COMPARISON OF 3 PRIMER SETS FOR THE DETECTION OF MYCOBACTERIUM-TUBERCULOSIS IN CLINICAL-SAMPLES BY POLYMERASE CHAIN-REACTION

A number of studies have underlined the interest of the polymerase cha in reaction (PCR) in the detection of Mycobacterium tuberculosis in cl inical samples. Among the different parameters to be carefully studied , the choice of target gene and primers is essential. The amplificatio n of nucleotidic sequences localised on three different target genes ( groEL, IS6110, Pab) was examined in 196 clinical samples from patients with suspected tuberculosis or receiving antituberculous therapy. The results obtained after hybridization with non-radioactive labelled pr obes were compared with the culture data. None of the primer sets stud ied-showed a satisfactory sensitivity (79% to 84%) suitable for it to be used alone. The false-negative specimens with the PCR tests usually corresponded to those that contained few mycobacteria. With the metho ds described in this study, the use of two or three primer sets locate d on different target genes allowed to improve the positivity rate com pared to the culture and sensitivity of the test (90-98%), particularl y for paucibacillary samples. On the other hand, the interpretation wa s easier when concordant results were obtained.