Bedaquiline Resistance after Effective Treatment of Multidrug-Resistant Tuberculosis, Namibia

Bedaquiline is currently a key drug for treating multidrug-resistant or rifampin-resistant tuberculosis. We report and discuss the unusual development of resistance to bedaquiline in a teenager in Namibia, despite an optimal background regimen and adherence. The report highlights the risk for bedaquiline resistance development and the need for rapid drug-resistance testing.

Implementation of targeted next-generation sequencing for the diagnosis of drug-resistant tuberculosis in low-resource settings: a programmatic model, challenges, and initial outcomes

Targeted next-generation sequencing (tNGS) from clinical specimens has the potential to become a comprehensive tool for routine drug-resistance (DR) prediction of Mycobacterium tuberculosis complex strains (MTBC), the causative agent of tuberculosis (TB). However, TB mainly affects low- and middle-income countries, in which the implementation of new technologies have specific needs and challenges. We propose a model for programmatic implementation of tNGS in settings with no or low previous sequencing capacity/experience. We highlight the major challenges and considerations for a successful implementation. This model has been applied to build NGS capacity in Namibia, an upper middle-income country located in Southern Africa and suffering from a high-burden of TB and TB-HIV, and we describe herein the outcomes of this process.

Case-Finding Strategies for Drug-Resistant Tuberculosis: Protocol for a Scoping Review

BACKGROUND

Transmission of drug-resistant tuberculosis (DR-TB) is ongoing. Finding individuals with DR-TB and initiating treatment as early as possible is important to improve patient clinical outcomes and to break the chain of transmission to control the pandemic. To our knowledge systematic reviews assessing effectiveness, cost-effectiveness, acceptability, and feasibility of different case-finding strategies for DR-TB to inform research, policy, and practice have not been conducted, and it is unknown whether enough research exists to conduct such reviews. It is unknown whether case-finding strategies are similar for DR-TB and drug-susceptible TB and whether we can draw on findings from drug-susceptible reviews to inform decisions on case-finding strategies for DR-TB.

OBJECTIVE

This protocol aims to describe the available literature on case-finding for DR-TB and to describe case-finding strategies.

METHODS

We will screen systematic reviews, trials, qualitative studies, diagnostic test accuracy studies, and other primary research that specifically sought to improve DR-TB case detection. We will exclude studies that invited individuals seeking care for TB symptoms, those including individuals already diagnosed with TB, or laboratory-based studies. We will search the academic databases including MEDLINE, Embase, The Cochrane Library, Africa-Wide Information, CINAHL, Epistemonikos, and PROSPERO with no language or date restrictions. We will screen titles, abstracts, and full-text articles in duplicate. Data extraction and analyses will be performed using Excel (Microsoft Corp).

RESULTS

We will provide a narrative report with supporting figures or tables to summarize the data. A systems-based logic model, developed from a synthesis of case-finding strategies for drug-susceptible TB, will be used as a framework to describe different strategies, resulting pathways, and enhancements of pathways. The search will be conducted at the end of 2021. Title and abstract screening, full text screening, and data extraction will be undertaken from January to June 2022. Thereafter, analysis will be conducted, and results compiled.

CONCLUSIONS

This scoping review will chart existing literature on case-finding for DR-TB-this will help determine whether primary studies on effectiveness, cost-effectiveness, acceptability, and feasibility of different case-finding strategies for DR-TB exist and will help formulate potential questions for a systematic review. We will also describe case-finding strategies for DR-TB and how they fit into a model of case-finding pathways for drug-susceptible TB. This review has some limitations. One limitation is the diverse, inconsistent use of intervention terminology within the literature, which may result in missing relevant studies. Poor reporting of intervention strategies may also cause misunderstanding and misclassification of interventions. Lastly, case-finding strategies for DR-TB may not fit into a model developed from strategies for drug-susceptible TB. Nevertheless, such a situation will provide an opportunity to refine the model for future research. The review will guide further research to inform decisions on case-finding policies and practices for DR-TB.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/40009.

