Studies on Baiting Methods for Isolation of Keratinophilic Fungi

Suh, C K

Abstract

There are innumerable known and unknown fungi which inhabit soil, from which the causative organisms of deep mycoses have been isolated from many years, so that the concept of the role of soil as a reservoir of pathogenic fungi has received strong support. but the keratinophilic fungi which are capable of causing superficial dermatomycoses have only recently been isolated. Even though there arc both the membrane filter method and the direct culture method for isolating the keratinophilic fungi from soil, it is extremely difficult to isolate these fungi because there are so many saprophytes which cause contamination. However, in 1%2, Vanbreuseghem developed a selective method for isolating keratinophilic fungi from soil which is known as the hair-baiting technique. By means of this technique, the new species of K. ajelloi and M. cookei including the previous1y 1 known M. gypseum have heen obtained by many workers, and these fungi have been found to he world-wide in distribution. Some other species of keratinophilic fungi were also isolated in a few different countries. Since human hair was used as bait by Vanbreuseghem in his technique, it has been used widely by many workers, Up to the present time little research has been done in this field about evaluating or comparing the various keratinaceous materials other than human hair as bait. The author studied different kinds of keratinaceous materials from various sources to compare the difference in with a view to finding a The fungi used were of the growth of the keratinophilic fungi. These studies were done more ideal bait for the isolation of the keratinophilic fungi. 5 different species of M. gypseum, M.cookei, K. ajelloi, M. vanbreuseghemii, and M. canis. The baiting materials were human scalp hairs from 6 different age groups and axillary and pubic hairs from 2 different age groups of both sexes, 11 different domestic animal hairs, and 2 kinds of birds feathers. Horns and hoofs of cattle, pig hoofs and human nails as well as same corn husks, rice and barley stalks, and barks and leaves of some trees were also used as baiting materials. By the results of experiments with each. fungal species baited with each material, the author chose the better baiting materials composed of horn and hoof of cattle, pig hoof, human nail, body and tail hairs of horse, beard and tail:: hairs of black goat, body and tail hairs of dog, female pubic hairs of 20 to 25 year age group, and male scalp hairs of 55 to 60 year age group in equal parts to see the growth of fungi in natural soil. These were compared with the poorer baiting materials of body and tail hairs of guinea-pig, cat, and rabbit; body hair of mouse, chicken feather, and female axillary hair of 20 to 25 year age group Conclusions l. Every keratinaceous materials could be used as bait, but the best materials were as follows, human nails and human pubic hairs and the hairs, horns and hoofs of the larger animals. Pathological scales and hairs of small animals were particularly poor baiting materials. 2. Among the hairs of human beings, pubic hairs were the best, regardless of sex and age. Scalp hairs of aged males were also better. 3. The growth of M, gypseum, M. cookei, and K. ajelloi was rapid and luxuriant but M. vanbreuseghemii and M. canis was delayed and poor. 4. M. gypseum, M. cookei, and K. ajelloi grew best on tail hairs of cattle and horse and goat beard, arnongst the various animal hairs used, but were slower growing and longer lasting on hairs of pig body and cattle tail. 5. Small animal hairs showed poor results in growth regardless of any of the 5 fungal species. 6. M. vanbreuseghemii were well baited on the body hairs of horses, and on the beard and body hairs of white goats. While M. canis were well baited on horse body hairs and on tail hairs of black and white goats. 7. Birds feathers were better baits than the hairs of small animals. Better results were obtained from horns and hoofs of cattle and pig hoofs than with human nails in the growth of M. gypseum, M. cookei and K. ajelloi. In contrast, human nails were better than horns and hoofs of cattle and hoofs of pig in the growth of M. vanbreuseghemii and M. canis. Human toe nails were the best for the growth of M. canis. 9. Poor results were obtained from psoriatic scales and except with M. vanbreuseghemii which showed good growth on callus materials. 10. No growths were observed on corn husks, rices and barley stalks, and on the barks and leaves of trees. 11. It was better to use baiting materials mixed together, than to use them each. 12. It was found that the mixture in equal parts of horns and hoofs of cattle, pig hoofs, human nails, body and tail hairs of horse, beard and tail hairs of black goat, body and tail hairs of dog, female pubic hairs of 20 to 25 year age group, and male scalp hairs of 55 to 60 year age group was the best baiting materials. This mixture showed rapid growth of fungi, and the characteristic growth of each fungus could be observed with naked eyes. 13. There vas a 2 or 3 days difference between the growth noted with the naked eyes and those with the stereoscopic microscope. 14. Perforating organ was formed in the thick hair filaments, but not observed in the thin ones and in keratinaceous materials other than hairs.

Studies on Baiting Methods for Isolation of Keratinophilic Fungi

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