Control and prevention of tuberculosis in the United Kingdom: code of practice 2000. Joint Tuberculosis Committee of the British Thoracic Society

Burden of drug-resistant tuberculosis among contacts of index cases: a protocol for a systematic review

INTRODUCTION

People having close contact with drug-resistant tuberculosis (DR-TB) patients are at increased risk of contracting and developing the disease. However, no comprehensive review has been undertaken to estimate the burden of DR-TB among contacts of DR-TB patients. Therefore, the current systematic review will quantify the prevalence and incidence of DR-TB among contacts of DR-TB patients.

METHOD AND ANALYSIS

Systematic searches will be conducted in Medline, Embase, Web of Science, Scopus, Cochrane Central Register of Controlled trials (CENTRAL) and Cumulative Index to Nursing and Allied Health Literature (CINHAL) databases. The search will be conducted without restrictions on time, language and geography. A random-effects meta-analysis will be conducted for effect estimates. The pooled prevalence and incidence of DR-TB will be compared between people with and without contact with DR-TB patients. The presence of heterogeneity between studies will be assessed by Higgins I2 statistics. Subgroup analysis will be conducted to determine the source of heterogeneity. The risk of bias will be assessed using a visual inspection of the funnel plot and Egger's regression test statistics. Trim and fill analysis will be done in the presence of publication bias. A sensitivity analysis will be conducted by trimming low-quality studies. The systematic review will be reported according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol guidelines.

ETHICS AND DISSEMINATION

Ethical approval will not be required for this study as it will be a systematic review and meta-analysis based on previously published evidence. The findings of the systematic review will be presented at scientific conferences and published in scientific journals.

PROTOCOL REGISTRATION

The protocol is published in PROSPERO with registration number CRD42023390339.

Exhaled Mycobacterium tuberculosis Predicts Incident Infection in Household Contacts

BACKGROUND

Halting transmission of Mycobacterium tuberculosis (Mtb) by identifying infectious individuals early is key to eradicating tuberculosis (TB). Here we evaluate face mask sampling as a tool for stratifying the infection risk of individuals with pulmonary TB (PTB) to their household contacts.

METHODS

Forty-six sputum-positive PTB patients in The Gambia (August 2016-November 2017) consented to mask sampling prior to commencing treatment. Incident Mtb infection was defined in 181 of their 217 household contacts as QuantiFERON conversion or an increase in interferon-γ of ≥1 IU/mL, 6 months after index diagnosis. Multilevel mixed-effects logistical regression analysis with cluster adjustment by household was used to identify predictors of incident infection.

RESULTS

Mtb was detected in 91% of PTB mask samples with high variation in IS6110 copies (5.3 × 102 to 1.2 × 107). A high mask Mtb level (≥20 000 IS6110 copies) was observed in 45% of cases and was independently associated with increased likelihood of incident Mtb infection in contacts (adjusted odds ratio, 3.20 [95% confidence interval, 1.26-8.12]; P = .01), compared with cases having low-positive/negative mask Mtb levels. Mask Mtb level was a better predictor of incident Mtb infection than sputum bacillary load, chest radiographic characteristics, or sleeping proximity.

CONCLUSIONS

Mask sampling offers a sensitive and noninvasive tool to support the stratification of individuals who are most infectious in high-TB-burden settings. Our approach can provide better insight into community transmission in complex environments.

Responding to pandemics and other disease outbreaks in homeless populations: A review of the literature and content analysis

Considering the recent COVID-19 pandemic, we recognised a lack of synthesis amongst the available literature pertaining to the intersections of homelessness and pandemic response and planning. Therefore, the purpose of this review was to identify relevant peer-reviewed literature in this area to thematically produce evidence-based recommendations that would inform community planning and response amongst homeless populations. Although this review is inspired by the COVID-19 pandemic, our intention was to produce relevant recommendations to for all current and future outbreaks and pandemics more generally. Our search criteria focused on pandemics and rapid-spread illnesses such as contagious respiratory diseases with contact spread and with an emphasis on individuals experiencing homelessness. Content analysis methods were followed to extract and thematically synthesise key information amongst the 223 articles that matched our search criteria between the years of 1984 and 2020. Two reviewers were assigned to the screening process and used Covidence and undertook two rounds of discussion to identify and finalise themes for extraction. This review illustrates that the current breadth of academic literature on homeless populations has thus far focused on tuberculosis (TB) rather than diseases that are more recent and closely related to COVID-19-such as Severe Acute Respiratory Syndrome (SARS) or H1N1. Our thematic content analysis revealed six themes that offer tangible and scalable recommendations which include (1) education and outreach, (2) adapting structure of services, (3) screening and contract tracing, (4) transmission and prevention strategies, (5) shelter protocols and (6) treatment, adherence and vaccination. The breadth and depth of reviews such as these are dependent on the quantity and quality of the available literature. Therefore, the limited existing literature outside of tuberculosis specific to homelessness in this review illustrates a need for more academic research into the intersections of pandemics and homelessness-particularly for evaluations of response and planning. Nonetheless, this review offers timely considerations for pandemic response and planning amongst homeless populations during the current COVID-19 pandemic and can facilitate future research in this area.

Cost-effectiveness of household contact investigation for detection of tuberculosis in Pakistan

OBJECTIVES

Despite WHO guidelines recommending household contact investigation, and studies showing the impact of active screening, most tuberculosis (TB) programmes in resource-limited settings only carry out passive contact investigation. The cost of such strategies is often cited as barriers to their implementation. However, little data are available for the additional costs required to implement this strategy. We aimed to estimate the cost and cost-effectiveness of active contact investigation as compared with passive contact investigation in urban Pakistan.

METHODS

We estimated the cost-effectiveness of 'enhanced' (passive with follow-up) and 'active' (household visit) contact investigations compared with standard 'passive' contact investigation from providers and the programme's perspective using a simple decision tree. Costs were collected in Pakistan from a TB clinic performing passive contact investigation and from studies of active contact tracing interventions conducted. The effectiveness was based on the number of patients with TB identified among household contacts screened.

RESULTS

The addition of enhanced contact investigation to the existing passive mode detected 3.8 times more cases of TB per index patient compared with passive contact investigation alone. The incremental cost was US$30 per index patient, which yielded an incremental cost of US$120 per incremental patient identified with TB. The active contact investigation was 1.5 times more effective than enhanced contact investigation with an incremental cost of US$238 per incremental patient with TB identified.

CONCLUSION

Our results show that enhanced and active approaches to contact investigation effectively identify additional patients with TB among household contacts at a relatively modest cost. These strategies can be added to the passive contact investigation in a high burden setting to find the people with TB who are missed and meet the End TB strategy goals.