Who is more likely to return for TB test results? A survey at three high-burden primary healthcare facilities in Cape Town, South Africa

BACKGROUND

In low- and middle-income countries with a high burden of tuberculosis (TB), a large proportion of people who are tested for TB do not return to the health facility to collect their test results and initiate treatment, thus putting themselves at increased risk of adverse outcomes.

METHODS

This prospective study aimed to identify predictors of returning to the primary health care (PHC) facility to collect TB test results. From 15 August to 15 December 2017, 1105 people who tested for pulmonary TB at three Cape Town PHC facilities were surveyed. Using multi-variate logistic regressions on an analysis sample of 1097 people, three groups of predictors were considered: (i) demographics, health and socio-economic status; (ii) costs and benefits; and (iii) behavioural factors.

RESULTS

Forty-four percent of people tested returned to the PHC facility to collect their test results within the stipulated 2 days, and 68% returned before the end of the study period. Return was strongly and positively correlated with expecting a TB-positive result, cognitive avoidance and postponement behaviour.

CONCLUSION

Interventions to improve pre-treatment loss to follow-up should target patients who think they do not have TB, and those with a history of postponement behaviour and cognitive avoidance.

Defining Outcomes of Tuberculosis (Treatment): From the Past to the Future

Untreated active tuberculosis (TB) has a very high long-term mortality. Treatment of TB reduces mortality dramatically and should maximize cure, preventing ongoing transmission and TB sequelae. However, predicting the risk of failure and relapse is crucial for the management of individual patients and for the evaluation of effectiveness of programs. Various outcome definitions for drug-sensitive and drug-resistant TB were developed, implemented, and endorsed since introduction of TB chemotherapy by the World Health Organization (WHO), mostly based on culture and smear results. They should be applicable for individual patient care, surveillance, and research. Definitions with focus on program evaluation differ from definitions to evaluate the efficacy and effectiveness of regimens. Lack of sputum production at the later stage of treatment reduces the easy applicability of current definitions. Definitions of failure and cure are sometimes difficult to apply. Alternative approaches suggest culture positivity at 6 months or more of treatment as an indicator for failure. New definitions for cure including a relapse-free period posttreatment and reduced number of culture and smear results are considered. Increasing variation and individualization of treatment and its duration urgently require new approaches using pathogen- or host-specific biomarkers, which indicate risk of failure and define cure. Such biomarkers are under evaluation but still far from translation in clinical routine practice.

Smoking and HIV associated with subclinical tuberculosis: analysis of a population-based prevalence survey

BACKGROUND: Despite multiple tuberculosis (TB) prevalence surveys reporting a relatively high frequency of bacteriologically confirmed, active TB among individuals reporting no typical symptoms of disease, our understanding of this phenomenon is limited.OBJECTIVE: To quantify the epidemiological burden and estimate associations between individual-level variables and this "subclinical" presentation.METHODS: We performed a secondary analysis of TB prevalence survey data from the South African communities of the Zambia, South Africa Tuberculosis and AIDS Reduction trial. Generalized estimating equations were used to estimate the association between individual-level demographic, behavioral, socio-economic, and medical variables and the risk of bacteriologically positive TB among participants not reporting any symptoms consistent with active TB.RESULTS: The crude prevalence of TB was 2222.1 cases per 100 000 population (95% CI 2053.4-2388.5); 44.7% (295/660) of all documented prevalent cases of TB were subclinical. Current tobacco smoking (OR 2.37, 95% CI 1.41-3.99) and HIV-positive status (OR 3.26, 95% CI 2.31-4.61) were significantly associated with subclinical TB.CONCLUSION: Individuals who smoke or have HIV may be at increased risk of active TB and not report typical symptoms consistent with disease. This suggests possible shortcomings of symptom-based case finding which may need to be addressed in similar settings.

Interpretation of serial interferon-gamma test results to measure new tuberculosis infection among household contacts in Zambia and South Africa

BACKGROUND

A more stringent QuantiFERON-TB Gold In-Tube (QFT) conversion (from negative to positive) definition has been proposed to allow more definite detection of recent tuberculosis (TB) infection. We explored alternative conversion definitions to assist the interpretation of serial QFT results and estimate incidence of TB infection in a large cohort study.

