Tuberculosis recurrence and mortality after successful treatment: impact of drug resistance

HIV co-infection increases the risk of post-tuberculosis mortality among persons who initiated treatment for drug-resistant tuberculosis

Little is known regarding the relationship between common comorbidities in persons with tuberculosis (TB) (including human immunodeficiency virus [HIV], diabetes, and hepatitis C virus [HCV]) with post-TB mortality. We conducted a retrospective cohort study among persons who initiated treatment for rifampicin-resistant and multi/extensively drug-resistant (RR and M/XDR) TB reported to the country of Georgia's TB surveillance during 2009-2017. Exposures included HIV serologic status, diabetes, and HCV status. Our outcome was all-cause post-TB mortality determined by cross-validating vital status with Georgia's death registry through November 2019. We estimated adjusted hazard rate ratios (aHR) and 95% confidence intervals (CI) of post-TB mortality among participants with and without comorbidities using cause-specific hazard regressions. Among 1032 eligible participants, 34 (3.3%) died during treatment and 87 (8.7%) died post-TB treatment. Among those who died post-TB treatment, the median time to death was 21 months (interquartile range 7-39) post-TB treatment. After adjusting for confounders, the hazard rates of post-TB mortality were higher among participants with HIV co-infection (aHR=3.74, 95%CI 1.77-7.91) compared to those without HIV co-infection. In our cohort, post-TB mortality occurred most commonly in the first three years post-TB treatment. Linkage to care for common TB comorbidities post-treatment may reduce post-TB mortality rates.

Improving measurement of tuberculosis care cascades to enhance people-centred care

Care cascades represent the proportion of people reaching milestones in care for a disease and are widely used to track progress towards global targets for HIV and other diseases. Despite recent progress in estimating care cascades for tuberculosis (TB) disease, they have not been routinely applied at national and subnational levels, representing a lost opportunity for public health impact. As researchers who have estimated TB care cascades in high-incidence countries (India, Madagascar, Nigeria, Peru, South Africa, and Zambia), we describe the utility of care cascades and identify measurement challenges, including the lack of population-based disease burden data and electronic data capture, the under-reporting of people with TB navigating fragmented and privatised health systems, the heterogeneity of TB tests, and the lack of post-treatment follow-up. We outline an agenda for rectifying these gaps and argue that improving care cascade measurement is crucial to enhancing people-centred care and achieving the End TB goals.

The incidence of tuberculosis recurrence: Impacts of treatment duration of and adherence to standard anti-tuberculous therapy

BACKGROUND

We investigated the impacts of the standard treatment durations of and adherence to standard anti-tuberculous therapy (ATT) on recurrence after the successful completion of tuberculosis (TB) treatment.

METHODS

We recruited patients with TB who had received treatment for six or nine months from the 2008-2017 databases of the Taiwanese National Health Insurance Research Database. Treatment duration and adherence to standard ATT were analyzed for their impacts on recurrence within two years. Complete adherence to standard ATT was defined as daily use of ethambutol, isoniazid, pyrazinamide, and rifampin for the first two months, and daily use of isoniazid and rifampin for the first six months.

RESULTS

A total of 33,298 TB patients with new-onset TB were identified and classified into two groups by treatment duration: six months (n = 25,849, 77.63%) and nine months (n = 7449). Sex and age distributions varied between the groups. Treatment duration did not affect TB recurrence within two years (adjusted hazard ratio (AHR): 1.18, 95% confidence interval (C.I.) [0.96-1.44], p = 0.1156). Multivariable logistic regression showed that incomplete adherence to standard anti-tuberculous therapy (80-89% and 90-99% standard anti-TB therapy, AHR: 1.57, 95% C.I. [1.26-1.95], and 1.63, 95% C.I. [1.26-2.06], respectively, p < 0.0001) increased TB recurrence. In addition, male sex, older age, and comorbidity with diabetes mellitus or chronic obstructive pulmonary disease were independent risk factors for TB recurrence within two years.

CONCLUSIONS

TB recurrence was 1.54% within two years under a DOT era. TB treatment durations of six or nine months did not affect TB recurrence within two years after completion of TB treatment, but incomplete adherence to standard anti-tuberculous therapy might increase the TB recurrence rate.

Global burden of disease due to rifampicin-resistant tuberculosis: a mathematical modeling analysis

In 2020, almost half a million individuals developed rifampicin-resistant tuberculosis (RR-TB). We estimated the global burden of RR-TB over the lifetime of affected individuals. We synthesized data on incidence, case detection, and treatment outcomes in 192 countries (99.99% of global tuberculosis). Using a mathematical model, we projected disability-adjusted life years (DALYs) over the lifetime for individuals developing tuberculosis in 2020 stratified by country, age, sex, HIV, and rifampicin resistance. Here we show that incident RR-TB in 2020 was responsible for an estimated 6.9 (95% uncertainty interval: 5.5, 8.5) million DALYs, 44% (31, 54) of which accrued among TB survivors. We estimated an average of 17 (14, 21) DALYs per person developing RR-TB, 34% (12, 56) greater than for rifampicin-susceptible tuberculosis. RR-TB burden per 100,000 was highest in former Soviet Union countries and southern African countries. While RR-TB causes substantial short-term morbidity and mortality, nearly half of the overall disease burden of RR-TB accrues among tuberculosis survivors. The substantial long-term health impacts among those surviving RR-TB disease suggest the need for improved post-treatment care and further justify increased health expenditures to prevent RR-TB transmission.

Healthcare Utilization After Respiratory Tuberculosis: A Controlled Interrupted Time Series Analysis

BACKGROUND

Despite data suggesting elevated morbidity and mortality among people who have survived tuberculosis disease, the impact of respiratory tuberculosis on healthcare utilization in the years following diagnosis and treatment remains unclear.

METHODS

Using linked health administrative data from British Columbia, Canada, we identified foreign-born individuals treated for respiratory tuberculosis between 1990 and 2019. We matched each person with up to four people without a tuberculosis diagnosis from the same source cohort using propensity score matching. Then, using a controlled interrupted time series analysis, we measured outpatient physician encounters and inpatient hospital admissions in the 5 years following respiratory tuberculosis diagnosis and treatment.

RESULTS

We matched 1216 individuals treated for respiratory tuberculosis to 4864 non-tuberculosis controls. Immediately following the tuberculosis diagnostic and treatment period, the monthly rate of outpatient encounters in the tuberculosis group was 34.0% (95% confidence interval [CI]: 30.7%, 37.2%) higher than expected, and this trend was sustained for the duration of the post-tuberculosis period. The excess utilization represented an additional 12.2 (95% CI: 10.6, 14.9) outpatient encounters per person over the post-tuberculosis period, with respiratory morbidity a large contributor to the excess healthcare utilization. Results were similar for hospital admissions, with an additional 0.4 (95% CI: .3, .5) hospital admissions per person over the post-tuberculosis period.

CONCLUSIONS

Respiratory tuberculosis appears to have long-term impacts on healthcare utilization beyond treatment. These findings underscore the need for screening, assessment, and treatment of post-tuberculosis sequelae, as it may provide an opportunity to improve health and reduce resource use.

Exploring the Potential of Fecal Microbiota Transplantation as a Therapy in Tuberculosis and Inflammatory Bowel Disease

This review explores the potential benefits of fecal microbiota transplantation (FMT) as an adjunct treatment in tuberculosis (TB), drawing parallels from its efficacy in inflammatory bowel disease (IBD). FMT has shown promise in restoring the gut microbial balance and modulating immune responses in IBD patients. Considering the similarities in immunomodulation and dysbiosis between IBD and TB, this review hypothesizes that FMT may offer therapeutic benefits as an adjunct therapy in TB. Methods: We conducted a systematic review of the existing literature on FMT in IBD and TB, highlighting the mechanisms and potential implications of FMT in the therapeutic management of both conditions. The findings contribute to understanding FMT's potential role in TB treatment and underscore the necessity for future research in this direction to fully leverage its clinical applications. Conclusion: The integration of FMT into the comprehensive management of TB could potentially enhance treatment outcomes, reduce drug resistance, and mitigate the side effects of conventional therapies. Future research endeavors should focus on well-designed clinical trials to develop guidelines concerning the safety and short- and long-term benefits of FMT in TB patients, as well as to assess potential risks.

Tuberculosis (TB) Aftermath: study protocol for a hybrid type I effectiveness-implementation non-inferiority randomized trial in India comparing two active case finding (ACF) strategies among individuals treated for TB and their household contacts

BACKGROUND

Approximately 7% of all reported tuberculosis (TB) cases each year are recurrent, occurring among people who have had TB in the recent or distant past. TB recurrence is particularly common in India, which has the largest TB burden worldwide. Although patients recently treated for TB are at high risk of developing TB again, evidence around effective active case finding (ACF) strategies in this population is scarce. We will conduct a hybrid type I effectiveness-implementation non-inferiority randomized trial to compare the effectiveness, cost-effectiveness, and feasibility of two ACF strategies among individuals who have completed TB treatment and their household contacts (HHCs).

