ABSTRACT
Fingerprinting of Mycobacterium tuberculosis strains from tuberculosis (TB) patients attended in Community Health Centers (CHCs) of Rio de Janeiro was performed to verify possible risk factors for TB transmission. A prospective community-based study was performed during the period of July 1996 to December 1996 by collecting sputum samples of 489 patients in 11 different CHCs in four different planning areas (APs) of the city. Bacteriological, clinical, and epidemiological information was collected and M. tuberculosis genotypes defined after restriction fragment length polymorphism (IS6110-RFLP) and double repetitive element (DRE) fingerprinting of RFLP-clustered cases. Risk factors for TB transmission were looked for using three levels of cluster stringency. Among 349 (71 percent) positive cultures obtained, IS6110-RFLP typing could be performed on strains from 153 different patients. When using identity of RFLP patterns as cluster definition, 49 (32 percent) of the strains belonged to a cluster and none of the clinical or epidemiologic characteristics was associated with higher clustering levels. However, higher clustering level was observed in the AP including the central region of the city when compared to others. This strongly suggests that more recent transmission occurs in that area and this may be related with higher incidence of TB and HIV in this region.
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Bacterial Typing Techniques , DNA Fingerprinting , Mycobacterium tuberculosis/classification , Tuberculosis/microbiology , Brazil/epidemiology , Cluster Analysis , Community Health Centers , Genotype , Mycobacterium tuberculosis/genetics , Polymorphism, Restriction Fragment Length , Prospective Studies , Risk Factors , Tuberculosis/epidemiology , Tuberculosis/transmissionABSTRACT
Objetivo: identificar fatores de risco associados à ocorrência de tuberculose pulmonar (TBP) paubacilar. Métodos: estudo transversal avaliando o resultado dos exames bacteriológicos de pacientes suspeitos de TBP atendidos em onze Centros Municipais de Saúde (CMS) na cidade do Rio de Janeiro, Brasil. Resultados: entre 1°. de Julho e 31 de Dezembro de 1996 foram entrecistados 423 pacientes com diagnóstico clínico-radiológico de TBP ativa. Noventa e quatro por cento (397/423) forneceram pelo menos duas amostras de escarro espontâneo para análise. A cultura foi positiva para Mycobacterium tuberculosis em 84% (333/397), com baciloscopia positiva em 64% (213/333) e baciloscopia negativa em 36% (121/333). Não se observou associação entre lesão pulmonar paucibacilar e gênero, vacinação com BCG, tempo de sintomas respiratórios, admissão prévia em prisão ou em asilos nos últimos 24 meses, comportamento sexual, uso de droga injetável, tratamento anti-TB no passado, contado com paciente tuberculoso pulmonar bacilífero nos últimos 12 meses, condições de moradia e residir em determinada área pragmática. Entretanto, a lesão pulmonar paucibacilar esteve associada significamente a escolaridade superior de 4 anos (1,87; 0,98-3,55; p=0,05), admissão prévia em hospital nos últimos 24 meses (2,53; 1,39-4,60; p=0,001) e sorologia positiva para infecção pelo vírus da imunodeficiência humana (HIV) (4,48;1,74-11,81; p=0,006). Conclusão: tuberculose pulmonar paubacilar deve ser considerada um problema em centros urbanos com elevada co-infecção /TB e HIV, onde a cultura para micobactéria e a testagem anti-HIV dvem ser disponibilizados para os pacientes com tais características.
Objective: to identify risk factors for negative sputum acid -fast bacilli smear among pulmonary tuberculosis (PTB) patients in CHC. Methods: cross sectional study, performed through bacteriological evaluation of mear negative/culture positive PTB cases attended in eleven Community Health Centers (CHC) in Rio de Janeiro City, Brazil. Results: from July 1st to December 31th, 1996, 423 patients with active PTB were interviewed and 397 had their spontaneous sputum evaluated. Afterwards 333 patients presented positive culture results for mycobacterium tuberculosis and among them 121 (36.2%) were smear negative. The agreement results (kappa value) between the first and the second sputa for smear acid-fast bacilli was moderate (0.49) but for culture was fair (0.31). No statistically significant association were identified among smear negative/culture positive results and be following variables: gender, BCG vaccionation, length of respiratory symptoms, previous admission at jails or at shelters in the previous 24 months, sexual behavior, intravenous drug use, anti-TB treatment in the past, contact with infectious PTB patients in the previous 12 months, living conditions and planning City Areas residence. Nevertheless, smear negative/culture positive PTB were observed as associated to 4.60; p=0.001) and, seropositivity for human immunodeficiency virus (HIV) (4.48; 1.74-11.81; p=0.006). Conclusion: Smear negative PTB should be considered a significant clinical problem, particularly in settings affected by dual HIV/TB epidemic. A wider availability of TB culture facilities should be pursued as well HIV testing for PTB suspect smear negative. So, to improve TB control in developing countries is urgently needed to update guidelines by both TB Control Program and AIDS Control Program.
Subject(s)
Humans , Male , Female , Cross-Sectional Studies , Data Analysis , Risk Factors , Tuberculosis/diagnosisABSTRACT
With the objective to evaluate PCR-mediated detection of Mycobacterium tuberculosis DNA as a diagnostic procedure for diagnosis of tuberculosis in individuals attending ambulatory services in Primary Health Units of the City Tuberculosis Program in Rio de Janeiro, Brazil, their sputum samples were collected and treated with a DNA extraction procedure using silica-guanidiniumthiocyanate. This procedure has been described to be highly efficient for extraction of different kind of nucleic acids from bacteria and clinical samples. Upon comparing PCR results with the number of acid-fast bacilli, no direct relation was observed between the number of bacilli present in the sample and PCR positivity. Part of the processed samples was therefore spiked with pure DNA of M. tuberculosis and inhibition of the PCR reaction was verified in 22 out of 36 (61 percent) of the samples, demonstrating that the extraction procedure as originally described should not be used for PCR analysis of sputum samples