Unusual Recurrence of Antituberculosis Drug-Induced Hepatotoxicity in Children: A Case Series

Case series

Patients: Male, 4-year-old • Female, 18-month-old • Male, 2-year-and-6-month-old • Female, 13-year-old • Female, 8-year-old • Male, 7-year-old

Final Diagnosis: Recurrent ADIH

Symptoms: Nausea • vomiting • yellowish skin

Medication: —

Clinical Procedure: Liver function test examination

Specialty: Infectious Diseases • Pulmonology

Social Enterprise Model (SEM) for private sector tuberculosis screening and care in Bangladesh

BACKGROUND

In Bangladesh, about 80% of healthcare is provided by the private sector. Although free diagnosis and care is offered in the public sector, only half of the estimated number of people with tuberculosis are diagnosed, treated, and notified to the national program. Private sector engagement strategies often have been small scale and time limited. We evaluated a Social Enterprise Model combining external funding and income generation at three tuberculosis screening centres across the Dhaka Metropolitan Area for diagnosing and treating tuberculosis.

METHODS AND FINDINGS

The model established three tuberculosis screening centres across Dhaka Metropolitan Area that carried the icddr,b brand and offered free Xpert MTB/RIF tests to patients visiting the screening centres for subsidized, digital chest radiographs from April 2014 to December 2017. A network of private and public health care providers, and community recommendation was formed for patient referral. No financial incentives were offered to physicians for referrals. Revenues from radiography were used to support screening centres' operation. Tuberculosis patients could choose to receive treatment from the private or public sector. Between 2014 and 2017, 1,032 private facilities networked with 8,466 private providers were mapped within the Dhaka Metropolitan Area. 64, 031 patients with TB symptoms were referred by the private providers, public sector and community residents to the three screening centres with 80% coming from private providers. 4,270 private providers made at least one referral. Overall, 10,288 pulmonary and extra-pulmonary tuberculosis cases were detected and 7,695 were bacteriologically positive by Xpert, corresponding to 28% of the total notifications in Dhaka Metropolitan Area.

CONCLUSION

The model established a network of private providers who referred individuals with presumptive tuberculosis without financial incentives to icddr,b's screening centres, facilitating a quarter of total tuberculosis notifications in Dhaka Metropolitan Area. Scaling up this approach may enhance national and international tuberculosis response.

Protection of healthcare workers against transmission of Mycobacterium tuberculosis in hospitals: a review of the evidence

Background

Employees in contact with infectious tuberculosis (TB) patients in healthcare facilities of low-incidence countries are still at considerable risk of acquiring TB infections. However, formal precautions recommended on the protection of healthcare workers may not only vary from country to country but also within a single country. The objective of this study was to compare current guidelines with respect to hospital infection control of TB, focusing on common shared priorities and discrepancies between sets of recommendations.

Methods

Five types of procedures captured in guidelines of the World Health Organization, the United States of America, the United Kingdom and Germany are compared and the underlying evidence is discussed.

Results

Uncontroversially, personal protection by respirators in the TB ward and during aerosol-generating procedures is key to reducing Mycobacterium tuberculosis exposure. However, there is no consensus on the types of masks that should be worn in different situations. Closely connected to this, there is considerable uncertainty with respect to the optimal date of removing sputum smear-negative and multidrug-resistant TB patients from isolation. Indeed, the use of notable new tools for this purpose, such as the highly sensitive PCR tests recommended by the World Health Organization for detecting TB/multidrug-resistant TB, have yet to be sufficiently incorporated into TB guidelines. Perceptions differ, too, as to whether long-term control measures for M. tuberculosis infections in healthcare workers by serial testing for latent TB infection should be established and, if so, how testing results should be interpreted.

Conclusions

Although the current recommendations on protection of healthcare workers are otherwise homogeneous, there are considerable discrepancies that have important implications for daily practice.

Current @WHO, US, UK and German recommendations on protecting employees in healthcare facilities against M. tuberculosis transmission show considerable practical discrepancies. Harmonisation and practical amendments of such guidelines is most desirable.http://bit.ly/2EzGlBN

Complicated Urinary Tract Tuberculosis in a 13-Year-Old Adolescent with Chronic Kidney Disease and Antituberculous Drug-Induced Hepatotoxicity

Urinary tract tuberculosis (TB) is a rare extrapulmonary manifestation of TB in children. The disease is potentially underdiagnosed because it clinically resembles other urinary tract infections. A 13-year-old adolescent girl presented with pain, difficulty in micturition, and gross hematuria for almost two years before admission, and she had left flank pain since one year ago and significant loss of body weight during the illness. The close TB contact was her grandmother who was on TB treatment. Acid-fast bacilli yielded positive result, Mantoux test was positive (17 mm), urine GeneXpert MTB/Rif was positive; tuberculoma was identified on kidney histopathology, and a diuretic renogram revealed an uncorrected glomerular filtration rate (GFR) of the right and left kidney to be 32.5 mL/min/1.73 m² and 5 mL/min/1.73 m², respectively. During the treatment, oral anti-TB drug-induced hepatotoxicity (ADIH) occurred to the patient. This problem was solved with management according to the British Thoracic Society (BTS) guidelines. Screening TB in children is very important for a better outcome. If children complain of some complicated urinary tract infection, TB should be suspected. Optimaly treating children with urinary tract TB exagerrated with ADIH and CKD is very challenging.

A population-based tuberculosis contact investigation in the country of Georgia

Setting: Identification and screening of contacts of patients with active tuberculosis (TB) is infrequent in low- and middle-income countries. Objective: To estimate the incidence, prevalence and risk factors of latent tuberculous infection (LTBI) and active TB among contacts of newly reported smear-positive TB patients. Design: A population-based contact investigation of sputum smear-positive pulmonary TB (PTB) cases diagnosed between April and December 2012 in Georgia was conducted. LTBI was assessed using the tuberculin skin test (TST). Contacts with active TB were identified from the National TB Program surveillance database. Results: Among 896 index patients with active TB, 3133 contacts were identified and 1157 (37%) underwent a TST, 34% of whom were positive. Most contacts were household contacts (86%) and female (58%). Among contacts, the 1-year period prevalence of active TB was 3.3% (95%CI 2.70-3.98); the incidence rate was 1101 per 100 000 person-years (95%CI 822-1443). In multivariable analysis, household contacts were more likely to have LTBI (adjusted OR [aOR] 2.28, 95%CI 1.49-3.49) than close contacts. Conclusions: A high prevalence of both LTBI and active TB was identified among contacts of PTB cases. Efforts aimed at active case finding among TB contacts should improve early case detection and enhance TB control efforts.

Expected background rates of latent TB infection in London inner city schools: lessons from a TB contact investigation exercise in a secondary school

Following an extensive contact tracing exercise at a school in a London borough with one of highest tuberculosis (TB) rates in England, we estimated the background prevalence of latent TB infection to be significantly less than the widely accepted 10%. We screened 271 pupils aged 14-15 years in two groups: 96 pupils in group 1 had significant exposure (>8 h/week in the same room) to a case of infectious TB and 175 in group 2 who had minimal exposure. In group 1, 26% were diagnosed with latent or active TB, compared to 6.3% in group 2. Risk factors for TB infection (e.g. previous exposure or link to high-prevalence communities) were analysed using a cohort study design. In the univariable analysis only being in contact group 1 was statistically significantly associated with being a case (OR 5.25, 95%, P < 0.001). In the multivariable model contact group 1 remained significantly associated with being a case (adjusted OR 4.40, P = 0.001). We concluded that the 6.3% yield of TB infection in contact group 2 is either similar to or higher than the background prevalence rate of latent TB infection (LTBI) in this high TB prevalence London borough. Other parts of England with lower TB prevalence are likely to have even lower LTBI rates.