METHODS

We used QFT serial results from TB household contacts aged ≥15 years, collected at baseline and during two follow-up visits (2006-2011) as part of a cohort study in 24 communities in Zambia and South Africa (SA). Conversion rates using the manufacturers' definition (interferon-gamma (IFN-g) < 0.35 to ≥0.35, 'def1') were compared with stricter definitions (IFN-g < 0.2 to ≥0.7 IU/ml, 'def2'; IFN-g < 0.2 to ≥1.05 IU/ml, 'def3'; IFN-g < 0.2 to ≥1.4 IU/ml, 'def4'). Poisson regression was used for analysis.

RESULTS

One thousand three hundred sixty-five individuals in Zambia and 822 in SA had QFT results available. Among HIV-negative individuals, the QFT conversion rate was 27.4 per 100 person-years (CI:22.9-32.6) using def1, 19.0 using def2 (CI:15.2-23.7), 14.7 using def3 (CI:11.5-18.8), and 12.0 using def4 (CI:9.2-15.7). Relative differences across def1-def4 were similar in Zambia and SA. Using def1, conversion was less likely if HIV positive not on antiretroviral treatment compared to HIV negative (aRR = 0.7, 95%CI = 0.4-0.9), in analysis including both countries. The same direction of associations were found using def 2-4.

CONCLUSION

High conversion rates were found even with the strictest definition, indicating high incidence of TB infection among household contacts of TB patients in these communities. The trade-off between sensitivity and specificity using different thresholds of QFT conversion remains unknown due to the absence of a reference standard. However, we identified boundaries within which an appropriate definition might fall, and our strictest definition plausibly has high specificity.

Two Pandemics, One Challenge-Leveraging Molecular Test Capacity of Tuberculosis Laboratories for Rapid COVID-19 Case-Finding

In many settings, the ongoing coronavirus disease (COVID-19) pandemic coincides with other major public health threats, in particular tuberculosis. Using tuberculosis (TB) molecular diagnostic infrastructure, which has substantially expanded worldwide in recent years, for COVID-19 case-finding might be warranted. We analyze the potential of using TB diagnostic and research infrastructures for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing. We focused on quality control by adapting the 12 Quality System Essentials framework to the COVID-19 and TB context. We conclude that diagnostic infrastructures for TB can in principle be leveraged to scale-up SARS-CoV-2 testing, in particular in resource-poor settings. TB research infrastructures also can support sequencing of SARS-CoV-2 to study virus evolution and diversity globally. However, fundamental principles of quality management must be followed for both TB and SARS-CoV-2 testing to ensure valid results and to minimize biosafety hazards, and the continuity of TB diagnostic services must be guaranteed at all times.

Development and validation of a prediction model for active tuberculosis case finding among HIV-negative/unknown populations

A prediction model of prevalent pulmonary tuberculosis (TB) in HIV negative/unknown individuals was developed to assist systematic screening. Data from a large TB screening trial were used. A multivariable logistic regression model was developed in the South African (SA) training dataset, using TB symptoms and risk factors as predictors. The model was converted into a scoring system for risk stratification and was evaluated in separate SA and Zambian validation datasets. The number of TB cases were 355, 176, and 107 in the SA training, SA validation, and Zambian validation datasets respectively. The area under curve (AUC) of the scoring system was 0·68 (95% CI 0·64-0·72) in the SA validation set, compared to prolonged cough (0·58, 95% CI 0·54-0·62) and any TB symptoms (0·6, 95% CI 0·56-0·64). In the Zambian dataset the AUC of the scoring system was 0·66 (95% CI 0·60-0·72). In the cost-effectiveness analysis, the scoring system dominated the conventional strategies. The cost per TB case detected ranged from 429 to 1,848 USD in the SA validation set and from 171 to 10,518 USD in the Zambian dataset. The scoring system may help targeted TB case finding under budget constraints.

Patient predictors of health-seeking behaviour for persons coughing for more than two weeks in high-burden tuberculosis communities: the case of the Western Cape, South Africa

Background

This study aimed to analyse the patient predictors of health-seeking behaviour for persons coughing for more than 2 weeks to better understand this vulnerable and important population.