METHODS

We will enroll 1076 adults (≥ 18 years) who have completed TB treatment at a public TB unit (TU) in Pune, India, along with their HHCs (averaging two per patient, n = 2152). Participants will undergo symptom-based ACF by existing healthcare workers (HCWs) at 6-month intervals and will be randomized to either home-based ACF (HACF) or telephonic ACF (TACF). Symptomatic participants will undergo microbiologic testing through the program. Asymptomatic HHCs will be referred for TB preventive treatment (TPT) per national guidelines. The primary outcome is rate per 100 person-years of people diagnosed with new or recurrent TB by study arm, within 12 months following treatment completion. The secondary outcome is proportion of HHCs < 6 years, by study arm, initiated on TPT after ruling out TB disease. Study staff will collect socio-demographic and clinical data to identify risk factors for TB recurrence and will measure post-TB lung impairment. In both arms, an 18-month "mop-up" visit will be conducted to ascertain outcomes. We will use the RE-AIM framework to characterize implementation processes and explore acceptability through in-depth interviews with index patients, HHCs and HCWs (n = 100). Cost-effectiveness will be assessed by calculating the incremental cost per TB case detected within 12 months and projected for disability-adjusted life years averted based on modeled estimates of morbidity, mortality, and time with infectious TB.

DISCUSSION

This novel trial will guide India's scale-up of post-treatment ACF and provide an evidence base for designing strategies to detect recurrent and new TB in other high burden settings.

TRIAL REGISTRATION

NCT04333485 , registered April 3, 2020. CTRI/2020/05/025059 [Clinical Trials Registry of India], registered May 6 2020.

Distinguishing Relapse From Reinfection With Whole-Genome Sequencing in Recurrent Pulmonary Tuberculosis: A Retrospective Cohort Study in Beijing, China

Background: Tuberculosis recurrence is still a major problem for the control of tuberculosis, and the cause of the recurrence is still unclear.

Methods: We retrospectively recruited 68 pairs of samples of Mycobacterium tuberculosis (MTB) from recurrent TB cases in Beijing Chest Hospital between January 2008 and December 2019. The whole-genome sequencing was conducted to analyze single-nucleotide polymorphism (SNP) and to identify whether recurrent disease was due to relapse or reinfection. The BACTEC MGIT was performed to compare differences in drug susceptibility profiles between two episodes.

Results: 62 (91.2%) out of 68 confirmed recurrence were due to relapse, whereas the remaining six (8.8%) were due to reinfection. And there was a strong association between earlier relapse and underlying chronic diseases. In addition, the MTB isolates from non-diabetic patients had a higher mutation rate than those from diabetic patients. A community transmission was also identified in our cohort. Levofloxacin resistance was the most frequently observed drug resistance for 12.9% relapse cases.

Conclusion: The relapse of a previous episode in Beijing. The underlying chronic diseases are associated with an earlier TB relapse. MTB isolates were more prone to develop levofloxacin resistance than moxifloxacin resistance after FQ exposure. The patients at high-risk for relapses deserve more careful investigation.

Relapse or Re-Infection, the Situation of Recurrent Tuberculosis in Eastern China

Purpose

Recurrent tuberculosis (TB) is defined by more than one TB episode per patient and is caused by re-infection with a new Mycobacterium tuberculosis (Mtb) strain or relapse with the previous strain. Recurrence of TB is one important obstacle for End TB strategy in the world and elucidating the triggers of recurrence is important for the current TB control strategy in China. This study aimed to analyze the sources of recurrent TB by the molecular genotyping method.

Method

A population-based surveillance was undertaking on all culture-positive TB cases in Jiangsu province, China from 2013 to 2019. Phenotypic drug susceptibility test (DST) by proportion method and mycobacterial interspersed repetitive units-variable number of tandem repeat (MIRU-VNTR) were adopted for drug resistance and genotype detection.

Results

A total of 1451 culture-positive TB patients were collected and 30 (2.06%, 30/1451) TB cases had recurrent TB episodes. Except 7 isolates were failed during subculture, 23 paired isolates were assessed. After genotyping by MIRU-VNTR, 12 (52.17%, 12/23) paired recurrence TB were demonstrated as relapse and 11 (47.83%,11/23) paired cases were identified as re-infection. The average interval time for recurrence was 24.04 (95%CI: 19.37-28.71) months, and there was no significant difference between relapse and re-infection. For the relapsed cases, two paired isolates exhibited drug resistance shifting, while four paired isolates revealed inconsistent drug resistance among the re-infection group including two multidrug-resistant tuberculosis (MDR-TB) at the second episode.

Conclusion

Relapse and re-infection contributed equally to the current situation of recurrence TB in Jiangsu, China. Besides, more efficient treatment assessment, specific and vigorous interventions are urgently needed for MDR-TB patients, considering obvious performance among re-infection cases.

Adherence and Associated Factors of Treatment Regimen in Drug-Susceptible Tuberculosis Patients

Background: Adherence to tuberculosis (TB) drugs is one of the key aspects of global TB control, yet there is a lack of epidemiological evidence on the factors influencing adherence to TB drugs. Thus, this study aimed to explore the adherence and factors associated with adherence among TB patients in South Korea. Methods: We conducted a cohort study using a sampled national healthcare database from 2017 to 2018. Our study population included incident TB patients initiating quadruple or triple regimen who were available for follow-up for 180-days. Adherence was evaluated using the proportion of days covered (PDC): 1) adherent group: patients with PDC ≥80%; 2) non-adherent group: patients with PDC <80%. Kaplan-Meier analysis was conducted to calculate the median time-to-discontinuation in the study population. We calculated the adjusted odds ratios (aOR) with 95% confidence intervals (CI) to assess factors associated with adherence to TB drugs using logistic regression. Results: Of 987 patients, 558 (56.5%) were adherent and 429 (43.5%) were non-adherent, with the overall mean PDC of 68.87% (standard deviation, 33.37%). The median time-to-discontinuation was 113 days (interquartile range 96-136) in the study population. Patients initiating quadruple regimen were more likely to adhere in comparison to the triple regimen (aOR 4.14; 95% CI 2.78-6.17), while those aged ≥65 years (aOR 0.53; 95% CI 0.35-0.81), with a history of dementia (aOR 0.53; 95% CI 0.34-0.85), and with history of diabetes mellitus (aOR 0.70; 95% CI 0.52-0.96) were less likely to adhere to the drug. Conclusion: Approximately 45% of TB patients were non-adherent to the drug, which is a major concern for the treatment outcome. We call for intensified attention from the authorities and healthcare providers to reinforce patients' adherence to the prescribed TB drugs.

Closing gaps in the tuberculosis care cascade: an action-oriented research agenda

The care cascade-which evaluates outcomes across stages of patient engagement in a health system-is an important framework for assessing quality of tuberculosis (TB) care. In recent years, there has been progress in measuring care cascades in high TB burden countries; however, there are still shortcomings in our knowledge of how to reduce poor patient outcomes. In this paper, we outline a research agenda for understanding why patients fall through the cracks in the care cascade. The pathway for evidence generation will require new systematic reviews, observational cohort studies, intervention development and testing, and continuous quality improvement initiatives embedded within national TB programs. Certain gaps, such as pretreatment loss to follow-up and post-treatment disease recurrence, should be a priority given a relative paucity of high-quality research to understand and address poor outcomes. Research on interventions to reduce death and loss to follow-up during treatment should move beyond a focus on monitoring (or observation) strategies, to address patient needs including psychosocial and nutritional support. While key research questions vary for each gap, some patient populations may experience disparities across multiple stages of care and should be a priority for research, including men, individuals with a prior treatment history, and individuals with drug-resistant TB. Closing gaps in the care cascade will require investments in a bold and innovative action-oriented research agenda.

Outcome Impacts Due to Pathogen-Specific Antimicrobial Resistance: A Narrative Review of Published Literature

Antimicrobial resistance (AMR) has become a global threat to not only public health impacts but also clinical and economic outcomes. During the past decades, there have been many studies focusing on surveillance, mechanisms, and diagnostics of AMR in infectious diseases but the impacts on public health, clinical and economic outcomes due to emergence of these AMRs are rarely studied and reported. This review was aimed to summarize the findings from published studies to report the outcome impacts due to AMR of malaria, tuberculosis and HIV and briefly discuss the implications for application to other infectious diseases. PubMed/Medline and Google Scholar databases were used for search of empirical and peer-reviewed papers reporting public health, clinical and economic outcomes due to AMR of malaria, tuberculosis and HIV. Papers published through 1 December 2019 were included in this review. A total of 76 studies were included for this review, including 16, 49 and 11 on public health, clinical and economic outcomes, respectively. The synthesized data indicated that the emergence and spread of AMR of malaria, tuberculosis and HIV have resulted in adverse public health, clinical and economic outcomes. AMR of malaria, tuberculosis and HIV results in significant adverse impacts on public health, clinical and economic outcomes. Evidence from this review suggests the needs to consider the similar studies for other infectious diseases.

