Resumen

Introduction: Tuberculosis (TB) causes significant morbidity and mortality worldwide as one of the leading infectious diseases. In India, more than 1.8 million new cases occur every year. Rapid and accurate diagnosis of TB would improve patient care and limit its transmission. This study aimed to evaluate a dual target polymerase chain reaction (PCR) diagnostic assay to detect Mycobacterium tuberculosis fron pulmonary and extra-pulmonary samples at a tertiary care centre in South India. Methodology: Samples were collected fron patients with a low index of suspicion of TB. Acid-fast smears were performed by Auramine O fluorescent microscopy and PCR was performed by using two site-specific primer pairs targeting IS6110 by nested PCR and TRC₄ by conventional PCR. Amplified products for IS6110 and/or TRC₄ were indicative of M. tuberculosis. Results: Among 114 (19 pulmonary and 95 extra-pulmonary) samples tested by PCR assay, 12 (11%) were positive for both IS6110 and TRC₄, of which 11 (10%) were non-respiratory and one was (1%) respiratory in origin. PCR for TRC₄ alone was positive for eight (7%) non-respiratory and two (2%) respiratory samples, while IS6110 alone tested positive for six (5%) non-respiratory samples and one (1%) respiratory sample. Of a total of 29 PCR positive samples, 17 (15 %) were acid-fast smear positive. Conclusion: Although the target site of IS6110 is specific for M. tuberculosis, some strains fron South India may lack this region. Therefore, the use of an additional target site (TRC₄) is required for improved detection of M. tuberculosis.

Palabras clave: Mycobacterium tuberculosis polymerase chain reaction IS6110 TRC₄ South India.

2012-03-14   |   353 visitas   |   Evalua este artículo 0 valoraciones

Vol. 6 Núm.1. Enero 2012 Pags. 46-52 J Infect Developing Countries 2012; 6(1)