The Mycological and Molecular Biological Studies on Arthroderma benhamiae Isolated for the First Time in Korea

Jun, Jae Bok; Sang, Young Ho; Chung, Sang Lip; Choi, Jong Soo; Suh, Soon Bong

Abstract

BACKGROUND
Arthroderma (A.) benhamiae, one of three telemorphs of Trichophyton (T.) mentagrophytes, has not been isolated until recently in Korea, but in Japan the first report on it was made in 1998. OBJECTIVE: To identify A. benhamiae for the first time in Korea. METHODS: Twelve strains suggestive of A. benhamiae grossly and microscopically were detected among 1, 059 of T. mentagrophytes isolated at the Catholic Skin Clinic, Daegu, from 1998 to 2000. They were examined by mating tests and molecular methods. In mating tests, they were respectively crossed with "+" and "-" tester strains of A. vanbreuseghemii, A. benhamiae African race, A. benhamiae Americano-European race. Molecular methods included the sequence analysis of internal transcribed spacer 2 (ITS2) region of ribosomal DNA and chitin synthase 1 (CHS1) gene, and random amplified DNA polymorphism (RAPD) with random primer OPAO-15 (5'-GAA GGC TCC C-3'). RESULTS: Mating tests revealed that 12 strains of T. mentagrophytes consisted of 6 of A. benhamiae, 4 of A. vanbreuseghemii and 2 of indeterminate. Six strains of A. benhamiae, all isolated from the patients with a history of contact with rabbits, included 1 of Americano-European race and 5 of African race of Americano-European race and 5 of African race. One clinical isolate, a strain of A. benhamiae Americano-European race "-" in mating tests, was almost identical with the standard strains of A. benhamiae Americano-European race with molecular methods as 99.2% (351/354) similarity of ITS2 sequence, 99.1% (313/ 316) similarity of CHS1 sequence, and similar RAPD pattern. Five clinical strains of A. benhamiae African race were identical with standard strains in ITS2 and CHS1 gene and RAPD pattern. CONCLUSION: The first isolation of 6 strains of A. benhamiae in Korea was reported. Five were identified as A. benhamiae African race "+", and 1 as A. benhamiae Americano-European race "-".