Tuberculosis recurrences and predictive factors in a vulnerable population in Catalonia

BACKGROUND

Patients with a history of tuberculosis (TB) have a high probability of recurrence because long-term cure is not always maintained in successfully treated patients. The aim of this study was to identify the probability of TB recurrence and its predictive factors in a cohort of socially vulnerable patients who completed treatment in the TB referral center in Catalonia, which acts as the center for patients with social and health problems.

METHODS

This retrospective open cohort study included all patients diagnosed with TB who were admitted and successfully treated in Serveis Clínics between 2000 and 2016 and who remained disease-free for a minimum of 1 year after treatment completion. We calculated the incidence density of TB recurrences per person-years of follow-up. We also estimated the cumulative incidence of TB recurrence at 1, 2, 5, and 10 years of follow-up. Bivariate analysis was conducted using Kaplan-Meier curves. Multivariate analysis was conducted using Cox regression. Hazard ratios (HR) were calculated with their 95% confidence intervals (95%CI).

RESULTS

There were 839 patients and 24 recurrences (2.9%), representing 0.49 per 100 person-years. The probability of a recurrence was 0.63% at 1 year of follow-up, 1.35% at 2 years, and 3.69% at 5 years. The multivariate analysis showed that the predictive factors of recurrence were age older than 34 years (aHR = 3.90; CI = 1.06-14.34 at age 35-45 years and aHR = 3.88; CI = 1.02-14.80 at age >45 years) and resistance to at least one anti-TB drug (aHR = 2.91; CI = 1.11-7.65).

CONCLUSIONS

Attention should be paid to socially vulnerable persons older than 34 years with a previous episode of resistant TB. Surveillance resources should be directed toward adequately treated patients who nevertheless have a high risk of recurrence.

What Can Go Wrong When Applying Immune Modulation Therapies to Target Persistent Bacterial Infections

Antibiotics can treat the acute phase of a disease, but often do not completely clear the etiologic agent, allowing the pathogen to establish persistent infection that can revive the disease in a frustrating recurrence of infection. The mechanisms that control chronic bacterial infections are complex and involve pathogen adaptations that favor survival from both host immune responses and antibiotic bactericidal activity. Often, the causative agents of persistent infections are not drug-resistant species. Instead, bacterial persister cells temporarily enter a physiological state that is refractory to different classes of antibiotics. Supplemental therapies that potentiate antibiotic bactericidal efficiency and/or immune clearance of persistent pathogenic species may greatly improve the outcome of infectious disease. Here, we discuss the various outcomes in experimental studies in which a mega-dose of the energy-boosting vitamin B3 (nicotinamide) was applied in murine models of chronic infection to stimulate immune clearance of chronic infection or as an immune prophylactic treatment against the highly infectious pathogen, Burkholderia pseudomallei. It is our intent to raise awareness of the risks associated with immune modulation therapies. There is great variance in host immune responses to pathogenic bacteria. Each immune modulation approach needs to be tailored to a well-characterized host-pathogen interaction.

Detection of Second Line Drug Resistance among Drug Resistant Mycobacterium Tuberculosis Isolates in Botswana

The emergence and transmission of multidrug resistant (MDR) and extensively drug resistant (XDR) Mycobacterium tuberculosis (M.tb) strains is a threat to global tuberculosis (TB) control. The early detection of drug resistance is critical for patient management. The aim of this study was to determine the proportion of isolates with additional second-line resistance among rifampicin and isoniazid resistant and MDR-TB isolates. A total of 66 M.tb isolates received at the National Tuberculosis Reference Laboratory between March 2012 and October 2013 with resistance to isoniazid, rifampicin or both were analyzed in this study. The genotypes of the M.tb isolates were determined by spoligotyping and second-line drug susceptibility testing was done using the Hain Genotype MTBDRsl line probe assay version 2.0. The treatment outcomes were defined according to the Botswana national and World Health Organization (WHO) guidelines. Of the 57 isolates analyzed, 33 (58%) were MDR-TB, 4 (7%) were additionally resistant to flouroquinolones and 3 (5%) were resistant to both fluoroquinolones and second-line injectable drugs. The most common fluoroquinolone resistance-conferring mutation detected was gyrA A90V. All XDR-TB cases remained smear or culture positive throughout the treatment. Our study findings indicate the importance of monitoring drug resistant TB cases to ensure rapid detection of second-line drug resistance.

Wirelessly observed therapy compared to directly observed therapy to confirm and support tuberculosis treatment adherence: A randomized controlled trial

BACKGROUND

Excellent adherence to tuberculosis (TB) treatment is critical to cure TB and avoid the emergence of resistance. Wirelessly observed therapy (WOT) is a novel patient self-management system consisting of an edible ingestion sensor (IS), external wearable patch, and paired mobile device that can detect and digitally record medication ingestions. Our study determined the accuracy of ingestion detection in clinical and home settings using WOT and subsequently compared, in a randomized control trial (RCT), confirmed daily adherence to medication in persons using WOT or directly observed therapy (DOT) during TB treatment.

METHODS AND FINDINGS

We evaluated WOT in persons with active Mycobacterium tuberculosis complex disease using IS-enabled combination isoniazid 150 mg/rifampin 300 mg (IS-Rifamate). Seventy-seven participants with drug-susceptible TB in the continuation phase of treatment, prescribed daily isoniazid 300 mg and rifampin 600 mg, used IS-Rifamate. The primary endpoints of the trial were determination of the positive detection accuracy (PDA) of WOT, defined as the percentage of ingestions detected by WOT administered under direct observation, and subsequently the proportion of prescribed doses confirmed by WOT compared to DOT. Initially participants received DOT and WOT simultaneously for 2-3 weeks to allow calculation of WOT PDA, and the 95% confidence interval (CI) was estimated using the bootstrap method with 10,000 samples. Sixty-one participants subsequently participated in an RCT to compare the proportion of prescribed doses confirmed by WOT and DOT. Participants were randomized 2:1 to receive WOT or maximal in-person DOT. In the WOT arm, if ingestions were not remotely confirmed, the participant was contacted within 24 hours by text or cell phone to provide support. The number of doses confirmed was collected, and nonparametric methods were used for group and individual comparisons to estimate the proportions of confirmed doses in each randomized arm with 95% CIs. Sensitivity analyses, not prespecified in the trial registration, were also performed, removing all nonworking (weekend and public holiday) and held-dose days. Participants, recruited from San Diego (SD) and Orange County (OC) Divisions of TB Control and Refugee Health, were 43.1 (range 18-80) years old, 57% male, 42% Asian, and 39% white with 49% Hispanic ethnicity. The PDA of WOT was 99.3% (CI 98.1; 100). Intent-to-treat (ITT) analysis within the RCT showed WOT confirmed 93% versus 63% DOT (p < 0.001) of daily doses prescribed. Secondary analysis removing all nonworking days (weekends and public holidays) and held doses from each arm showed WOT confirmed 95.6% versus 92.7% (p = 0.31); WOT was non-inferior to DOT (difference 2.8% CI [-1.8%, 9.1%]). One hundred percent of participants preferred using WOT. WOT associated adverse events were <10%, consisting of minor skin rash and pruritus associated with the patch. WOT provided longitudinal digital reporting in near real time, supporting patient self-management and allowing rapid remote identification of those who needed more support to maintain adherence. This study was conducted during the continuation phase of TB treatment, limiting its generalizability to the entire TB treatment course.

CONCLUSIONS

In terms of accuracy, WOT was equivalent to DOT. WOT was superior to DOT in supporting confirmed daily adherence to TB medications during the continuation phase of TB treatment and was overwhelmingly preferred by participants. WOT should be tested in high-burden TB settings, where it may substantially support low- and middle-income country (LMIC) TB programs.

TRIAL REGISTRATION

ClinicalTrials.gov NCT01960257.

