Recurrent tuberculosis in the pre-elimination era

The Mechanism of Inhibition of Mycobacterial (p)ppGpp Synthetases by a Synthetic Analog of Erogorgiaene

The synthesis of (p)ppGpp alarmones plays a vital role in the regulation of metabolism suppression, growth rate control, virulence, bacterial persistence, and biofilm formation. The (p)ppGpp alarmones are synthesized by proteins of the RelA/SpoT homolog (RSH) superfamily, including long bifunctional RSH proteins and small alarmone synthetases. Here, we investigated enzyme kinetics and dose-dependent enzyme inhibition to elucidate the mechanism of 4-(4,7-dimethyl-1,2,3,4-tetrahydronaphthalen-1-yl)pentanoic acid (DMNP) action on the (p)ppGpp synthetases RelMsm and RelZ from Mycolicibacterium smegmatis and RelMtb from Mycobacterium tuberculosis. DMNP was found to inhibit the activity of RelMtb. According to the enzyme kinetics analysis, DMNP acts as a noncompetitive inhibitor of RelMsm and RelZ. Based on the results of molecular docking, the DMNP-binding site is located in the proximity of the synthetase domain active site. This study might help in the development of alarmone synthetase inhibitors, which includes relacin and its derivatives, as well as DMNP - a synthetic analog of the marine coral metabolite erogorgiaene. Unlike conventional antibiotics, alarmone synthetase inhibitors target metabolic pathways linked to the bacterial stringent response. Although these pathways are not essential for bacteria, they regulate the development of adaptation mechanisms. Combining conventional antibiotics that target actively growing cells with compounds that impede bacterial adaptation may address challenges associated with antimicrobial resistance and bacterial persistence.

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.

Recurrent Tuberculosis Treatment Episodes in Children Presenting With Presumptive Pulmonary Tuberculosis in Cape Town, South Africa

BACKGROUND

Limited data are available on tuberculosis (TB) recurrence in children. The aim of this study was to explore the burden of and risk factors for recurrent TB treatment in children.

METHODS

A prospective, observational cohort study of children (0-13 years) presenting with presumptive pulmonary TB in Cape Town, South Africa from March 2012 to March 2017. Recurrent TB was defined as more than 1 episode of TB treatment (microbiologically confirmed and unconfirmed).

RESULTS

Of 620 children enrolled with presumptive pulmonary TB, data of 608 children were reviewed for TB recurrence after exclusions. The median age was 16.7 [interquartile range (IQR) 9.5-33.3] months, 324 (53.3%) were male and 72 (11.8%) children living with HIV (CLHIV). TB was diagnosed in 297 out of 608 (48.8%), of whom 26 had previously received TB treatment, giving a prevalence of 8.8% recurrence: 22 (84.6%) had 1 and 4 (15.4%) had 2 prior TB treatment episodes. The median age of children with recurrent TB was 47.5 (IQR: 20.8-82.5) months at the current episode: 19 out of 26 (73.1%) were CLHIV, of whom 12 out of 19 (63.2%) were on antiretroviral therapy for a median 43.1 months and all 12 for longer than 6 months. None of the 9 children on antiretroviral treatment with available viral load (VL) data were virally suppressed (median VL, 22,983 copies/ml). Three of 26 (11.6%) children had documented microbiologically confirmed TB at 2 episodes. Four children (15.4%) received drug-resistant TB treatment at recurrence.

CONCLUSIONS

There was a high rate of recurrent treatment for TB in this cohort of young children, with CLHIV at the highest risk.

Contribution of Reinfection to Annual Rate of Tuberculosis Infection (ARI) and Incidence of Tuberculosis Disease

BACKGROUND

Modeling studies have concluded that 60-80% of tuberculosis (TB) infections result from reinfection of previously infected persons. The annual rate of infection (ARI), a standard measure of the risk of TB infection in a community, may not accurately reflect the true risk of infection among previously infected persons. We constructed a model of infection and reinfection with Mycobacterium tuberculosis to explore the predictive accuracy of ARI and its effect on disease incidence.