Methods

The study analysed data from a cohort study (SOCS - Secondary Outcome Cohort Study) embedded in a community randomised trial ZAMSTAR (Zambia and South Africa TB and AIDS Reduction Study) in eight high-burden TB communities in the Western Cape, South Africa. These datasets are unique as they contain TB-related data as well as data on health, health-seeking behaviour, lifestyle choices, employment, socio-economic status, education and stigma. We use uni- and multivariate logistic regressions to estimate the odds ratios of consulting for a cough (of more than 2 weeks duration) for a range of relevant patient predictors.

Results

Three hundred and forty persons consulted someone about their cough and this represents 37% of the 922 participants who reported coughing for more than 2 weeks. In the multivariate analysis, respondents of black ethnic origin (OR 1.99, 95% CI 1.28–3.12, P < 0.01), those with higher levels of education (OR 1.05 per year of education, 95% CI 1.00–1.10, P = 0.05), and older respondents (OR 1.02 per year, 95% CI 1.01–1.04, P < 0.01) had a higher likelihood of consulting for their chronic cough. Individuals who smoked (OR 0.63, 95% CI 0.45–0.88, P < 0.01) and those with higher levels of socio-economic status (OR 0.81, 95% CI 0.71–0.92, P < 0.01) were less likely to consult. We find no evidence of stigma playing a role in health-seeking decisions, but caution that this may be due to the difficulty of accurately and reliably capturing stigma due to, amongst other factors, social desirability bias.

Conclusions

The low levels of consultation for a cough of more than 2 weeks suggest that there are opportunities to improve case-finding. These findings on health-seeking behaviour can assist policymakers in designing TB screening and active case-finding interventions that are targeted to the characteristics of those with a chronic cough who do not seek care.

Electronic supplementary material

The online version of this article (10.1186/s12913-019-3992-6) contains supplementary material, which is available to authorized users.

Secondary analysis of tuberculosis stigma data from a cluster randomised trial in Zambia and South Africa (ZAMSTAR)

SETTING

Zambian and South African TB and HIV Reduction (ZAMSTAR) cluster-randomised trial (CRT) communities, 2006-2009.

OBJECTIVES

To develop TB stigma items, and evaluate changes in them in response to a household intervention aimed at reducing TB transmission and prevalence but not tailored to reduce stigma.

DESIGN

TB stigma was measured at baseline and 18 months later among 1826 recently diagnosed TB patients and 1235 adult members of their households across 24 communities; 12 of 24 communities were randomised to receive the household intervention. We estimated the impact of the household intervention on TB stigma using standard CRT analytical methods.

RESULTS

Among household members, prevalence of blame and belief in transmission myths fell in both study arms over time: adjusted prevalence ratios (aPRs) comparing the household intervention with the non-household intervention arm were respectively 0.61 (95%CI 0.26-1.44) and 0.77 (95%CI 0.48-1.25) at 18-month follow-up. Among TB patients, at baseline a low percentage experienced social exclusion and poor treatment by health staff and a relatively high percentage reported 'being made fun of', with little change over time. Disclosure of TB status increased over time in both study arms. Internalised stigma was less prevalent in the household arm at both baseline and follow-up, with an aPR of 0.85 (95%CI 0.41-1.76). Variability in stigma levels between countries and across communities was large.

CONCLUSION

Robust TB stigma items were developed. TB stigma was not significantly reduced by the household intervention, although confidence intervals for estimated intervention effects were wide. We suggest that stigma-specific interventions are required to effectively address TB stigma.

Health care workers' gender bias in testing could contribute to missed tuberculosis among women in South Africa

SETTING

Eight communities with high tuberculosis (TB) prevalence, Western Cape, South Africa.

OBJECTIVE

To identify sex differences in TB health-seeking behaviour and diagnosis in primary health care facilities and how this influences TB diagnosis.

DESIGN

We used data from a prevalence survey among 30,017 adults conducted in 2010 as part of the Zambia, South Africa Tuberculosis and AIDS Reduction (ZAMSTAR) trial.