Outbreak column 21: Tuberculosis (TB): Still a nosocomial threat

This outbreak column explores the epidemiology and infection prevention guidance on tuberculosis (TB) in the UK. The column finds that, at present, national guidance leaves UK hospitals ill-prepared to prevent nosocomial TB transmission. Reasons for this conclusion are as follows: (1) while TB is predominantly a disease that affects people with 'social ills', it has the potential to infect anyone who is sufficiently exposed; (2) nosocomial transmission is documented throughout history; (3) future nosocomial exposures may involve less treatable disease; and (4) current UK guidance is insufficient to prevent nosocomial transmission and is less than that advocated by the World Health Organization and the Centers for Disease Control and Prevention.

High prevalence of TB disease in contacts of adults with extrapulmonary TB

UK guidelines no longer recommend routine screening of household contacts of adult patients with extrapulmonary TB (EPTB). From 27 March 2012 to 28 June 2016, we investigated the prevalence of active TB disease in household contacts of 1023 EPTB index cases in North West England, and compared estimates with: published new entrant migrant screening programme prevalence (~147/100 000 person-years); London-based contact screening data (700/100 000 contacts screened); and National Institute for Health and Care Excellence (NICE) new entrant TB screening thresholds (TB prevalence >40/100 000 people). Active TB disease prevalence in EPTB contacts was 440/100 000 contacts screened, similar to UK new entrant screening programmes, London EPTB contact prevalence and >10 times NICE’s threshold for new entrant screening. The decision to no longer recommend routine screening of EPTB contacts should be re-evaluated and cost-effectiveness analyses of screening strategies for EPTB contacts should be performed.

Recent household transmission of tuberculosis in England, 2010-2012: retrospective national cohort study combining epidemiological and molecular strain typing data

BACKGROUND

We estimate the proportion of tuberculosis (TB) in England due to recent household transmission, identify factors associated with being a household transmitter, and investigate the impact that identification of a case has on time to treatment of subsequent cases.

METHODS

TB cases notified between 2010 and 2012 in England in the same household as another case were identified; 24 locus MIRU-VNTR strain typing (ST) was used to identify household cases with likely recent transmission. Treatment delay in index and subsequent cases was compared. Risk factors for being a household transmitter were identified in univariable and multivariable analyses.

RESULTS

Overall, 7.7% (1849/24,060) of TB cases lived in a household with another case. We estimate that 3.9% were due to recent household transmission. ST data was unavailable for 67% (1242) of household pairs. For those with ST data, 64% (386) had confirmed, 11% probable (66) and 25% (155) refuted household transmission. The median treatment delay was 65 days for index cases and 37 days for subsequent asymptomatic cases. Risk factors for being a household transmitter included being under 25 years old, UK-born with Black African, Indian or Pakistani ethnicity, or born in Somalia or Romania.

CONCLUSIONS

This study has a number of implications for household TB contact tracing in low incidence countries, including the potential to reduce the diagnostic delay for subsequent household cases and the benefit of using ST to identify when to conduct source contact tracing outside the household. As 25% of TB cases in households had discordant strains, households with multiple TB cases do not necessarily represent household transmission. The additional fact that 25% of index cases within households only had extra-pulmonary TB demonstrates that, if household contact tracing is limited to pulmonary TB cases (as recently recommended in UK guidelines), additional cases of active TB in households will be missed. Our finding that no lineage of TB was associated with recent household transmission and with no increased transmissibility in the Beijing lineage compared to others, suggests that the lineage need not impact contact tracing efforts. Improvements in contact tracing have the potential to reduce transmission of TB in low incidence countries.

European policies on tuberculosis prevention in healthcare workers: Which role for BCG? A systematic review

National recommendations regarding the immunization of healthcare workers (HCWs) against tuberculosis differ throughout Europe. We searched multiple sources to identify legal acts, guidelines or papers addressing European national policies on BCG immunization for HCWs. For each policy, we reviewed the criteria used to recommend immunization, their level of evidence, the evidence supporting them and the actions required in cases of refusal. Four legal acts, 15 policies and 6 papers from 14 European countries met the inclusion criteria. Among European national agencies, 5 only recommend the immunization of HCWs employed in high-risk sectors, highlighting the lack of evidence of Bacillus Calmette-Guerin (BCG) efficacy in HCWs; 5 recommend BCG vaccination for all previously unvaccinated Mantoux-negative HCWs, underlining that some studies provide arguments of some BCG efficacy in HCWs; and four do not recommend the vaccine. Different interpretations of existing evidence on BCG efficacy and the demographics of HCWs may have influenced national policies.

Tuberculosis and infection control: a review of the evidence

xposure to patients with infectious tuberculosis is a well-recognised hazard of health care and although the risks associated with this hazard cannot be completely eliminated, they can be controlled and minimised. Risk reduction strategies rely upon a hierarchy of control measures to prevent the nosocomial transmission of tuberculosis in healthcare settings. In this article, the authors discuss the background to these strategies and review the evidence that underpins clinically effective administrative and engineering controls and personal respiratory protection. The authors conclude with recommendations and guide readers to further sources of reliable information.

Non-Pulmonary Tuberculosis--A Case Report: Importance and Pitfalls of Diagnosis

A case of tuberculosis presenting as a neck lump is highlighted. Tuberculosis is on the increase. There are national and international strategies to improve the management of tuberculosis in the United Kingdom, and raising clinical awareness of tuberculosis is an important part of that strategy. Neck lumps can present in the dental setting and the differential diagnosis should include tuberculosis, with referral to an appropriate multidisciplinary team. Special tests to aid diagnosis are helpful but not completely discriminating. Tuberculosis is a notifiable disease and it must be treated by a designated specialist medical team. CPD/Clinical Relevance: Tuberculosis is a differential diagnosis for a persistent neck lump and clinicians should understand the problems of diagnosis and the importance of appropriate referral for treatment in the national and international strategy to reduce this disease.

[Results of tuberculosis screening in children with household contact]

INTRODUCTION

Tuberculosis screening in children is important to identify and treat latent tuberculosis infection and thus avoid progression to disease.

METHODS

It is a prospective study realized in 83 children between November 2009 and January 2013 who consulted after a household contact for tuberculosis in the pediatric department B of Abderrahmen Mami hospital of Ariana.

RESULTS

The mean age of the children was 4.8 years (3 months-15 years). A latent tuberculosis infection was diagnosed in 31.3% of children, 10.8% had tuberculosis and 57.8% were considered healthy. Fifty-seven children (68.7%) had a close daytime contact with the index and 57.8% slept in the same bedroom of the contaminator. The identified risk factors were the diagnosis delay of the index of more than 30 days (P=0.023), presence of cavitations on the chest X-ray of the index (P=0.029) and a close daytime contact (P=0.004).