METHODS

We created a deterministic simulation of the progression from TB infection to disease and simulated the prevalence of TB infection at the beginning and end of a theoretical year of infection. We considered 10 disease prevalence scenarios ranging from 100/100 000 to 1000/100 000 in simulations where TB exposure probability was homogeneous across the whole simulated population or heterogeneously stratified into high-risk and low-risk groups. ARI values, rates of progression from infection to disease, and the effect of multiple reinfections were obtained from published studies.

RESULTS

With homogeneous exposure risk, observed ARI values produced expected numbers of infections. However, when heterogeneous risk was introduced, observed ARI was seen to underestimate true ARI by 25-58%. Of the cases of TB disease that occurred, 36% were among previously infected persons when prevalence was 100/100 000, increasing to 79% of cases when prevalence was 1000/100 000.

CONCLUSIONS

Measured ARI underestimates true ARI as a result of heterogeneous population mixing. The true force of infection in a community may be greater than previously appreciated. Hyperendemic communities likely contribute disproportionally to the global TB disease burden.

Efficacy and Safety of Adjunctive Recombinant Human Interleukin-2 for Patients with Pulmonary Tuberculosis: A Meta-Analysis

Background. The results of previous clinical trials evaluating the efficacy and safety of recombinant human interleukin-2 (rhuIL-2) for adult patients with pulmonary tuberculosis showed inconsistent results. Accordingly, a comprehensive systematic review and meta-analysis was performed. Methods. Relevant randomized controlled trials (RCTs) were retrieved by searching the PubMed, Embase, Cochrane’s Library, Web of Science, Wanfang, and CNKI databases. A random-effects model was used to combine the results. Results. 18 RCTs with 2630 patients were included in this meta-analysis. Pooled results showed that adjunctive rhuIL-2 significantly increased the odds of sputum culture conversion to negative (risk ratio [RR]: 1.27, 95% CI: 1.09 to 1.47, $p=0.002$ , I2 = 80%), sputum smear conversion to negative (RR: 1.35, 95% CI: 1.17 to 1.57, $p<0.001$ , I2 = 83%), radiographic focus absorption (RR: 1.17, 95% CI: 1.06 to 1.30, $p=0.002$ , I2 = 72), and cavity closure (RR: 1.24, 95% CI: 1.09 to 1.40, $p<0.001$ , I2 = 23). The use of rhuIL-2 was not related to any severe adverse events which led to discontinuation of the treatment. Results showed that rhuIL-2 was related to an increased risk of fever (RR: 2.46, 95% CI: 1.29 to 4.70, $p=0.006$ , I2 = 0%). The incidence of other adverse events, such as musculoskeletal pain, hepatic injury, and renal toxicity, was not significantly different between groups ( $p$ all >0.05). Conclusions. rhuIL-2 is an effective adjunctive immunotherapy for patients with pulmonary tuberculosis.

A rare case series of HIV-negative patients with early relapsing cervical tuberculosis lymphadenitis

Most patients with early recurrent tuberculous lymphadenitis (RTL) can be overlooked due to the paucibacillary character of Mycobacterium tuberculosis complex (MTBC) causing difficulty in the differential diagnosis. Here, we present three cases with early RTL that occurred after completing pulmonary tuberculosis (TB) therapy with a cure, and that improved by early diagnosis and therapy. A 30-year-old migrant male, HIV-negative patient, who had used immunosuppressive drugs for Crohn's disease presented to the TB outpatient clinic with a new anterior cervical lymph node enlargement. Two months ago, his therapy for pulmonary TB and intra-abdominal tuberculous lymphadenitis (TL) was completed. Real-time polymerase chain reaction (RT-PCR) of purulent fine-needle aspiration (FNA) specimen from the anterior cervical lymphadenopathy (LAP) was detected positive for MTBC. Isoniazid (H) resistance was determined via the Seegene system. The 6 cm anterior cervical LAP regressed to a 1.6 cm LAP at the 4^th month of initial therapy with first-line antitubercular drugs. A 25-year-old female, the HIV-negative patient, was admitted to the TB outpatient clinic with a bulge on the submandibular area 3 months after the cessation of pulmonary multidrug-resistance TB therapy lasting 2 years. She had an index case but no comorbidity. The cytomorphology of FNA biopsy from the submandibular LAP reported granuloma with necrosis. RT-PCR of the purulent FNA specimen was positive for MTBC. H and rifampicin (R) resistances were found via the Seegene system. The right submandibular 2.9 cm LAP improved to a 1.7 cm LAP 6 months after the initiation of second-line antitubercular therapy. A 19-year-old male, the HIV-negative patient, presented to the TB outpatient clinic with a new bulge on the left supraclavicular area 9 months after cessation of pulmonary TB. He had no comorbidity and index case. RT-PCR of the purulent FNA specimen was positive for MTBC. H and R sensitivities were determined via the Seegene system. After the initial therapy with first-line antitubercular drugs for 2 months, the 1.5 cm left supraclavicular LAP improved to a 1.2 cm LAP.