RESULTS

A total of 1670 (5.4%) adults indicated they had a cough of ⩾2 weeks, 950 (56.9%) of whom were women. Women were less likely to report a cough of ⩾2 weeks (5.1% vs. 6.4%, P < 0.001), but were more likely to seek care for their cough (32.6% vs. 26.9%, P = 0.012). Of all adults who sought care, 403 (80.0%) sought care for their cough at a primary health care (PHC) facility (79.0% women vs. 81.4% men, P = 0.511). Women were less likely to be asked for a sputum sample at the PHC facility (63.3% vs. 77.2%, P = 0.003) and less likely to have a positive sputum result (12.6% vs. 20.7%, P = 0.023).

CONCLUSION

The attainment of sex equity in the provision of TB health services requires adherence to testing protocols. Everyone, irrespective of sex, who seeks care for a cough of ⩾2 weeks should be tested.

Why test for tuberculosis? A qualitative study from South Africa

Setting: Early testing and treatment initiation are crucial for controlling the tuberculosis (TB) epidemic, especially in high-burden countries such as South Africa. Objective: To explore reasons why patients opted to test for TB and the context in which they were tested. Design: This qualitative study was nested in a larger study evaluating patients who did not initiate anti-tuberculosis treatment after diagnosis. In-depth interviews were conducted with 41 patients across five provinces of South Africa. Results: While most patients presented for testing because of their symptoms, unfortunately many waited until their symptoms were severe and thus remained infectious for longer. Outreach campaigns and TB screening at primary health care facilities were perceived favourably, although some respondents were unclear as to the nature of the tests being performed and had concerns about the implications. Positive health care worker attitudes towards presumptive TB patients contributed towards prompt testing and treatment initiation. Conclusion: As patients often delayed presenting for testing, strategies to engage early with presumptive TB patients so that testing and treatment can commence without delay should be a priority for TB programmes.

It's complicated: why do tuberculosis patients not initiate or stay adherent to treatment? A qualitative study from South Africa

BACKGROUND

Individuals who test positive for active tuberculosis (TB) but do not initiate treatment present a challenge to TB programmes because they contribute to ongoing transmission within communities. To better understand why individuals do not initiate treatment, or are adherent after initiating treatment, South African respondents were approached to obtain insights as to which factors enabled and inhibited the treatment process.

METHODS

This qualitative work was nested in a larger study investigating initial loss to follow-up (LTFU) amongst new smear positive TB patients across five provinces of South Africa. In-depth interviews were done with 41 adherent and initial LTFU respondents.

RESULTS

Key issues contributing to initial LTFU appeared to be a poor knowledge, or low awareness of TB treatment; stigma around TB including its connection to HIV; immediate problems in the respondents' lives particularly poverty, lack of access to transport and the need to continue working; and problems in the healthcare facilities including under resourced facilities, poor functioning health systems and negative staff attitudes. In contrast the reasons given for being adherent related to the level of illness, support received at home and healthcare facilities, a belief in the health system and positive experiences in the health service including positive attitudes from staff.

CONCLUSIONS

Key changes need to be made to the healthcare system to enable patients to initiate treatment and remain adherent, but the six month regimen of daily observed treatment presents real practical and personal challenges to patients. Alternative strategies to DOTS at facility level should be investigated to bring services closer to communities to encourage patients to access care, initiate and adhere to treatment.

Uptake of HIV testing and HIV positivity among presumptive tuberculosis patients at Puducherry, South India

SETTING

Puducherry, a district in South India with a low prevalence of human immunodeficiency virus (HIV) infection (<1% among antenatal women).

OBJECTIVES

1) To estimate the proportion of patients with known HIV status who were HIV-positive, 2) to describe the demographic and clinical characteristics of patients with unknown HIV status among presumptive TB patients, and 3) to assess the additional workload at HIV testing centres.

DESIGN

In this cross-sectional study, consecutive presumptive TB patients attending microscopy centres for diagnosis during March-May 2013 were asked if they knew their HIV status. Patients with unknown HIV status were offered voluntary counselling and HIV testing.

