Prevalence of Pulmonary Tuberculosis among Prison Inmates in Ethiopia,a Cross-Sectional Study

Setting

Tuberculosis (TB) is one of the major health problems in prisons.

Objective

This study was done to assess the prevalence and determinants of active tuberculosis in Ethiopian prisons.

Design

A cross-sectional study was conducted from January 2013 to December 2013 in 13 zonal prisons. All incarcerated inmates underwent TB symptom screening according to WHO criteria. From identified TB-suspects two sputum samples were analyzed using smear microscopy and solid culture. A standardized questionnaire assessing TB risk factors was completed for each TB suspect.

Results

765 (4.9%) TB suspects were identified among 15,495 inmates. 51 suspects were already on anti-TB treatment (6.67%) and 20 (2.8%) new culture-confirmed TB cases were identified in the study, resulting in an overall TB prevalence of 458.1/100,000 (95%CI: 350-560/100,000). Risk factors for active TB were alcohol consumption, contact with a TB case before incarceration and no window in prison cell. HIV prevalence was not different between TB suspects and active TB cases. Further, the TB burden in prisons increased with advancing distance from the capital Addis Ababa.

Conclusions

The overall TB prevalence in Ethiopian prisons was high and extremely variable among different prisons. TB risk factors related to conditions of prison facilities and the impact of implemented TB control measures need to be further studied in order to improve TB control among inmates.     

Survival among Patients with HIV Infection and Smear-Negative Pulmonary Tuberculosis - United States, 1993–2006

Background

In patients with HIV and tuberculosis (TB) in resource-constrained settings, smear-negative disease has been associated with higher mortality than smear-positive disease. Higher reported mortality may be due to misdiagnosis, diagnostic delays, or because smear-negative disease indicates more advanced immune suppression.

Methods

We analyzed culture-confirmed, pulmonary TB among patients with TB and HIV in the United States from 1993–2008 to calculate prevalence ratios (PRs) for smear-negative disease by demographic and clinical characteristics. Allowing two years for treatment outcome to be reported, we determined hazard ratios (HRs) for survival by smear status, adjusted for significant covariates on patients before 2006.

Results

Among 16,710 cases with sputum smear results, 6,739 (39%) were sputum smear-negative and 9,971 (58%) were sputum smear-positive. The prevalence of smear-negative disease was lower in male patients (PR: 0.89, 95% confidence interval [CI]: 0.86–0.93) and in those who were homeless (PR: 0.92, CI: 0.87–0.97) or used alcohol excessively (PR: 0.91, CI: 0.87–0.95), and higher in persons diagnosed while incarcerated (PR: 1.20, CI: 1.13–1.27). Patients with smear-negative disease had better survival compared to patients with smear-positive disease, both before (HR: 0.82, CI: 0.75–0.90) and after (HR: 0.81, CI: 0.71–0.92) the introduction of combination anti-retroviral therapy.

Conclusions

In the United States, smear-negative pulmonary TB in patients with HIV was not associated with higher mortality, in contrast to what has been documented in high TB burden settings. Smear-negative TB can be routinely and definitively diagnosed in the United States, whereas high-burden countries often rely solely on AFB-smear microscopy. This difference could contribute to diagnostic and treatment delays in high-burden countries, possibly resulting in higher mortality.     

The High Burden of Tuberculosis (TB) and Human Immunodeficiency Virus (HIV) in a Large Zambian Prison: A Public Health Alert

Background

Tuberculosis (TB) and human immunodeficiency virus (HIV) represent two of the greatest health threats in African prisons. In 2010, collaboration between the Centre for Infectious Disease Research in Zambia, the Zambia Prisons Service, and the National TB Program established a TB and HIV screening program in six Zambian prisons. We report data on the prevalence of TB and HIV in one of the largest facilities: Lusaka Central Prison.

Methods

Between November 2010 and April 2011, we assessed the prevalence of TB and HIV amongst inmates entering, residing, and exiting the prison, as well as in the surrounding community. The screening protocol included complete history and physical exam, digital radiography, opt-out HIV counseling and testing, sputum smear and culture. A TB case was defined as either bacteriologically confirmed or clinically diagnosed.

