Assessing potential drug-drug interactions between clofazimine and other frequently used agents to treat drug-resistant tuberculosis

Clofazimine is included in drug regimens to treat rifampicin/drug-resistant tuberculosis (DR-TB), but there is little information about its interaction with other drugs in DR-TB regimens. We evaluated the pharmacokinetic interaction between clofazimine and isoniazid, linezolid, levofloxacin, and cycloserine, dosed as terizidone. Newly diagnosed adults with DR-TB at Klerksdorp/Tshepong Hospital, South Africa, were started on the then-standard treatment with clofazimine temporarily excluded for the initial 2 weeks. Pharmacokinetic sampling was done immediately before and 3 weeks after starting clofazimine, and drug concentrations were determined using validated liquid chromatography-tandem mass spectrometry assays. The data were interpreted with population pharmacokinetics in NONMEM v7.5.1 to explore the impact of clofazimine co-administration and other relevant covariates on the pharmacokinetics of isoniazid, linezolid, levofloxacin, and cycloserine. Clofazimine, isoniazid, linezolid, levofloxacin, and cycloserine data were available for 16, 27, 21, 21, and 6 participants, respectively. The median age and weight for the full cohort were 39 years and 52 kg, respectively. Clofazimine exposures were in the expected range, and its addition to the regimen did not significantly affect the pharmacokinetics of the other drugs except levofloxacin, for which it caused a 15% reduction in clearance. A posteriori power size calculations predicted that our sample sizes had 97%, 90%, and 87% power at P < 0.05 to detect a 30% change in clearance of isoniazid, linezolid, and cycloserine, respectively. Although clofazimine increased the area under the curve of levofloxacin by 19%, this is unlikely to be of great clinical significance, and the lack of interaction with other drugs tested is reassuring.

Patterns and profiles of drug resistance-conferring mutations in Mycobacterium tuberculosis genotypes isolated from tuberculosis-suspected attendees of spiritual holy water sites in Northwest Ethiopia

Purpose

This study examined the patterns and frequency of genetic changes responsible for resistance to first-line (rifampicin and isoniazid), fluoroquinolones, and second-line injectable drugs in drug-resistant Mycobacterium tuberculosis (MTB) isolated from culture-positive pulmonary tuberculosis (PTB) symptomatic attendees of spiritual holy water sites (HWSs) in the Amhara region.

Patients and methods

From June 2019 to March 2020, a cross-sectional study was carried out. A total of 122 culture-positive MTB isolates from PTB-suspected attendees of HWSs in the Amhara region were evaluated for their drug resistance profiles, and characterized gene mutations conferring resistance to rifampicin (RIF), isoniazid (INH), fluoroquinolones (FLQs), and second-line injectable drugs (SLIDs) using GenoType®MTBDRplus VER2.0 and GenoType®MTBDRsl VER2.0. Drug-resistant MTB isolates were Spoligotyped following the manufacturer's protocol.

Results

Genetic changes (mutations) responsible for resistance to RIF, INH, and FLQs were identified in 15/122 (12.3%), 20/122 (16.4%), and 5/20 (25%) of MTB isolates, respectively. In RIF-resistant, rpoB/Ser531Lue (n = 12, 80%) was most frequent followed by His526Tyr (6.7%). Amongst INH-resistant isolates, katG/Ser315Thr1 (n = 19, 95%) was the most frequent. Of 15 MDR-TB, the majority (n = 12, 80%) isolates had mutations at both rpoB/Ser531Leu and katG/Ser315Thr1. All 20 INH and/or RIF-resistant isolates were tested with the MTBDRsl VER 2.0, yielding 5 FLQs-resistant isolates with gene mutations at rpoB/Ser531Lue, katG/Ser315Thr1, and gyrA/Asp94Ala genes. Of 20 Spoligotyped drug-resistant MTB isolates, the majority (n = 11, 55%) and 6 (30%) were SIT149/T3-ETH and SIT21/CAS1-Kili sublineages, respectively; and they were any INH-resistant (mono-hetero/multi-). Of 15 RIF-resistant (RR/MDR-TB) isolates, 7 were SIT149/T3-ETH, while 6 were SIT21/CAS1-Kili sublineages. FLQ resistance was detected in four SIT21/CAS1-Kili lineages.

Conclusion

In the current study, the most common gene mutations responsible for resistance to INH, RIF, and FLQs were identified. SIT149/T3-ETH and SIT21/CAS1-Kili constitute the majority of drug-resistant TB (DR-TB) isolates. To further understand the complete spectrum of genetic changes/mutations and related genotypes, a sequencing technology is warranted.

