Onychomycosis and Trichosporon beigelii

Han, Man Heui; Choi, Jee Ho; Sung, Kyung Jeh; Moon, Kee Chan; Koh, Jai Kyoung; Kim, Bong Chul

Abstract

BACKGROUND: Onychomycosis is a common superficial fungal infection. Causative organisms in onychomycosis have been extensively studied, but the role of non-dermatophytes is controversial. Trichosporon beigelii are soil and water inhabiting yeasts, occasionally found in flora normally associated with human skin, mouth, and nails. Several reports in the literature have suggested that T. beigelii is one of the pathogens in onychomycosis.
OBJECTIVE
We performed mycologic studies to investigate the causative organisms of onychomycosis and to confirm the pathogenic role of T. beigeliis in onychomycosis.
METHODS
We performed a survey of the mycologic labaratory records of patients clinically suspected of onychomycosis from July 1996 to December 1998.
RESULTS
1) Out of a total of 1934 nail samples examined, 928(48.0%) of these were culture positive, including 192(10.8%)cases with T. beigelii. 2) The overall positive rate for the KOH mount examination was 59% and in the cases with T. beigelii was 89.1%. 3) Among the age groups, the incidence rate was highest in the fifth decade(26.6%). 4) The monthly prevalence of onychomycosis was highest in July(10.6%), the distribution of T. beigelii was high in July and August. 5) The most common causative organism of onychomycosis was Trichophyton rubrum(62.0%), and the others in decreasing frequency were T. beigelii(20.7%), Candida spp.(7.2%), Trichophyton mentagrophytes(4.0%) and mixed infection(2.2%). 6) T. beigelii was repeatedly isolated in the successive nail cultures from 10 out of 20 patients with T. beigelii nail infection.
CONCLUSION
T. beigelii was the second commonly isolated fungus in onychomycosis had the high positive rate of the which KOH mount examination on nails and successive repeated cultures. We suggest that T. beigelii might be a pathogen of onychomycosis.