Multidrug-resistant Tuberculosis Therapy Research Articles

Evaluation of the multiple doses thiozonide’s pharmacokinetics in patients diagnosed with pulmonary tuberculosis with multidrug-resistant or extensively drug-resistant <i>Mycobacterium tuberculosis</i>

Relevance. The increase in the number of cases of multidrug-resistant tuberculosis (MDR-TB) determines the relevance of the development of new anti-TB drugs (ATDs). Determining the pharmacokinetics of a drug in the context of MDR-TB therapy is an integral part of the study of the original drug. Objective. Evaluation of the pharmacokinetic properties of a new original drug, thiozonide, in patients with MDR-TB with multiple doses of the drug. Methods. Thiozonide was used in patients with a verified diagnosis of MDR-TB as part of a clinical trial according to protocol No. THIO22 "Multicenter 12-week doubleblind, randomized, placebo-controlled clinical trial on the selection of optimal dosages of the drug thiozonide, capsules (CJSC Pharm-Sintez") for against the background of standard anti-tuberculosis chemotherapy in patients diagnosed with pulmonary tuberculosis with multidrug-resistant or extensively drugresistant Mycobacterium tuberculosis” (permission of the Ministry of Health of the Russian Federation No. 661 dated 11/24/2014). Results. The pharmacokinetic characteristics of thiozonide were determined during its repeated use in patients diagnosed with pulmonary tuberculosis with multidrug-resistant or extensively drug-resistant mycobacterium tuberculosis, receiving standard anti-tuberculosis chemotherapy, by HPLC with mass spectrometric detection. The time to reach the maximum concentration T max of thiozonide with repeated administration at a dose of 200 mg, 400 mg and 600 mg was 4.21 ± 1.23 hours, 4.9 ± 1.08 and 5.29 ± 0.91, respectively; the half-life T1/2 for the same dosages of the drug was 7.84 ± 1.86, 7.56 ± 1.92 and 6.3 ± 2.12 hours, respectively. The maximum concentration of thiozonide after taking the drug thiozoinide by volunteers was Cmax was observed at the level of 1386.89 ± 533.68 ng / ml in the group taking 200 mg of thiozonide per day, 2684.48 ± 712.40 when taking the drug at a dosage of 400 mg and 5558, 99 ± 2143.81 – at a dosage of 600 mg. Conclusion. A linear dependence of the maximum concentration and the area under the pharmacokinetic curve on the dose taken and also the average concentration of thiozonide in the blood plasma of patients with pulmonary tuberculosis with multidrug resistance of the causative agent of the disease was revealed.

MHealth application for improving treatment outcomes for patients with multidrug-resistant tuberculosis in Vietnam: an economic evaluation protocol for the V-SMART trial

IntroductionThe Strengthen the Management of Multidrug-Resistant Tuberculosis in Vietnam (V-SMART) trial is a randomised controlled trial of using mobile health (mHealth) technologies to improve adherence to medications and management of...

The course of multidrug-resistant pulmonary tuberculosis in HIV-infected people with COVID-19

Aim. To analyze the course of multidrug-resistant tuberculosis (MDR-TB) in HIV-infected people, depending on the time to COVID-19 diagnosis, using the example of clinical cases from our own observation. Materials and methods. The article presents 3 clinical cases of our own observation of MDR-TB in HIV-infected persons depending on the time to COVID-19 diagnosis in patients, who were treated in the Pulmonary Tuberculosis Department No. 2, clinical base of the Department of Tuberculosis and Pulmonology ZSMU – Municipal non-profit enterprise “Zaporizhzhia Regional Phthisiopulmonology Clinical Medical and Diagnostic Center” of Zaporizhzhia Regional Council. Results. In clinical case 1, in an HIV-infected patient, MDR TB was detected after COVID-19. This clinical case has shown that after mild and treated COVID-19, even on the background of severe immunosuppression, but with AMBT and ART timely prescribed, MDR-TB in the patient had a favorable course with positive dynamics. In clinical case 2, in an HIV-infected patient, MDR-TB was detected concomitantly with COVID-19. The clinical case indicated that the patient received all 3 therapies for MDR-TB, HIV and COVID-19 in full and on time. In contrast to clinical case 1, the patient was diagnosed with a more severe process that required a longer period of treatment, although it was effective. In clinical case 3, an HIV-infected patient with COVID-19 was diagnosed after 5 months of MDR-TB treatment. Against this background, there was culture positivity. But after prescription of appropriate COVID-19 treatment against the background of AMBT and ART, positive dynamics and culture negativity were determined. All 3 patients completed antimycobacterial therapy of MDR-TB with results – recovery. Conclusions. Regardless of the HIV infection duration with underlying severe immunosuppression (<200 CD4 lymphocyte cells) and the time to COVID-19 diagnosis (before, during or after the diagnosis of MDR-TB) on the background of timely therapy of MDR-TB, HIV and COVID-19, positive results can be achieved while saving the lives of patients.