Results

A total of 2323 participants completed screening. A majority (88%) were male, median age 31 years and body mass index 21.9. TB symptoms were found in 1430 (62%). TB was diagnosed in 176 (7.6%) individuals and 52 people were already on TB treatment at time of screening. TB was bacteriologically confirmed in 88 cases (3.8%) and clinically diagnosed in 88 cases (3.8%). Confirmed TB at entry and exit interventions were 4.6% and 5.3% respectively. Smear was positive in only 25% (n = 22) of bacteriologically confirmed cases. HIV prevalence among inmates currently residing in prison was 27.4%.

Conclusion

Ineffective TB and HIV screening programs deter successful disease control strategies in prison facilities and their surrounding communities. We found rates of TB and HIV in Lusaka Central Prison that are substantially higher than the Zambian average, with a trend towards concentration and potential transmission of both diseases within the facility and to the general population. Investment in institutional and criminal justice reform as well as prison-specific health systems is urgently required.     

Modeling the impact of tuberculosis control strategies in highly endemic overcrowded prisons

Background

Tuberculosis (TB) in prisons is a major health problem in countries of high and intermediate TB endemicity such as Brazil. For operational reasons, TB control strategies in prisons cannot be compared through population based intervention studies.

Methodology/Principal Findings

A mathematical model is proposed to simulate the TB dynamics in prison and evaluate the potential impact on active TB prevalence of several intervention strategies. The TB dynamics with the ongoing program was simulated over a 10 year period in a Rio de Janeiro prison (TB prevalence 4.6 %). Then, a simulation of the DOTS strategy reaching the objective of 70 % of bacteriologically-positive cases detected and 85 % of detected cases cured was performed; this strategy reduced only to 2.8% the average predicted TB prevalence after 5 years. Adding TB detection at entry point to DOTS strategy had no major effect on the predicted active TB prevalence. But, adding further a yearly X-ray mass screening of inmates reduced the predicted active TB prevalence below 1%. Furthermore, according to this model, after applying this strategy during 2 years (three annual screenings), the TB burden would be reduced and the active TB prevalence could be kept at a low level by associating X-ray screening at entry point and DOTS.

Conclusions/Significance

We have shown that X-ray mass screenings should be considered to control TB in highly endemic prison. Prisons with different levels of TB prevalence could be examined thanks to this model which provides a rational tool for public health deciders.     

Screening and Rapid Molecular Diagnosis of Tuberculosis in Prisons in Russia and Eastern Europe: A Cost-Effectiveness Analysis

Background

Prisons of the former Soviet Union (FSU) have high rates of multidrug-resistant tuberculosis (MDR-TB) and are thought to drive general population tuberculosis (TB) epidemics. Effective prison case detection, though employing more expensive technologies, may reduce long-term treatment costs and slow MDR-TB transmission.

Methods and Findings

We developed a dynamic transmission model of TB and drug resistance matched to the epidemiology and costs in FSU prisons. We evaluated eight strategies for TB screening and diagnosis involving, alone or in combination, self-referral, symptom screening, mass miniature radiography (MMR), and sputum PCR with probes for rifampin resistance (Xpert MTB/RIF). Over a 10-y horizon, we projected costs, quality-adjusted life years (QALYs), and TB and MDR-TB prevalence. Using sputum PCR as an annual primary screening tool among the general prison population most effectively reduced overall TB prevalence (from 2.78% to 2.31%) and MDR-TB prevalence (from 0.74% to 0.63%), and cost US$543/QALY for additional QALYs gained compared to MMR screening with sputum PCR reserved for rapid detection of MDR-TB. Adding sputum PCR to the currently used strategy of annual MMR screening was cost-saving over 10 y compared to MMR screening alone, but produced only a modest reduction in MDR-TB prevalence (from 0.74% to 0.69%) and had minimal effect on overall TB prevalence (from 2.78% to 2.74%). Strategies based on symptom screening alone were less effective and more expensive than MMR-based strategies. Study limitations included scarce primary TB time-series data in FSU prisons and uncertainties regarding screening test characteristics.

Conclusions

In prisons of the FSU, annual screening of the general inmate population with sputum PCR most effectively reduces TB and MDR-TB prevalence, doing so cost-effectively. If this approach is not feasible, the current strategy of annual MMR is both more effective and less expensive than strategies using self-referral or symptom screening alone, and the addition of sputum PCR for rapid MDR-TB detection may be cost-saving over time. Please see later in the article for the Editors'' Summary     

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.     

Prevalence,Risk Factors and Social Context of Active Pulmonary Tuberculosis among Prison Inmates in Tajikistan

Setting

Tuberculosis (TB) is highly prevalent in prisons of the former Soviet Union.

