Detection of Mycobacterium leprae in Skin Biopsy Sepcimens From Leprosy patients by Polymerase Chain Reaction

Yoon, Kyeong Han; Cho, Sang Nae; Lee, Jung Bok; Kim, Joo Deuk

Abstract

BACKGROUND: Polymerase chain reaction(PCR) has brought an oppotunity for rapid detection of Mycobacterium leprae in clinical pecimens for the diagnosis of leprosy. Th DNA segment specific to M. leprae was detectable in a matteir of hours and DNA from one orgnisa appeared positive by PCR. However, the PCR tool has not been evaluated using elinical specimeriis from leprosy patients and controls.
OBJECTIVE
& METHODS: The primers amplifying 372bp segment of rebetitive sequence of M. leprae DNA were used in PCR. Skin biopsy specimens from 102 leprosy patient, and controls were examined for the presence of M. leprae by PCR and the results were aomared with microscopic and histopathologic findings.
RESULTS
1. As a result, of PCR after DNA preparation of M. leprae, six other mycobacteria, ten other bacteria, and skin from leprosy with five other skin biopsy tissues, 372bp DNA fragment was specifically amplified from M. leprae. 2. Dot blot, hybridization of PCR products showed that the 372bp DNA from skin biopsy specimens were derived from M. leprae. 3. As a result of PCR after DNA preparation of 10-fold diluted M. legrae from mouse footpad, PCR gave a positive result as low as one organism. 4. Of 87 specimens in which acid-fast bacilli were found under microcopic examinations 97% had positive PCR results. 5. Of 97 specimens which hadihistopathologic evidences of leprosy 95% had positive PCR results. 6. Of 15 specimens in which acid-fast bacilli were not found under n!icroscopic examinations 73% had positive PCR results. In three of five cases which had neither histopathologic nor microscopic evidences of leprosy had positive PCR results.
CONCLUSION
PCR method amplifying 372bp fragment of repetitive seqi,ence was highly sensitive and specific in detecting M. leprae DNA in skin biopsy specimens, thus may be a useful tool as an additive diagnostic method, espcially for cases where microscopic antihystopathologic findings are not definite.