Discovery, Synthesis, and Optimization of 1,2,4-Triazolyl Pyridines Targeting Mycobacterium tuberculosis

The rise in multidrug resistant tuberculosis cases underscores the urgent need to develop new treatment strategies for tuberculosis. Herein, we report the discovery and synthesis of a new series of compounds containing a 3-thio-1,2,4-triazole moiety that show inhibition of Mycobacterium tuberculosis (Mtb) growth and survival. Structure-activity relationship studies led us to identify several potent analogs displaying low micromolar to nanomolar inhibitory activity, specifically against Mtb. The potent analogs demonstrated no cytotoxicity in mammalian cells at over 100 times the effective concentration required in Mtb and were bactericidal against Mtb during infection of macrophages. In the exploratory ADME investigations, we observed suboptimal ADME characteristics, which prompted us to identify potential metabolic liabilities for further optimization. Our preliminary investigations into the mechanism of action suggest that this series is not engaging the promiscuous targets that arise from many phenotypic screens. We selected for resistant mutants with the nanomolar potent nitro-containing compound 20 and identified resistant isolates with mutations in genes required for coenzyme F420 biosynthesis and the nitroreductase Ddn. This suggests that the aromatic nitro-1,2,4-triazolyl pyridines are activated by F420-dependent Ddn activity, similar to the nitro-containing TB drug pretomanid. We were able to circumvent the requirement for F420-dependent Ddn activity using compounds that contained non-nitro groups, identifying a key feature to be modified to avoid this predominant resistance mechanism. These studies provide the foundation for the development of a new class of 1,2,4-triazole compounds for the treatment of tuberculosis.

Rifampin Mono-Resistant Tuberculosis in New York City, 2010-2021: A Retrospective Case Series

Background

Although relatively rare, rifampin mono-resistant tuberculosis (RMR TB) poses important challenges to effective TB treatment and control. Information on the burden of RMR TB and treatment outcomes is needed to inform diagnosis and management.

Methods

Standardized variables were collected from the New York City (NYC) tuberculosis surveillance system for patients treated for RMR TB in NYC during 2010-2021.

Results

Of 7097 TB cases reported in 2010-2021, 31 (<1%) were treated clinically as RMR TB. Five (16%) of these patients had HIV. Seventeen patients (55%) had TB that was rifampin-resistant by both molecular and phenotypic drug susceptibility testing; 2 (6%) had rifampin resistance by phenotypic tests, and molecular tests were not done; and 12 (39%) were identified based only on molecular tests. Among these 12, 7 were rifampin-sensitive by phenotypic tests, and phenotypic testing could not be done for the other 5. Ten of the 31 (32%) were diagnosed in 2010-2015; the other 21 (including 10/12 diagnosed by molecular tests alone) were diagnosed in 2016-2021. Of the 31 patients, 21 (68%) completed treatment (median treatment duration of 18 months). Although the interval between tuberculosis treatment initiation and change to a non-rifamycin-containing regimen decreased significantly during the study period, the overall duration of treatment did not decrease significantly between 2010 and 2021.

Conclusions

Molecular drug susceptibility tests identified cases of RMR TB that were not detected by phenotypic testing and helped enable timely adjustment of tuberculosis treatment regimens. Short-course regimens are needed to reduce duration of treatment for RMR TB.

The Detection of Mutations and Genotyping of Drug-Resistant Mycobacterium tuberculosis Strains Isolated from Patients in the Rural Eastern Cape Province

Drug-resistant tuberculosis (DR-TB) is still a major public health concern in South Africa. Mutations in M. tuberculosis can cause varying levels of phenotypic resistance to anti-TB medications. There have been no prior studies on gene mutations and the genotyping of DR-TB in the rural Eastern Cape Province; hence, we aimed to identify DR-TB mutations, genetic diversity, and allocated lineages among patients in this area. Using Xpert^® MTB/RIF, we assessed the rifampin resistance of sputum samples collected from 1157 patients suspected of having tuberculosis. GenoType MTBDR plus VER 2.0 was used for the detection of mutations causing resistance to anti-TB medications. The next step was to spoligotype 441 isolates. The most prevalent rifampin resistance-conferring mutations were in rpoB codon S531L in INH-resistant strains; the katG gene at codon S315TB and the inhA gene at codon C-15TB had the most mutations; 54.5% and 24.7%, respectively. In addition, 24.6% of strains showed mutations in both the rpoB and inhA genes, while 69.9% of strains showed mutations in both the katG and rpoB genes. Heteroresistance was seen in 17.9% of all cases in the study. According to spoligotyping analysis, Beijing families predominated. Investigation of the evolutionary lineages of M. tuberculosis isolates can be carried out using the information provided by the study's diversity of mutations. In locations wherein these mutations have been discovered, decision-making regarding the standardization of treatment regimens or individualized treatment may be aided by the detection frequency of rpoB, katG, and inhA mutations in various study areas.

Gender and Drug-Resistant Tuberculosis in Nigeria

We conducted a retrospective study of 2555 DR-TB patients admitted to treatment between 2010 and 2016 in six geopolitical zones in Nigeria. We characterized the gender distribution of DR-TB cases and the association between demographics and clinical data, such as age, treatment category, number of previous TB treatment cycles, and geopolitical zone, with gender. The independent effects of being a male or female DR-TB patient were determined using bivariate and multivariate analyzes with statistical significance of p < 0.05 and a 95% confidence interval. Records from a total of 2555 DR-TB patients were examined for the study. A majority were male (66.9%), largest age-group was 30-39 years old (35.8%), most had MDR-TB (61.4%), were HIV-negative (76.6%), and previously treated for TB (77.1%). The southwest treatment zone had the highest proportion of DR-TB patients (36.9%), and most DR-TB diagnoses occurred in 2016 (36.9%). On bivariate analysis, age, HIV status, treatment zone, and clinical patient group in DR-TB were significantly associated with male gender. On multivariate analysis, males aged 20-29 years (AOR: 0.19, 95% CI: 0.33-0.59, p = 0.001) and HIV-positive males (AOR: 0.44, 95% CI: 0.33-0.59, p = 0.001) had lower likelihood of MDR-TB as males in the south-south treatment zone (AOR: 1.88, 95% CI: 1.23-2.85, p = 0.03), and being male and aged ≥60 years (AOR: 2.19, 95% CI: 1.05-4.54, p = 0.036) increased the probability of DR-TB. The older male population from south-southern Nigeria and women of childbearing age had lower incidence of DR-TB than men of the same age. Tailored interventions to reduce HIV and DR-TB prevalence in the general population, particularly among women of childbearing potential, and treatment support for young and older men are relevant strategies to reduce DR-TB in Nigeria.