CONCLUSION

Our study showed a high rate of contamination in children with a household contact. Efforts are needed to shorten the time to diagnosis of adults' tuberculosis.

Half of Pulmonary Tuberculosis Cases Were Left Undiagnosed in Prisons of the Tigray Region of Ethiopia: Implications for Tuberculosis Control

Introduction

Prison settings have been often identified as important but neglected reservoirs for TB. This study was designed to determine the prevalence of undiagnosed pulmonary TB and assess the potential risk factors for such TB cases in prisons of the Tigray region.

Method

A cross-sectional study was conducted between August 2013 and February 2014 in nine prisons. A standardized symptom-based questionnaire was initially used to identify presumptive TB cases. From each, three consecutive sputum samples were collected for acid-fast bacilli (AFB) microscopy and culture. Blood samples were collected from consented participants for HIV testing.

Result

Out of 809 presumptive TB cases with culture result, 4.0% (95% CI: 2.65–5.35) were confirmed to have undiagnosed TB. The overall estimated point prevalence of undiagnosed TB was found to be 505/100,000 prisoners (95% CI: 360–640). Together with the 27 patients who were already on treatment, the overall estimated point prevalence of TB would be 793/100,000 prisoners (95% CI: 610–970), about four times higher than in the general population. The ratio of active to passive case detection was 1.18:1. The prevalence of HIV was 4.4% (36/809) among presumptive TB cases and 6.3% (2/32) among undiagnosed TB cases. In a multivariate logistic regression analysis, chewing Khat (adjusted OR = 2.81; 95% CI: 1.02–7.75) and having had a close contact with a TB patient (adjusted OR = 2.18; 95% CI: 1.05–4.51) were found to be predictors of undiagnosed TB among presumptive TB cases.

Conclusions

This study revealed that at least half of symptomatic pulmonary TB cases in Northern Ethiopian prisons remain undiagnosed and hence untreated. The prevalence of undiagnosed TB in the study prisons was more than two folds higher than in the general population of Tigray. This may indicate the need for more investment and commitment to improving TB case detection in the study prisons.

Updates on the risk factors for latent tuberculosis reactivation and their managements

The preventive treatment of latent tuberculosis infection (LTBI) is of great importance for the elimination and control of tuberculosis (TB) worldwide, but existing screening methods for LTBI are still limited in predicting the onset of TB. Previous studies have found that some high-risk factors (including human immunodeficiency virus (HIV), organ transplantation, silicosis, tumor necrosis factor-alpha blockers, close contacts and kidney dialysis) contribute to a significantly increased TB reactivation rate. This article reviews each risk factor's association with TB and approaches to address those factors. Five regimens are currently recommended by the World Health Organization, and no regimen has shown superiority over others. In recent years, studies have gradually narrowed down to the preventive treatment of LTBI for high-risk target groups, such as silicosis patients, organ-transplantation recipients and HIV-infected patients. This review discusses regimens for each target group and compares the efficacy of different regimens. For HIV patients and transplant recipients, isoniazid monotherapy is effective in treating LTBI, but for others, little evidence is available at present.

Synthesis, 3D-QSAR analysis and biological evaluation of quinoxaline 1,4-di-N-oxide derivatives as antituberculosis agents

A series of quinoxaline 1,4-di-N-oxide derivatives variously substituted at C-2 position were synthesized and evaluated for in vitro antimycobacterial activity. Seventeen compounds exhibited potential activity (MIC ⩽6.25μg/mL) against Mycobacterium tuberculosis (H37Rv), in particular the compounds 3d and 3j having an MIC value of 0.39μg/mL. None of the compounds exhibited cytotoxicity when using an MTT assay in VERO cells. To further investigate the structure-activity relationship, CoMFA (q(2)=0.507, r(2)=0.923) and CoMSIA (q(2)=0.665, r(2)=0.977) models were performed on the basis of antimycobacterial activity data. The 3D-QSAR study of these compounds can provide useful information for further rational design of novel quinoxaline 1,4-di-N-oxides for treatment of tuberculosis.

Mycobacterium bovis cervical lymphadenitis: A representative case and review

Mycobacterium bovis is a tuberculosis causing bacterium that commonly presents with cervical lymphadenopathy. It is important to differentiate M. bovis from other Mycobacterial pathogens to ensure selection of correct anti-microbial therapy. This may decrease the number of treatment failures, the prevalence of anti-mycobacterial drug resistance patterns, and the need for surgical intervention. M. bovis has universal resistance to pyrazinamide and thus may not respond to typical first line mycobacterial drugs and may require surgical intervention. This case report and review of M. bovis cervical lymphadenitits demonstrates the need for accurate diagnosis as well as combined management with infectious disease and public health specialists.

Interferon-γ release assay for the diagnosis of latent Mycobacterium tuberculosis infection in children younger than 5 years: a meta-analysis

BACKGROUND

Interferon-γ release assays (IGRAs) have been widely used for the diagnosis of latent and active tuberculosis in adults, but their role in diagnosing latent tuberculosis infection (LTBI) in children younger than 5 years remains unclear.

OBJECTIVE

To evaluate the diagnostic performance of IGRAs for LTBI in children younger than 5 years.

METHODS

We searched the PubMed, EMBASE, Cochrane Library, and Web of Knowledge databases. According to inclusion criteria, the diagnostic studies of IGRAs for LTBI in children younger than 5 years were included. The study quality was assessed using the 14-item Quality Assessment of Diagnostic Accuracy Studies instrument. The Meta-Analyst software was used to analyze the data.

RESULTS

Seven studies (627 patients) were included. Meta-analysis showed that compared with tuberculin skin test (TST), the pooled sensitivity (Sen), specificity (Spe), positive likelihood ratio (PLR), negative likelihood ratio (NLR), positive predictive value (PPV), negative predictive value (NPV), accuracy and diagnosis odds ratio (DOR), and summary receiver operating characteristic (SROC) curve of QuantiFERON-TB (values in parentheses are 95% confidence intervals) were 0.841 (0.733-0.911), 0.895 (0.861-0.922), 8.046 (5.953-10.876), 0.192 (0.113-0.326), 0.622 (0.527-0.709), 0.970 (0.946-0.983), 0.891 (0.861-0.916), 50.718 (24.201-106.287), and 0.809 respectively. The pooled Sen, Spe, PLR, NLR, PPV, NPV, accuracy, DOR, and SROC curve of T-SPOT.TB test were 0.931 (0.760-0.983), 0.767 (0.684-0.833), 3.947 (2.854-5.459), 0.095 (0.026-0.354), 0.523 (0.398-0.645), 0.977 (0.914-0.994), 0.806 (0.737-0.860), 65.270 (13.463-316.434), and 0.855, respectively.

CONCLUSION

This meta-analysis showed that the sensitivity and specificity of IGRAs were slightly higher than TST and can be used as supporting tools to detect LTBI in children younger than 5 years. The methodological quality of diagnostic test needs to be improved.