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.

Tuberculosis reinfection and relapse in eastern China: A prospective study using whole-genome sequencing

OBJECTIVES

Tuberculosis recurrence after an initial successful treatment episode can occur from either reinfection or relapse. In a population-based sample and whole genome sequencing (WGS) in eastern China, we aimed to evaluate risk factors for tuberculosis recurrence, and assess the proportion of recurrence due to either reinfection or relapse.

METHODS

Successfully treated pulmonary tuberculosis patients with sputum culture positive results were recruited from five cities in Jiangsu Province from 2013-2015 and followed for two years for tuberculosis recurrence. Among patients developing a second tuberculosis episode, WGS was performed to distinguish relapse or reinfection through a distance threshold of 6-single-nucleotide polymorphisms (SNP). We analyzed risk factors for recurrence and epidemiological characteristics of different types of recurrent patients.

RESULTS

Of 1,897 successful treated tuberculosis patients, 7.4% (141/1879) developed recurrent tuberculosis. Compared with non-recurrent tuberculosis, patients were at higher risk of recurrence in older age (Adjusted Odds Ratio [AOR], 1.02 for each additional year; 95% CI, 1.01-1.03, P=0.003), patients previously treated for tuberculosis (AOR=2.22; 95% CI, 1.52-3.26, P<0.001), or with bilateral cavities (AOR, 1.56; 95% CI, 1.05-2.32, P=0.029). Among 27.0% (38/141) recurrent tuberculosis patients with successfully sequenced pairs, relapse was substantially more common than reinfection (71.1% versus 28.9%, P=0.014).

CONCLUSIONS

Endogenous relapse was significantly more common than exogenous reinfection in the first two years after treatment in eastern China. Prioritization of high-risk groups for recurrence, such as the elderly, with a previous tuberculosis diagnosis, or with bilateral cavities, may provide opportunities to reduce post-tuberculosis morbidity.

Breathing Back Better! A State of the Art on the Benefits of Functional Evaluation and Rehabilitation of Post-Tuberculosis and Post-COVID Lungs

Currently, tuberculosis (TB) and COVID-19 account for substantial morbidity and mortality worldwide, not only during their acute phase, but also because of their sequelae. This scoping review aims to describe the specific aspects of post-TB and post-COVID (long-COVID-19) sequelae, and the implications for post-disease follow-up and rehabilitation. In particular, evidence on how to identify patients affected by sequelae is presented and discussed. A section of the review is dedicated to identifying patients eligible for pulmonary rehabilitation (PR), as not all patients with sequelae are eligible for PR. Components of PR are presented and discussed, as well as their effectiveness. Other essential components to implement comprehensive rehabilitation programmes such as counselling and health education of enrolled patients, evaluation of cost-effectiveness of PR and its impact on health systems as well as research priorities for the future are included in this scoping review.