Autologous Cytokine-Induced Killer Cell Immunotherapy Enhances Chemotherapy Efficacy against Multidrug-Resistant Tuberculosis.

Objective Multidrug-resistant tuberculosis (MDR-TB) causes persistent infection and challenges tuberculosis control worldwide. T cell-mediated immunity plays a critical role in controlling Mycobacterium tuberculosis (Mtb) infection, and therefore, enhancing Mtb-specific T cell immune responses represents a promising therapeutic strategy against TB. Cytokine-induced killer (CIK) immunotherapy is based on autologous infusion of in vitro expanded bulk T cells, which include both pathogen-specific and nonspecific T cells from patient peripheral blood mononuclear cells (PBMC) into TB patients. Preclinical mouse studies have shown that the adoptive T cell therapy inhibited Mtb infection. However, the efficacy of CIK immunotherapy in the treatment of MDR-TB infection has not been evaluated in clinical trials. Methods We performed a retrospective study of MDR-TB patients who received CIK immunotherapy in combination with anti-TB chemotherapy and those who had standard chemotherapy. Results Our results showed that CIK immunotherapy in combination with anti-TB chemotherapy treatment increased the conversion rate of sputum smear and Mtb culture, alleviated symptoms, improved lesion absorption, and increased recovery. The kinetics of serology and immunology index monitoring data showed good safety profiles for the CIK treatment. Conclusion Our study has provided strong evidence that CIK immunotherapy in combination with anti-TB chemotherapy is beneficial for MDR-TB patients. A multicenter clinical trial is warranted to evaluate CIK as a new immune therapy for MDR-TB.

Spray-Dried Powder Formulation of Capreomycin Designed for Inhaled Tuberculosis Therapy.

Multi-drug-resistant tuberculosis (MDR-TB) is a huge public health problem. The treatment regimen of MDR-TB requires prolonged chemotherapy with multiple drugs including second-line anti-TB agents associated with severe adverse effects. Capreomycin, a polypeptide antibiotic, is the first choice of second-line anti-TB drugs in MDR-TB therapy. It requires repeated intramuscular or intravenous administration five times per week. Pulmonary drug delivery is non-invasive with the advantages of local targeting and reduced risk of systemic toxicity. In this study, inhaled dry powder formulation of capreomycin targeting the lung was developed using spray drying technique. Among the 16 formulations designed, the one containing 25% capreomycin (w/w) and spray-dried at an inlet temperature of 90 °C showed the best overall performance with the mass median aerodynamic diameter (MMAD) of 3.38 μm and a fine particle fraction (FPF) of around 65%. In the pharmacokinetic study in mice, drug concentration in the lungs was approximately 8-fold higher than the minimum inhibitory concentration (MIC) (1.25 to 2.5 µg/mL) for at least 24 h following intratracheal administration (20 mg/kg). Compared to intravenous injection, inhaled capreomycin showed significantly higher area under the curve, slower clearance and longer mean residence time in both the lungs and plasma.