Effectiveness and cost effectiveness of screening immigrants schemes for tuberculosis (TB) on arrival from high TB endemic countries to low TB prevalent countries

BACKGROUND

Immigrants to developed countries are a major source of TB. Therefore amongst strategies adopted for TB control in developed countries include; 1) Screening immigrants at ports of entry referred to as "Port of Arrival Screening" (PoA) and 2) Passive screening (PS) for TB which means screening immigrants through general practices, hospitals, chest-clinics and emergency departments. Evidence of the effectiveness and cost effectiveness of these strategies is not consistent.

OBJECTIVE

Evaluate efficiency of active PoA TB screening for immigrants from TB endemic-regions compared with Passive Screening of immigrant-populations from TB endemic-regions.

METHODS

Major electronic-databases and reference lists of relevant studies were searched. Experts of immigrants' TB screening were contacted for additional studies published or unpublished. Systematic search of major databases identified only retrospective cohort-studies. Their qualities were assessed using Scottish Intercollegiate Guidelines Network (SIGN) methodological checklist for comparative cohort-studies.

RESULTS

Systematic electronic searches identified 1443 citations. Of these 74 studies were retrieved for evaluation against the review's inclusion/exclusion criteria (see study inclusion/exclusion criteria). Four studies met the inclusion criteria (figure 2) which were low in the evidence hierarchy of primary effectiveness studies and had heterogeneities between them. Thus descriptive data-synthesis was performed. Proportionately PoA screening had the lowest percentage of receipt of tuberculin skin test (TST) and the highest percentage of non-attendance for TST reading (table 2). Active PoA screening reduced infectiousness by 34% compared to 30% by passive screening and new entrants screened at PoA were 80% less likely to be hospitalised Odds ratio (OR) = 0.2 (95% confidence interval (CI) 0.1 - 0.2). [Table: see text].

ECONOMIC ANALYSIS

One cost effectiveness analysis was found that compared the costs of; active PoA screening, general practice screening and homeless screening groups. The cost of detecting a case of TB were; £1.26, £13.17 and £96.36 for PS, homeless screening and active PoA screening respectively. The cost of preventing a case of TB were; £6.32, £23.00 and £10.00 for PS, homeless screening and PoA screening respectively, showing there is little difference between the different strategies.

CONCLUSION

Active PoA screening is worth doing with significant benefits including early identification of risk groups with possible timely treatment/chemoprophylaxis intervention, prevention of transmission by significantly reducing infectiousness with subsequent avoidance of hospitalisation in active PoA screening group.

Impact of GeneXpert MTB/RIF on patients and tuberculosis programs in a low-burden setting. a hypothetical trial

RATIONALE

Guidelines recommend routine nucleic-acid amplification testing in patients with presumed tuberculosis (TB), but these tests have not been widely adopted. GeneXpert MTB/RIF (Xpert), a novel, semiautomated TB nucleic-acid amplification test, has renewed interest in this technology, but data from low-burden countries are limited.

OBJECTIVES

We sought to estimate Xpert's potential clinical and public health impact on empiric treatment, contact investigation, and housing in patients undergoing TB evaluation.

METHODS

We performed a prospective, cross-sectional study with 2-month follow-up comparing Xpert with standard strategies for evaluating outpatients for active pulmonary TB at the San Francisco Department of Public Health TB Clinic between May 2010 and June 2011. We calculated the diagnostic accuracy of standard algorithms for initial empiric TB treatment, contact investigation, and housing in reference to three Mycobacterium tuberculosis sputum cultures, as compared with that of a single sputum Xpert test. We estimated the incremental diagnostic value of Xpert, and the hypothetical reductions in unnecessary treatment, contact investigation, and housing if Xpert were adopted to guide management decisions.

MEASUREMENTS AND MAIN RESULTS

A total of 156 patients underwent Xpert testing. Fifty-nine (38%) received empiric TB treatment. Thirteen (8%) had culture-positive TB. Xpert-guided management would have hypothetically decreased overtreatment by 94%, eliminating a median of 44 overtreatment days (interquartile range, 43-47) per patient and 2,169 total overtreatment days (95% confidence interval, 1,938-2,400) annually, without reducing early detection of TB patients. We projected similar benefits for contact investigation and housing.

CONCLUSIONS

Xpert could greatly reduce the frequency and impact of unnecessary empiric treatment, contact investigation, and housing, providing substantial patient and programmatic benefits if used in management decisions.

Yield of tuberculosis contact investigation in a low-incidence country

BACKGROUND

Tuberculosis (TB) contact tracing is a valid public health measure to control the spread of TB infection in low-burden settings. The aim of this study was to assess the yield of the Piedmont TB contact investigation program and to evaluate the role of its main determinants.

METHODS

The Piedmont TB notification systems were used to identify index TB cases. All cases were classified by contagiousness (sputum-smear-positive, AFB+; culture-positive, CULT+; other-than-defined). TB contacts were screened for active and latent TB infection by clinical manifestations and Tuberculin Skin Test (TST).

RESULTS

833 index TB cases with at least one contact were identified; 4441 contacts were screened, and 3942 (82.8%) were evaluated. TB contacts aged ≤ 35 years, regular and household contacts had a higher probability of being evaluated; foreign-born TB contacts were the least traceable. Higher rates of TB infection were observed in contacts at 35 years of age or younger who also lived in the same household with index cases or exposed to AFB+ or CULT+ index cases.

CONCLUSION

More efforts should be focused on young TB contacts, since they are likely to be new infections. An early identification and treatment of TB Infection in this group contributes to the prevention and control of TB transmission. The program should also be extended to the contacts of CULT+ cases.

Tuberculosis: which patients do not identify their contacts?

SETTING

It is not known what the magnitude of non-identified TB contacts is in our country, or the reasons why contacts at risk are not identified.

OBJECTIVE

The purpose of this study was to analyze the determinants associated with non-identification of contacts.

DESIGN

This cross-sectional study included all cases of pulmonary tuberculosis diagnosed and treated in the Chest Disease Centre of Vila Nova de Gaia and their contacts, from 1st January to 31st December 2010. It included information collected from patients related to the identification of contacts in risk, and the information collected by the Public Health Unit during home, work and social places visits.

RESULTS

During the period of study, 61 cases of pulmonary TB were diagnosed: 41 cases (67.2%) identified all their contacts and 20 cases (32.8%) did not. 646 contacts were identified: 154 (23.8%) were identified only by the Public Health Unit (mean age of 40.67), and 492 (76.2%) were identified by the index cases (mean age of 33.25), (p=0.001). A mean of 10.59 contacts were identified per index case, of which, 83 (19.3%) screened positive. From those identified by the Public Health Unit, 10 (9.8%) had LTBI and 5 (4.9%) had active TB, and by the index case 61 (18.6%) had LTBI and 7 (2.1%) had active TB (crude OR=1.52; CI=0.83-2.79). The multivariate analysis showed that employment (adjusted OR=4.82; 95%CI=1.71-13.54) was associated to non-identification of contacts and patients preferably tended to identify relatives and co-habitants (adjusted OR=0.22; 95%CI=0.10-0.47).

CONCLUSION

TB patients tend to identify relatives and co-habitant contacts; contact at place of employment was found to be an independent risk factor for not being identified.