RESULTS

Of 1886 presumptive TB patients, HIV status was ascertained for 842 (44.6%); 28 (3.3%) were HIV-positive. The uptake of HIV testing was significantly higher in younger age groups, males, residents of Puducherry and smear-positive TB patients. The median increase in the number of clients tested for HIV per day per testing centre was 1 (range 0-6).

CONCLUSION

The uptake of HIV testing was low. HIV prevalence was higher among presumptive TB patients than in antenatal women, and as high as in TB patients. With minimal increase in workload at HIV testing centres, HIV testing could be implemented using existing resources.

Number of sputum specimens during treatment follow-up of tuberculosis patients: two or one?

SETTING

National Institute for Research in Tuberculosis clinics in Chennai and Madurai, India.

OBJECTIVE

To examine the pattern of serial smears (negative-negative [NN], negative-positive [NP], positive-negative [PN], positive-positive [PP]) during treatment follow-up of culture-confirmed new smear-positive tuberculosis (TB) patients, and the proportion of culture-negatives in each category.

DESIGN

We reviewed the records and extracted follow-up smear (fluorescent microscopy) and culture (Löwenstein-Jensen) results of patients enrolled in clinical trials from January 2000 to August 2012 and treated with the Category I regimen (2EHRZ3/4HR3). Data entry and analysis were performed using EpiData.

RESULTS

Among 520 patients (176 infected with the human immunodeficiency virus), the proportions of culture-negative patients with NN, discordant (PN or NP) and PP patterns were approximately 98%, 80% and 40%, respectively. The smear-positive culture-negative phenomenon was more frequent in follow-up smear results graded 1+, followed by 2+ and 3+.

CONCLUSION

There is justification for discontinuing the examination of second specimens during treatment follow-up among TB patients. However, a positive result on the first smear needs to be confirmed by a second positive result before making clinical management decisions. The World Health Organization may need to reconsider its recommendation on this issue.

Factors influencing increased expertise for a sustainable workforce at a research centre in South Africa

SETTING

The Desmond Tutu Tuberculosis (TB) Centre (DTTC), Stellenbosch University, South Africa.

OBJECTIVES

1) To determine whether access to designated funding is associated with the development of expertise in employees, and 2) which other factors are associated with the development of expertise in employees.

DESIGN

This was a retrospective study. The target population consisted of all employees at the DTTC during the period 1 January 2004 to 31 December 2011. Improvement in expertise during employment was the primary outcome; the secondary outcome was an increase in educational level linked to the National Qualifications Framework.

RESULTS

There was no association between access to funding and expertise development, but an association between the number of months employed and improvement of expertise during employment was observed (OR 1.03, 95%CI 1.02-1.04, P < 0.001), controlling for age at appointment, sex, access to designated funding and education level.

CONCLUSION

The study shows that almost a third of employees increased their expertise, more than 90% had access to designated funding and personnel employed for a longer duration were more likely to experience improvements in expertise. We encourage research organisations in low- and middle-income countries to implement strategies to retain employees in order to build their expertise.

Symptom reporting among prevalent tuberculosis cases who smoke, are HIV-positive or have hyperglycaemia

Data from a tuberculosis (TB) prevalence survey conducted in 24 communities in Zambia and the Western Cape, South Africa, January-December 2010, were analysed to determine the influence of smoking, hyperglycaemia and human immunodeficiency virus (HIV) infection on TB symptom reporting in culture-confirmed TB cases. Of 123 790 adults eligible for enrolment, 90 601 (73%) consented and 64 463 had evaluable sputum samples. ORs and 95%CIs were calculated using a robust standard errors logistic regression model adjusting for clustering at community level. HIV-positive TB cases were more likely to report cough, weight loss, night sweats and chest pain than non-HIV-positive TB cases. TB cases who smoked or had hyperglycaemia did not report symptoms differently from cases without these comorbidities.

Are we justified in treating for multidrug-resistant tuberculosis based on positive follow-up smear results?

SETTING

National Institute for Research in Tuberculosis, India.

OBJECTIVE

To assess, among new culture-confirmed smear-positive pulmonary tuberculosis (TB) patients, the proportion of follow-up smear-positives that were culture-negative (S+C-) by month of follow-up examination, human immunodeficiency virus (HIV) status, pre-treatment drug susceptibility status and smear grading.

