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High Fungal Spore Load in Corncob Bedding Associated with Fungal-Induced Rhinitis in Two Rats
Michael A. Royals1, David M. Getzy, Sue VandeWoude
1Laboratory Animal Resources, Colorado State University, Fort Collins, Colorado 80523.
Abstract:
Two types of commonly used contact bedding, aspen chip and corncob, were analyzed for the presence of fungal spores after two rats in a toxicology study were diagnosed with fungal rhinitis. A range of 700 to 5440 spores per g consisting of six species of fungus (Cladosporidium, Acremonium, Penicillium, Aspergillus, Fusarium, and Scolobasidium) were isolated from non-autoclaved corncob bedding obtained from two vendors. Negligible spore counts were detected in autoclaved corncob bedding and from either autoclaved or non-autoclaved aspen chip bedding. The present study demonstrates that high fungal spore counts may occur in untreated corncob bedding and that these may be associated with opportunistic disease in healthy, non-immunosuppressed animals. Autoclaving reduced the viable fungal spore load to an undetectable level.
Insights
Untreated corncob bedding can harbor high fungal spore counts, potentially causing opportunistic infections in laboratory animals. Autoclaving effectively eliminates these fungal contaminants from bedding materials.
Area of Science:
- Veterinary Mycology
- Laboratory Animal Science
- Toxicology
Background:
- Fungal rhinitis diagnosed in rats prompted an investigation into common bedding materials.
- Aspen chip and corncob bedding are widely used in laboratory animal housing.
Purpose of the Study:
- To quantify fungal spore contamination in non-autoclaved and autoclaved corncob and aspen chip bedding.
- To determine the association between bedding type, fungal load, and animal health.
Main Methods:
- Fungal spore counts were determined for corncob and aspen chip bedding from two vendors.
- Bedding samples included both non-autoclaved and autoclaved conditions.
- Fungal species were identified using standard mycological techniques.
Main Results:
- Non-autoclaved corncob bedding yielded high fungal spore counts (700-5440 spores/g) of six species.
- Autoclaved corncob bedding and all aspen chip bedding (autoclaved or non-autoclaved) showed negligible spore counts.
- Fungal contamination was significantly higher in untreated corncob bedding.
Conclusions:
- Untreated corncob bedding poses a risk of significant fungal spore contamination.
- This contamination may lead to opportunistic diseases in healthy laboratory animals.
- Autoclaving is an effective method to eliminate fungal spores from bedding, ensuring animal safety.