Cost-Effectiveness of Bedaquiline in Multidrug Resistant Tuberculosis: A Review

Background: Multidrug Resistant Tuberculosis (MDR-TB) remains a burden on the healthcare system and public health. Evidence on cost and cost-effectiveness of MDR-TB treatment option is necessary in order to provide evidence-based recommendation for policymakers. The main therapy for MDR-TB consists of a combination of at least five types of anti-tuberculosis drugs, including second-line injections that have proven to be effective. Bedaquiline is a relatively new drug recommended by the World Health Organization (WHO) and European Medicines Agency (EMA) for the treatment of MDR-TB. Aims and Objectives: This study examines the cost-effectiveness of using regimens containing bedaquiline compared to those containing second-line injections. Methods: The design of this study is a literature review study. The following keywords used for the search were: “MDR-TB,” “cost effectiveness analysis of MDR-TB,” “cost effectiveness analysis of MDR-TB patients,” “WHO guideline for MDR-TB,” “Bedaquiline cost effectiveness,” and “kanamycin cost effectiveness.” The relevant references were derived from several databases, including PubMed, NCBI, and the Journal of Indonesian Health Economics. A total of 170 articles were obtained during the initial search, then extracted with inclusion criteria, namely articles assessing cost effectiveness, QALY, DALY, articles in English and Indonesian, and publications within the last 10 years. Results: The addition of bedaquiline in standard therapy showed favourable effect and safety due to faster culture conversion time and less incidence of side effects, based on the results of studies. The faster the culture conversion occurs and the less patients experiencing side effects, the faster their health improvement, which prospectively will reduce treatment costs and productivity loss. Conclusion: This is demonstrated by the results of cost-effectiveness analysis which shows that the replacement of the second-line injection regimen to bedaquiline, and the addition of bedaquiline to the standard regimen of therapy was assessed to be a more cost-effective option.

Population pharmacokinetics of oral levofloxacin in healthy volunteers and dosing optimization for multidrug-resistant tuberculosis therapy.

Levofloxacin is considered a key component of a multidrug-resistant tuberculosis (MDR-TB) regimen. However, there is considerable concern regarding the subtherapeutic concentrations of the currently used doses and the development of drug resistance. Therefore, this study aimed to describe the population pharmacokinetics (PPK) of oral levofloxacin in healthy volunteers and to evaluate the probability of target attainment (PTA) in an attempt to optimize the dosing regimens for MDR-TB therapy. Data of levofloxacin in healthy volunteers from a previous study were used to construct a PPK model. Monte Carlo simulations were performed to derive the PTAs of various regimens. A two-compartment model with linear elimination and transit absorption compartments best described the pharmacokinetics (PK) of levofloxacin. The estimated PK parameters (interindividual variability, %) were: apparent clearance 8.32Lh-1 (22.6%), apparent central volume of distribution 35.8L (45.2%), apparent peripheral volume of distribution 39.7L, intercompartmental clearance 40.6Lh-1 (43.8%), absorption rate constant 7.45h-1 (150%), mean absorption transit time 0.355h (52.4%), and total number of transit compartments 6.01 (131.9%). Monte Carlo simulations using levofloxacin 750-1000mg yielded a probability of achieving a target free area under the concentration-time curve/minimum inhibitory concentration (MIC) of 100 at greater than 90% for Mycobacterium tuberculosis with an MIC < 0.5mg L-1 , while a dose of 1500mg was required for strains with an MIC of 1mg L-1 . A higher dose of levofloxacin might be needed to treat tuberculosis. However, further studies on the efficacy and safety of this dose are needed to confirm our findings.

Acceptability of the Medication Event Reminder Monitor for Promoting Adherence to Multidrug-Resistant Tuberculosis Therapy in Two Indian Cities: Qualitative Study of Patients and Health Care Providers.

BackgroundPatients with multidrug-resistant tuberculosis (MDR-TB) face challenges adhering to medications, given that treatment is prolonged and has a high rate of adverse effects. The Medication Event Reminder Monitor (MERM) is a digital pillbox that provides pill-taking reminders and facilitates the remote monitoring of medication adherence.ObjectiveThis study aims to assess the MERM’s acceptability to patients and health care providers (HCPs) during pilot implementation in India’s public sector MDR-TB program.MethodsFrom October 2017 to September 2018, we conducted qualitative interviews with patients who were undergoing MDR-TB therapy and were being monitored with the MERM and HCPs in the government program in Chennai and Mumbai. Interview transcripts were independently coded by 2 researchers and analyzed to identify the emergent themes. We organized findings by using the Unified Theory of Acceptance and Use of Technology (UTAUT), which outlines 4 constructs that predict technology acceptance—performance expectancy, effort expectancy, social influence, and facilitating conditions.ResultsWe interviewed 65 patients with MDR-TB and 10 HCPs. In patient interviews, greater acceptance of the MERM was related to perceptions that the audible and visual reminders improved medication adherence and that remote monitoring reduced the frequency of clinic visits (performance expectancy), that the device’s organization and labeling of medications made it easier to take them correctly (effort expectancy), that the device facilitated positive family involvement in the patient’s care (social influences), and that remote monitoring made patients feel more cared for by the health system (facilitating conditions). Lower patient acceptance was related to problems with the durability of the MERM’s cardboard construction and difficulties with portability and storage because of its large size (effort expectancy), concerns regarding stigma and the disclosure of patients’ MDR-TB diagnoses (social influences), and the incorrect understanding of the MERM because of suboptimal counseling (facilitating conditions). In their interviews, HCPs reported that MERM implementation resulted in fewer in-person interactions with patients and thus allowed HCPs to dedicate more time to other tasks, which improved job satisfaction.ConclusionsSeveral features of the MERM support its acceptability among patients with MDR-TB and HCPs, and some barriers to patient use could be addressed by improving the design of the device. However, some barriers, such as disease-related stigma, are more difficult to modify and may limit use of the MERM among some patients with MDR-TB. Further research is needed to assess the accuracy of MERM for measuring adherence, its effectiveness for improving treatment outcomes, and patients’ sustained use of the device in larger scale implementation.