An Update on Tuberculosis Vaccines

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is a leading cause of mortality and morbidity due to a single infectious agent. Aerosol infection with Mtb can result in a range of responses from elimination, active, incipient, subclinical, and latent Mtb infections (LTBI), depending on the host's immune response and the dose and nature of infecting bacilli. Currently, BCG is the only vaccine approved to prevent TB. Although BCG confers protection against severe forms of childhood TB, its use in adults and those with comorbid conditions, such as HIV infection, is questionable. Novel vaccines, including recombinant BCG (rBCG), were developed to improve BCG's efficacy and use as an alternative to BCG in a vulnerable population. The first-generation rBCG vaccines had different Mtb antigens and were tested as a prime, prime-boost, or immunotherapeutic intervention. The novel vaccines target one or more of the following requirements, namely prevention of infection (POI), prevention of disease (POD), prevention of recurrence (POR), and therapeutic vaccines to treat a TB disease. Several vaccine candidates currently in development are classified into four primary categories: live attenuated whole-cell vaccine, inactivated whole-cell vaccine, adjuvanted protein subunit vaccine, and viral-vectored vaccine. Each vaccine's immunogenicity, safety, and efficacy are tested in preclinical animal models and further validated through various phases of clinical trials. This chapter summarizes the various TB vaccine candidates under different clinical trial stages and promises better protection against TB.

A Prospective Cohort Study on the Prevalent and Recurrent Tuberculosis Isolates Using the MIRU-VNTR Typing

The study aims to describe the clustering characteristics of Mycobacterium tuberculosis (M.tb) strains circulating in eastern China and determine the ratio of relapse and reinfection in recurrent patients. We recruited sputum smear-positive pulmonary tuberculosis cases from five cities of Jiangsu Province, China, during August 2013 and December 2015. Patients were followed for the treatment outcomes and recurrence based on a cohort design. M.tb strains were isolated and genotyped using the 12-locus MIRU-VNTR. The Beijing family was identified by the extended Region of Difference (RD) analysis. The Hunter-Gaston Discriminatory Index (HGDI) was used to judge the resolution ability of MIRU-VNTR. The odds ratio (OR) together with 95% confidence interval (CI) were used to estimate the strength of association. We performed a cluster analysis on 2098 M.tb isolates and classified them into 545 genotypes and five categories (I, 0.19%; II, 0.43%; III, 3.34%; IV, 77.46%; V, 18.59%). After adjusting for potential confounders, the Beijing family genotype (OR = 118.63, 95% CI: 79.61–176.79, P = 0.001) was significantly related to the dominant strain infections. Patients infected with non-dominant strains had a higher risk of the pulmonary cavity (OR = 1.39, 95% CI: 1.01–1.91, P = 0.046). Among 37 paired recurrent cases, 22 (59.46%) were determined as endogenous reactivation, and 15 (40.54%) were exogenous reinfection. The type of M.tb strains prevalent in Jiangsu Province is relatively single. Beijing family strains infection is dominant in local tuberculosis cases. Endogenous reactivation appears to be a major cause of recurrent tuberculosis in Eastern China. This finding emphasizes the importance of case follow-up and monitoring after the completion of antituberculosis treatment.

Clinical standards for the assessment, management and rehabilitation of post-TB lung disease

BACKGROUND: Increasing evidence suggests that post-TB lung disease (PTLD) causes significant morbidity and mortality. The aim of these clinical standards is to provide guidance on the assessment and management of PTLD and the implementation of pulmonary rehabilitation (PR).METHODS: A panel of global experts in the field of TB care and PR was identified; 62 participated in a Delphi process. A 5-point Likert scale was used to score the initial ideas for standards and after several rounds of revision the document was approved (with 100% agreement).RESULTS: Five clinical standards were defined: Standard 1, to assess patients at the end of TB treatment for PTLD (with adaptation for children and specific settings/situations); Standard 2, to identify patients with PTLD for PR; Standard 3, tailoring the PR programme to patient needs and the local setting; Standard 4, to evaluate the effectiveness of PR; and Standard 5, to conduct education and counselling. Standard 6 addresses public health aspects of PTLD and outcomes due to PR.CONCLUSION: This is the first consensus-based set of Clinical Standards for PTLD. Our aim is to improve patient care and quality of life by guiding clinicians, programme managers and public health officers in planning and implementing adequate measures to assess and manage PTLD.

Tuberculosis recurrence over a 7-year follow-up period in successfully treated patients in a routine program setting in China: a prospective longitudinal study

OBJECTIVES

To determine tuberculosis (TB) recurrence in previously successfully treated patients in a routine program setting and baseline characteristics associated with TB recurrence.

METHODS

A prospective longitudinal study in Jiangxi Province, China. Patients, ≥14 years old, were consecutively registered and were followed up for seven years to assess TB recurrence against a patients' individual baseline data that had been entered into a database at TB registration.