Objective

To understand the behavioral, demographic and biological factors placing inmates in Tajikistan at risk for active TB.

Design

We administered a behavioral and demographic survey to 1317 inmates in two prison facilities in Sughd province, Tajikistan along with radiographic screening for pulmonary TB. Suspected cases were confirmed bacteriologically. Inmates undergoing TB treatment were also surveyed. In-depth interviews were conducted with former prisoners to elicit relevant social and behavioral characteristics.

Results

We identified 59 cases of active pulmonary TB (prevalence 4.5%). Factors independently associated with increased prevalence of active TB were: HIV-infection by self-report (PR 7.88; 95%CI 3.40–18.28), history of previous TB (PR 10.21; 95%CI 6.27–16.63) and infrequent supplemental nutrition beyond scheduled meals (PR 3.00; 95%CI 1.67–5.62). Access to supplemental nutrition was associated with frequency of visits from friends and family and ability to rely on other inmates for help.

Conclusion

In prison facilities of Tajikistan, HIV-infection, injection drug use and low access to supplemental nutrition were associated with prevalent cases of active pulmonary TB. Policies that reduce HIV transmission among injection drug users and improve the nutritional status of socially isolated inmates may alleviate the TB burden in Tajikistan’s prisons.     

Active Case Finding of Tuberculosis (TB) in an Emergency Room in a Region with High Prevalence of TB in Brazil

Setting

Public hospital emergency room (ER) in Porto Alegre, Brazil, a setting with high prevalence of tuberculosis (TB) and human immunodeficiency virus (HIV) infection.

Objective

To determine the prevalence of PTB, using a symptom based active case finding (ACF) strategy in the ER of a public hospital in an area with high prevalence of TB and HIV, as well as variables associated with pulmonary TB diagnosis.

Methods

Cross sectional study. All patients ≥18 years seeking care at the ER were screened for respiratory symptoms and those with cough ≥2 weeks were invited to provide a chest radiograph and two unsupervised samples of sputum for acid-fast bacilli smear and culture.

Results

Among 31,267 admissions, 6,273 (20.1%) reported respiratory symptoms; 197 reported cough ≥2 weeks, of which pulmonary TB was diagnosed in 30. In multivariate analysis, the variables associated with a pulmonary tuberculosis diagnosis were: age (OR 0.94, 95% CI: 0.92–0.97; p<0.0001), sputum production (OR 0.18, 95% CI 0.06–0.56; p = 0.003), and radiographic findings typical of TB (OR 12.11, 95% CI 4.45–32.93; p<0.0001).

Conclusions

This study identified a high prevalence of pulmonary TB among patients who sought care at the emergency department of a tertiary hospital, emphasizing the importance of regular screening of all comers for active TB in this setting.     

Epidemiology of Tuberculosis in an Urban Slum of Dhaka City,Bangladesh

Background

The objectives of this study were to assess the tuberculosis (TB) burden and to provide an insight into the type of circulating M. tuberculosis species in urban slums of Bangladesh. We also aimed to test the feasibility of a larger transmission study in this setting.

Methods

This cross-sectional study was conducted in an urban slum of Dhaka city. The household members were actively screened to assess the presence of TB-related signs and symptoms; cough ≥3 weeks and body mass index (BMI) <17 kg/m². Sputum specimens from suspects were collected for acid fast bacilli (AFB) microscopy, culture and drug susceptibility testing. Genotyping of M. tuberculosis was done using spoligotyping and variable number tandem repeats of mycobacterial interspersed repetitive units typing.

Results

Among 9,877 adult screened for pulmonary TB (PTB), 25 were positive for AFB on microscopy and/or culture and the prevalence of new PTB cases was estimated to be 253/100,000. Only one child TB case was diagnosed among 5,147 child screened. Out of 26 cases, 21(81%) had cough for several duration and 5(19%) did not present with cough at the time of screening. One multidrug resistant case was found. Fifty two percent of all TB cases had BMI <17 kg/m2 (p = <0.001). Among the 20 analyzed isolates, 13 different spoligotype patterns were identified in which 5 clusters contained 12 strains and 8 strains had unique pattern.

Conclusions

The study revealed high prevalence of TB in urban slums. Screening using low BMI can be beneficial among risk group population. It is important to conduct larger study to validate clinical variables like cough <3 weeks and low BMI to define TB suspect and also to investigate the transmission of TB in slum settings.     