The Cholinergic System Contributes to the Immunopathological Progression of Experimental Pulmonary Tuberculosis.

The cholinergic system is present in both bacteria and mammals and regulates inflammation during bacterial respiratory infections through neuronal and non-neuronal production of acetylcholine (ACh) and its receptors. However, the presence of this system during the immunopathogenesis of pulmonary tuberculosis (TB) in vivo and in its causative agent Mycobacterium tuberculosis (Mtb) has not been studied. Therefore, we used an experimental model of progressive pulmonary TB in BALB/c mice to quantify pulmonary ACh using high-performance liquid chromatography during the course of the disease. In addition, we performed immunohistochemistry in lung tissue to determine the cellular expression of cholinergic system components, and then administered nicotinic receptor (nAChR) antagonists to validate their effect on lung bacterial burden, inflammation, and pro-inflammatory cytokines. Finally, we subjected Mtb cultures to colorimetric analysis to reveal the production of ACh and the effect of ACh and nAChR antagonists on Mtb growth. Our results show high concentrations of ACh and expression of its synthesizing enzyme choline acetyltransferase (ChAT) during early infection in lung epithelial cells and macrophages. During late progressive TB, lung ACh upregulation was even higher and coincided with ChAT and α7 nAChR subunit expression in immune cells. Moreover, the administration of nAChR antagonists increased pro-inflammatory cytokines, reduced bacillary loads and synergized with antibiotic therapy in multidrug resistant TB. Finally, in vitro studies revealed that the bacteria is capable of producing nanomolar concentrations of ACh in liquid culture. In addition, the administration of ACh and nicotinic antagonists to Mtb cultures induced or inhibited bacterial proliferation, respectively. These results suggest that Mtb possesses a cholinergic system and upregulates the lung non-neuronal cholinergic system, particularly during late progressive TB. The upregulation of the cholinergic system during infection could aid both bacterial growth and immunomodulation within the lung to favor disease progression. Furthermore, the therapeutic efficacy of modulating this system suggests that it could be a target for treating the disease.

Determinants of Delay in Diagnosis and Treatment in Multi Drug-Resistant Tuberculosis Patients in Health Facilities