Effect of mixed infection on TB dynamics

Poor living conditions, overcrowding and strain diversity are some of the factors that influence mixed infection in Tuberculosis (TB) at the population level. We formulate a mathematical model for mixed infection in TB using nonlinear ordinary differential equations where such factors were represented as probabilities of acquiring mixed infection. A qualitative analysis of the model shows that it exhibits multiple endemic equilibria and backward bifurcation for certain parameter values. The reactivation rate and transmission rate of individuals with mixed infection were of importance as well as the probabilities for latent individuals to acquire mixed infection. We calculate the prevalence of mixed infection from the model and the effect of mixed infection on TB incidence, TB prevalence and Mycobacterium tuberculosis (MTB) infection rate. Numerical simulations show that mixed infection may explain high TB incidences in areas which have a high strain diversity, poor living conditions and are overcrowded even without HIV.

The generation of T-cell memory to protect against tuberculosis

Tuberculosis (TB) kills more individuals each year than any other single pathogen and a more effective vaccine is critical for the global control of the disease. Although there has been recent progress in the clinical testing of candidates, no new vaccine has been licensed for use and correlates of protective immunity in humans have not been defined. Prior Mycobacterium tuberculosis infection does not appear to confer long-term protective immunity in humans; thus mimicking the natural immune response to infection may not be a suitable approach to develop improved TB vaccines. Data from animal testing are used to progress vaccines through the "vaccine pipeline", but studies in animals have not been able to predict efficacy in humans. Furthermore, although the generation of conventional CD4⁺ T-cell responses are considered necessary to control infection with M. tuberculosis, these do not necessarily correlate with protection induced by candidate vaccines and other immune components may play a role, including donor unrestricted T cells, tissue-resident memory T cells and anti-M. tuberculosis antibodies. This review will summarize the current understanding of the protective immune responses following M. tuberculosis infection or vaccination, with a particular focus on vaccines that have recently entered clinical trials.

Predictors of recurrent TB in sputum smear and culture positive adults: a prospective cohort study

Objective

To explore simple inexpensive non-culture based predictors of recurrent pulmonary tuberculosis (PTB).

Setting and study population

HIV-infected and uninfected adults with the first episode of smear positive, culture-confirmed pulmonary tuberculosis in a high tuberculosis burden country.

Design

A nested prospective cohort study of participants with pulmonary tuberculosis (PTB) presenting to a hospital out-patient clinic.

Results

A total of 630 TB culture confirmed participants were followed up for eighteen months of which 57 (9%) developed recurrent recurrent TB. On univariate analysis,4.7% low grade(1+) pre-treatment sputum smear participants developed recurrent tuberculosis Vs 8.8% with high grade(3+) smears (OR=0.31,95%CI: 0.10–0.93, p=0.037).On multivariate analysis: participants with extensive fibro-cavitation had a high risk of recurrent TB Vs minimal end of treatment fibro-cavitation (18%Vs12%, OR=2.3,95%CI:1.09–4.68, p=0.03). Weight gain with HIV infection was assosciated with a high risk of recurrent TB Vs weight gain with no HIV infection(18%Vs 6%, OR=6.8,95%CI:165–27.83, p=0.008) where as weight gain with a low pre-treatment high bacillary burden was assosciated with a low risk of recurrent TB Vs weight gain with a high pre-treatmentbacillary burden(6.5%Vs7.9%, OR=0.2,95%CI:0.05–0.79, p=0.02).

Conclusion

Extensive end of treatment pulmonary fibro-cavitation, high pre-treatment bacillary burden with no weight gain and HIV infection could be reliable predictors of recurrent tuberculosis.

Tuberculosis mortality and associated factors at King Abdulaziz Medical City Hospital

BACKGROUND

Tuberculosis (TB) continues to be a public health challenge in Saudi Arabia, particularly for the elderly. This study was conducted to estimate mortality per 1000 person-year among TB and resistant TB cases and to identifying factors associated with mortality.

METHODS

This is a retrospective cohort study of 713 new TB cases at King Abdulaziz Medical City in Riyadh diagnosed between January 1, 2000, and December 31, 2016. Patient medical records and microbiology lab databases were used to identify TB cases. Through reviews were conducted of patients' medical records, including physician notes, physical examinations, radiology (scans and imaging), laboratory tests, and follow-up notes. Collected data include demographic information, clinical features, diagnoses, comorbidities, and death rates.

RESULTS

Of the 713 TB patients included in this study, 110 died, giving an average mortality rate of 22 per 1000 person-years (PY; 95% CI: 18.2-26.4). Elderly patients (≥ 60 years) had a higher mortality rate of 36.5 per 1000 PY (95% CI: 28.9-45.5). As age increases by one year, the hazard of mortality increase by 2.4% (aHR: 1.024 [95% CI: 1.009-1.039, P = 0.002]). Higher hazard of mortality was found among males (aHR: 2.014 [95% CI: 1.186-3.418, P = 0.010]). Patients with respiratory and other types of comorbidities and cancer had a higher mortality hazard (aHR: 1.898 [95% CI: 1.005-3.582, P = 0.048]; aHR: 2.346 [95% CI: 1.313-4.192, P = 0.004]; aHR: 3.292 [95% CI: 1.804-6.006, P = 0.001]), respectively. Multidrug-resistant TB (MDR-TB) was found in 2 cases (0.28%) (95% CI: 0.08-1.02), 1.68% were resistant to only one antibiotic, 0.14% had rifampicine-resistant TB (RR-TB), 0.28% had MDR-TB, and 0.14% had extensively drug-resistant TB (XDR-TB).

CONCLUSIONS

The mortality rate among TB patients was found to be 22 per 1000 person-year at our center. TB was associated with high mortality rates among males, the elderly, and patients with cancer, respiratory illness, and other comorbidities. Future clinical practice should include establishing an efficient TB diagnostic program and continued hazard assessment of TB treatment options.

Genetic diversity of Mycobacterium tuberculosis strains circulating in Botswana

BACKGROUND

Molecular typing of Mycobacterium tuberculosis (M.tb) isolates can inform Tuberculosis (TB) control programs on the relative proportion of transmission driving the TB epidemic. There is limited data on the M. tb genotypes that are circulating in Botswana. The aim of this study was to generate baseline data on the genetic diversity of M.tb isolates circulating in the country.

METHODS

A total of 461 M.tb isolates received at the Botswana National Tuberculosis Reference Laboratory between March 2012 and October 2013 were included in this study. Drug susceptibility testing was conducted using the BD BACTEC MGIT 960 System. M.tb strains were genotyped using spoligotyping and spoligotype patterns were compared with existing patterns in the SITVIT Web database. A subset of drug resistant isolates which formed spoligo clusters (n = 65) was additionally genotyped with 12-loci MIRU. Factors associated with drug resistance and clustering were evaluated using logistic regression.

RESULTS

Of the 461 isolates genotyped, 458 showed 108 distinct spoligotype patterns. The predominant M.tb lineages were Lineage 4 (81.9%), Lineage 2 (9%) and Lineage 1 (7.2%). The predominant spoligotype families within Lineage 4 were LAM (33%), S (14%), T (16%), X (16%). Three hundred and ninety-two (86%) isolates could be grouped into 44 clusters (2-46 isolates per cluster); giving a clustering rate of 76%. We identified 173 (37.8%) drug resistant isolates, 48 (10.5%) of these were multi-drug resistant. MIRU typing of the drug resistant isolates allowed grouping of 46 isolates into 14 clusters, giving a clustering rate of 49.2%. There was no association between age, sex, treatment category, region and clustering.

CONCLUSIONS

This study highlights the complexity of the TB epidemic in Botswana with multiple strains contributing to disease and provides baseline data on the population structure of M.tb strains in Botswana.

Intestinal dysbiosis compromises alveolar macrophage immunity to Mycobacterium tuberculosis

Current treatments for tuberculosis (TB) are effective in controlling Mycobacterium tuberculosis (Mtb) growth, yet have significant side effects and do not prevent reinfection. Therefore, it is critical to understand why our host defense system is unable to generate permanent immunity to Mtb despite prolonged anti-tuberculosis therapy (ATT). Here, we demonstrate that treatment of mice with the most widely used anti-TB drugs, rifampicin (RIF) or isoniazid (INH) and pyrazinamide (PYZ), significantly altered the composition of the gut microbiota. Unexpectedly, treatment of mice with the pro-Mtb drugs INH and PYZ, but not RIF, prior to Mtb infection resulted in an increased bacterial burden, an effect that was reversible by fecal transplantation from untreated animals. Mechanistically, susceptibility of INH/PYZ-treated mice was associated with impaired metabolism of alveolar macrophages and defective bactericidal activity. Collectively, these data indicate that dysbiosis induced by ATT administered to millions of individuals worldwide may have adverse effects on the anti-Mtb response of alveolar macrophages.

