Classification and Typing of Trichophyton mentagrophytes Isolated from a Korean Population

Kim, Woo Jin; Kim, Joon Goon; Choi, Jin Hwa; Shin, Dong Hoon; Choi, Jong Soo; Kim, Ki Hong; Jun, Jae Bok; Bang, Yong Jun

Abstract

BACKGROUND
Trichophyton mentagrophytes complex is a heterogeneous group. A new classification, based on molecular biology, has replaced the one based on morphology, physiology, and mating behavior.
OBJECTIVE
T. mentagrophytes isolates from Korean patients were classified using the new method and compared with the classic classification.
METHODS
During 2010-2011, fungal isolates were collected at the Catholic skin clinic from 562 patients infected with T. mentagrophytes; clinical characteristics were reviewed. Patients were divided into four groups based on the morphological characteristics of the isolates. Thirty-four strains of T. mentagrophytes were randomly selected from the four groups for mycological and molecular biology analyses, including analyses of morphological characteristics, ribosomal DNA (rDNA) internal transcribed spacer (ITS) sequence, and rDNA nontranscribed spacer (NTS) typing.
RESULTS
Among the 562 isolates, persicolor (41.6%) was the most common strain type, followed by the powdery (38.4%), downy (11.2%), and granular (8.7%) types. The granular type differed from the other three with respect to the isolation site, patient's age, seasonal variation, and microscopic characteristics. Among the selected 34 strains, the microscopic characteristics varied for each strain. The powdery, persicolor, and downy types had ITS sequences identical to those of the anthropophilic T. interdigitale/A. vanbreuseghemii. The ITS sequence of granular type was similar to that of zoophilic T. interdigitale/A. vanbreuseghemii. The granular type had different NTS types than the other types did.
CONCLUSION
The T. mentagrophytes strains isolated were classified as T. interdigitale/A. vanbreuseghemii; the majority (91.7%) was anthropophilic and 8.3% were zoophilic and granular type.