The outcome of a cohort of tuberculin-positive predominantly South Asian new entrants aged 16-34 to the UK: Blackburn 1989-2001

SETTING

Blackburn, Hyndburn and Ribble Valley Local Government areas of England and Wales, the former a high tuberculosis (TB) prevalence district.

BACKGROUND

The incidence of tuberculosis in new entrants aged 16-34 with positive tuberculin skin tests but normal chest X-rays after initial entry is not definitely known, and was previously estimated from cross-sectional national surveys and derived data for the 2006 and 2011 NICE economic appraisals of new entrant TB screening.

METHODS

New entrants aged 16-34 years predominantly from South Asia (India, Pakistan and Bangladesh), with tuberculin tests inappropriately positive for their BCG history were identified for the years 1989-2001 inclusive from a new entrant database. These entrants were compared with the current GP registration database to see if local residence could be confirmed and the local TB notification database to October 2008. Survival analysis was carried out using Kaplan-Meier survival curves and a Cox Regression model.

RESULTS

Four hundred and seventy-nine such new entrants with normal initial chest X-rays were identified. Of these 402 (84%) registered with a General Practitioner in East Lancashire for a period of time and could be followed up by this study. The crude incidence density of active TB amongst these individuals with latent disease was 1297 per 100 000 person-years (95% CI; 991-1698 per 100 000 person-years). After 10 and 15 years of follow-up 13.5 and 16.3% of individuals, respectively, had progressed on to active disease.

CONCLUSION

This patient-derived, rather than estimated, data shows a minimum risk of TB disease of 16.3% at 15 years. The 2006 NICE economic appraisal, suggested that treatment for latent TB infection (LTBI) was cost-effective when the incidence of clinical TB over 15 years surpassed 18% in these populations. The 2011 NICE economic appraisal reduced this to 12% active TB over 15 years, and showed that at 16% active TB over 15 years a single interferon gamma release assay was the most cost-effective strategy. Further cohort studies are urgently needed to confirm or revise the assumptions behind the 2011 NICE economic appraisal.

Household contact investigation for tuberculosis in Vietnam: study protocol for a cluster randomized controlled trial

Background

Tuberculosis is an infectious disease that continues to cause considerable morbidity and mortality globally. Only 65% of patients worldwide are currently diagnosed. Contact investigation is a strategy that aims to increase case detection and reduce transmission of tuberculosis, yet there is little evidence to show its effectiveness.

Methods/Design

We will conduct a cluster randomized controlled trial of contact investigation within the national tuberculosis control program of Vietnam. Household contacts of patients with smear-positive pulmonary tuberculosis will be invited to attend district tuberculosis units for symptom screening, examination, and chest radiography on four occasions over a two-year period. The primary endpoint is clinically confirmed tuberculosis among contacts during the 24 months of follow-up, ascertained using capture-recapture analysis. Microbiologically proven tuberculosis and treatment completion rates among contacts diagnosed with tuberculosis will be secondary endpoints. The incremental cost-effectiveness ratio will be estimated. The study will have 80% power to detect a 50% increase in the primary endpoint in the active intervention arm compared with the control arm. The study will include 8,829 contacts in each of the active screening and control groups, within 70 districts in 8 provinces in Vietnam, in both rural and urban settings.

Discussion

The effectiveness of contact investigation as a tool for improved tuberculosis case finding has not been established. This cluster randomized trial will provide valuable operational information for national tuberculosis programs in high-prevalence countries, in order to select the most cost-effective strategies to improve tuberculosis case detection.

Trial registration

The ACT2 study has been registered with the Australian New Zealand Clinical Trials Registry (ACTRN12610000600044).

Incidence and prevalence of tuberculosis among household contacts of pulmonary tuberculosis patients in a peri-urban population of South Delhi, India

BACKGROUND

Tuberculosis (TB), caused by Mycobacterium tuberculosis, is one of the leading causes of mortality and morbidity across all age groups throughout the world, especially in developing countries.

METHODOLOGY/PRINCIPAL FINDINGS

In this study, we have included 432 open index cases with their 1608 household contacts in a prospective cohort study conducted from May 2007 to March 2009. The follow-up period was 2 years. All Index cases were diagnosed on the basis of suggestive signs and symptoms and sputum being AFB positive. Among the 432 index patients, 250 (57.9%) were males and 182 (42.1%) females; with mean age of 34 ± 14.4 yr and 26 ± 11.1 yr, respectively. Out of 1608 household contacts, 866 (53.9%) were males and 742 (46.1%) females; with mean age of 26.5 ± 15.8 and 26.5 ± 16.0 yr, respectively. Of the total 432 households, 304 (70.4%) had ≤ 4 members and 128 (29.6%) had ≥ 5 members. The median size of the family was four. Of the 1608 contacts, 1206 were able to provide sputum samples, of whom 83 (6.9%) were found MTB culture positive. Household contacts belonging to adult age group were predominantly (74, 89.2%) infected as compared to the children (9, 10.8%). On screening the contact relationship status with index patients, 52 (62.7%) were first-degree relatives, 18 (34.6%) second-degree relatives and 12 (14.5%) spouses who got infected from their respective index patients. Co-prevalent and incident tuberculosis was found in 52 (4.3%) and 31 (2.6%) contacts, respectively. In incident cases, the diagnosis could be made between 4 to 24 months of follow-up, after their baseline evaluation.

CONCLUSION

Active household contact investigation is a powerful tool to detect and treat tuberculosis at early stages and the only method to control TB in high-TB-burden countries.

Contact investigation in households of patients with tuberculosis in Hanoi, Vietnam: a prospective cohort study

Setting

Existing tuberculosis control strategies in Vietnam are based on symptomatic patients attending health services for investigation. This approach has not resulted in substantial reductions in the prevalence of tuberculosis disease, despite the National Tuberculosis Program achieving high treatment completion rates. Alternative approaches are being considered.

Objective

To determine the feasibility and yield of contact investigation in households of patients with smear positive pulmonary tuberculosis among household members of tuberculosis patients in Hanoi, Vietnam.

Methods

Household contacts of patients with smear positive pulmonary tuberculosis were recruited at four urban and rural District Tuberculosis Units in Hanoi. Clinical and radiological screening was conducted at baseline, six months and 12 months. Sputum microscopy and culture was performed in contacts suspected of having tuberculosis. MIRU-VNTR molecular testing was used to compare the strains of patients and their contacts with disease.

Results

Among 545 household contacts of 212 patients, four were diagnosed with tuberculosis at baseline (prevalence 734 cases per 100,000 persons, 95% CI 17–1451) and one was diagnosed with tuberculosis during the subsequent 12 months after initial screening (incidence 180 cases per 100,000 person-years, 95% CI 44–131). Two of these cases were culture positive for M. tuberculosis and both had identical or near-identical MIRU-VNTR strain types.

Conclusion

Household contacts of patients with potentially infectious forms of tuberculosis have a high prevalence of disease. Household contact investigation is feasible in Vietnam. Further research is required to investigate its effectiveness.