RESULTS

There were 800 TB patients registered at baseline, and 634 (79.2%) of them completed anti-TB treatments. Fifty-nine (9.3%) died, and 21 (3.3%) were lost to follow-up over the follow-up period. There were 96 patients with recurrent episodes (total incidence 15.2% or annual incidence 2,200/100,000). Of the recurrent cases, 53 (55.2%) happened within 2-year after completion of anti-TB treatments. After controlling confounding factors, the risk of TB recurrence was significantly higher in the age range 34-73 years (P<0.01) and current smokers (P<0.01).

CONCLUSIONS

Overall recurrence rate among previously treated TB patients was much higher than the initial incidence in the same population (61-98/100,000) and settings with similar TB incidence. TB programs should consider closer monitoring of these patients for early detection of recurrence. Particular attention should be given to those between 34-73 years and those who use tobacco products.

Surface-Shaving Proteomics of Mycobacterium marinum Identifies Biofilm Subtype-Specific Changes Affecting Virulence, Tolerance, and Persistence

The complex cell wall and biofilm matrix (ECM) act as key barriers to antibiotics in mycobacteria. Here, the ECM and envelope proteins of Mycobacterium marinum ATCC 927, a nontuberculous mycobacterial model, were monitored over 3 months by label-free proteomics and compared with cell surface proteins on planktonic cells to uncover pathways leading to virulence, tolerance, and persistence. We show that ATCC 927 forms pellicle-type and submerged-type biofilms (PBFs and SBFs, respectively) after 2 weeks and 2 days of growth, respectively, and that the increased CelA1 synthesis in this strain prevents biofilm formation and leads to reduced rifampicin tolerance. The proteomic data suggest that specific changes in mycolic acid synthesis (cord factor), Esx1 secretion, and cell wall adhesins explain the appearance of PBFs as ribbon-like cords and SBFs as lichen-like structures. A subpopulation of cells resisting 64× MIC rifampicin (persisters) was detected in both biofilm subtypes and already in 1-week-old SBFs. The key forces boosting their development could include subtype-dependent changes in asymmetric cell division, cell wall biogenesis, tricarboxylic acid/glyoxylate cycle activities, and energy/redox/iron metabolisms. The effect of various ambient oxygen tensions on each cell type and nonclassical protein secretion are likely factors explaining the majority of the subtype-specific changes. The proteomic findings also imply that Esx1-type protein secretion is more efficient in planktonic (PL) and PBF cells, while SBF may prefer both the Esx5 and nonclassical pathways to control virulence and prolonged viability/persistence. In conclusion, this study reports the first proteomic insight into aging mycobacterial biofilm ECMs and indicates biofilm subtype-dependent mechanisms conferring increased adaptive potential and virulence of nontuberculous mycobacteria.

IMPORTANCE Mycobacteria are naturally resilient, and mycobacterial infections are notoriously difficult to treat with antibiotics, with biofilm formation being the main factor complicating the successful treatment of tuberculosis (TB). The present study shows that nontuberculous Mycobacterium marinum ATCC 927 forms submerged- and pellicle-type biofilms with lichen- and ribbon-like structures, respectively, as well as persister cells under the same conditions. We show that both biofilm subtypes differ in terms of virulence-, tolerance-, and persistence-conferring activities, highlighting the fact that both subtypes should be targeted to maximize the power of antimycobacterial treatment therapies.

Prevalence and molecular characteristics of drug-resistant Mycobacterium tuberculosis in Hainan, China: from 2014 to 2019

Background

The emergence of antimicrobial resistance against Mycobacterium tuberculosis (M. tuberculosis) has become the major concern in global tuberculosis control due to its limited therapy options and high mortality. However, the clinical and molecular characteristics of drug-resistant strains vary in different geographical areas. Hainan Island located in southern China, is a high drug-resistant tuberculosis burden area. This study aimed to determine the dynamic changes of drug-resistance patterns and drug-related gene mutation types of M. tuberculosis in Hainan from 2014 to 2019.