Background: Multidrug-resistant tubercu­lo­sis (MDR-TB) is a serious threat to global TB control programs. According to WHO, there are 23,000 cases of TB multidrug-/rifampicin-resistant (MDR/RR-TB) in Indonesia. In 2017, there were 442,000 of TB cases. There were 8,600 - 15,000 MDR/RR-TB cases, of which 2.4% were new cases and 13% were previously treated TB cases. This study aims to determine the factors that influence the delay in diagnosis and treatment of MDR-TB patients. Subjects and Method: This study was a cross-sectional study conducted at Dr. Moe­wardi hospital, from Sep­tem­ber to October 2017, Surakarta, Central Java. A sample of 73 MDR-TB patients with disabilities on medical records was selected for this study. The depen­dent variables were delay in diagnosis and delay in therapy of MDR-TB cases. The inde­pendent variables were age, gender, distance to health facilities, and type of health facilities. Data were collected from medical records of MDR-TB patients who were treated from March 2012 to March 2017. Data were analyzed using the chi-square model. Results: Median delay in diagnosis = 4 days. Median treatment delay = 12 days. The average patient who had delayed MDR-TB therapy (≥4 days) was 44 years old (Mean= 44.19; SD= 12.64). Delay in MDR-TB diagnosis was not significantly associated with gender (OR= 0.53; 95% CI= 0.18 to 1.57; p= 0.264), distance to health facility (OR= 1.56; 95% CI= 0.58 to 4.21; p= 0.389), and type of health facility (OR= 0.60; 95% CI= 0.26 to 1.41; p= 0.983). The average of patient who had delayed MDR-TB therapy (≥12 days) was 41 years old (Mean= 41.39; SD= 12.69). Treatment delay was not significantly related to gender (OR= 0.45; 95% CI= 0.16 to 1.26; p= 0.137), distance to health facility (OR=1.44; 95% CI= 0.55 to 3.78; p= 0.466), and type of health facility (OR= 2.31; 95% CI= 1.03 to 5.21; p= 2.967). Conclusion: There was no statistically sig­nificant relationship between gender, dis­tance from the patient's home to health facilities, and type of health facility with the delay in diag­nosis and treatment of MDR-TB patients. Keyword s : diagnosis, treatment, TB-MDR Correspondence: Yusup Subagio Sutanto. Department of Pulmo­nology and Respiratory Medicine, Faculty of Medicine Universitas Sebelas Maret/ Dr. Moe­wardi Hospital, Surakarta. Jl. Kolonel Sutarto No.132, Jebres, Surakarta, Central Java 57126. Email: dr_yusupsubagio@yahoo.com. Mobile: 0811284165. Indonesian Journal of Medicine (2021), 06(01): 14-22 https://doi.org/10.26911/theijmed.2021.06.01.02

Mucosal Therapy of Multi-Drug Resistant Tuberculosis With IgA and Interferon-γ.

New evidence has been emerging that antibodies can be protective in various experimental models of tuberculosis. Here, we report on protection against multidrug-resistant Mycobacterium tuberculosis (MDR-TB) infection using a combination of the human monoclonal IgA 2E9 antibody against the alpha-crystallin (Acr, HspX) antigen and mouse interferon-gamma in mice transgenic for the human IgA receptor, CD89. The effect of the combined mucosal IgA and IFN-γ; treatment was strongest (50-fold reduction) when therapy was applied at the time of infection, but a statistically significant reduction of lung bacterial load was observed even when the therapy was initiated once the infection had already been established. The protection involving enhanced phagocytosis and then neutrophil mediated killing of infected cells was IgA isotype mediated, because treatment with an IgG version of 2E9 antibody was not effective in human IgG receptor CD64 transgenic mice. The Acr antigen specificity of IgA antibodies for protection in humans has been indicated by their elevated serum levels in latent tuberculosis unlike the lack of IgA antibodies against the virulence-associated MPT64 antigen. Our results represent the first evidence for potential translation of mucosal immunotherapy for the management of MDR-TB.

Comparison of the effectiveness of conservative and surgical methods for treatment of patients with multidrug-resistant tuberculosis

Objective — referring to literature data on the effectiveness of antibacterial therapy in multidrug-resistant tuberculosis (MDR TB) of lungs, to develop an algorithm for treating patients with such forms of tubercu-losis. It based on comparing the effectiveness of conservative antibiotic therapy and surgical treatment according to the methods, developed by the authors on the background of double collapse of the lungs.Materials and methods. Under the supervision of the authors during 2011—2017 there were two groups of patients. The comparison group included 1136 patients with multidrug resistant pulmonary tuberculosis treated only with antimycobacterial drugs. The main group consisted of 107 patients with multidrug resistant pulmonary tuberculosis, who were operated on according to the methods developed in the TB clinic of Sumy State University. The proposed technique is based on the double collapse of the operated lung. Observation in the remote period was conducted during 7 years.Results and discussion. The treatment of patients in the main group was more frequent than the comparison groups in 2.2 times. Among patients in the comparison group during the observation period, 20 % of patients died, in the main group — 3.7 %, which is less 5.4 times (p &lt; 0.05); unsuccessful treatment with interrupted in the comparison group was fixed at 32.7 %, in the main group — 7.5 %, which is less 4.4 times (p &lt; 0.05).Conclusions. Double collapse of the lungs is a reliable alternative to antibiotic therapy in the proposed methods of surgical treatment of MDR TB. Surgical treatment of patients with limited prevalence of MRI can be applied by the type of resection, and in common processes — by the type of extrapleural thoraco-plasty.Surgery for multidrug-resistant pulmonary tuberculosis, according to the proposed algorithm, contributes to a positive effect (negative smear conversion, closure of decay cavities), which exceeds that in conservative treatment by 1.9 times. The unsuccessful effect at conservative therapy occurs more often than at surgical intervention in 3.5 times, and dies of such patients more in 5.4 times.