Adherence by Dutch public health nurses to the national guidelines for tuberculosis contact investigation

Objectives

To assess whether public health nurses adhered to Dutch guidelines for tuberculosis contact investigations and to explore which factors influenced the process of identifying contacts, prioritizing contacts for testing and scaling up a contact investigation.

Methods

A multiple-case study (2010–2012) compared the contact investigation guidelines as recommended with their use in practice. We interviewed twice 14 public health nurses of seven Public Health Services while they conducted a contact investigation.

Results

We found more individuals to be identified as contacts than recommended, owing to a desire to gain insight into the infectiousness of the index case and prevent anxiety among potential contacts. Because some public health nurses did not believe the recommendations for prioritizing contacts fully encompassed daily practice, they preferred their own regular routine. In scaling up a contact investigation, they hardly applied the stone-in-the-pond principle. They neither regularly compared the infection prevalence in the contact investigation with the background prevalence in the community, especially not in immigrant populations. Nonadherence was related to ambiguity of the recommendations and a tendency to act from an individual health-care position rather than a population health perspective.

Conclusions

The adherence to the contact investigation guidelines was limited, restraining the effectiveness, efficiency and uniformity of tuberculosis control. Adherence could be optimized by specifying guideline recommendations, actively involving the TB workforce, and training public health nurses.

Tracing contacts of TB patients in Malaysia: costs and practicality

Tuberculin skin testing (TST) and chest X-ray are the conventional methods used for tracing suspected tuberculosis (TB) patients. The purpose of the study was to calculate the cost incurred by Penang General Hospital on performing one contact tracing procedure using an activity based costing approach. Contact tracing records (including the demographic profile of contacts and outcome of the contact tracing procedure) from March 2010 until February 2011 were retrospectively obtained from the TB contact tracing record book. The human resource cost was calculated by multiplying the mean time spent (in minutes) by employees doing a specific activity by their per-minute salaries. The costs of consumables, Purified Protein Derivative vials and clinical equipment were obtained from the procurement section of the Pharmacy and Radiology Departments. The cost of the building was calculated by multiplying the area of space used by the facility with the unit cost of the public building department. Straight-line deprecation with a discount rate of 3% was assumed for the calculation of equivalent annual costs for the building and machines. Out of 1024 contact tracing procedures, TST was positive (≥10 mm) in 38 suspects. However, chemoprophylaxis was started in none. Yield of contact tracing (active tuberculosis) was as low as 0.5%. The total unit cost of chest X-ray and TST was MYR 9.23 (2.90 USD) & MYR 11.80 (USD 3.70), respectively. The total cost incurred on a single contact tracing procedure was MYR 21.03 (USD 6.60). Our findings suggest that the yield of contact tracing was very low which may be attributed to an inappropriate prioritization process. TST may be replaced with more accurate and specific methods (interferon gamma release assay) in highly prioritized contacts; or TST-positive contacts should be administered 6H therapy (provided that the chest radiography excludes TB) in accordance with standard protocols. The unit cost of contact tracing can be significantly reduced if radiological examination is done only in TST or IRGA positive contacts.

Tuberculosis in travellers

Tuberculosis (TB) incidence is increasing in many countries which are popular with international travellers. The development of active TB is a two-stage process; the risk of acquiring new TB infection depends primarily on the risk of contact with an individual with infectious TB, and the risk of disease on the immune status of the newly infected person. The risk of TB infection is low for most holiday-makers, but among long-term travellers to countries with high TB incidence, the risk may be similar to that experienced by the local population (0.5-2.5% per year); the risk to people working in health care is particularly high. Effective pre-travel advice involves assessing the traveller's risk of TB infection and disease. Recommendations on the prevention of TB in travellers vary between countries. Possible strategies include avoidance of exposure; BCG vaccination; and tuberculin skin testing before and after travel, with preventive therapy for those whose post-travel skin tests indicate recent infection. For those at highest risk of progression to disease, there may be value in preventive therapy during travel to reduce the risk of new TB infection. Further information on the contribution of recent travel to incident TB in industrialised countries would be valuable.

Contact investigation for tuberculosis: a systematic review and meta-analysis

Investigation of contacts of patients with tuberculosis (TB) is a priority for TB control in high-income countries, and is increasingly being considered in resource-limited settings. This review was commissioned for a World Health Organization Expert Panel to develop global contact investigation guidelines. We performed a systematic review and meta-analysis of all studies reporting the prevalence of TB and latent TB infection, and the annual incidence of TB among contacts of patients with TB. After screening 9,555 titles, we included 203 published studies. In 95 studies from low- and middle-income settings, the prevalence of active TB in all contacts was 3.1% (95% CI 2.2-4.4%, I(2)=99.4%), microbiologically proven TB was 1.2% (95% CI 0.9-1.8%, I(2)=95.9%), and latent TB infection was 51.5% (95% CI 47.1-55.8%, I(2)=98.9%). The prevalence of TB among household contacts was 3.1% (95% CI 2.1-4.5%, I(2)=98.8%) and among contacts of patients with multidrug-resistant or extensively drug-resistant TB was 3.4% (95% CI 0.8-12.6%, I(2)=95.7%). Incidence was greatest in the first year after exposure. In 108 studies from high-income settings, the prevalence of TB among contacts was 1.4% (95% CI 1.1-1.8%, I(2)=98.7%), and the prevalence of latent infection was 28.1% (95% CI 24.2-32.4%, I(2)=99.5%). There was substantial heterogeneity among published studies. Contacts of TB patients are a high-risk group for developing TB, particularly within the first year. Children <5 yrs of age and people living with HIV are particularly at risk. Policy recommendations must consider evidence of the cost-effectiveness of various contact tracing strategies, and also incorporate complementary strategies to enhance case finding.

Contact tracing in pulmonary and non-pulmonary tuberculosis

AIM

The aim of our study was to determine the effectiveness of contact tracing for both pulmonary and non-pulmonary tuberculosis (TB).

METHODS

The authors studied contact tracing in South East of Scotland, Edinburgh TB Clinic, UK, for 3 years. New index cases of both pulmonary and non-pulmonary TB were identified from reviewing TB nurses records. Pulmonary involvement was excluded from all non-pulmonary cases. Active TB was diagnosed as per the national TB guidelines. Latent TB was diagnosed based on history, tuberculin skin test and interferon γ release assay. TB contacts were identified from reviewing TB nurses notes on index TB patients. A positive screening episode was defined as identification of either active or latent TB in a contact following relevant investigations.

RESULTS

Total number of positive screening episodes for pulmonary TB was 43.1% and non-pulmonary TB was 26.1%. Of these, 78.8% were household contacts and 21.2% were casual contacts.

CONCLUSION

Contact tracing in low-prevalence TB countries, for both pulmonary and non-pulmonary TB, is an essential intervention to identify and reduce the number of infected patients that will progress to active disease. This is the key for effective TB control.