The Determinants of Treatment Delay and Quality of Life among the Newly Diagnosed Pulmonary Tuberculosis Patients in Northeastern Thailand: A Cross-Sectional Study

BACKGROUND/OBJECTIVE

Delays in diagnosing pulmonary tuberculosis (PTB) are linked to financial difficulties, employment limits, dependency, and symptomatic treatment, all of which have an impact on the patient's quality of life. Patients' psychological, economic, and social well-being are also harmed by delayed therapy. The goal of this research was to evaluate sociodemographic characteristics and quality of life in new pulmonary TB patients and determine the associated factors with delayed TB diagnosis.

METHODS

This was a cross-sectional study conducted in the Choke Chai Community Hospital, in Northeastern Thailand between 2016 and 2018. The information related to the patient's medical history and laboratory tests were gathered from 332 newly diagnosed tuberculosis patients at the hospital's tuberculosis clinic; of those 15 died and were excluded from the final analysis. Data were analyzed using SPSS version 17.0.

RESULTS

The cases included new cases (94%) and those returning to receive treatment after discontinuation of treatment, relapse, or recurrence of the disease (6%). The sample consisted of 68.7% males and 31.3% females. The average age was 52.7 years (S.D = 15.64). The majority of patients were married (60.5%), employed (68.6%), received a low income (66.6%), had a history of chronic diseases (73%), drank alcohol (31.7%), and smoked (85.7%). Approximately half of PTB experienced treatment delay and had a low quality of life (QoL) (46.6%). The treatment delay was associated with age > 50 years (p <0.05), low self-care (p <0.05), long distance to facility (p <0.05), unavailable caretaker to treat (p <0.05), no caregiver in family (p <0.05), high expenses (p <0.01), and lack of information (p <0.001).

CONCLUSION

It appeared that the patients' health-related quality of life could be deteriorated as a result of pulmonary tuberculosis. Treatment delays can be significantly reduced by changing the understanding of family caregivers, increasing awareness, providing adequate support for patients, and guaranteeing early diagnosis and treatment by implementing an efficient surveillance system.

Drug-Resistant Tuberculosis Treatment Outcomes among Children and Adolescents in Karachi, Pakistan

BACKGROUND

Significant data gaps exist for children and adolescents with drug-resistant (DR) TB, particularly from high TB incidence settings. This report provides a descriptive analysis of programmatic outcomes among children and adolescents treated for DR-TB in Pakistan.

METHODS

We extracted programmatic data from January 2014 to December 2019 from a tertiary care hospital with specialised child and adolescent DR-TB services. A physician assessed all children and adolescents (0-19 years) with presumptive DR-TB, including details of exposure to DR-TB, medical history, radiology, and laboratory results. All patients received treatment as per national DR-TB management guidelines based on WHO recommendations.

RESULTS

There were 262 treatment episodes for 247 patients enrolled during the study period. The median age of the cohort was 16 years (IQR: 13-18 years) with 16 (6.1%) children being under 5 years; 237 (90.5%) patients had pulmonary TB. The majority of the patients (194 or 74.1%) experienced a favourable treatment outcome and 26 (9.9%) died while on treatment. Female patients (78.5%) were more likely to experience favourable outcomes compared to males (64.7%; chi-sqr p-value = 0.02).

CONCLUSIONS

We found high rates of favourable outcomes in children and adolescents treated for DR-TB. However, there were few young children in our cohort and there was a considerable gender gap that enhanced efforts to diagnose DR-TB in young children and to elucidate and mitigate the reasons for poor outcomes amongst males.

Chest X-ray Features in Drug-Resistant Tuberculosis Patients in Nigeria; a Retrospective Record Review

Chest X-ray (CXR) characteristics of patients with drug-resistant tuberculosis (DR-TB) depend on a variety of factors, and therefore, identifying the influence of these factors on the appearance of DR-TB in chest X-rays can help physicians improve diagnosis and clinical suspicion. Our aim was to describe the CXR presentation of patients with DR-TB and its association with clinical and demographic factors. A retrospective analysis of the CXRs of DR-TB patients in Nigeria between 2010 and 2016 was performed, reviewing features of chest radiographs, such as cavitation, opacity and effusion, infiltration and lung destruction. The association of these abnormal CXR findings with clinical and demographic characteristics was evaluated using bivariate and multivariate models, and a p-value < 0.05 was considered statistically significant with a 95% confidence interval. A total of 2555 DR-TB patients were studied, the majority (66.9%) were male, aged 29−38 years (36.8%), previously treated (77%), from the South West treatment zone (43.5%), HIV negative (76.7%) and bacteriologically diagnosed (89%). X-ray findings were abnormal in 97% of the participants, with cavitation being the most common (41.5%). Cavitation, effusion, fibrosis, and infiltration were higher in patients presenting in the South West zone and in those previously treated for DR-TB, while lung destruction was significantly higher in patients who are from the South South zone, and in those previously treated for DR-TB. Patients from the South East zone (AOR: 6.667, 95% CI: 1.383−32.138, p = 0.018), the North East zone (AOR: 6.667, 95% CI: 1.179−37.682, p = 0.032) and the North West zone (AOR: 6.30, 95% CI: 1.332−29.787, p = 0.020) had a significantly increased likelihood of abnormal chest X-ray findings, and prior TB treatment predisposed the patient to an increased likelihood of abnormal chest X-ray findings compared to new patients (AOR: 8.256, 95% CI: 3.718−18.330, p = 0.001). The finding of a significantly higher incidence of cavities, effusions and fibrosis in DR-TB patients previously treated could indicate late detection or presentation with advanced DR-TB disease, which may require a more individualized regimen or surgical intervention.