Synthesis and biological activity of Ub2 derived peptides as potential host-directed antitubercular therapy

The correlation of mycobactericidal property of macrophages with its potential to deliver bacteria to hydrolytic lysosomes, augmented with ubiquitin-derived peptides (Ub2), activates the process of autophagy. This leads to the formation of phagolysosomes supported by factor involving increased cationic charges which regulate the acidic pH causing elimination of Mycobacterium. To better understand this interaction of cationic-rich ubiquitin-derived peptides with mycobacteria and to identify putative mycobacterial intrinsic resistance mechanisms for phagolysosome formation, we have synthesized a new series of Ub2 peptides, wherein the Gly residues are replaced with azaGly with the aim to improve metabolic stability. In addition to that a new methodology is reported for the synthesis of heteroaryl tethered peptides using azaGly as a linker. We have demonstrated that positive puncta (directly proportional to the acidification of lysosome) in cytosol was significantly increased after 6 hours on the treatment of macrophage with Ub2 peptide derivatives (1, 6, 10, and 11) causing the higher intensity of lysosome observed through LysoTracker Red Dye. The circular dichroism spectral studies are carried out in water and water:TFE mixture and demonstrated that the Ub2 peptides have helix-forming tendency in the presence of TFE. The recognizable intracellular killing of Mycobacterium tuberculosis by Ub2 peptides provides a new approach for host-directed therapy.

Constructing care cascades for active tuberculosis: A strategy for program monitoring and identifying gaps in quality of care

The cascade of care is a model for evaluating patient retention across sequential stages of care required to achieve a successful treatment outcome. This approach was first used to evaluate HIV care and has since been applied to other diseases. The tuberculosis (TB) community has only recently started using care cascade analyses to quantify gaps in quality of care. In this article, we describe methods for estimating gaps (patient losses) and steps (patients retained) in the care cascade for active TB disease. We highlight approaches for overcoming challenges in constructing the TB care cascade, which include difficulties in estimating the population-level burden of disease and the diagnostic gap due to the limited sensitivity of TB diagnostic tests. We also describe potential uses of this model for evaluating the impact of interventions to improve case finding, diagnosis, linkage to care, retention in care, and post-treatment monitoring of TB patients.

Delineating the factors associated with recurrence of tuberculosis in programmatic settings of rural health block, Himachal Pradesh, India

BACKGROUND

Tuberculosis (TB) recurrence observed to be an important event in its treatment and has future implications under national TB control efforts. The present study was carried out to assess the recurrence rate along with its risk factors among patients undergoing treatment for TB under Revised National TB Control Program (RNTCP).

MATERIAL AND METHODS

Total 204 patients in health block of district Una, Himachal Pradesh were studied using pretested structured interviewer-administered questionnaire. Along with univariate a non-hierarchal multi-way frequency analysis (MFA) was done to study the one and multi-way effects between the discrete variables included in a hypothesized model. The variables were under-nutrition, pulmonary TB, injecting drug use (IDU), multi-drug resistant (MDR) TB, and past TB (recurrent cases).

RESULTS

Total 29 cases (14.2%) had recurrence (17.7/100,000 population) with significantly high fraction for alternate residence (Recurrent: 50.0%, Non-recurrent: 47.4%; p = 0.001), Multi-drug resistance (MDR) TB (Recurrent: 13.8%, Non-recurrent: 2.3%; p = 0.003), and sputum negative patients (Recurrent: 51.7%, Non-recurrent: 14.5%; p = 0.000). Non-recurrent cases had significantly high fraction for sputum positive cases (Recurrent: 48.3%, Non-recurrent: 72.1%; p = 0.011), and extra-pulmonary TB (Recurrent: 00.0%, Non-recurrent: 13.4%; p = 0.036). MFA observed all significant one-way effects. Significant two-way effects were IDU and pulmonary TB (p = 0.001), MDR and past TB (p = 0.004), IDU and past TB (p = 0.019), and IDU and MDR-TB (p = 0.039).

CONCLUSION

Proportion of TB recurrence was expected with a significant difference between the history of change of residence, MDR-TB, pulmonary and extra-pulmonary nature of the disease. Hypothesized model observed with a significant association of IDU, pulmonary TB, MDR-TB and past TB.

Compensatory evolution drives multidrug-resistant tuberculosis in Central Asia

Bacterial factors favoring the unprecedented multidrug-resistant tuberculosis (MDR-TB) epidemic in the former Soviet Union remain unclear. We utilized whole genome sequencing and Bayesian statistics to analyze the evolutionary history, temporal emergence of resistance and transmission networks of MDR Mycobacterium tuberculosis complex isolates from Karakalpakstan, Uzbekistan (2001-2006). One clade (termed Central Asian outbreak, CAO) dating back to 1974 (95% HPD 1969-1982) subsequently acquired resistance mediating mutations to eight anti-TB drugs. Introduction of standardized WHO-endorsed directly observed treatment, short-course in Karakalpakstan in 1998 likely selected for CAO-strains, comprising 75% of sampled MDR-TB isolates in 2005/2006. CAO-isolates were also identified in a published cohort from Russia (2008-2010). Similarly, the presence of mutations supposed to compensate bacterial fitness deficits was associated with transmission success and higher drug resistance rates. The genetic make-up of these MDR-strains threatens the success of both empirical and standardized MDR-TB therapies, including the newly WHO-endorsed short MDR-TB regimen in Uzbekistan.

Comparison of different treatments for isoniazid-resistant tuberculosis: an individual patient data meta-analysis

BACKGROUND

Isoniazid-resistant, rifampicin-susceptible (INH-R) tuberculosis is the most common form of drug resistance, and is associated with failure, relapse, and acquired rifampicin resistance if treated with first-line anti-tuberculosis drugs. The aim of the study was to compare success, mortality, and acquired rifampicin resistance in patients with INH-R pulmonary tuberculosis given different durations of rifampicin, ethambutol, and pyrazinamide (REZ); a fluoroquinolone plus 6 months or more of REZ; and streptomycin plus a core regimen of REZ.

METHODS

Studies with regimens and outcomes known for individual patients with INH-R tuberculosis were eligible, irrespective of the number of patients if randomised trials, or with at least 20 participants if a cohort study. Studies were identified from two relevant systematic reviews, an updated search of one of the systematic reviews (for papers published between April 1, 2015, and Feb 10, 2016), and personal communications. Individual patient data were obtained from authors of eligible studies. The individual patient data meta-analysis was performed with propensity score matched logistic regression to estimate adjusted odds ratios (aOR) and risk differences of treatment success (cure or treatment completion), death during treatment, and acquired rifampicin resistance. Outcomes were measured across different treatment regimens to assess the effects of: different durations of REZ (≤6 months vs >6 months); addition of a fluoroquinolone to REZ (fluoroquinolone plus 6 months or more of REZ vs 6 months or more of REZ); and addition of streptomycin to REZ (streptomycin plus 6 months of rifampicin and ethambutol and 1-3 months of pyrazinamide vs 6 months or more of REZ). The overall quality of the evidence was assessed using GRADE methodology.

FINDINGS

Individual patient data were requested for 57 cohort studies and 17 randomised trials including 8089 patients with INH-R tuberculosis. We received 33 datasets with 6424 patients, of which 3923 patients in 23 studies received regimens related to the study objectives. Compared with a daily regimen of 6 months of (H)REZ (REZ with or without isoniazid), extending the duration to 8-9 months had similar outcomes; as such, 6 months or more of (H)REZ was used for subsequent comparisons. Addition of a fluoroquinolone to 6 months or more of (H)REZ was associated with significantly greater treatment success (aOR 2·8, 95% CI 1·1-7·3), but no significant effect on mortality (aOR 0·7, 0·4-1·1) or acquired rifampicin resistance (aOR 0·1, 0·0-1·2). Compared with 6 months or more of (H)REZ, the standardised retreatment regimen (2 months of streptomycin, 3 months of pyrazinamide, and 8 months of isoniazid, rifampicin, and ethambutol) was associated with significantly worse treatment success (aOR 0·4, 0·2-0·7). The quality of the evidence was very low for all outcomes and treatment regimens assessed, owing to the observational nature of most of the data, the diverse settings, and the imprecision of estimates.

INTERPRETATION

In patients with INH-R tuberculosis, compared with treatment with at least 6 months of daily REZ, addition of a fluoroquinolone was associated with better treatment success, whereas addition of streptomycin was associated with less treatment success; however, the quality of the evidence was very low. These results support the conduct of randomised trials to identify the optimum regimen for this important and common form of drug-resistant tuberculosis.

FUNDING

World Health Organization and Canadian Institutes of Health Research.

