Direct Detection of Mycobacterium Tuberculosis in Respiratory Specimens by Ligase Chain Reaction

Song, Ae Sook; Park, Young In

Abstract

BACKGROUND: The most common clinical manifestation of tuberculosis is respiratory tract infections. Currently, respiratory tract tuberculosis is diagnosed by using X-ray, acid-fast smear, culture, or DNA probe technology. The nucleic acid amplification technologies include the polymerase chain reaction (PCR) and the ligase chain reaction (LCR). The potential utility of LCx (Abbott Lab.) kit for the detection and identification of Mycobacterium tuberculosis in respiratory specimens has been measured.
METHODS
Four different methods such as acid-fast smear, culture, PCR, and LCR were evaluated using 58 specimens isolated from patients. The IS6110 sequences for Mycobacterium tuberculosis synthesized and provided by Applied Biosystems were used for PCR procedure. The LCR assay using LCx kit was performed according to the manufacturer's instruction (Abbott Lab., U.S.A.).
RESULTS
Sensitivity, specificity, and positive and negative predicative values for acid-fast smear method were 72, 100, 100 and 89%, respectively and were 89, 100, 100 and 95%, respectively for culture method. Whereas those values for PCR method were 78, 100, 100, and 91% respectively, and those for LCR were 100, 95, 90 and 100%, respectively.
CONCLUSIONS
The LCR assay performed on respiratory specimens for the detection of Mycobacterium tuberculosis has been evaluated as a highly effective method among 4 different identification systems.