Avaliação da reação em cadeia da polimerase no diagnóstico da tuberculose pulmonar em pacientes indígenas e não indígenas

Abstract

Positivity and isolation of nontuberculous mycobacteria in the acid-fast smear in conjunction with polymerase chain reaction positivity raise the following hypotheses: nontuberculous mycobacteria species with DNA regions homologous to, or even still possessing, the M. tuberculosis IS6110 exist in the Amazon; colonization of the oropharynx or of a tuberculous lesion accelerates the growth of the nontuberculous mycobacteria present in the sputum samples, making it impossible to isolate M. tuberculosis; A history of tuberculosis results in positivity for M. tuberculosis DNA. The absence of bacteriological positivity in the presence of polymerase chain reaction positivity raises questions regarding the inherent technical characteristics of the bacteriological methods or regarding patient history of tuberculosis.

Quality of sputum in the performance of polymerase chain reaction for diagnosis of pulmonary tuberculosis

“…According to some authors, fungi and bacteria from these sites can affect the results of PCR from sputum. 16 However, others have reported high PCR sensitivity and specificity for tuberculosis diagnosis, despite the fact that the samples were clearly contaminated with these microorganisms. 17 In our study, we utilized only one sample for the same sputum.…”

Pulmonary Nontuberculous Mycobacterial Infections in the State of Para, an Endemic Region for Tuberculosis in North of Brazil

“…Barreto and Campos (2000) found 35 patients with NTM and showed that isolates of the M. avium complex, M. terrae and M. fortuitum were most common in samples collected between 1994 and 1999 in North of Brazil. A study that evaluated respiratory samples of non-indigenous and indigenous patients from Amazonas State with suspected pulmonary TB identified 19 patients with NTM infection, but the study did not report the identity of the isolates at the species level (Santos et al, 2006 Zamarioli et al 2008;Pedro et al, 2008).…”

Avaliação do protocolo PCR4 de Marchetti em tecidos parafinizados para o diagnóstico da tuberculose cutânea e ganglionar

“…e colonização da lesão cutânea, visto que existe o relato da presença de várias espécies de micobactérias na flora da pele normal de pessoas residentes no estado do Amazonas (19,20) ; a existência, na Amazônia, de espécies de MNT contendo a IS6110, conforme também relatado por Santos et al (18) ; ou a uma homologia entre o DNA destas MNTs e a IS6110, semelhante ao exposto por outros autores (3,11,15) . Visto que em quatro amostras o problema parece estar relacionado com o impedimento de desenvolvimento do M. tuberculosis, a falsa-positividade foi de 9,5% para todos os casos.…”