The utility of polymerase chain reaction (PCR) in the diagnosis of pulmonary tuberculosis

Department of Microbiology, University Hospital and Medical School, Valencia, Spain.
Chest (Impact Factor: 7.48). 07/1995; 107(6):1631-5. DOI: 10.1378/chest.107.6.1631
Source: PubMed


A fragment of DNA of 123 bp belonging to insertion sequence IS6110, specific of Mycobacterium tuberculosis complex, was amplified by polymerase chain reaction (PCR) of respiratory samples, for the diagnosis of pulmonary tuberculosis. A total of 314 samples (286 sputum and 28 bronchoalveolar lavages) from 242 patients were evaluated by PCR, and the results were compared with the those obtained by acid-fast-stained smears, culture, and clinical diagnosis. Mycobacterium tuberculosis was detected by PCR in 102 of 105 patients with clinical diagnosis of pulmonary tuberculosis. All smear and culture-positive samples were PCR positive. The sensitivity of PCR, culture, and staining was 97%, 88%, and 65%, respectively, and the specificity was 100% in all cases. In ten patients with old residual lesions, but no active disease, M tuberculosis genome was detected by PCR. In our experience, PCR proved to be a useful method for the rapid diagnosis of pulmonary tuberculosis.

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    • "Kocagoz et al. (1993) recorded that sensitivity, specificity and positive and negative predictive values of ZN smear were respectively 68, 100, 100 and 70 %. Similar results were reported by Querol et al. (1995), who found a microscopic sensitivity of 65 % and specificity of 100 %. Also, Herrera & Segovia (1996) recorded that, considering clinical diagnosis as the 'gold standard', the sensitivity, specificity and positive and negative predictive values for ZN smear were respectively 69, 87, 84 and 74 %. "
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    • "Noordhoek et al. (1995) observed that phenol extraction of DNA removes inhibiting substances from those samples in which inhibitors were present even after DNA extraction with guanidinium thiocyanate (GuSCN) and silica particles. Querol et al. (1995) achieved 97% PCR positivity by using phenol:chloroform:iso amyl alcohol extraction followed by isopropanol precipitation of DNA. Similarly, some workers (Sjobring et al., 1990; Boddinghaus et al., 1990) reported that the use of phenol and chloroform for extraction and ethanol and/or isopropanol for precipitation of DNA surely improves the yield of the purified target DNA, which finally results in increased sensitivity of PCR. "
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