DESIGN

We extracted follow-up smear (fluorescence microscopy) and culture (Löwenstein-Jensen) results of patients enrolled in clinical trials from January 2000 to August 2012 and treated with the WHO Category I regimen (2EHRZ3/4HR3).

RESULTS

Of 520 patients, including 176 who were HIV-infected, respectively 199, 81, 47 and 43 were smear-positive at months 2, 4, 5 and 6; of these, respectively 138 (69%), 62 (75%), 32 (68%) and 27 (63%) were culture-negative. The S+C- phenomenon was more pronounced among '1+ positive' patients than in 2+ or 3+ positive patients and in 'pan-susceptible' patients than in those with any resistance, and did not vary by HIV status.

CONCLUSION

Nearly two thirds of patients with follow-up smears positive at months 5 and 6 were culture-negative. Starting multidrug-resistant TB (MDR-TB) treatment empirically based on smear results, even in resource-limited settings, is incorrect and can have hazardous consequences. There is an urgent need to revisit the WHO recommendation concerning empirical MDR-TB treatment.

Validation of biomarkers for distinguishing Mycobacterium tuberculosis from non-tuberculous mycobacteria using gas chromatography-mass spectrometry and chemometrics

Tuberculosis (TB) remains a major international health problem. Rapid differentiation of Mycobacterium tuberculosis complex (MTB) from non-tuberculous mycobacteria (NTM) is critical for decisions regarding patient management and choice of therapeutic regimen. Recently we developed a 20-compound model to distinguish between MTB and NTM. It is based on thermally assisted hydrolysis and methylation gas chromatography-mass spectrometry and partial least square discriminant analysis. Here we report the validation of this model with two independent sample sets, one consisting of 39 MTB and 17 NTM isolates from the Netherlands, the other comprising 103 isolates (91 MTB and 12 NTM) from Stellenbosch, Cape Town, South Africa. All the MTB strains in the 56 Dutch samples were correctly identified and the model had a sensitivity of 100% and a specificity of 94%. For the South African samples the model had a sensitivity of 88% and specificity of 100%. Based on our model, we have developed a new decision-tree that allows the differentiation of MTB from NTM with 100% accuracy. Encouraged by these findings we will proceed with the development of a simple, rapid, affordable, high-throughput test to identify MTB directly in sputum.

Effect of household and community interventions on the burden of tuberculosis in southern Africa: the ZAMSTAR community-randomised trial

BACKGROUND

Southern Africa has had an unprecedented increase in the burden of tuberculosis, driven by the HIV epidemic. The Zambia, South Africa Tuberculosis and AIDS Reduction (ZAMSTAR) trial examined two public health interventions that aimed to reduce the burden of tuberculosis by facilitating either rapid sputum diagnosis or integrating tuberculosis and HIV services within the community.

METHODS

ZAMSTAR was a community-randomised trial done in Zambia and the Western Cape province of South Africa. Two interventions, community-level enhanced tuberculosis case-finding (ECF) and household level tuberculosis-HIV care, were implemented between Aug 1, 2006, and July 31, 2009, and assessed in a 2×2 factorial design between Jan 9, 2010, and Dec 6, 2010. All communities had a strengthened tuberculosis-HIV programme implemented in participating health-care centres. 24 communities, selected according to population size and tuberculosis notification rate, were randomly allocated to one of four study groups using a randomisation schedule stratified by country and baseline prevalence of tuberculous infection: group 1 strengthened tuberculosis-HIV programme at the clinic alone; group 2, clinic plus ECF; group 3, clinic plus household intervention; and group 4, clinic plus ECF and household interventions. The primary outcome was the prevalence of culture-confirmed pulmonary tuberculosis in adults (≥18 years), defined as Mycobacterium tuberculosis isolated from one respiratory sample, measured 4 years after the start of interventions in a survey of 4000 randomly selected adults in each community in 2010. The secondary outcome was the incidence of tuberculous infection, measured using tuberculin skin testing in a cohort of schoolchildren, a median of 4 years after a baseline survey done before the start of interventions. This trial is registered, number ISRCTN36729271.

