Michelle C. Callegan, PhD, FARVO

Research Summary

Our research involves the identification and characterization of the molecular mechanisms involved in vision loss and inflammation in bacterial endophthalmitis, an infection of the posterior segment of the eye. The severity of this type of infection ranges from a mild intraocular inflammation and full recovery to irreversible blindness. Virulent bacteria cause the latter type of endophthalmitis and, despite appropriate therapeutic and surgical intervention, typically results in significant loss of vision (or the eye itself) within 1 to 2 days. Bacterial toxins are collectively responsible for a majority of the retinal function loss associated with endophthalmitis. The explosive inflammatory response is also likely responsible for a good percentage of this vision loss. Our research includes analyses of retinal function in infected eyes with toxin-producing and avirulent strains, the interactions of toxins with the retina, bacterial triggers for the explosive intraocular inflammatory response, the mechanisms of retinal cell toxicity and death leading to vision loss during infection, the mechanisms involved in blood-ocular barrier permeability during infection, and the role of diabetes in bloodstream-to-eye spread of bacteria. Based on these studies, we are developing novel target-based therapeutics to be used with antibiotics, anti-inflammatory, and surgical regimens in order to preserve vision during this blinding disease. Our research program provides instructional backgrounds, mastery of techniques, and publications in the areas of ophthalmology, microbiology, immunology, and vision neuroscience.