Xpert MTB/RIF Use Is Associated With Earlier Treatment Initiation and Culture Conversion Among Patients With Sputum Smear-Negative Multidrug-Resistant Tuberculosis

Background

Although rapid molecular diagnostic tests for tuberculosis (TB) have decreased detection time of Mycobacterium tuberculosis and drug resistance, whether their use improves clinical care and outcomes is uncertain. To address these knowledge gaps, we evaluated whether use of the Xpert MTB/RIF assay impacts treatment and clinical outcome metrics among patients treated for sputum smear-negative multidrug-resistant (MDR)-TB.

Methods

We conducted a retrospective cohort study of adult patients initiating treatment for sputum smear-negative MDR-TB at the National Center for Tuberculosis and Lung Diseases in Tbilisi, Georgia from 2011 to 2016. The Xpert MTB/RIF was introduced in Georgia in 2010 and implemented into programmatic use in 2014. Exposure was availability of an Xpert result at time of diagnosis. Time to second-line treatment initiation, sputum culture conversion, and end-of-treatment outcomes were determined. Time to event was compared using a Cox proportional hazards model.

Results

Among 151 patients treated for sputum smear-negative MDR-TB (96% culture positive), the Xpert was utilized in the clinical management of 78 (52%) patients and not used in 73 (48%). An adjusted analysis controlling for potential confounders found that patients in the Xpert group had shorter median time to second-line treatment (13 vs 56 days; adjusted hazard ratio [aHR], 10.21; P < .0001) and culture conversion (61 vs 93 days; aHR, 1.93; P < .001). There was no difference in treatment outcomes.

Conclusions

Use of the Xpert in the management of sputum smear-negative MDR-TB decreases time to second-line therapy and sputum culture conversion, providing evidence of its clinical impact and supporting its programmatic utility.

Trends, Characteristics and Treatment Outcomes of Patients with Drug-Resistant Tuberculosis in Uzbekistan: 2013-2018

Uzbekistan has a high burden of drug-resistant tuberculosis (TB). Although conventional treatment for multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) has been available since 2013, there has been no systematic documentation about its use and effectiveness. We therefore documented at national level the trends, characteristics, and outcomes of patients with drug-resistant TB enrolled for treatment from 2013–2018 and assessed risk factors for unfavorable treatment outcomes (death, failure, loss to follow-up, treatment continuation, change to XDR-TB regimen) in patients treated in Tashkent city from 2016–2017. This was a cohort study using secondary aggregate and individual patient data. Between 2013 and 2018, MDR-TB numbers were stable between 2347 and 2653 per annum, while XDR-TB numbers increased from 33 to 433 per annum. At national level, treatment success (cured and treatment completed) for MDR-TB decreased annually from 63% to 57%, while treatment success for XDR-TB increased annually from 24% to 57%. On multivariable analysis, risk factors for unfavorable outcomes, death, and loss to follow-up in drug-resistant TB patients treated in Tashkent city included XDR-TB, male sex, increasing age, previous TB treatment, alcohol abuse, and associated comorbidities (cardiovascular and liver disease, diabetes, and HIV/AIDS). Reasons for these findings and programmatic implications are discussed.

Acquired Resistance to Isoniazid During Isoniazid Monotherapy in a Subject with Latent Infection Following Household Rifampicin-Resistant Tuberculosis Contact: A Case Report

Appropriate treatment is the key element in eliminating tuberculosis (TB), and requires prompt diagnosis. We presented a case of a household contact of rifampicin-resistant TB revealing reactive IFN-gamma release assay with unsuspicious clinical and radiologic examinations. She was diagnosed with latent tuberculosis infection (LTBI) and treated with isoniazid monotherapy. On the ninth month, she developed a progressive cough and was found to harbor active TB disease with added resistance to isoniazid. An individualized anti-TB regimen consisting of moxifloxacin, kanamycin, prothionamide, ethambutol, and pyrazinamide was prescribed for 20 months, leading to sputum culture conversion and improvement of the reported symptom. No recurrence was observed on one-year follow-up. Assuming high compliance to therapy, we propose that the patient may have been underdiagnosed and received sub-optimal treatment leading to acquired-drug resistance. Conventional diagnosis methods based on immunological assay and radiographical findings may be insufficient to distinguish the incipient and subclinical states of TB from LTBI.