Results

A total of 1484 culture-confirmed M. tuberculosis were included in this study. It was found that the proportions of drug resistance to isoniazid and rifampin were 31.3 and 31.1% respectively. Overall the proportion of multidrug resistant M. tuberculosis was 24.9%. Multivariate logistic regression analysis showed that age and the treatment history were independent influencing factors of drug resistant tuberculosis. The proportions of drug-resistant tuberculosis in retreatment patients were considerably higher than those in new patients. The most common mutation types of isoniazid were Ser315 → Thr (66.3%), and the most common mutation types of rifampin were Ser531 → Leu (41.5%).

Conclusions

Our data suggests that the prevalence of drug resistant TB remains high in Hainan, and the risks for developing drug resistance with diversified mutation types increased significantly in retreatment patients. These results contribute to the knowledge of the prevalence of drug resistance in Hainan Province and expand the molecular characteristics of drug resistance in China simultaneously.

Recurrent Tuberculosis in a Young Child

A young child, 19 months of age, presented with a second episode of tuberculosis after full recovery from initial tuberculosis disease 6 months earlier. Mycobacterium tuberculosis strains isolated from both episodes were genotyped and differed from one another. We present the first case of proven tuberculosis reinfection in a likely immunocompetent child, living in a high-risk environment favorable for exposition to M. tuberculosis but in a low-incidence country.

Vaccination Against Tuberculosis: Revamping BCG by Molecular Genetics Guided by Immunology

Tuberculosis (TB) remains a major health threat. Although a vaccine has been available for almost 100 years termed Bacille Calmette-Guérin (BCG), it is insufficient and better vaccines are urgently needed. This treatise describes first the basic immunology and pathology of TB with an emphasis on the role of T lymphocytes. Better understanding of the immune response to Mycobacterium tuberculosis (Mtb) serves as blueprint for rational design of TB vaccines. Then, disease epidemiology and the benefits and failures of BCG vaccination will be presented. Next, types of novel vaccine candidates are being discussed. These include: (i) antigen/adjuvant subunit vaccines; (ii) viral vectored vaccines; and (III) whole cell mycobacterial vaccines which come as live recombinant vaccines or as dead whole cell or multi-component vaccines. Subsequently, the major endpoints of clinical trials as well as administration schemes are being described. Major endpoints for clinical trials are prevention of infection (PoI), prevention of disease (PoD), and prevention of recurrence (PoR). Vaccines can be administered either pre-exposure or post-exposure with Mtb. A central part of this treatise is the description of the viable BCG-based vaccine, VPM1002, currently undergoing phase III clinical trial assessment. Finally, new approaches which could facilitate design of refined next generation TB vaccines will be discussed.

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.

[New vaccines against tuberculosis]

With about 10 million active disease cases and 1.5 million deaths in 2018, tuberculosis (TB) remains one of the most threatening infectious diseases. Yet, the World Health Organization (WHO) aims to reduce morbidity and mortality by 90 and 95%, respectively, between 2015 and 2035. Although diagnostics, therapeutics, and a vaccine are available, it is beyond doubt that better intervention measures are needed to accomplish this ambitious goal. The vaccine bacille Calmette-Guérin (BCG) partially protects infants against TB, but it is virtually ineffective against pulmonary TB in adolescents and adults. The efficacy of this vaccine, however, has not yet been fully exploited. In addition, new vaccine candidates are currently being assessed in clinical trials.Because a quarter of all people are latently infected with Mycobacterium tuberculosis (Mtb), new vaccines must be applied not only prior to infection (pre-exposure vaccination) but also after infection (postexposure vaccination). Prevention of infection, prevention of disease, and prevention of recurrence are currently assessed as clinical endpoints. Because protection against TB is primarily mediated by T lymphocytes, TB vaccine development focuses on protective T cell responses. Protein adjuvant formulations, viral vectors, and killed and live bacterial vaccines are currently being assessed in clinical trials. Moreover, therapeutic vaccination is clinically tested, notably in adjunct to canonical drug therapy to multiresistant TB. It is likely that a single vaccine cannot accomplish the various indications and that different vaccination strategies are required.