Ursolic acid and carvacrol may be potential inhibitors of dormancy protein small heat shock protein16.3 of Mycobacterium tuberculosis

Small heat shock protein16.3 (sHSP16.3) is a crucial protein for survival of Mycobacterium tuberculosis (MTB) in its host. Besides, this protein acts as a molecular chaperone during stress and is indispensable for MTB's growth, virulence and cell-wall thickening. sHSP16.3 is also a promising candidate for vaccine, serodiagnosis and drug design as well. In the present study, we have targeted sHSP16.3 with two phytochemicals, namely ursolic acid and carvacrol using in silico approach. Molecular docking analysis showed that both phytochemicals (ursolic acid and carvacrol) have docked with sHSP16.3 and shown tendency to inhibit the function of this vital protein of MTB. In addition, both compounds have exhibited strong compatibility with sHSP16.3 during whole 60 ns duration of molecular dynamics simulation. Further, the molecular mechanic/generalized Born/Poisson-Boltzmann surface area (MM/G/P/BSA) free energies were calculated which showed that both phytocompounds have stable and favourable binding energies causing strong binding with binding site of sHSP16.3. Taking together, the data of present study suggest that both phytocompounds may be potential inhibitor of sHSP16.3 of MTB and a best alternative to standard anti-tuberculosis drugs.

Tubercular septal abscess in a postoperative patient: a novel entity

Extrapulmonary tuberculosis is a rather uncommon and potentially challenging phenomenon. Such manifestation, particularly in the scenario of a late postoperative period, is extremely rare and requires a high index of suspicion, prompt diagnosis and appropriate treatment.We present the case scenario of a patient with history of successfully treated pulmonary tuberculosis many years earlier, without any signs of recurrence, who developed primary nasal septal tuberculosis after undergoing septoplasty to correct his septal deviation. His postoperative course remained uneventful for 4 months. He then presented with a spontaneous nasal septal abscess, which proved to be tubercular in nature on investigations. Appropriate diagnosis was established, and the patient was treated successfully with antituberculous therapy.Recurrent tuberculosis may present a diagnostic challenge for healthcare professionals. Only a high index of suspicion, modern diagnostic tools and institution of appropriate treatment including surgical intervention as required will ensure a promising outcome.

Relapse Versus Reinfection of Recurrent Tuberculosis Patients in a National Tuberculosis Specialized Hospital in Beijing, China

Tuberculosis (TB) recurrence can result from either relapse of an original infection or exogenous reinfection with a new strain of Mycobacterium tuberculosis (MTB). The aim of this study was to assess the roles of relapse and reinfection among recurrent TB cases characterized by a high prevalence rate of drug-resistant TB within a hospital setting. After 58 paired recurrent TB cases were genotyped to distinguish relapse from reinfection, 37 (63.8%) were demonstrated to be relapse cases, while the remaining 21 were classified as reinfection cases. Statistical analysis revealed that male gender was a risk factor for TB reinfection, odds ratios and 95% confidence interval (OR [95% CI]: 4.188[1.012–17.392], P = 0.049). Of MTB isolates obtained from the 37 relapse cases, 11 exhibited conversion from susceptible to resistance to at least one antibiotic, with the most frequent emergence of drug resistance observed to be levofloxacin. For reinfection cases, reemergence of rifampicin-resistant isolates harboring double gene mutations, of codon 531 of rpoB and codon 306 of embB, were observed. In conclusion, our data demonstrate that relapse is a major mechanism leading to TB recurrence in Beijing Chest Hospital, a national hospital specialized in TB treatment. Moreover, male patients are at higher risk for reinfection. The extremely high rate of multidrug-resistant tuberculosis (MDR-TB) among reinfection cases reflects more successful transmission of MDR-TB strains versus non-resistant strains overall.

A nested case-control study of predictors for tuberculosis recurrence in a large UK Centre

Background

Tuberculosis (TB) recurrence represents a challenge to control programs. In low incidence countries, the prevailing risk factors leading to recurrence are poorly characterised.

Methods

We conducted a nested case–control study using the Leicester TB service TBIT database. Cases were identified from database notifications between 1994 and 2014. Controls had one episode and were matched to cases on a ratio of two to one by the date of notification. Multiple imputation was used to account for missing data. Multivariate conditional logistic regression analysis was employed to identify clinical, sociodemographic and TB specific risk factors for recurrence.

Results

From a cohort of 4628 patients, 82 TB recurrences occurred (1.8%). Nineteen of 82 patients had paired isolates with MIRU-VNTR strain type profiles available, of which 84% were relapses and 16% reinfections. On multivariate analysis, smoking (OR 3.8; p = 0.04), grade 3/4 adverse drug reactions (OR 5.6; p = 0.02), ethnicity ‘Indian subcontinent’ (OR 8.5; p = <0.01), ethnicity ‘other’ (OR 31.2; p = 0.01) and receipt of immunosuppressants (OR 6.8; p = <0.01) were independent predictors of TB recurrence.

Conclusions

Within this UK setting, the rate of TB recurrence was low, predominantly due to relapse. The identification of an elevated recurrence risk amongst the ethnic group contributing most cases to the national TB burden presents an opportunity to improve individual and population health.

Electronic supplementary material

The online version of this article (10.1186/s12879-017-2933-4) contains supplementary material, which is available to authorized users.

Factors associated with tuberculosis retreatment in priority districts of Maranhão, Brazil

This study investigated factors associated with cases of tuberculosis retreatment due to relapse and readmission after treatment abandonment. This is an analytical cross-sectional study type of cases reported in the Information System for Notifiable Diseases in priority municipalities in the State of Maranhão, from January 2005 to December 2010. A logistic regression model was used to identify the association. Patients aged between 40 and 59 years (OR = 1.49, p = 0.029) with a pulmonary clinical form (OR = 2.79, p = 0.016) were more likely to incur relapse. Readmissions after abandonment were more likely in males (OR = 1.53, p = 0.046), aged between 20 and 39 years (OR = 1.65, p = 0.007), with less than eight years of schooling (OR = 2.01, p = 0.037) and with alcohol dependence (OR=1.66, p = 0.037), which showed a higher probability of another abandonment (OR = 5.96, p < 0.001). These data reinforce the need for strategies aimed at this group, such as increased supervised treatment, intensified active search, post-discharge follow-up and health education action.

Recurrent tuberculosis and associated factors: A five - year countrywide study in Uzbekistan

BACKGROUND

In Uzbekistan, despite stable and relatively high tuberculosis treatment success rates, relatively high rates of recurrent tuberculosis have recently been reported. Recurrent tuberculosis is when a patient who was treated for pulmonary tuberculosis and cured, later develops the disease again. This requires closer analysis to identify possible causes and recommend interventions to improve the situation. Using countrywide data, this study aimed to analyse trends in recurrent tuberculosis cases and describe their associations with socio-demographic and clinical factors.

METHOD

Countrywide retrospective cohort study comparing recurrent tuberculosis patients with all new tuberculosis patients registered within the NTP between January 2006 and December 2010 using routinely collected data. Determinants studied were baseline characteristics and treatment outcomes.

RESULTS

Of 107,380 registered patients during the period January 2006 and December 2010, 9358 (8.7%) were recurrent cases. Between 2006 and 2008, the number of recurrent cases per annum increased from 1530 to 2081, then fell slightly thereafter from 2081 to 1888 cases. The proportion of all notified cases during this period increased from 6.5% to 9.9%. Factors associated with recurrent tuberculosis included age (35-55 years old), having smear positive pulmonary tuberculosis, residing in certain areas of Uzbekistan, having particular co-morbidities (including chronic obstructive pulmonary disease and HIV), and being unemployed, a pensioner or disabled. Recurrent tuberculosis patients also had a higher likelihood of having an unfavourable treatment outcome.

CONCLUSION

Despite signs of declining national tuberculosis notifications between 2006 and 2010, the relative proportion of recurrent cases appears to have increased. These findings, together with the identification of possible risk factors associated with recurrent tuberculosis, highlight various areas where Uzbekistan needs to focus its tuberculosis control efforts, particularly in light of the country's rapidly emerging multi drug resistant tuberculosis epidemic.

Recurrent tuberculosis in an urban area in China: Relapse or exogenous reinfection?

Recurrent tuberculosis is an important indicator of the effectiveness of tuberculosis control and can occur by relapse or exogenous reinfection. We conducted a retrospective cohort study on all bacteriologically confirmed tuberculosis cases that were successfully treated between 2000 and 2012 in Shanghai, an urban area with a high number but a low prevalence rate of tuberculosis cases and a low prevalence of HIV infection. Genotyping the Mycobacterium tuberculosis from clinical isolates was used to distinguish between relapse and reinfection. In total, 5.3% (710/13,417) of successfully treated cases had a recurrence, a rate of 7.55 (95% CI 7.01-8.13) episodes per 1000 person-years, more than 18 times the rate of tuberculosis in the general population. Patients who were male, age 30-59, retreatment cases, had cavitation, diabetes, drug-resistant or multidrug-resistant tuberculosis in their initial episode of tuberculosis, were at high risk for a recurrence. Among 141 recurrent cases that had paired isolates, 59 (41.8%) had different genotypes, indicating reinfection with a different strain. Patients who completed treatment were still at high risk of another episode of tuberculosis and exogenous reinfection contributed a significant proportion of the recurrent tuberculosis cases. Targeted control strategies are needed to prevent new tuberculosis infections in this setting.