FINDINGS

Prevalence of tuberculosis was evaluated in 64,463 individuals randomly selected from the 24 communities; 894 individuals had active tuberculosis. Averaging over the 24 communities, the geometric mean of tuberculosis prevalence was 832 per 100,000 population. The adjusted prevalence ratio for the comparison of ECF versus non-ECF intervention groups was 1·09 (95% CI 0·86-1·40) and of household versus non-household intervention groups was 0·82 (0·64-1·04). The incidence of tuberculous infection was measured in a cohort of 8809 children, followed up for a median of 4 years; the adjusted rate ratio for ECF versus non-ECF groups was 1·36 (95% CI 0·59-3·14) and for household versus non-household groups was 0·45 (0·20-1·05).

INTERPRETATION

Although neither intervention led to a statistically significant reduction in tuberculosis, two independent indicators of burden provide some evidence of a reduction in tuberculosis among communities receiving the household intervention. By contrast the ECF intervention had no effect on either outcome.

FUNDING

Bill & Melinda Gates Foundation.

Comparing same day sputum microscopy with conventional sputum microscopy for the diagnosis of tuberculosis--Chhattisgarh, India

BACKGROUND

The World Health Organization (WHO) recommends same day sputum microscopy (spot-spot) in preference to conventional strategy (spot-morning) for the diagnosis of smear positive tuberculosis with the view that completing diagnosis on a single day may be more convenient to the patients and reduce pre-treatment losses to follow-up.

METHODS

We conducted a cross-sectional study in seven selected district level hospitals of Chhattisgarh State, India. During October 2012 - March 2013, two sputum specimens (spot-early morning) were collected from consecutively enrolled adult (≥ 18 years) presumptive TB patients as per current national guidelines. In addition, a second sample was collected (one hour after the collection of first spot sample) from the same patients. All the samples were examined by ziehl-Neelsen (ZN) microscopy. McNemar's test was used to compare statistical differences in the proportion smear positive between the two approaches (spot-spot versus spot-morning).

RESULTS

Of 2551 presumptive TB patients, 69% were male. All patients provided the first spot specimen, 2361 (93%) provided the second spot specimen, and 2435 (96%) provided an early morning specimen. 72% of specimens were mucopurulent in conventional strategy as compared to 60% in same day strategy. The proportion of smear-positive patients diagnosed by same day microscopy was 14%, as compared to 17% by the conventional method (p<0.001). A total of 73 (16.9%) potential cases were missed by the same day method compared to only 2 (0.5%) by the conventional method.

CONCLUSION

Same-day microscopy method missed 17% of smear-positive cases and contrary to prior perception, did not increase the proportion of suspects providing the second sample. These findings call for an urgent need to revisit the WHO recommendation of switching to same-day diagnosis over the current policy.

A potato tuber-expressed mRNA with homology to steroid dehydrogenases affects gibberellin levels and plant development

Using cDNA-AFLP RNA fingerprinting throughout potato tuber development, we have isolated a transcript-derived fragment (TDF511) with strong homology to plant steroid dehydrogenases. During in vitro tuberization, the abundance profile of the TDF shows close correlation to the process of tuber formation. However, when tuberization is inhibited by the addition of gibberellins (GAs) to the growth medium, the appearance of TDF511 in the fingerprint is delayed, then steadily increases in intensity during later stages of development. TDF511 was used to isolate the corresponding cDNA (CB12). The DNA and deduced amino-acid sequences of the cDNA show high homology to a fruit-ripening gene from tomato, a series of steroid dehydrogenases, and the maize Ts2 gene. A section of the cDNA was cloned in antisense orientation behind a 35S CaMV promoter and transformed into potato. Transgenic plants expressing the antisense gene showed significantly earlier emergence, an increase in height, and longer tuber shape. In vitro tuberization experiments reveal extended stolon lengths in comparison to the controls. The analysis of endogenous GA levels showed that the transgenic antisense plants have elevated levels of biologically active GAs and their respective precursors. We propose that this gene plays a role in the metabolism of plant-growth substances important for tuber life cycle and plant development.