Two-step tuberculin skin test and booster phenomenon prevalence among Brazilian medical students.

SETTING: Five medical schools in three cities in Rio de Janeiro State, Brazil, with different tuberculosis (TB) incidence rates. OBJECTIVE: To evaluate the prevalence of the booster phenomenon and its associated factors in a young universally BCG-vaccinated TB-exposed population. DESIGN: A two-step tuberculin skin test (TST) was performed among undergraduate medical students. Boosting was defined as an induration > or =10 mm in the second TST (TST2), with an increase of at least 6 mm over the first TST (TST1). The association of boosting with independent variables was evaluated using multivariate analysis. RESULTS: Of the 764 participants (mean age 21.9 +/- 2.7 years), 672 (87.9%) had a BCG scar. The overall booster phenomenon prevalence was 8.4% (95%CI 6.5-10.6). Boosting was associated with TST1 reactions of 1-9 mm (aOR 2.5, 95%CI 1.04-5.9) and with BCG vaccination, mostly after infancy, i.e., after age two years (aOR 9.1, 95%CI 1.2-70.7). CONCLUSION: The prevalence of the booster phenomenon was high. A two-step TST in young BCG-vaccinated populations, especially in those with TST1 reactions of 1-9 mm, can avoid misdiagnosis as a false conversion and potentially reduce unnecessary treatment for latent TB infection.

Latent tuberculosis infection among undergraduate medical students in Rio de Janeiro State, Brazil.

SETTING: Five medical schools in three cities with different tuberculosis (TB) incidence rates in Rio de Janeiro State, Brazil. OBJECTIVE: To estimate prevalence of and associated factors for latent tuberculosis infection (LTBI) among medical students. DESIGN: A cross-sectional survey was conducted among undergraduate students in pre-clinical, early and late clinical years from schools in cities with low (28/100,000), intermediate (63/100,000) and high (114/100,000) TB incidence rates. Information on socio-demographic profile, previous BCG vaccination, potential TB exposure, co-morbidity and use of respiratory protective masks was obtained. A tuberculin skin test (TST) was performed using the Mantoux technique by an experienced professional. A positive TST, defined as induration > or = 10 mm, was considered LTBI. RESULTS: LTBI prevalence was 6.9% (95%CI 5.4-8.6). In multivariate analysis, male sex (adjusted odds ratio [aOR] 1.8; 95% CI 1.1-3.0), late clinical years (aOR 1.9; 95% CI 1.01-3.5), intermediate TB incidence (aOR 4.3; 95% CI 1.3-14.6) and high TB incidence in the city of medical school (aOR 5.1; 95% CI 1.6-16.8) were significantly associated with LTBI. CONCLUSIONS: The higher prevalence of LTBI in late clinical years suggests that medical students are at increased risk for nosocomial Mycobacterium tuberculosis infection. The implementation of a TB control program may be necessary in medical schools, particularly in cities with higher TB incidence.

Pleural tuberculosis and human immunodeficiency virus co-infection.

SETTING: Department of internal medicine in a general hospital in Rio de Janeiro, Brazil, which provides secondary care to the poor population. OBJECTIVE: The aim of this study was to evaluate the prevalence of human immunodeficiency virus (HIV) infection in patients with pleural tuberculosis (TB) and to compare its manifestations in HIV-negative and HIV-infected patients. DESIGN: Cross-sectional study. METHODS: Forty-three patients with a final diagnosis of pleural TB were submitted to HIV testing (ELISA), chest X-ray, and thoracentesis for biochemical, cytological and bacteriological analysis. Pleural tissue was obtained in 36 patients for histopathological examination. PPD testing was performed in 29 patients. Whenever productive cough was present, sputum acid-fast smears and culture for Mycobacterium tuberculosis were performed. RESULTS: The HIV prevalence was high (30%). TB symptoms were similar in both groups. Atypical radiological aspects were observed in HIV-infected patients with concurrent pulmonary TB (P = 0.03). Pleural fluid, tissue aspects and PPD testing were comparable in both groups. CONCLUSION: Only atypical radiographic patterns in patients with concurrent pulmonary TB were indicative of HIV infection. Therefore, a high index of suspicion is necessary for the early recognition of HIV/TB co-infection. We suggest that all patients presenting with pleural TB should be screened for anti-HIV antibodies.

The study of tuberculosis-attributed deaths as a tool for disease control planning in Rio de Janeiro, Brazil.

SETTING: Two tuberculosis (TB) reference hospitals and three general hospitals in Rio de Janeiro (RJ). OBJECTIVE: To analyze TB-attributed deaths as a tool for evaluating the TB control program in RJ. DESIGN: Retrospective study based on 302 medical records selected from the 1998 death database. RESULTS: Of 1146 registered adult (>14 years) TB-attributed deaths in RJ, 328 occurred in five hospitals, and 302 records were analyzed. Median age was 47.5 (17-89) years; 237 (78.5%) were male. Median time elapsed from onset of symptoms until diagnosis was 60 (7-730) days; median hospitalization was 60 (0-517) days. Acid-fast bacilli sputum smears were performed in 200 (69%) of 290 cases of pulmonary disease. Among 32 (36%) smear-negative patients, culture was done in only one. The recommended regimen (RHZ) was used in 175 (58%). Among 125 re-treatment patients, 55 (44%) were on RHZ instead of RHZE. Notification to health authorities was recorded in 131 (43.4%) cases. CONCLUSION: In RJ, young people die from TB. Major issues identified in the public health system were poor detection and notification and a high default rate, perpetuating the spread of TB. Treating professionals do not follow guidelines, and political commitment is needed to ensure TB control in the state and in the country.

Changes in QuantiFERON®-TB Gold In-Tube results during treatment for tuberculous infection.

SETTING: Randomised trial comparing 9 months of isoniazid with 4 months of rifampicin for the treatment of high-risk tuberculin skin test positive subjects in Rio de Janeiro, Brazil. OBJECTIVES: To compare QuantiFERON®-TB Gold In-Tube (QFT-GIT) responses before and 1, 4 and 9 months after starting treatment for latent tuberculous infection (LTBI) according to adherence to one of the two regimens. DESIGN: Participants in the trial were invited to undergo serial QFT-GIT. Within-subject differences at different time points were analysed as quantitative responses and categorised as positive or negative using different cut-off points. RESULTS: Of 215 participants, 118 completed treatment, of whom 58 underwent all three tests; and 97 did not complete treatment, of whom 10 underwent all tests. After 1 month of treatment, there was no significant difference in QFT-GIT response between the groups. After 4 and 9 months, reversions were more frequent in non-adherent subjects. Marked within-subject fluctuations were observed. No cut-off point could be established at which QFT-GIT responses were consistently positive or associated with adherence or type of treatment. CONCLUSION: Frequent within-subject variability in QFT-GIT responses, not associated with LTBI treatment, makes it difficult for clinicians to interpret QFT-GIT conversions and reversions.

Tuberculosis treatment outcomes and socio-economic status: a prospective study in Duque de Caxias, Brazil.

A prospective study was conducted to evaluate tuberculosis treatment outcomes according to socio-economic status (SES) using different classification criteria. Patients aged ≥18 years under treatment for ≤8 weeks were interviewed. Outcomes were classified as successful (cure/completed) or unsuccessful (default/failure/death). The overall treatment default ratio was 20.9% and the unsuccessful outcome rate was 24.1%. Unsuccessful treatment was associated with SES according to any criteria used, except for the definition of poverty line. Poverty seems to be hampering the achievement of the World Health Organization targeted 90% cure rate in developing settings.