Polymerase chain reaction for detection of Mycobacterium tuberculosis

Rapid diagnosis of tuberculosis is essential, and therefore we use a polymerase chain reaction. In this report, we describe two cases of tuberculous lymphadenitis in childhood. Although histopathological findings were not specific for tuberculosis in both cases, distinct positive bands were amplified. For DNA diagnosis of tuberculosis, a lysis method of extracting chromosomal DNA from lipid-rich cell walls of mycobacteria is of critical importance. We made use of a simple lysozyme-proteinase K treatment for biopsied tissues. Although this extraction procedure was less efficient than those reported previously, it was considered sufficient for detecting mycobacterial DNA with the use of a highly sensitive polymerase chain reaction. We conclude that DNA amplification in combination with lysozyme lysis can be used routinely in clinical laboratories as a rapid and sensitive test for the diagnosis of tuberculosis.