Abstract

Fungi are ubiquitous in the Pribilof Rookeries but frank dermatophyte infections are rare. A detailed examination of the skin by histology, depot fat by GLC, and in-vitro inhibition of selected dermatophytes by certain fatty acids was made. The deep stratum corneum, interlamellar lipids, and tight collar of keratinized cells in the follicle shaft appear to aid in preventing fungal penetration. The fat contains greater proportions of C:15 and short chain fatty acids than other seal species. The short chain fatty acids were capable of inhibiting Autochthonous Dermatophytes in vitro. The role of various factors which might interfere with this balanced parasitism is discussed.

Notes

Four barriers to fungi exist:

1. Serum factor -α-2 macroglobulin
2. Immune factor - precipitates C reactive protein
3. Skin
4. Fatty acids - fungistatic or fungicidal

An isolation medium containing aged seawater was best for growing marine fungi.

Fur seals excrete fatty acids on their skin. This aids in thermoregulation as well as fungal resistance.

Gas layer chromatography was used to isolate the fatty acids.

Dermatophytes seem to be more susceptible to odd numbered short chain fatty acids. The following are listed in order of increasing inhibitory power, starting with the least inhibitory fatty acid: C₁₀, C₈, C₁₃, C₁₆, C₁₂, C₂₁, C₉, C₁₁, C₁₇, C_14.1, C₁₅

The oxidative process removes 2 carbons at a time so that if one begins with an odd numbered fatty acid, one eventually reaches propionic acid which is the antifungal agent used to preserve bread.

Further studies needed:

1. Evaluate effectiveness of systemic versus topical antibiotic treatment for dermatophytes. Do systemically administered antibiotics reach the skin surface?
2. Analyze the reactions which are occurring.
3. Define the role of dermatophyte depilation and its effect on thermoregulation.