Culture Conversion Rate at 2 Months of Treatment According to Diagnostic Methods among Patients with Culture-Positive Pulmonary Tuberculosis

Introduction

The culture-negative conversion rate of sputum after 2 months of treatment in patients with pulmonary tuberculosis (TB) is used as a reliable surrogate marker for relapse after completion of treatment. We hypothesized that culture conversion of sputum at 2 months of anti-TB treatment and the time to culture conversion are different among pulmonary TB patients who are diagnosed using different methods.

Methods

Culture-confirmed pulmonary TB patients who were diagnosed between 1 January, 2011 and 31 December, 2012 were classified into three groups based on the diagnostic method that prompted treatment initiation: positive acid-fast bacilli (AFB) staining of sputum (smear-positive group), negative AFB staining, but Mycobacterium tuberculosis was cultured from sputum (culture-positive group), and positive AFB staining, positive polymerase chain reaction (PCR) for M. tuberculosis, or culture of M. tuberculosis from a bronchoscopic specimen (bronchoscopy group). Rates of negative mycobacterial culture conversion at 2 months of anti-TB treatment and the time to negative culture conversion of sputum were compared among the three groups.

Results

A total of 203 patients with culture-confirmed pulmonary TB were included in the final analysis. TB patients in the culture-positive group (94.1%) and the bronchoscopy group (97.6%) showed a higher culture conversion rate at 2 months of treatment than those in the smear-positive group (78.7%, P = 0.001). Additionally, the time to culture conversion was longer in the smear-positive group (median, 40 days) than in the culture-positive (median, 19 days; P = 0.009) and bronchoscopy groups (median, 29 days; P = 0.004).

Conclusions

The higher culture conversion rate at 2 months and the shorter time to culture conversion among pulmonary TB patients with a negative AFB smear suggests the feasibility of shortening treatment duration and isolation in these patients.     

Clinical and Radiographic Factors Do Not Accurately Diagnose Smear-Negative Tuberculosis in HIV-infected Inpatients in Uganda: A Cross-Sectional Study

Background

Although World Health Organization guidelines recommend clinical judgment and chest radiography for diagnosing tuberculosis in HIV-infected adults with unexplained cough and negative sputum smears for acid-fast bacilli, the diagnostic performance of this approach is unknown. Therefore, we sought to assess the accuracy of symptoms, physical signs, and radiographic findings for diagnosing tuberculosis in this population in a low-income country with a high incidence of tuberculosis.

Methodology

We performed a cross-sectional study enrolling consecutive HIV-infected inpatients with unexplained cough and negative sputum smears for acid-fast bacilli at Mulago Hospital in Kampala, Uganda. Trained medical officers prospectively collected data on standard symptoms and signs of systemic respiratory illness, and two radiologists interpreted chest radiographs in a standardized fashion. We calculated positive- and negative-likelihood ratios of these factors for diagnosing pulmonary tuberculosis (defined when mycobacterial cultures of sputum or bronchoalveolar lavage fluid were positive). We used both conventional and novel regression techniques to develop multivariable prediction models for pulmonary tuberculosis.

Principal Findings

Among 202 enrolled HIV-infected adults with negative sputum smears for acid-fast bacilli, 72 (36%) had culture-positive pulmonary tuberculosis. No single factor, including respiratory symptoms, physical findings, CD4+ T-cell count, or chest radiographic abnormalities, substantially increased or decreased the likelihood of pulmonary tuberculosis. After exhaustive testing, we were also unable to identify any combination of factors which reliably predicted bacteriologically confirmed tuberculosis.

Conclusions and Significance

Clinical and radiographic criteria did not help diagnose smear-negative pulmonary tuberculosis among HIV-infected patients with unexplained cough in a low-income setting. Enhanced diagnostic methods for smear-negative tuberculosis are urgently needed.     

Yield of Two Consecutive Sputum Specimens for the Effective Diagnosis of Pulmonary Tuberculosis

Background

From long instances, it is debatable whether three sputum specimens are required for the diagnosis of pulmonary tuberculosis (TB) or TB can be diagnosed effectively using two consecutive sputum specimens. This study was set out to evaluate the significance of examining multiple sputum specimens in diagnosis of TB.

Methods

We retrospectively reviewed the acid-fast bacillus (AFB) smear and culture results of three consecutive days’ sputum specimens from 413 confirmed TB patients which were detected as part of a larger active case finding study in Dhaka Central Jail, the largest correctional facility in Bangladesh.