Weak spots inhibition in the Mycobacterium tuberculosis antigen 85C target for antitubercular drug design through selective irreversible covalent inhibitor-SER124

Mycobacterium tuberculosis (Mtb) encoded secreted antigen 85 enzymes (Ag85A/Ag85B/Ag85C) play that critical roles in the virulence, survival and drug-resistant TB of the pathogen. Ag85 proteins are potential antitubercular drug targets because they are essential in the catalytic synthesis of trehalose moieties and mycolic acid attachment to the Mtb cell wall. Recently, experimental protocols led to the discovery of a selective covalent Ag85 inhibitor, β-isomer monocyclic enolphosphorus Cycliphostin (CyC_8β) compound, which targets the Ag85 serine 124 to exhibit a promising therapeutic activity. For the first time, our study unravelled the structural features among Mtb Ag85C homologs and motions and dynamics of Ag85C when the CyC_8β bound covalently and in open model conformations to the protein using bioinformatics tools and integrated Molecular dynamics simulations. Comparative Ag85C sequence analysis revealed conserved regions; 70% active site, 90% Adeniyi loop L1 and 50% loop L2, which acts as a switch between open and closed conformations. The average C-α atoms RMSD (2.05 Å) and RMSF (0.9 Å) revealed instability and high induced flexibility in the CyC_8β covalent-bound compared to the apo and open model systems, which displayed more stability and lower fluctuations. DSSP showed structural transitions of α-helices to bend and loops to 3₁₀-helices in the bound systems. SASA of CyC_8β covalent bound showed active site hydrophobic residues exposure to huge solvent. Therefore, these findings present the potential opportunity hotspots in Ag85C protein that would aid the structure-based design of novel chemical entities capable of resulting in potent antitubercular drugs.Communicated by Ramaswamy H. Sarma.

Geno-Spatial Distribution of Mycobacterium Tuberculosis and Drug Resistance Profiles in Myanmar-Thai Border Area

Worldwide, studies investigating the relationship between the lineage of Mycobacterium tuberculosis (MTB) across geographic areas has empowered the “End TB” program and understand transmission across national boundaries. Genomic diversity of MTB varies with geographical locations and ethnicity. Genomic diversity can also affect the emergence of drug resistance. In Myanmar, we still have limited genetic information about geographical, ethnicity, and drug resistance linkage to MTB genetic information. This study aimed to describe the geno-spatial distribution of MTB and drug resistance profiles in Myanmar–Thailand border areas. A cross-sectional study was conducted with a total of 109 sequenced isolates. The lineages of MTB and the potential associated socio-demographic, geographic and clinical factors were analyzed using Fisher’s exact tests. p value of statistically significance was set at < 0.05. We found that 67% of the isolates were lineage 1 (L1)/East-African-Indian (EAI) (n = 73), followed by lineage 2 (L2)/Beijing (n = 26), lineage 4 (L4)/European American (n = 6) and lineage 3 (L3)/Delhi/Central Asian (n = 4). “Gender”, “type of TB patient”, “sputum smear grading” and “streptomycin resistance” were significantly different with the lineages of MTB. Sublineages of L1, which had never been reported elsewhere in Myanmar, were detected in this study area. Moreover, both ethnicity and lineage of MTB significantly differed in distribution by patient location. Diversity of the lineage of MTB and detection of new sublineages suggested that this small area had been resided by a heterogeneous population group who actively transmitted the disease. This information on distribution of lineage of MTB can be linked in the future with those on the other side of the border to evaluate cross-border transmission.

Delivery of long-term-injectable agents for TB by lay carers: pragmatic randomised trial

BACKGROUND

People with recurrent or drug-resistant TB require long courses of intramuscular injections. We evaluate a novel system in which patient-nominated lay carers were trained to deliver intramuscular injections to patients in their own homes.

METHODS

A pragmatic, individually randomised non-inferiority trial was conducted at two hospitals in Malawi. Adults starting TB retreatment were recruited. Patients randomised to the intervention received home-based care from patient-nominated lay people trained to deliver intramuscular streptomycin. Patients receiving standard care were admitted to hospital for 2 months of streptomycin. The primary outcome was successful treatment (alive and on treatment) at the end of the intervention.

RESULTS

Of 456 patients screened, 204 participants were randomised. The trial was terminated early due to futility. At the end of the intervention, 97/101 (96.0%) in the hospital arm were still alive and on treatment compared with 96/103 (93.2%) in the home-based arm (risk difference -0.03 (95% CI -0.09 to 0.03); p value 0.538). There were no differences in the proportion completing 8 months of anti-TB treatment; or the proportion experiencing 2-month sputum culture conversion. The mean cost of hospital-based management was US$1546.3 per person, compared to US$729.2 for home-based management. Home-based care reduced risk of catastrophic household costs by 84%.

CONCLUSIONS

Although this trial failed to meet target recruitment, the available data demonstrate that training patient-nominated lay people has potential to provide a feasible solution to the operational challenges associated with delivering long-term-injectable drugs to people with recurrent or drug-resistant TB in resource-limited settings, and substantially reduce costs. Further data under operational conditions are required.

TRIAL REGISTRATION NUMBER

ISRCTN05815615.