Long-term Prognosis of Tuberculosis Infection and Disease in Swedish Children

BACKGROUND

Reports of the outcome of treatment of tuberculosis (TB) disease and infection (TBI) in children are scarce. Since 2010, we routinely use interferon-gamma release assays in addition to clinical history for the exclusion of TBI, although the safety of this approach has been questioned. We present the frequency of recurrent TB or progression to TB after treatment for TB disease or TB infection, respectively, and progression to disease in children considered TB uninfected at our pediatric TB clinic.

METHODS

We included 4707 patients from 1990 to 2017. At the initial assessment, 96 (2.0%) had previously received TB treatment, 253 (5.4%) had TB disease, 1625 (35%) had TBI and 2733 (58%) children were considered uninfected. Patients were passively followed at our clinic, at the adult TB clinics in Stockholm and at the Swedish national TB registry.

RESULTS

During a median follow-up time of 8.4 years, we found 36 cases of TB disease, with true relapses in 3/243 (1.2%) successfully treated TB patients. Preventive treatment of TBI reduced the risk of progression to TB by 85%, from 4.3% (15/349) to 0.6% (8/1262). In children considered uninfected, the risk of later developing TB was 0.07% (2/2733).

CONCLUSIONS

The effectiveness of TB management was acceptable. Our routine procedures for the exclusion of TBI appear safe.

Morbidity and mortality up to 5 years post tuberculosis treatment in South Africa: A pilot study

BACKGROUND

A high risk of tuberculosis (TB), chronic lung disease, and mortality have been reported among people with a history of previous TB treatment, but data from high-incidence settings remain limited. The aim of this study was to characterize general morbidity and mortality among adults who had successfully completed TB treatment in the past 5 years in a high-incidence setting in South Africa.

METHODS

Adults (≥18 years) who had completed treatment for pulmonary TB between 2013 and 2017 were randomly selected from TB treatment registers. Household visits were conducted to locate and interview former TB (FTB) patients, and bacteriological testing for TB was offered. Additional data sources were used to ascertain the vitality status of FTB patients who could not be located.

RESULTS

Addresses were located for 200 of the 223 FTB patients sampled and 89 FTB patients were contacted of whom 51 agreed to be interviewed. Approximately half reported persistent respiratory symptoms, such as shortness of breath and wheezing, and repeated lung infections. One (3.6%) of 28 patients who provided a sputum sample had culture-positive TB and another two were currently on re-treatment for TB. Fifteen deaths post treatment were ascertained, resulting in a standardized mortality ratio of 3.8 (95% confidence interval 2.3-6.3) after successful TB treatment relative to the general population.

CONCLUSIONS

In this high-incidence setting, locating and interviewing FTB patients was challenging. The study findings are consistent with a high rate of respiratory disease, including recurrent TB, and substantially elevated mortality among FTB patients.

Demographic, socio-economic and behavior as risk factors of tuberculosis in Malaysia: a systematic review of the literature

Background Tuberculosis (TB) is making a comeback and has remained one of the main causes of mortality among the list of infectious diseases in Malaysia. Objective To evaluate the burden and demographic, socio-economic and behavior as risk factors of TB among communities in Malaysia. Method A comprehensive search of Scopus, Sciencedirect, PubMed, DOAJ, CINAHL Plus, MyJournal, BIREME, BMC Public Health, Medline, CAB, EMBASE (Excerpta Medica dataBASE), and Web of Science (WoS) was undertaken from the articles published from 1st January 2008 to 31st December 2017 using medical subject heading (MeSH) key terms. Results Of 717 papers screened, 31 eligible studies met our inclusion criteria. Gender, age, marriage status, ethnicity, area of living, being in prison and immigrant were evaluated as demographic factors, while educational level, occupation and household income were evaluated as socio-economic factors. For behavioral factors, smoking, drug abuse, alcohol consumption and other lifestyle practices were evaluated. However, not all the studies were statistically significantly associated with these risk factors. Studies on household income were few and too small to permit a conclusion. We also did not find any study that investigated TB infection among sex workers. Conclusion Immigrant in high density settings may increase the progression of disease infection in Malaysia. The risk factors for the development of TB, specifically in a high-risk population, should be targeted through the implementation of specialized interventions. Further research into the role of indoor and outdoor physical environments is required to better understand the association between the physical environment and the social environment with TB infection.