Genetic diversity, transmission dynamics and drug resistance of Mycobacterium tuberculosis in Angola

Tuberculosis (TB) poses a serious public health problem in Angola. No surveillance data on drug resistance is available and nothing is known regarding the genetic diversity and population structure of circulating Mycobacterium tuberculosis strains. Here, we have genotyped and evaluated drug susceptibility of 89 Mycobacterium tuberculosis clinical isolates from Luanda. Thirty-three different spoligotype profiles corresponding to 24 different Shared International Types (SIT) and 9 orphan profiles were detected. SIT 20 (LAM1) was the most prevalent (n = 16, 18.2%) followed by SIT 42 (LAM9; n = 15, 17.1%). Overall, the M. tuberculosis population structure in this sample was dominated by LAM (64.8%) and T (33.0%) strains. Twenty-four-loci MIRU-VNTR analysis revealed that a total of 13 isolates were grouped in 5 distinct clusters. Drug susceptibility data showed that 22 (24.7%) of the 89 clinical isolates were resistant to one or more antibacillary drugs of which 4 (4.5%) were multidrug resistant. In conclusion, this study demonstrates a high predominance of LAM strains circulating in the Luanda setting and the presence of recent transmission events. The rate and the emergence dynamics of drug resistant TB found in this sample are significant and highlight the need of further studies specifically focused on MDR-TB transmission.

Impact of Multidrug Resistance on Tuberculosis Recurrence and Long-Term Outcome in China

Little is known about the impact of drug resistance on recurrence in TB. We conducted a cohort study to measure the impact of multi-drug resistance (MDR) on TB recurrence over nine years in Henan Province China. We reviewed medical records and conducted field interviews of 100 MDR and 150 non-MDR TB patients who were treated between 2001 and 2002. We compared long-term recurrence rates, risk factors, and outcomes in 2010 for 234 individuals who could be followed up. About one third (29.5%, 69/234) suffered recurrence after completion of treatment. The overall recurrence rate was 35/1,000 patient-years (PY), with a much higher rate (65/1,000 PY) among MDR-TB patients. MDR (HR: 2.75; CI: 1.58–4.79) and patient annual household income less than 10,000 Yuan (HR: 2.05; CI 1.11–3.80) were associated with recurrence. The mean time for recurrence among MDR-TB patients was 5.7 years, compared to 7.2 years among non-MDR-TB patients. Among the recurrence group members, 61.3% died, and 18.8% had failed treatments. We believe that the high TB recurrence rate after 9 years suggests that a high cure rate cannot accurately predict long-term outcome. We recommend that TB surveillance and control should be strengthened with a focus on MDR-TB and directly observed treatment, to reduce TB recurrence and transmission of MDR-TB.

Treatment of isoniazid-resistant tuberculosis with first-line drugs: a systematic review and meta-analysis

BACKGROUND

The results of some reports have suggested that treatment of isoniazid-resistant tuberculosis with the recommended regimens of first-line drugs might be suboptimal. We updated a previous systematic review of treatment outcomes associated with use of first-line drugs in patients with tuberculosis resistant to isoniazid but not rifampicin.

METHODS

In this systematic review, we updated the results of a previous review to include randomised trials and cohort studies published in English, French, or Spanish to March 31, 2015, containing results of standardised treatment of patients with bacteriologically confirmed isoniazid-resistant tuberculosis (but not multidrug-resistant tuberculosis-ie, not resistant to rifampicin) in whom failure and relapse were bacteriologically confirmed. Results in patients with drug-sensitive tuberculosis included in the same studies were also analysed. We pooled treatment outcomes with random-effects meta-analysis.

FINDINGS

We identified 19 cohort studies and 33 trials with 3744 patients with isoniazid-resistant tuberculosis and 19 012 patients with drug-sensitive disease. The pooled rates of failure or relapse, or both, and acquired drug resistance with all drug regimens were 15% (95% CI 12-18) and 3·6% (2-5), respectively, in patients with isoniazid-resistant tuberculosis and 4% (3-5) and 0·6% (0·3-0·9) in those with drug-sensitive tuberculosis. Of patients with initial isoniazid-resistant tuberculosis with acquired drug resistance, 96% (93-99) had acquired multidrug-resistant disease. Treatment of isoniazid-resistant tuberculosis with the WHO standard regimen for new patients resulted in treatment failure, relapse, and acquired multidrug resistance in 11% (6-17), 10% (5-15) and 8% (3-13), respectively; treatment with the standard WHO regimen for previously treated patients resulted in treatment failure in 6% (2-10), relapse in 5% (2-8), and acquisition of multidrug resistance in 3% (0-6). For patients with drug-sensitive disease treated with the standard retreatment regimen the rates were 1% (0-2), 5% (4-7), and 0·3% (0-0·6).

INTERPRETATION

Treatment of isoniazid-resistant tuberculosis with first-line drugs resulted in suboptimal outcomes, supporting the need for better regimens. Standardised empirical treatment of new cases could be contributing substantially to the multidrug-resistant epidemic, particularly in settings where the prevalence of isoniazid resistance is high.

FUNDING

Canadian Institutes of Health Research.

Multidrug-resistant tuberculosis treatment failure detection depends on monitoring interval and microbiological method

Debate persists about monitoring method (culture or smear) and interval (monthly or less frequently) during treatment for multidrug-resistant tuberculosis (MDR-TB). We analysed existing data and estimated the effect of monitoring strategies on timing of failure detection.

We identified studies reporting microbiological response to MDR-TB treatment and solicited individual patient data from authors. Frailty survival models were used to estimate pooled relative risk of failure detection in the last 12 months of treatment; hazard of failure using monthly culture was the reference.

Data were obtained for 5410 patients across 12 observational studies. During the last 12 months of treatment, failure detection occurred in a median of 3 months by monthly culture; failure detection was delayed by 2, 7, and 9 months relying on bimonthly culture, monthly smear and bimonthly smear, respectively. Risk (95% CI) of failure detection delay resulting from monthly smear relative to culture is 0.38 (0.34–0.42) for all patients and 0.33 (0.25–0.42) for HIV-co-infected patients.

Failure detection is delayed by reducing the sensitivity and frequency of the monitoring method. Monthly monitoring of sputum cultures from patients receiving MDR-TB treatment is recommended. Expanded laboratory capacity is needed for high-quality culture, and for smear microscopy and rapid molecular tests.

Monthly culture monitoring is crucial to earlier detection of treatment failure in MDR-TB patientshttp://ow.ly/w2MI301mK8M

A novel therapeutic strategy of lipidated promiscuous peptide against Mycobacterium tuberculosis by eliciting Th1 and Th17 immunity of host

Regardless of the fact that potent drug-regimen is currently available, tuberculosis continues to kill 1.5 million people annually. Tuberculosis patients are not only inflicted by the trauma of disease but they also suffer from the harmful side-effects, immune suppression and drug resistance instigated by prolonged therapy. It is an exigency to introduce radical changes in the existing drug-regime and discover safer and better therapeutic measures. Hence, we designed a novel therapeutic strategy by reinforcing the efficacy of drugs to kill Mtb by concurrently boosting host immunity by L91. L91 is chimera of promiscuous epitope of Acr1 antigen of Mtb and TLR-2 agonist Pam2Cys. The adjunct therapy using drugs and L91 (D-L91) significantly declined the bacterial load in Mtb infected animals. The mechanism involved was through enhancement of IFN-γ⁺TNF-α⁺ polyfunctional Th1 cells and IL-17A⁺IFN-γ⁺ Th17 cells, enduring memory CD4 T cells and downregulation of PD-1. The down-regulation of PD-1 prevents CD4 T cells from undergoing exhaustion and improves their function against Mtb. Importantly, the immune response observed in animals could be replicated using T cells of tuberculosis patients on drug therapy. In future, D-L91 therapy can invigorate drugs potency to treat tuberculosis patients and reduce the dose and duration of drug-regime.

Determining treatment outcome of smear-positive pulmonary tuberculosis cases in Afar Regional State, Ethiopia: A retrospective facility based study

OBJECTIVE/BACKGROUND

The World Health Organization (WHO) declared tuberculosis (TB) as a global public health emergency and recommended directly observed treatment, short-course (DOTS) as a standard strategy to control the disease. In Ethiopia the strategy was started in 1992 as a pilot in the Arsi and Bale zone, Oromia Region. The DOTS strategy has been subsequently scaled up in the country and implemented at a national level reaching better coverage, although there are recognizable variations from region to region and district to district. The aim of this study was to assess the impact of the DOTS strategy on smear-positive pulmonary TB case findings and their treatment outcomes in the Afar Regional State, Ethiopia, from 2003 to 2012 and from 2002 to 2011, respectively.

