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Updated: Aug 10, 2026
Intravitreal Injection and Quantitation of Infection Parameters in a Mouse Model of Bacterial Endophthalmitis
Published on: February 6, 2021
Fungal endophthalmitis. An experimental study with a review of 17 human ocular cases
T W McGuire1, J D Bullock, J D Bullock
1Wright State University School of Medicine, Dayton, OH.
Abstract:
Pseudallescheria boydii is an opportunistic fungus that is histologically indistinguishable from Aspergillus fumigatus. Pseudallescheria boydii has been reported to cause endophthalmitis, orbital cellulitis, and corneal ulceration and is, thus, important to the ophthalmologist. A clinical review of 17 patients with P boydii ophthalmic infections is presented. In addition, animal models of endophthalmitides caused by A fumigatus and P boydii were created and compared. Dutch-Belted rabbits used for the experimental models were immunosuppressed with methylprednisolone acetate (Depomedrol). Exogenous and endogenous models of P boydii endophthalmitis were created in immunocompetent and immunosuppressed animals. An exogenous model of A fumigatus endophthalmitis was created in immunocompetent and immunosuppressed animals for comparison. The clinical and histopathologic features of A fumigatus and P boydii endophthalmitis are indistinguishable in the immunocompetent and immunosuppressed exogenously infected rabbits. Endogenous P boydii endophthalmitis has a similar fundus appearance to that caused by Nocardia asteroides.
Insights
Pseudallescheria boydii causes eye infections that look similar to Aspergillus fumigatus infections in rabbits. This study highlights the importance of identifying P. boydii in ophthalmic cases.
Area of Science:
- Ophthalmology
- Mycology
- Infectious Diseases
Background:
- Pseudallescheria boydii is an opportunistic fungus causing ophthalmic infections.
- It is histologically indistinguishable from Aspergillus fumigatus.
- P. boydii infections are significant for ophthalmologists.
Purpose of the Study:
- To review clinical cases of P. boydii ophthalmic infections.
- To compare P. boydii and A. fumigatus endophthalmitis in animal models.
- To evaluate the impact of immunosuppression on these infections.
Main Methods:
- Clinical review of 17 patients with P. boydii eye infections.
- Creation of experimental endophthalmitis models in Dutch-Belted rabbits.
- Immunosuppression of rabbits using methylprednisolone acetate.
- Comparison of exogenous P. boydii and A. fumigatus models in immunocompetent and immunosuppressed rabbits.
- Creation of endogenous P. boydii endophthalmitis models.
Main Results:
- Clinical and histopathologic features of P. boydii and A. fumigatus endophthalmitis were indistinguishable in exogenously infected rabbits, regardless of immune status.
- Endogenous P. boydii endophthalmitis presented with a fundus appearance similar to Nocardia asteroides infections.
Conclusions:
- P. boydii and A. fumigatus cause clinically and histopathologically similar endophthalmitis in rabbits.
- Immunosuppression does not alter the indistinguishable presentation of these fungal infections.
- Endogenous P. boydii endophthalmitis may mimic other microbial infections.
