Kasmera (Aug 2005)
Evaluation of Baciloscopy, Cultivation and Polimerasa Chain Reaction for the Diagnostic of Lung Tuberculosis
Abstract
The utility of baciloscopy, cultivation and Polimerasa Chain Reaction of (PCR) was evaluated in 31 sputum samples, of patient of both sexes, without distinction of etnial grup and ages between 17 and 80 years, with clinical manifestations, discoveries radiological and/or suggestive epidemic data of lung tuberculosis. To all the samples they were practiced baciloscopy using the technique of Ziehl-Neelsen. The Ogawa-Kudoh cultivation was used like standard. The objectives for the rehearsal of PCR were the genes that code the protein 32-KDa (alpha antigen) and the insertion sequence IS6110. After the amplification was obtained a fragment of 984 couples of bases corresponding to the sequence of insert IS6110 and another of 506 couples corresponding to the alpha antigen. Of the total of samples examined by the Ziehl-Neelsen method, 19 were positive and 12 were negative (61.29 and 38.71% respectively). 19 samples (61.29%) were positive and 12 (38.71%) were negative to the cultivation. Of all amplified samples, 22 (70.69%) showed the presence of fragments corresponding to DNA so much to the sequence of insert IS6110 like the antigen alpha 32-KDa, while in 9 (20.04%) presence of DNA mycobacterium was not detected for RCP method. The sensibility of the RCP test was virtually 100% and its specificity was of 100%. It was demonstrated that RCP, based on the simultaneous amplification of the insertion element IS6110 and the gene that codes the alpha antigen in a single step, can identify mycobacterium infections. We conclude also that is more sensitive that routine bacteriological procedures (direct exam and cultivation) and can be a very powerful tool for the diagnosis of lung tuberculosis and other mycobacterium diseases.