Results

AFB was detected from 81% (n = 334) patients, of which 89% (n = 297) were diagnosed from the first and additional 9% (n = 30) were from the second sputum specimen. M. tuberculosis growth was observed for 406 patients and 85% (n = 343) were obtained from the first sputum and additional 10% (n = 42) were from the second one. The third specimen didn’t show significant additional diagnostic value for the detection of AFB by microscopy or growth of the M. tuberculosis.

Conclusions

We concluded from our study results that examining two consecutive sputum specimens is sufficient enough for the effective diagnosis of TB. It can also decrease the laboratory workload and hence improve the quality of work in settings with high TB burden like Bangladesh.     

Can Follow-Up Examination of Tuberculosis Patients Be Simplified? A Study in Chhattisgarh,India

Background

Each follow-up during the course of tuberculosis treatment currently requires two sputum examinations. However, the incremental yield of the second sputum sample during follow-up of different types of tuberculosis patients has never been determined precisely.

Objectives

To assess the incremental yield of the second sputum sample in the follow-up of tuberculosis patients under the Revised National Tuberculosis Control Programme (RNTCP) in Chhattisgarh, India.

Methodology

A record review of tuberculosis (TB) patients registered in 2009 using a structured proforma from two sources, Tuberculosis and Laboratory Register, was undertaken in the six districts of Chhattisgarh, India.

Results

In smear positive cases, of 10,048 follow-up examinations, 45 (0.5%) were found to be smear positive only on the second sputum when the result of the first sample was negative. In smear negative pulmonary and extra pulmonary TB patients, of 6,206 follow-up smear examinations, 11(0.2%) were found to be smear positive.

Conclusions

The incremental yield of a second smear examination was very low, indicating that examination of one sputum sample is enough during follow-up among TB patients. There is insufficient yield to support sputum smear microscopy for monitoring smear negative pulmonary TB and extra pulmonary TB patients. These results indicate that the follow-up smear microscopy can be substantially simplified with favourable resource implications.     

The Risk and Timing of Tuberculosis Diagnosed in Smear-Negative TB Suspects: A 12 Month Cohort Study in Harare,Zimbabwe

Background

Cases of smear-negative TB have increased dramatically in high prevalence HIV settings and pose considerable diagnostic and management challenges.

Methods and Findings

Between February 2006 and July 2007, a cohort study nested within a cluster-randomised trial of community-based case finding strategies for TB in Harare, Zimbabwe was undertaken. Participants who had negative sputum smears and remained symptomatic of TB were follow-up for one year with standardised investigations including HIV testing, repeat sputum smears, TB culture and chest radiography. Defaulters were actively traced to the community. The objectives were to investigate the incidence and risk factors for TB. TB was diagnosed in 218 (18.2%) participants, of which 39.4% was bacteriologically confirmed. Most cases (84.2%) were diagnosed within 3 months, but TB incidence remained high thereafter (111.3 per 1000 person-years, 95% CI: 86.6 to 146.3). HIV prevalence was 63.3%, and HIV-infected individuals had a 3.5-fold higher risk of tuberculosis than HIV-negative individuals.

Conclusion

We found that diagnosis of TB was insensitive and slow, even with early radiography and culture. Until more sensitive and rapid diagnostic tests become widely available, a much more proactive and integrated approach towards prompt initiation of ART, ideally from within TB clinics and without waiting for TB to be excluded, is needed to minimise the risk and consequences of diagnostic delay.     

Population Based National Tuberculosis Prevalence Survey among Adults (>15 Years) in Pakistan, 2010–2011

Background

We aimed to determine the prevalence of pulmonary tuberculosis (TB) amongst the adult population in 2010–2011 in Pakistan.

Method

A nationwide cross-sectional survey with multistage cluster sampling was conducted among adults (≥15 years) in 95 clusters in 2010–2011. All consenting participants were screened for cough and by chest X-ray. Participants with presumptive TB submitted two sputum samples for smear microscopy, culture, and molecular testing if needed. The TB prevalence estimates were adjusted for missing data and the cluster design.

