科研之友
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摘要
background: the appearance of tuberculosis/human immunodeficiency virus co-infection and the growing number of diseases caused by nontuberculous mycobacteria, as well as the confusion that these can cause in relation to emerging multidrug-resistant strains, require more accurate and rapid laboratory results, not only in the isolation of strains but also in their identification. objective: a comparative study evaluating a new tool of molecular identification, which uses a genetic probe based on the 16s rdna sequence of the mycobacterium tuberculosis gene (gen-probe accuprobeˋ gen probe, inc.), and the classic methodology. method: fifty-five mycobacterium strains, isolated from the sputum of patients treated at a tuberculosis reference clinic, were selected for study. subcultures were performed in three tubes: one submitted to genetic identification, one analyzed through classical tests (production and accumulation of niacin; growth in the lowenstein-jensen medium with the inhibitor agents p-nitrobenzoic acid and thiophene-2-carboxylic acid hydrazide added), and one held in reserve. results: the probe identified 51 cases as belonging to the m. tuberculosis complex (one associated with m. kansasii) and the other 4 as nontuberculous mycobacteria, later identified as m. kansasii (3) and m. avium (1). using traditional methods, 47 samples were identified as belonging to the m. tuberculosis complex, 4 were classified as fitting the profile of nontuberculous mycobacteria (in agreement with the genetic probe results), and 4 were unidentified, 1 of which presented the exact characteristics that 2 mycobacterium species have in common. conclusion: the benefits of the molecular biology technique justify its implementation and routine use, in combination with classical methods, in a high-traffic clinic where complex cases of tuberculosis are treated.