The Impact of Concurrent Antiretroviral Therapy and MDR-TB Treatment on Adverse Events.

South Africa has among the highest incidence of multidrug-resistant tuberculosis (MDR-TB) and more than 70% of patients are HIV co-infected. MDR-TB treatment is associated with frequent adverse events (AEs). Although guidelines recommend concurrent treatment of MDR-TB and HIV, safety data on concurrent therapy are limited. We conducted a prospective observational study of MDR-TB patients with and without HIV-coinfection in South Africa between 2011 and 2015. Participants received standardized MDR-TB and HIV regimens. Participants were followed monthly for the duration of MDR-TB therapy and screened for clinical and laboratory AEs. Audiometry was performed monthly during the intensive phase; color discrimination testing was performed every 2 months. We enrolled 150 HIV-infected and 56 HIV-uninfected participants. Nearly all experienced at least one clinical (93%) or laboratory (96%) AE. The most common clinical AEs were peripheral neuropathy (50%) and difficulty sleeping (48%); the most common laboratory AEs were hypokalemia (47%) and decreased creatinine clearance (46%). Among 19 clinical and lab AEs examined, there were no differences by HIV status, except for diarrhea (27% HIV-infected vs. 13% HIV-uninfected, P = 0.03). Hearing loss was experienced by 72% of participants (8% severe loss). Fourteen percent experienced color discrimination loss (4% severe loss). There were no differences in frequency or severity of hearing or vision loss by HIV status. AEs were common, but not more frequent or severe among MDR-TB/HIV co-infected participants receiving concurrent antiretroviral therapy. Given the favorable treatment outcomes associated with concurrent treatment, antiretroviral therapy initiation should not be delayed in MDR-TB patients with HIV-coinfection.

Abandonment of therapy in multidrug-resistant tuberculosis: Associated factors in a region with a high burden of the disease in Perú

Introduction: In the context of multidrug-resistant tuberculosis, abandonment of therapy represents a serious public health problem that affects the quality of life of patients, families, and communities. Managing this phenomenon places a burden on health systems since it causes free sources of transmission in the community, thereby increasing prevalence and mortality. Thus, there is a need to study factors associated with this problem. Objective: This study sought to identify risk factors associated with the abandonment of therapy by patients with multidrug-resistant tuberculosis in the Peruvian region of Callao. Materials and methods: We conducted an analytical case-control study (cases=80; controls=180) in patients under treatment from January 1st, 2010, to December 31, 2012. Risk factors were identified using logistic regression; odds ratios (OR) and 95% confidence intervals (CI) were calculated. Results: The multivariate analysis identified the following risk factors: Being unaware of the disease (OR=23.10; 95% CI 3.6-36.79; p=0.002); not believing in healing (OR=117.34; 95% CI 13.57-124.6; p=0.000); not having social support (OR=19.16; 95% CI 1.32-27.77; p=0.030); considering the hours of attention to be inadequate (OR=78.13; 95% CI 4.84-125.97; p=0.002), and not receiving laboratory reports (OR=46.13; 95% CI 2.85-74.77; p=0.007). Conclusion: Health services must focus on the early detection of conditions that may represent risk factors to proactively implement effective, rapid and high-impact interventions.

Tryptophan Fluorescence Quenching in β-Lactam-Interacting Proteins Is Modulated by the Structure of Intermediates and Final Products of the Acylation Reaction.