Result

Of 131,329 eligible individuals, 105,913 (81%) participated in the survey, of whom 10,471 (9.9%) were eligible for sputum examination. We found 341 bacteriologically positive TB cases of whom 233 had sputum smear-positive TB. The adjusted prevalence estimates for smear and bacteriologically positive TB were 270/100,000 (95% confidence interval (CI) 217–323), and 398/100,000 (95% CI 333–463), respectively. Only 61% of the diagnosed TB cases screened positive on symptoms (cough >2wks), whereas the other TB cases were detected based on X-ray abnormalities. The TB prevalence increased with age and was 1.8 times higher among men than women. The prevalence-to-notification ratio of smear-positive TB was 3.1 (95% CI 2.5–3.7), was higher among men than women, and increased with age.

Conclusion

Our data suggest that there is under-detection and/or -notification of TB, especially among men and elderly. TB control should be strengthened specifically in these risk groups. X-ray examination should be combined with symptom screening to enhance case detection.     

High Tuberculosis Prevalence in a South African Prison: The Need for Routine Tuberculosis Screening

Background

Tuberculosis is a major health concern in prisons, particularly where HIV prevalence is high. Our objective was to determine the undiagnosed pulmonary tuberculosis (“undiagnosed tuberculosis”) prevalence in a representative sample of prisoners in a South African prison. In addition we investigated risk factors for undiagnosed tuberculosis, to explore if screening strategies could be targeted to high risk groups, and, the performance of screening tools for tuberculosis.

Methods and Findings

In this cross-sectional survey, male prisoners were screened for tuberculosis using symptoms, chest radiograph (CXR) and two spot sputum specimens for microscopy and culture. Anonymised HIV antibody testing was performed on urine specimens. The sensitivity, specificity and predictive values of symptoms and investigations were calculated, using Mycobacterium tuberculosis isolated on sputum culture as the gold standard.From September 2009 to October 2010, 1046 male prisoners were offered enrolment to the study. A total of 981 (93.8%) consented (median age was 32 years; interquartile range [IQR] 27–37 years) and were screened for tuberculosis. Among 968 not taking tuberculosis treatment and with sputum culture results, 34 (3.5%; 95% confidence interval [CI] 2.4–4.9%) were culture positive for Mycobacterium tuberculosis. HIV prevalence was 25.3% (242/957; 95% CI 22.6–28.2%). Positive HIV status (adjusted odds ratio [aOR] 2.0; 95% CI 1.0–4.2) and being an ex-smoker (aOR 2.6; 95% CI 1.2–5.9) were independently associated with undiagnosed tuberculosis. Compared to the gold standard of positive sputum culture, cough of any duration had a sensitivity of 35.3% and specificity of 79.6%. CXR was the most sensitive single screening modality (sensitivity 70.6%, specificity 92.2%). Adding CXR to cough of any duration gave a tool with sensitivity of 79.4% and specificity of 73.8%.

Conclusions

Undiagnosed tuberculosis and HIV prevalence was high in this prison, justifying routine screening for tuberculosis at entry into the prison, and intensified case finding among existing prisoners.     

Nucleic acid amplification tests for diagnosis of smear-negative TB in a high HIV-prevalence setting: a prospective cohort study

Background

Nucleic acid amplification tests are sensitive for identifying Mycobacterium tuberculosis in populations with positive sputum smears for acid-fast bacilli, but less sensitive in sputum-smear-negative populations. Few studies have evaluated the clinical impact of these tests in low-income countries with high burdens of TB and HIV.

Methods

We prospectively enrolled 211 consecutive adults with cough ≥2 weeks and negative sputum smears at Mulago Hospital in Kampala, Uganda. We tested a single early-morning sputum specimen for Mycobacterium tuberculosis DNA using two nucleic acid amplification tests: a novel in-house polymerase chain reaction targeting the mycobacterial secA1 gene, and the commercial Amplified® Mycobacterium tuberculosis Direct (MTD) test (Gen-Probe Inc, San Diego, CA). We calculated the diagnostic accuracy of these index tests in reference to a primary microbiologic gold standard (positive mycobacterial culture of sputum or bronchoalveolar lavage fluid), and measured their likely clinical impact on additional tuberculosis cases detected among those not prescribed initial TB treatment.

Results

Of 211 patients enrolled, 170 (81%) were HIV-seropositive, with median CD4+ T-cell count 78 cells/µL (interquartile range 29-203). Among HIV-seropositive patients, 94 (55%) reported taking co-trimoxazole prophylaxis and 29 (17%) reported taking antiretroviral therapy. Seventy-five patients (36%) had culture-confirmed TB. Sensitivity of MTD was 39% (95% CI 28–51) and that of secA1 was 24% (95% CI 15–35). Both tests had specificities of 95% (95% CI 90–98). The MTD test correctly identified 18 (24%) TB patients not treated at discharge and led to a 72% relative increase in the smear-negative case detection rate.