Direct Detection of Pyrazinamide Resistance in Mycobacterium tuberculosis by Use of pncA PCR Sequencing

An in-house-developed pncA sequencing assay for analysis of pyrazinamide (PZA) resistance was evaluated using 162 archived Mycobacterium tuberculosis complex (MTBC) isolates with phenotypic PZA susceptibility profiles that were well defined by analysis of Bactec MGIT 960 PZA kit and PZase activity data. Preliminary results showed 100% concordance between pncA sequencing and phenotypic PZA drug susceptibility test (DST) results among archived isolates. Also, 637 respiratory specimens were prospectively collected, and 158 were reported as MTBC positive by the Abbott Realtime MTB assay (96.3% sensitivity [95% confidence interval {CI}: 92.2% to 98.7%]; 100% specificity [95% CI: 99.2% to 100.0%]). Genotypic and phenotypic PZA resistance profiles of these 158 MTBC-positive specimens were analyzed by pncA sequencing and Bactec MGIT 960 PZA kit, respectively. For analysis of PZA resistance, pncA sequencing detected pncA mutations in 5/5 (100%) phenotypic PZA-resistant respiratory specimens within 4 working days. No pncA mutations were detected among PZA-susceptible specimens. Combining archived isolates with prospective specimens, 27 were identified as phenotypic PZA resistant with pncA mutation. Among these 27 samples, 6/27 (22.2%) phenotypic PZA-resistant strains carried novel pncA mutations without rpsA and panD mutations. These included 5 with mutations (a deletion [Del] at 383T [Del383T], Del 380 to 390, insertion of A [A Ins] at position 127, A Ins at position 407, and G Ins at position 508) in pncA structural genes and 1 with a mutation (T-12C) at the pncA promoter region. All six of these strains had no or reduced PZase activities, indicating that the novel mutations might confer PZA resistance. Additionally, 25/27 phenotypic PZA-resistant strains were confirmed multidrug-resistant tuberculosis (MDR-TB) strains. As PZA is commonly used in MDR-TB treatment regimens, direct pncA sequencing will rapidly detect PZA resistance and facilitate judicious use of PZA in treating PZA-susceptible MDR-TB.

Robustness of the Line Probe Assay for the Rapid Diagnosis and Characterization of Mutations in Extensively Drug-Resistant Tuberculosis

Introduction: Extensively drug-resistant tuberculosis (XDRTB) is a public health concern. We evaluated the diagnostic accuracy of Genotype^® MTBDRsl for detection of resistance to fluoroquinolones (FQs) and second-line injectable drugs (SLIDs) and characterized mutations seen. Materials and Methods: MTBDRsl was carried out either directly on sputum samples or indirectly on culture isolates (n = 100) from known multidrug-resistant tuberculosis (MDRTB) patients from July 2015 to September 2017. Diagnostic accuracy for the detection of resistance to FQs and SLIDs was calculated in comparison with conventional culture-based drug susceptibility testing. Mutations at the gyrA and rrs loci, as well as discrepant phenotypic and genotypic results, were studied. A subset of isolates underwent pyrosequencing. Results: Out of 100 MDRTB samples/isolates tested, 59% were pre-XDRTB and 7% were XDRTB. The sensitivity and specificity for the detection of resistance to FQs were 96.6% [95% confidence interval (CI): 88.3-99.6] and 80% [95% CI: 64.4-90.9] and those for SLIDs were 70% [95% CI: 34.8-93.3] and 100% [95% CI: 95.9-100]. The most frequent mutations were the absence of wild type 3 with corresponding mutation 3c (20/66) at the gyrA locus, and absence of wild type 1 and corresponding mutation 1 (6/7) at the rrs locus. The absence of a wt2 band with a corresponding mutation at the gyrA locus was seen in four of eight patients with discrepant genotypic and phenotypic results for FQ resistance. All isolates tested by pyrosequencing (n = 5) were concordant with the line probe assay for FQ resistance with identical mutations (D94G) and four of five isolates were concordant with SLIDs with identical mutations (A1401G). Conclusion: The MTBDRsl is a useful test for accurate diagnosis of XDRTB and may help to tailor therapy.

Management of drug-resistant tuberculosis in special sub-populations including those with HIV co-infection, pregnancy, diabetes, organ-specific dysfunction, and in the critically ill

Tuberculosis remains a major problem globally, and is the leading cause of death from an infectious agent. Drug-resistant tuberculosis threatens to marginalise the substantial gains that have recently been made in the fight against tuberculosis. Drug-resistant TB has significant associated morbidity and a high mortality, with only half of all multidrug-resistant TB patients achieving a successful treatment outcome. Patients with drug-resistant TB in resource-poor settings are now gaining access to newer and repurposed anti-tuberculosis drugs such as bedaquiline, delamanid and linezolid. However, with ever increasing rates of co-morbidity, there is little guidance on how to manage complex patients with drug-resistant TB. We address that knowledge gap, and outline principles underpinning the management of drug-resistant TB in special situations including HIV co-infection, pregnancy, renal disease, liver disease, diabetes, and in the critically ill.