In most bacteria, β-lactam antibiotics inhibit the last cross-linking step of peptidoglycan synthesis by acylation of the active-site Ser of d,d-transpeptidases belonging to the penicillin-binding protein (PBP) family. In mycobacteria, cross-linking is mainly ensured by l,d-transpeptidases (LDTs), which are promising targets for the development of β-lactam-based therapies for multidrug-resistant tuberculosis. For this purpose, fluorescence spectroscopy is used to investigate the efficacy of LDT inactivation by β-lactams but the basis for fluorescence quenching during enzyme acylation remains unknown. In contrast to what has been reported for PBPs, we show here using a model l,d-transpeptidase (Ldtfm) that fluorescence quenching of Trp residues does not depend upon direct hydrophobic interaction between Trp residues and β-lactams. Rather, Trp fluorescence was quenched by the drug covalently bound to the active-site Cys residue of Ldtfm. Fluorescence quenching was not quantitatively determined by the size of the drug and was not specific of the thioester link connecting the β-lactam carbonyl to the catalytic Cys as quenching was also observed for acylation of the active-site Ser of β-lactamase BlaC from M. tuberculosis. Fluorescence quenching was extensive for reaction intermediates containing an amine anion and for acylenzymes containing an imine stabilized by mesomeric effect, but not for acylenzymes containing a protonated β-lactam nitrogen. Together, these results indicate that the extent of fluorescence quenching is determined by the status of the β-lactam nitrogen. Thus, fluorescence kinetics can provide information not only on the efficacy of enzyme inactivation but also on the structure of the covalent adducts responsible for enzyme inactivation.

RpoB Mutations Causing Discordant Rifampicin Susceptibility in Mycobacterium tuberculosis: Retrospective Analysis of Prevalence, Phenotypic, Genotypic, and Treatment Outcomes.

BackgroundDiscordant genotypic/phenotypic rifampicin susceptibility testing in Mycobacterium tuberculosis is a significant challenge, yet there are limited data on its prevalence and how best to manage such patients. Whether to treat isolates with rpoB mutations not conferring phenotypic resistance as susceptible or multidrug-resistant tuberculosis (MDR-TB) is unknown. We describe phenotypic and genotypic characteristics of discordant isolates and clinical characteristics and treatment outcomes of affected patients in KwaZulu-Natal, South Africa.MethodsWe analyzed clinical isolates showing rifampicin resistance on GenoType MTBDRplus while susceptible on 1% agar proportion method. We measured rifampicin minimum inhibitory concentrations (MICs) using Middlebrook 7H10 agar dilution and BACTEC MGIT 960. Sensititre MYCOTB plates were used for drug-susceptibility testing, and rpoB gene sequencing was performed on all isolates. Local MDR-TB program data were reviewed for clinical information and patient outcomes.ResultsDiscordant isolates constituted 4.6% (60) of 1302 rifampicin-resistant cases over the study period. Of these, 62% remained susceptible to isoniazid and 98% remained susceptible to rifabutin. Rifampicin MICs were close to the critical concentration of 1 µg/mL (0.5–2 µg/mL) for 83% of isolates. The most frequent rpoB mutations were Q513P (25.3%), D516V (19.2%), and D516Y (13.3%). Whereas 70% were human immunodeficiency virus infected, the mean CD4 count was 289 cells/mm3 and 87% were receiving antiretroviral therapy. Standard therapy for MDR-TB was used and 53% achieved successful treatment outcomes.ConclusionsRifampicin-discordant TB is not uncommon and sequencing is required to confirm results. The high susceptibility to rifabutin and isoniazid and poor treatment outcomes with the current regimen suggest a potential utility for rifabutin-based therapy.

Expert Consensus on Short-Course Therapy of Multi-drug Resistant Tuberculosis

为提高我国广大结核病防治工作者对耐多药结核病（MDR-TB）的诊治能力，更好地掌握和实施不同MDR-TB的短程化疗方案，中华医学会结核病学分会制定了"耐多药结核病短程治疗中国专家共识"。该共识根据近年来国内外MDR-TB短程治疗的研究状况，推荐了2套MDR-TB短程化疗方案，并提出了其适应证、禁忌证和排除标准，介绍了治疗转归的判断标准，同时对MDR-TB短程治疗过程中所遇到的相关问题进行了解答，并强调了短程治疗的有关注意事项。.

Trends in C-Reactive Protein, D-Dimer, and Fibrinogen during Therapy for HIV-Associated Multidrug-Resistant Tuberculosis.

