Prevalence and predictors of positive tuberculin skin test results in a research laboratory

Abstract

Latent tuberculosis was studied in a research laboratory. A prevalence of positive tuberculin skin test results (≥ 15mm) of 20% was found and the main predictors were place of birth in a foreign country with high prevalence of tuberculosis and a history of contact with patients with untreated active tuberculosis.Key-words: Latent tuberculosis. Prevalence. �isk factors. �esearch laboratory.�isk factors. �esearch laboratory. RESUMOA tuberculose latente foi estudada em um laboratório de investigação. Foi encontrada uma prevalência de 20% de resultados positivos para o teste cutâneo de tuberculina (≥ 15mm) e os principais fatores preditores foram ser natural de um país estrangeiro com alta prevalência de tuberculose e ter uma história de contato com doentes com tuberculose ativa não tratada. Palavras COMUNICAÇÃO/COMMUNICATIONLatent tuberculosis after infection with Mycobacterium tuberculosis with no evidence of disease affects up to one third of the world population 5 18 . The frequency of a positive tuberculin skin test (TST) reaction as a diagnostic test for latent tuberculosis 13 14 in the general population in Asia is: India 41% 9 12 14 , Pakistan 40%, South Korea 87%, Cambodia 39% and Afghanistan 34%; in Africa: South Africa 38% and Zimbabwe 64% 5 , in Europe: the Netherlands 4% 1 , Germany 29% 4 , Italy 40% 16 and United Kingdom 27% 9 17 , and in America: the Pacific �egion 15%, Canada 17% and USA 22% 5 . We studied the frequency of positive TST results among laboratory members and epidemiological risk factors for positive tuberculin skin test results to identify subjects with a high likelihood of latent tuberculosis.Study subjects. We evaluated 65 out of 100 laboratory members (scientists and technicians) who provided informed consent for their participation. No formal sample size calculation was performed. The exclusion criteria were medical illness (e.g. diabetes) or taking immunosuppressive drugs (e.g. corticosteroids).Setting. The setting was an inner-city biomedical research laboratory in Berlin with a biosafety level 3 facility that included research with Mycobacterium tuberculosis. Study approval. All probands provided informed consent and the study was approved by the institutional review board.In total, 65 probands were studied (mean age 33 years and range 23 -57 years); 34 (52%) were male and 31 (48%) were female (Table 1). Thirteen (20%) probands had a TST result ≥ 15mm, two (3%) ≥ 10mm, 17 (26%) ≥ 5mm and 33 (51%) less than 5mm. According to clinical risk factors, 13 (20%) probands had a positive tuberculin skin reaction and 52 (80%) had a negative reaction 17 .Fifty-four (83%) robands had a history of BCG (Bacille Calmette-Guérin) vaccination, eight (12%) had not had the

Prevalence of latent tuberculosis and treatment adherence among patients with chronic kidney disease in Campo Grande, State of Mato Grosso do Sul

“…These results, however, disagree with the prevalences of 15% from studies in Belgium 35 and 20% from studies in Berlin 36 .…”

“…This result was supported by studies that reported that prior contact with an active TB patient is required for the development of latent infection 12,36 . A signifi cant percentage of cases of active TB is usually due to the reactivation of LTB, which reinforces the need to limit contacts with patients with active TB in the community.…”

Baixa prevalência de PPD reativo prévia ao uso de infliximabe: estudo comparativo em população amostral do Hospital Geral de Fortaleza

“…16 Laurindo et al 30 have reported that, in São Paulo, the frequency of positive PPD was significantly lower in RA patients (27%) as compared with the control group (58.6%), comprised by healthy individuals with a mean age of 34 years, working at the hospital administration office. However, those two national studies have factors that elevate the population frequency of the PPD reaction, such as previous vaccination 33 and/or health care professionals included in the control groups, 34,35 favoring the reported statistical differences between the groups compared. In a study developed in Peru, 36 where TB is endemic and the prevalence of the BCG scar is higher than 80%, the PPD test performed in a group of RA patients was compared with that of immunocompetent volunteers, paired by sex and age.…”