The TB Portals: an Open-Access, Web-Based Platform for Global Drug-Resistant-Tuberculosis Data Sharing and Analysis

The TB Portals program is an international consortium of physicians, radiologists, and microbiologists from countries with a heavy burden of drug-resistant tuberculosis working with data scientists and information technology professionals. Together, we have built the TB Portals, a repository of socioeconomic/geographic, clinical, laboratory, radiological, and genomic data from patient cases of drug-resistant tuberculosis backed by shareable, physical samples. Currently, there are 1,299 total cases from five country sites (Azerbaijan, Belarus, Moldova, Georgia, and Romania), 976 (75.1%) of which are multidrug or extensively drug resistant and 38.2%, 51.9%, and 36.3% of which contain X-ray, computed tomography (CT) scan, and genomic data, respectively. The top Mycobacterium tuberculosis lineages represented among collected samples are Beijing, T1, and H3, and single nucleotide polymorphisms (SNPs) that confer resistance to isoniazid, rifampin, ofloxacin, and moxifloxacin occur the most frequently. These data and samples have promoted drug discovery efforts and research into genomics and quantitative image analysis to improve diagnostics while also serving as a valuable resource for researchers and clinical providers. The TB Portals database and associated projects are continually growing, and we invite new partners and collaborations to our initiative. The TB Portals data and their associated analytical and statistical tools are freely available at https://tbportals.niaid.nih.gov/.

Evaluation of the GenoType MTBDRsl Version 2.0 Assay for Second-Line Drug Resistance Detection of Mycobacterium tuberculosis Isolates in South Africa

Early detection of resistance to second-line antituberculosis drugs is important for the management of multidrug-resistant tuberculosis (MDR-TB). The GenoType MTBDRsl version 2.0 (VER 2.0) line probe assay has been redesigned for molecular detection of resistance-conferring mutations of fluoroquinolones (FLQ) (gyrA and gyrB genes) and second-line injectable drugs (SLID) (rrs and eis genes). The study evaluated the diagnostic performance of the GenoType MTBDRsl VER 2.0 assay for the detection of second-line drug resistance compared with phenotypic drug susceptibility testing (DST), using the Bactec MGIT 960 system on Mycobacterium tuberculosis complex isolates from South Africa. A total of 268 repository isolates collected between 2012 and 2014, which were rifampin monoresistant or MDR based on DST, were selected. MTBDRsl VER 2.0 testing was performed on these isolates and the results analyzed. The MTBDRsl VER 2.0 sensitivity and specificity indices for culture isolates were the following: FLQ, 100% (95% confidence interval [CI] 95.8 to 100%) and 98.9% (95% CI, 96.1 to 99.9%); SLID, 89.2% (95% CI, 79.1 to 95.6%) and 98.5% (95% CI, 95.7 to 99.7%). The sensitivity and specificity observed for individual SLID were the following: amikacin, 93.8% (95% CI, 79.2 to 99.2%) and 98.5% (95% CI, 95.5 to 99.7%); kanamycin, 89.2% (95% CI, 79.1 to 95.6%) and 98.5% (95% CI, 95.5 to 99.7%); and capreomycin, 86.2% (95% CI, 68.3 to 96.1%) and 95.9% (95% CI, 92.2 to 98.2%). An interoperator reproducibility of 100% and an overall interlaboratory performance of 93% to 96% were found. The overall improvement in sensitivity and specificity with excellent reproducibility makes the GenoType MTBDRsl VER 2.0 a highly suitable tool for rapid screening of clinical isolates for second-line drug resistance for use in high-burden TB/HIV settings.

Global Progress and Challenges in Implementing New Medications for Treating Multidrug-Resistant Tuberculosis

Two new drugs—bedaquiline and delamanid—have recently been approved by stringent regulatory authorities to treat multidrug-resistant tuberculosis (TB) and recommended by the World Health Organization for use under defined programmatic conditions. Introducing the medications in TB programs worldwide has not kept pace with the need for these drugs. In response, the DR-TB STAT (Drug-Resistant TB Scale-up Treatment Action Team) task force was formed in April 2015 to monitor progress and help overcome challenges. Information was collected from multiple sources and assessed monthly. Some progress has been made in introducing bedaquiline: as of October 2015, a total of 1,258 persons were on the medication under programmatic conditions. For delamanid, >100 patients, but few under programmatic conditions, have received the medication. Coordinated global action might help assist making these medications accessible for persons who need them most.

Granulomas and Inflammation: Host-Directed Therapies for Tuberculosis

Tuberculosis (TB) remains a leading global health problem that is aggravated by emergence of drug-resistant strains, which account for increasing number of treatment-refractory cases. Thus, eradication of this disease will strongly require better therapeutic strategies. Identification of host factors promoting disease progression may accelerate discovery of adjunct host-directed therapies (HDTs) that will boost current treatment protocols. HDTs focus on potentiating key components of host anti-mycobacterial effector mechanisms, and limiting inflammation and pathological damage in the lung. Granulomas represent a pathological hallmark of TB. They are comprised of impressive arrangement of immune cells that serve to contain the invading pathogen. However, granulomas can also undergo changes, developing caseums and cavities that facilitate bacterial spread and disease progression. Here, we review current concepts on the role of granulomas in pathogenesis and protective immunity against TB, drawing from recent clinical studies in humans and animal models. We also discuss therapeutic potential of inflammatory pathways that drive granuloma progression, with a focus on new and existing drugs that will likely improve TB treatment outcomes.

CT and microbiologic follow-up in primary multidrug-resistant pulmonary tuberculosis

BACKGROUND

Little attention has been paid to the initial and follow-up computed tomography (CT) features in primary multi-drug resistant tuberculosis (pMDR-TB) setting.

PURPOSE

To describe serial CT findings and clinical course of pMDR-TB with antibiotic treatment.

