Abstract:

Objective To determine the degree of damage to hairs by Geotrichum, and to compare the difference in infection duration and intensity by Geotrichum silvicola isolates from skin lesions and blood and Geotrichum candidumn isolates between hairs from different age groups. Methods In vitro hair perforation test was carried out on the hairs from healthy individuals of different age groups. Scanning electron microscopy was performed to observe hairs perforated by Geotrichum silvicola isolates from skin lesions and blood as well as Geotrichum candidumn isolates. Results Both Geotrichum silvicola and Geotrichum candidumn isolates could perforate hairs. The time taken to perorate hairs was significantly different between isolates of Geotrichum silvicola from skin lesions, blood and Geotrichum candidumn in every age groups（all P < 0.05）. The Geotrichum silvicola isolates from blood perforated hairs in the shortest time （range: 53 - 64 days, mean: 58.07 ± 3.15 days）, followed by those from skin lesions （range: 57 - 66 days, mean: 61.05 ± 2.55 days）, and Geotrichum candidumn （range: 61 - 74 days, mean: 67.11 ± 3.78 days）. The time taken to perforate hairs by Geotrichum significantly increased with age, and significant difference was observed between hairs from the four age groups, i.e., < 2 years, 2 - 13 years, 14 - 19 yeas, > 19 years, but not between the age group of < 2 years and that of 2 - 13 years （P > 0.05）. As scanning electron microscopy showed, both Geotrichum silvicola and Geotrichum candidumn could damage hairs, and the degree of damage by Geotrichum silvicola was more severe than that by Geotrichum candidumn. Conclusions The damage to hairs by Geotrichum silvicola is earlier and more severe than that by Geotrichum candidumn. The younger the age, the more liable the hairs to be damaged by Geotrichum.

Key words: Geotrichum Silvicola, Skin Lesion, Blood, Geotrichum candidumn, Hair perforation in vitro