COMPARISON AMONG PCR, BACILOSCOPY AND CULTURE IN HUMAN TUBERCULOSIS DIAGNOSIS

Abstract

Two hundred samples, 195 of sputum and five of urine, sent to Adolfo Lutz Institute, Bauru Regional, were analyzed for baciloscopy, culture and polymerase chain reaction (PCR) aiming to study comparatively these tests and to evaluate the implantation of PCR in a Zoonosis Diagnosis Center, considering the importance of previous tuberculosis diagnosis to the institution of the therapy, aiming the treatment of the patient and decreasing the transmission to other persons and animals. After de concentrated baciloscopy, the samples were stained by Ziehl-Neelsen dye. The decontaminated samples, by N-actetil-L-cisteine and 2% sodium hydroxide methods were cultured in Löwenstein-Jensen, Löwenstein-Jensen with para-nitrobenzoic and Stonebrink medias. PCR was performed using primers to Complex Mycobacterium spp., M. tuberculosis and M. bovis. Sixtieth samples were positive to the isolation of M. tuberculosis and only one to M. flavescens. Seventieth samples were positive to the baciloscopy. The PCR result allowed the identification of 25 M. tuberculosis samples for IS6110 primer and only one sample biochemically identified and by Complex Mycobacterium spp. primer. The PCR sensitivity and specificity compared to the culture, golden-standard, were 94.74% and 96.67%. PCR presented higher sensitivity than baciloscopy and the culture, and these didn’t differ from each other. PCR showed itself to be reproducible on the identification of M. tuberculosis and Mycobacterium spp., being capable to perform an important differential diagnosis with M. bovis, being capable to be applied at the tuberculosis diagnosis routine as a confident method based in sensitivity and specificity.