MATERIAL AND METHODS

For the last 10 years, 340 MDR-TB patients were managed in a tertiary referral hospital. Among them, we included 44 (27 men, 17 women; mean age, 40 years; age range, 20-81 years) pMDR-TB patients; 37 treated with chemotherapy only and seven treated with medical therapy plus surgery. CT findings were evaluated regarding tree-in-bud sign, acinar nodule, peribronchial, segmental or lobar consolidation and cavity, and their extent. Sputum negative conversion rates and serial CT scores were assessed. To compare changes in disease extent between initial and follow-up CT studies, paired t-test was performed.

RESULTS

Two most frequent patterns of lung abnormality were tree-in-bud sign (37 of 44, 84.1%) and acinar nodule (41 of 44, 93.2%). Among 37 patients treated with chemotherapy only, 36 showed negative sputum conversion within 3 months after second-line drug commencement, maintained for >12 months. The other seven undergoing surgery during medical treatment showed excellent outcome with negative conversion achieved within one month after surgery and maintained for >12 months. CT scores showed significant decrease on serial CT studies (P < 0.001) in all.

CONCLUSION

In pMDR-TB, two most frequent abnormal CT patterns are tree-in-bud sign and acinar nodule. In 98% of patients, negative sputum conversion is achieved, and CT score also shows decrease in extent after TB chemotherapy.

Moxifloxacin: An Alternative to Ethambutol for the Treatment of Presumed Ocular Tuberculosis

OBJECTIVE

To present moxifloxacin as an alternative treatment option to ethambutol in an anti-tubercular therapy (ATT) regime in patients with presumed ocular tuberculosis (TB).

METHODS

We identified all cases in our hospital referred for treatment of presumed ocular TB between 2009 and 2013. Age, gender, ophthalmic examination, blood tests, treatment regimens, adverse drug reactions, and outcomes were collected and analyzed for the patients who had moxifloxacin as part of their ATT.

RESULTS

Forty-three cases of presumed ocular TB were treated with moxifloxacin as a part of ATT. Mean age was 44.18 ± 12.47 years; 62.8% were male. A response to treatment, with no evidence of disease recurrence, was seen in 72.1% of cases. Shortened ATT duration was associated with increased risk of treatment failure (p = 0.02, 95% CI: -0.77 to -0.00).

CONCLUSIONS

Moxifloxacin can be considered as a safe and effective alternative to ethambutol for the treatment of presumed ocular TB.

Randomized, placebo-controlled phase II trial of heat-killed Mycobacterium vaccae (Longcom batch) formulated as an oral pill (V7)

One-month Phase II trial was conducted in 43 sputum smear-positive patients with pulmonary tuberculosis randomized into treatment (n = 22) and placebo (n = 21) arms to investigate the safety and efficacy of an orally-administered therapeutic TB vaccine (V7) containing 10 μg of heat-killed Mycobacterium vaccae provided by Longcom company. Immunotherapy and control groups comprised 8 newly diagnosed (1stDx TB; 18.6%), 6 re-treated (RTB; 14%), and 29 multidrug-resistant (MDR-TB; 67.4%) cases distributed at 5:4:13 and 3:2:16 ratios, respectively. Both arms received conventional TB drugs administered under directly observed therapy. The average weight gain in V7 arm was modest, but statistically significant (0.6 kg; p = 0.004), while placebo patients lost 0.1 kg (p = 0.77). Except defervescence and increased lymphocyte percentage, other secondary endpoints such as erythrocyte sedimentation rate (ESR), leukocyte counts and hemoglobin content were not significantly affected. In control patients only one secondary endpoint, ESR, has improved. After one month mycobacterial clearance in sputum smears was observed in 31.8% (p = 0.03) and 9.5% (p = 0.83) of patients on V7 and placebo. However, the difference between outcomes in two arms was below significance threshold (p = 0.07). Thus, larger population of patients with prolonged follow-up is required to support these preliminary findings.

Effect of universal MODS access on pulmonary tuberculosis treatment outcomes in new patients in Peru

SETTING

Primary health care centres in Callao, Peru.

OBJECTIVES

To evaluate the effect of universal access to the microscopic-observation drug susceptibility (MODS) assay on treatment outcomes in new and primary multidrug-resistant tuberculosis (MDR-TB) patients and on the process of drug susceptibility testing (DST).

DESIGN

Retrospective review of tuberculosis (TB) registers and clinical records before (2007) and after (2009) the introduction of MODS in 2008.

RESULTS

There were 281 patients in each cohort. Favourable treatment outcomes for 2007 (81%) and 2009 (77%) cohorts were similar. There was an increase in loss to follow-up (from 6% to 10%, P = 0.04) and a reduction in failure rates (from 4% to 0.4%, P = 0.01) in the 2009 compared with the 2007 cohort. In new MDR-TB cases (n = 22), a favourable treatment outcome was improved (from 46% to 82%, P = 0.183) in the 2009 cohort. DST coverage improved (from 24% to 74%, P < 0.001), and a significant reduction in time to diagnosis of drug-susceptible (from 118 to 33 days, P < 0.001) and MDR-TB (from 158 to 52 days, P =30.003) was observed in the 2009 cohort.

CONCLUSION

Universal access to MODS increased DST coverage, reduced the time required to obtain DST results and was associated with reduced failure rates. MODS can make an important contribution to TB management and control in Peru.