over a 12-month period. Patients were diagnosed as DR Tb using the Gene Xpert machine to confirm Rifampicin resistance. All eligible 70 out of 87 consenting patients were consecutively recruited into the study. Patients had baseline (admission) and serial pure tone audiometries (PTAs) performed at 4 weekly intervals until discharge after 4 months of admission. Audiometric confirmation of aminoglycoside-induced ototoxicity was done by comparing serial with baseline PTA. RESULTS: Among the 70 patients the male:female ratio was 1.7:1. Nine patients (12.9%) were retroviral-positive, and 16 patients (22.9%) were confirmed to have ototoxicity by audiometric criteria. The duration of treatment when ototoxicity was detected in the patients ranged 4-17 (Mean±SD; 9.4±3.4) weeks. Ototoxicity was detected in the audiometric low frequency ranges in 7 (43.8%) and at the high frequencies in 4 (25.0%) of the patients. Univariate analyses of clinical parameters found that age, underlying diabetes mellitus, deranged baseline PTAv >25dB HL, BMI on admission and retroviral status were significantly associated, while sex and previous drug regimen failure were not associated with ototoxicity. Multivariate adjusted logistic regression analyses, controlling for sex, revealed age (OR=1.068, p=0.018), BMI on admission (OR=0.673, p=0.012) and retroviral positivity (OR=8.822, p=0.014) of patients could significantly predict aminoglycoside-induced ototoxicity. CONCLUSION: Incidence of aminoglycoside-induced ototoxicity in DR Tb patients was 22.9%. The clinical predictors for ototoxicity were age, BMI on admission, and co-existing retroviral infection in the patients. Clinicians should consider these factors in making choices of aminoglycosides to be used during intensive phase of treatment with second line anti-Tuberculous therapy.

Prothionamide susceptibility testing of Mycobacterium tuberculosis using the resazurin microtitre assay and the BACTECMGIT 960 system.

Resazurin microtitre assay (RMA) has been successfully used to detect minimal inhibitory concentrations (MICs) of both first-line and several second-line drugs in drug susceptibility testing (DST) of Mycobacterium tuberculosis (MTB). In this study, we firstly compared prothionamide (PTH) susceptibility testing of Mycobacterium tuberculosis (MTB) using resazurin microtitre assay (RMA) and MGIT. Overall, the sensitivity and specificity of RMA for detecting PTH susceptibility was 96.5% [95% confidence interval (CI): 91.7-100.0] and 93.2% (95% CI: 89.6-96.8) respectively. In addition, the median time to positivity was significantly shorter for RMA than for the automated MGIT 960 (RMA, 8 days [range: 8-8 days] vs MGIT, 10.1 days, [range: 5.0-13.0]; P < 0.01). Concordance rate for MICs between RMA and MGIT for PTH-resistant group was 64.3% (95% CI: 46.5-82.0), which was significantly lower than that of PTH-susceptible group (85.9%, 95% CI: 78.8-93.0; P= 0.01). In conclusion, our data demonstrated that RMA can be used as an acceptable alternative for determination of PTH susceptibility with shorter turn-around time. When compared with MGIT 960, RMA method was prone to produce higher MICs for PTH-resistant MTB strains.