METHODS

A health facility-based retrospective study was conducted. Data were collected and reported on a quarterly basis using the WHO reporting format for TB case findings and their treatment outcomes from all DOTS-implementing health facilities in all zones of the region to the Federal Ministry of Health.

RESULTS

A total of 34,894 of TB cases had been registered in the period from 2003 to 2012. Out of these, 11,595 (33.2%) were smear-positive pulmonary TB, 13,859 (39.7%) smear-negative pulmonary TB, and 9838 (28.2%) extrapulmonary TB. The case detection rate (CDR) of smear-positive pulmonary TB had increased from 18.3% to 37.2%, with the average value being 32% (standard deviation=6.8) from the total TB cases to its peak of 39% in 2008. The treatment success rate (TSR) had an average value of 86.2% from 2002 to 2011 with its peak value being 96.5% in 2007. Moreover, the average values of treatment defaulter and treatment failure rate were 2.9% and 2.7%, respectively.

CONCLUSION

The implementation for the DOTS strategy in the area improved the CDR of smear-positive TB, although it is unacceptably lower than the recommended WHO target of 70%. Additionally, the WHO target of 85% for TSR had already been achieved in the region. However, continued efforts should be in place to increase the CDR and maintain the high TSR registered.

The incidence of recurrence of tuberculosis and its related factors in smear-positive pulmonary tuberculosis patients in Iran: A retrospective cohort study

Background and Aim:

Studying the recurrence of smear-positive pulmonary tuberculosis (TB) is a convenient way to evaluate the effectiveness of TB control programs and identify vulnerable patients. In the present study, the rate of recurrence of TB and its predictors were determined in Iran.

Materials and Methods:

This study was a retrospective cohort. Eligible people were patients with smear-positive TB who were diagnosed from 2002 to 2011. The end of the follow-up time was December 2013. The number of people who entered the cohort was 1,271 subjects. In order to determine the predictors of recurrence, multivariate logistic regression was used. Analysis was done using SPSS 20.

Results:

The recurrence incidence was 8.3% and in 85.9% of these patients, it occurred in the time interval of 1-5 years after successful treatment. The recurrence rate was not significantly related to gender, age group, and diabetes. But it was significantly higher in patients whose sputum smear grading before treatment was 2 + or more, patients with positive sputum smear at the end of the second month of the treatment, patients who had completed treatment, and patients who were smokers (P < 0.05).

Conclusions:

Our study showed that a considerable percentage of smear-positive pulmonary TB patients experience recurrence and that some patients are at a higher risk of recurrence.

Predicting the Incidence of Smear Positive Tuberculosis Cases in Iran Using Time Series Analysis

BACKGROUND

Determining the temporal variation and forecasting the incidence of smear positive tuberculosis (TB) can play an important role in promoting the TB control program. Its results may be used as a decision-supportive tool for planning and allocating resources. The present study forecasts the incidence of smear positive TB in Iran.

METHODS

This a longitudinal study using monthly tuberculosis incidence data recorded in the Iranian National Tuberculosis Control Program. The sum of registered cases in each month created 84 time points. Time series methods were used for analysis. Based on the residual chart of ACF, PACF, Ljung-Box tests and the lowest levels of AIC and BIC, the most suitable model was selected.

RESULTS

From April 2005 until March 2012, 34012 smear positive TB cases were recorded. The mean of TB monthly incidence was 404.9 (SD=54.7). The highest number of cases was registered in May and the difference in monthly incidence of smear positive TB was significant (P<0.001). SARIMA (0,1,1)(0,1,1)12 was selected as the most adequate model for prediction. It was predicted that the incidence of smear positive TB for 2015 will be about 9.8 per 100,000 people.

CONCLUSION

Based on the seasonal pattern of smear positive TB recorded cases, seasonal ARIMA model was suitable for predicting its incidence. Meanwhile, prediction results show an increasing trend of smear positive TB cases in Iran.

Directly observed treatment short-course (DOTS) for treatment of new tuberculosis cases in Somali Regional State, Eastern Ethiopia: ten years retrospective study

Background

A third of the world population is infected with tuberculosis (TB) bacilli. TB accounts for 25 % of all avoidable deaths in developing countries. The objective of the study was to assess impact of directly observed treatment short-course (DOTS) strategy on new tuberculosis case finding and treatment outcomes in Somali Regional State, Ethiopia from 2003 up to 2012 and from 2004 up to 2013, respectively.

Methods

A health facility based retrospective study was employed. Quarterly reports were collected using World Health Organization (WHO) reporting format for TB case finding and treatment outcome from all zones in the region to the Federal Ministry of Health.

Results

A total of 31, 198 all types of new TB cases were registered and reported during the period from 2003 up to 2012, in the region. Out of these, smear positive pulmonary TB cases were 12,466 (40 %), and 10,537 (33.8 %) and 8195 (26.2 %) for smear negative pulmonary TB and extra-pulmonary TB cases, respectively. An average case detection rate (CDR) of 19.1 % (SD 3.6) and treatment success rate (TSR) of 85.5 % (SD 5.0) for smear positive pulmonary TB were reported for the specified years period. For the overall study period, trend chi-squire analysis for CDR was X² = 2.1; P > 0.05 and X² = 5.64; P < 0.05 for TSR.

Conclusions

The recommended TSR set by WHO was achieved (85.5 %) and the CDR reported was far below (19.1 %) from the recommended target. Extensive efforts should be established to maintain the achieved TSR and to increase the low CDR for the smear positive pulmonary TB cases through implementing alternative case finding strategies.

Resistance profile and risk factors of drug resistant tuberculosis in the Baltic countries

The rates of multi- and extensively drug-resistant tuberculosis (X/MDRTB) in the Baltic countries are the highest within the European Union hampering recent achievements of national TB control programmes. We included all consecutive culture-confirmed X/MDRTB patients registered for treatment in 2009 in Latvia, Lithuania and Estonia into this multicenter case-control study. Cases were compared with randomly selected controls with non-MDRTB registered for treatment in the same year across these sites. Of 495 MDRTB patients, 243 (49.7%) showed resistance to at least one second-line drug, 206 (42.1%) had pre-XDRTB (i.e. MDRTB with additional resistance to a second-line injectable or fluoroquinolones) and 64 (13.1%) had XDRTB. Younger age, male gender and known contact with an MDRTB case were associated with increased risk of primary infection with X/MDRTB strains. Previous treatment and alcohol abuse were strong predictors for MDRTB acquisition; defaults and failures in the past triggered XDRTB development. All patients received appropriate therapy; less than half of the patients were fully adherent. An erroneous treatment strategy is unlikely to drive resistance development. Increasing patients' compliance, addressing issues of social support, rapid detection of drug resistance and improving infection control is crucial for prevention of further spread of X/MDRTB and achieving higher cure rates.

Tuberculosis-related knowledge is associated with patient outcomes in shantytown residents; results from a cohort study, Peru

OBJECTIVES

Tuberculosis is frequent among poor and marginalized people whose limited tuberculosis-related knowledge may impair healthcare access. We characterised tuberculosis-related knowledge and associations with delayed treatment and treatment outcome.

METHODS

Tuberculosis patients (n = 943), people being tested for suspected tuberculosis (n = 2020), and randomly selected healthy controls (n = 476) in 16 periurban shantytowns were interviewed characterizing: socio-demographic factors; tuberculosis risk-factors; and patients' treatment delay. Principle component analysis was used to generate a tuberculosis-related knowledge score. Patients were followed-up for median 7.7 years. Factors associated with tuberculosis treatment delay, treatment outcome and tuberculosis recurrence were assessed using linear, logistic and Cox regression.

RESULTS

Tuberculosis-related knowledge was poor, especially in older people who had not completed schooling and had never been diagnosed with tuberculosis. Tuberculosis treatment delay was median 60 days and was more delayed for patients who were poorer, older, had more severe tuberculosis and in only unadjusted analysis with incomplete schooling and low tuberculosis-related knowledge (all p ≤ 0.03). Lower than median tuberculosis-related knowledge was associated with tuberculosis recurrence (unadjusted hazard ratio = 2.1, p = 0.008), and this association was independent of co-morbidities, disease severity and demographic factors (multiple regression adjusted hazard ratio = 2.6, p = 0.008).

CONCLUSIONS

Low tuberculosis-related knowledge independently predicted tuberculosis recurrence. Thus health education may improve tuberculosis prognosis.