Resumen de Reacción en cadena de la polimerasa: una contribución para el diagnóstico de la tuberculosis extrapulmonar y de las micobacteriosis

Gloria Puerto, Claudia M. Castro, Wellman Ribón

• español

  Introducción. La Organización Mundial de la Saluddefine la tuberculosis extrapulmonar como la enfermedadtuberculosa localizada en cualquier órganodiferente a los pulmones y, la micobacteriosis, comola infección bacteriana producida por micobacteriasno tuberculosas. El diagnóstico de tuberculosisextrapulmonar y micobacteriosis se hace fundamentalmentepor el cultivo y la posterior identificaciónde la micobacteria por pruebas bioquímicas, así comopor baciloscopia para el primer caso.El cultivo de micobacterias presenta limitaciones,especialmente, por el tiempo de incubación quepuede tardar hasta 12 semanas y por la sensibilidadpara determinar la presencia del microorganismo.Actualmente, se utilizan herramientas molecularesque permiten disminuir el tiempo de diagnóstico.Entre ellas está la reacción en cadena de lapolimerasa (PCR) que es una prueba rápida conbuena sensibilidad y especificidad para la identificaciónde patógenos.

• English

  Introduction: The World Health Organization defines extrapulmonary tuberculosis as the disease located in any type of organ different from the lungs, and mycobacteriosis as the bacterial infection produced by environmental Mycobacteria. The diagnosis of extrapulmonary tuberculosis and mycobacteriosis is achieved fundamentally by culture and later identification of bacteria by biochemical tests, as well as by sputum smear for the first case. Culture presents limitations specially related with the time of incubation that can last up to 12 weeks and with the sensitivity to the presence of the microorganism. Currently, molecular tools allow a decrease in the time of diagnosis. Among these tools, the polymerase chain reaction (PCR) is a rapid test with good sensitivity and specificity for the identification of pathogenic Mycobacteria.Objective: To implement PCR as support to the diagnosis of  extrapulmonary tuberculosis and mycobacteriosis to decrease the time in obtaining results and to contribute to the implementation of appropriate treatments for these diseases.Materials and methods: The study was carried out between June 2005 and August 2006. 57 clinical samples of 15 hospitals throughout the country were analyzed by PCR for the sequence of insertion of IS6110 and for the  gene hsp65. Clinical information of the patients, age, sex, and VIH test were included.Results: Results of amplification for PCR IS6110 were positive in 6 patients suggesting extrapulmonary tuberculosis and for PCR hsp65 in an equivalent number, suggesting a process of mycobacteriosis. The study contributed to the diagnosis of meningeal tuberculosis in 4 (6.9%) patients, followed by skin tuberculosis and miliar tuberculosis each one with 1 (1.7%) patient. We identified ¿non-Mycobacteryum tuberculosis? ¿lNMT? in 6 (10.3%) cases, which were differentiated as follows: 4 (7%) patients in sputum, 1 (1.75 %) patient in secretion of abdomen and 1 (1,75 %) patient in secretion of skin injuries. Mycobacterium chelonae isolation of the skin was associated with cosmetic mesotherapy. No relation was found between VIH status and the studied pathologies. Discussion: This study shows PCR as a valuable diagnostic technique for patients, specifically for obtaining results within three days.