Pan-London tuberculosis services: a service evaluation

Background

London has the largest proportion of tuberculosis (TB) cases of any western European capital, with almost half of new cases drug-resistant. Prevalence varies considerably between and within boroughs with research suggesting inadequate control of TB transmission in London. Economic pressures may exacerbate the already considerable challenges for service organisation and delivery within this context. This paper presents selected findings from an evaluation of London’s TB services’ organisation, delivery, professional workforce and skill mix, intended to support development of a strategic framework for a pan-London TB service. These may also interest health service professionals and managers in TB services in the UK, other European cities and countries and in services currently delivered by multiple providers operating independently.

Methods

Objectives were: 1) To establish how London’s TB services are structured and delivered in relation to leadership, management, organisation and delivery, coordination, staffing and support; 2) To identify tools/models for calculating skill mix as a basis for identifying skill mix requirements in delivering TB services across London; 3) To inform a strategic framework for the delivery of a pan-London TB service, which may be applicable to other European cities. The multi-method service audit evaluation comprised documentary analysis, semi-structured interviews with TB service users (n = 10), lead TB health professionals and managers (n = 13) representing London’s five sectors and focus groups with TB nurses (n = 8) and non-London network professionals (n = 2).

Results

Findings showed TB services to be mainly hospital-based, with fewer community-based services. Documentary analysis and professionals’ interviews suggested difficulties with early access to services, low suspicion index amongst some GPs and restricted referral routes. Interviews indicated lack of managed accommodation for difficult to treat patients, professional workforce shortages, a need for strategic leadership, nurse-led clinics and structured career paths for TB nurses and few social care/outreach workers to support patients with complex needs.

Conclusions

This paper has identified key issues relating to London’s TB services’ organisation, delivery, professional workforce and skill mix. The majority of these present challenges which need to be addressed as part of the future development of a strategic framework for a pan-London TB service. More consistent strategic planning/co-ordination and sharing of best practice is needed, together with a review of pan-London TB workforce development strategy, encompassing changing professional roles, skills development needs and patient pathways. These findings may be relevant with the development of TB services in other European cities.

Serial interferon-gamma release assays after chemoprophylaxis in a tuberculosis outbreak cohort

PURPOSE

Interferon-gamma release assay (IGRA) results have been suggested as a surrogate marker of treatment response in latent tuberculosis infection (LTBI). However, data have not been consistent, and most previous studies focused on participants taking isoniazid prophylaxis. The aim of this study was to elucidate the changes in the IGRA results in patients who underwent chemoprophylaxis with isoniazid and rifampicin daily for 3 months.

METHODS

In a TB outbreak cohort, 26 asymptomatic close contacts with normal chest radiographs and positive QuantiFERON-TB Gold In-Tube assay (QFT-GIT) results were recruited. These patients were treated with isoniazid and rifampicin daily for 3 months. The QFT-GIT was repeated at 3 and 6 months following treatment initiation.

RESULTS

Compared with the initial QFT-GIT results (3.59 ± 3.39 IU/mL), the interferon-gamma (IFN-γ) levels had decreased significantly at 6 months (0.84 ± 1.14 IU/mL; P = 0.005), but not at 3 months (3.58 ± 3.64 IU/mL; P = 0.98). Reversions occurred in seven (26.9 %) patients at 3 months and in an additional two participants at 6 months; a total of nine participants (34.6 %) had reversions. Recent conversion was associated with reversion of the test results (odds ratio 26.3, 95 % confidence interval 3.04-226.6).

CONCLUSION

Chemoprophylaxis with isoniazid and rifampicin generally decreased IFN-γ levels among tuberculosis contacts. However, only a small portion of participants achieved reversion.

Lumbo-sacral spine disease due to bovine tuberculosis in a patient with concurrent pulmonary disease

Lumbo-sacral spinal disease due to bovine tuberculosis (TB) in a patient with concurrent pulmonary disease is rare. We report this unpredicted finding in an immunocompetent patient and discuss the natural history in an area of low prevalence.

Poor Compliance Makes Treatment of Latent Tuberculosis Infection Unsatisfactory

Objectives: The recommended treatment for latent tuberculosis infection is isoniazid for 9 months, but this regimen has a low completion rate. The authors wanted to compare treatment with isoniazid and treatment with isoniazid and rifampin in the typical public health setting in a large diverse state and recover as much information as possible from a state database. Methods: Patients who received latent tuberculosis infection treatment were identified in the Texas Department of State Health Services database for the years 1995-2002. Treatment completion, adverse reactions, and disease development were recorded. Results were analyzed using logistic regression to predict disease development. Results: In sum, 50 578 patients received isoniazid, and 280 received isoniazid/rifampin. Sixty-one percent of the isoniazid group and 54% of the isoniazid/rifampin group completed treatment. Eighteen percent of the isoniazid/rifampin group possibly had adverse reactions and discontinued treatment; 3% of the isoniazid group discontinued therapy because of side effects. More than 70% of patients with adverse reactions in the isoniazid/rifampin group took the treatment for more than 4 months. Overall, 168 patients in the isoniazid group with a normal chest X-ray and a positive skin test developed tuberculosis during follow-up to 2008; no patients in the isoniazid/rifampin group who had a normal X-ray and completed chemoprophylaxis developed tuberculosis during follow-up. Conclusions: The isoniazid/rifampin regimen appears to be as effective as the isoniazid regimen. However, completion rates on combination therapy were slightly lower. This regimen needs more formal clinical study since it has the potential to decrease administrative costs and improve completion rates. In addition, state departments of health need to develop networks using community-based resources to reach patients and increase completion rates.

Challenges and opportunities in developing novel drugs for TB

Mycobacterium tuberculosis is a difficult pathogen to combat and the first-line drugs currently in use are 40-60 years old. The need for new TB drugs is urgent, but the time to identify, develop and ultimately advance new drug regimens onto the market has been excruciatingly slow. On the other hand, the drugs currently in clinical development, and the recent gains in knowledge of the pathogen and the disease itself give us hope for finding new drug targets and new drug leads. In this article we highlight the unique biology of the pathogen and several possible ways to identify new TB chemical leads. The Global Alliance for TB Drug Development (TB Alliance) is a not-for-profit organization whose mission is to accelerate the discovery and development of new TB drugs. The organization carries out research and development in collaboration with many academic laboratories and pharmaceutical companies around the world. In this perspective we will focus on the early discovery phases of drug development and try to provide snapshots of both the current status and future prospects.

Control of tuberculosis in large cities in developed countries: an organizational problem

Tuberculosis (TB) is still a serious public health issue, even in large cities in developed countries. Control of this old disease is based on complicated programs that require completion of long treatments and contact tracing. In an accompanying research article published in BMC Public Health, Bothamley and colleagues found that areas with a ratio lower than one nurse per forty notifications had increased rates with respect to TB notifications, smear-positive cases, loss to follow-up and treatment abandonment across the UK. Furthermore, in these areas there was less opportunity for directly observed therapy, assistance with complex needs, educational outreach and new-entrant screening. In this commentary, we discuss the importance of improving organizational aspects and evaluating TB control programs. According to Bothamley and colleagues, a ratio of one nurse per forty notifications is an effective method of reducing the high TB incidences observed in London and in other cities in developed countries, or to maintain the decline in incidence in cities with lower incidences. It is crucial to evaluate TB programs every year to detect gaps early.