HIV-positive adults on treatment for multi drug-resistant tuberculosis (MDR-TB) experience high mortality. Biomarkers of HIV/MDR-TB treatment response may enable earlier treatment modifications that improve outcomes. To determine whether changes in C-reactive protein (CRP), D-dimer, and fibrinogen were associated with treatment outcome among those with HIV/MDR-TB coinfection, we studied 20 HIV-positive participants for the first 16 weeks of MDR-TB therapy. Serum CRP, fibrinogen, and D-dimer were measured at baseline and serially while on treatment. At baseline, all biomarkers were elevated above normal levels, with median CRP 86.15 mg/L (interquartile range [IQR] 29.25-149.32), D-dimer 0.85 µg/mL (IQR 0.34-1.80), and fibrinogen 4.11 g/L (IQR 3.75-6.31). C-reactive protein decreased significantly within 10 days of treatment initiation and fibrinogen within 28 days; D-dimer did not change significantly. Five (25%) participants died after a median of 32 days. Older age (median age of 38y among survivors and 54y among deceased, P = 0.008) and higher baseline fibrinogen (3.86 g/L among survivors and 6.37 g/L among deceased, P = 0.02) were significantly associated with death. After adjusting for other measured variables, higher CRP concentrations at the beginning of each measurement interval were significantly associated with a higher risk of death during that interval. Trends in fibrinogen and CRP may be useful for evaluating early response to treatment among individuals with HIV/MDR-TB coinfection.

Occurrence of adverse events in patient receiving community-based therapy for multidrug-resistant tuberculosis in Pakistan.

Pakistan ranks 4th among 22 multidrug resistant tuberculosis (MDR-TB) high burden countries. The increasing rate of MDR-TB in Pakistan underscores the importance of effective treatment programs of drug-resistant TB. Clinical management of MDR-TB requires prolonged multidrug regimens that often cause adverse events (AEs). This retrospective case series study include all patients who were enrolled for MDR-TB treatment during January 2014 till April 2015 at Programmatic Management of Drug Resistant TB (PMDT) unit at tertiary care hospital, Lady Reading Hospital (LRH) Peshawar Pakistan. In this study we sought to ascertain the occurrence of treatment related adverse events and factors associated with these events. Here we also examined the frequency of and reasons for changing drug regimens. We further sought to determine whether the occurrence of adverse events negatively impacts the treatment outcome and management of adverse effects without requiring the discontinuation of MDR-TB therapy. At the time of analysis final outcomes of all 200 enrolled patients exist. Among these 52.5% were females and (81.5%) were aged ≤ 44 years. Among study cases 155 (77.2%) experienced at least one adverse event during treatment. The most commonly reported events were psychiatric issues (70%) whereas the less common was skin rashes (7.5%). A change in drug dose due to adverse events occurred in 16.5% cases, while 13.5% cases had at least one drug discontinued temporarily. Younger age and lung cavities at baseline were positive association with occurrence of adverse events. Association was also found between adverse events and treatment outcomes (OR 0.480, 0.236-0.978, p= 0.041). Adverse events were prevalent among MDR-TB patients treated at PMDT-LRH Peshawar. All patients who were younger aged and cavitory lungs should be closely monitored for occurrence of adverse events.

Incorporating social justice and stigma in cost-effectiveness analysis: drug-resistant tuberculosis treatment.

Novel therapies for multidrug-resistant tuberculosis (MDR-TB) are likely to be expensive. The cost of novel drugs (e.g., bedaquiline, delamanid) may be so prohibitively high that a traditional cost-effectiveness analysis (CEA) would rate regimens containing these drugs as not cost-effective. Traditional CEA may not appropriately account for considerations of social justice, and may put the most disadvantaged populations at greater risk. Using the example of novel drug regimens for MDR-TB, we propose a novel methodology, 'justice-enhanced CEA', and demonstrate how such an approach can simultaneously assess social justice impacts alongside traditional cost-effectiveness ratios. Justice-enhanced CEA, as we envision it, is performed in three steps: 1) systematic data collection about patients' lived experiences, 2) use of empirical findings to inform social justice assessments, and 3) incorporation of data-informed social justice assessments into a decision analytic framework that includes traditional CEA. These components are organized around a core framework of social justice developed by Bailey et al. to compare impacts on disadvantage not otherwise captured by CEA. Formal social justice assessments can produce three composite levels: 'expected not to worsen…', 'may worsen…', and 'expected to worsen clustering of disadvantage'. Levels of social justice impact would be assessed for each major type of outcome under each policy scenario compared. Social justice assessments are then overlaid side-by-side with cost-effectiveness assessments corresponding to each branch pathway on the decision tree. In conclusion, we present a 'justice-enhanced' framework that enables the incorporation of social justice concerns into traditional CEA for the evaluation of new regimens for MDR-TB.