Chain reaction of polimerase (PCR) and its variations such as the nested-PCR have been outstanding as promising molecular techniques for the fast diagnosis of the tuberculosis (TB). In the present study the nested-PCR was evaluated using as molecular markers the sequence IS6110 and the antigen b applied to the diagnosis of TB. One hundred and thirty six clinical samples of patients with suspicion of TB were submitted to the baciloscopia, culture and nested-PCR. The diagnosis of pulmonary tuberculosis was attributed to 116 patients, of these, 97 were multi-bacilli and 111 presented positive culture for M. tuberculosis. The nested-PCR reactions identified 70% (antigen b) and 94% (IS6110) of the acid-fast smear negative cases of tuberculosis. The sensibility values determined for culture, and nested-PCR of IS6110 and antigen b were 95%, 98% and 86%, respectively. The specificity was 100%, 15% and 45% for culture, nested-PCR of IS6110 and antigen b, respectively. The molecular diagnosis of the tuberculosis should be based in the combined analysis of several parameters, as the baciloscopia, culture, clinical manifestations, therapeutic proves and previous history of tuberculosis.
M. tuberculosis; Tuberculosis; antigen b; IS6110; Nested-PCR; PCR