Conclusions

The secA1 and MTD nucleic acid amplification tests had moderate sensitivity and high specificity for TB in a predominantly HIV-seropositive population with negative sputum smears. Although newer, more sensitive nucleic acid assays may enhance detection of Mycobacterium tuberculosis in sputum, even currently available tests can provide substantial clinical impact in smear-negative populations.     

High Incidence of Tuberculosis,Low Sensitivity of Current Diagnostic Scheme and Prolonged Culture Positivity in Four Colombian Prisons. A Cohort Study

Objective

To determine the incidence of pulmonary tuberculosis (TB) in inmates, factors associated with TB, and the time to sputum smear and culture conversion during TB treatment.

Methods

Prospective cohort study. All prisoners with respiratory symptoms (RS) of any duration were evaluated. After participants signed consent forms, we collected three spontaneous sputum samples on consecutive days. We performed auramine-rhodamine staining, culturing with the thin-layer agar method, Löwestein-Jensen medium and MGIT, susceptibility testing for first-line drugs; and HIV testing. TB cases were followed, and the times to smear and culture conversion to negative were evaluated.

Results

Of 9,507 prisoners held in four prisons between April/30/2010 and April/30/2012, among them 4,463 were screened, 1,305 were evaluated for TB because of the lower RS of any duration, and 72 were diagnosed with TB. The annual incidence was 505 cases/100,000 prisoners. Among TB cases, the median age was 30 years, 25% had <15 days of cough, 12.5% had a history of prior TB, and 40.3% had prior contact with a TB case. TB-HIV coinfection was diagnosed in three cases. History of prior TB, contact with a TB case, and being underweight were risk factors associated with TB. Overweight was a protective factor. Almost a quarter of TB cases were detected only by culture; three cases were isoniazid resistant, and two resistant to streptomycin. The median times to culture conversion was 59 days, and smear conversion was 33.

Conclusions

The TB incidence in prisons is 20 times higher than in the general Colombian population. TB should be considered in inmates with lower RS of any duration. Our data demonstrate that patients receiving adequate anti-TB treatment remain infectious for prolonged periods. These findings suggest that current recommendations regarding isolation of prisoners with TB should be reconsidered, and suggest the need for mycobacterial cultures during follow-up.     

Risk Factors for Inadequate TB Case Finding in Rural Western Kenya: A Comparison of Actively and Passively Identified TB Patients

Background

The findings of a prevalence survey conducted in western Kenya, in a population with 14.9% HIV prevalence suggested inadequate case finding. We found a high burden of infectious and largely undiagnosed pulmonary tuberculosis (PTB), that a quarter of the prevalent cases had not yet sought care, and a low case detection rate.

Objective and methods

We aimed to identify factors associated with inadequate case finding among adults with PTB in this population by comparing characteristics of 194 PTB patients diagnosed in a health facility after self-report, i.e., through passive case detection, with 88 patients identified through active case detection during the prevalence survey. We examined associations between method of case detection and patient characteristics, including HIV-status, socio-demographic variables and disease severity in univariable and multivariable logistic regression analyses.

Findings

HIV-infection was associated with faster passive case detection in univariable analysis (crude OR 3.5, 95% confidence interval (CI) 2.0–5.9), but in multivariable logistic regression this was largely explained by the presence of cough, illness and clinically diagnosed smear-negative TB (adjusted OR (aOR) HIV 1.8, 95% CI 0.85–3.7). Among the HIV-uninfected passive case detection was less successful in older patients aOR 0.76, 95%CI 0.60–0.97 per 10 years increase), and women (aOR 0.27, 95%CI 0.10–0.73). Reported current or past alcohol use reduced passive case detection in both groups (0.42, 95% CI 0.23–0.79). Among smear-positive patients median durations of cough were 4.0 and 6.9 months in HIV-infected and uninfected patients, respectively.

Conclusion

HIV-uninfected patients with infectious TB who were older, female, relatively less ill, or had a cough of a shorter duration were less likely found through passive case detection. In addition to intensified case finding in HIV-infected persons, increasing the suspicion of TB among HIV-uninfected women and the elderly are needed to improve TB case detection in Kenya.