Primary Faculty

Michelle C. Callegan, PhD

Michelle C. Callegan, PhD

George Lynn Cross Research Professor


Ph.D. : 1995, Louisiana State University Medical Center

Awards and Honors:

George Lynn Cross Research Professorship, University of Oklahoma
Dean A. McGee Endowed Chair in Ophthalmology
Edith Kinney Gaylord Presidential Professorship, University of Oklahoma

Research Interests:

Molecular Pathogenesis of Bacterial Ocular Infections

Contact Information:

Office: DMEI PA418


Lab Website:

Research Interests:

Bacillus cereus is an insidious ocular pathogen, causing a rapid and fulminant endophthalmitis that invariably leads to blindness within one to two days. Despite aggressive antibiotic and surgical intervention, B. cereus endophthalmitis has a relatively poor prognosis. There is presently no universal therapeutic regimen for successful treatment of Bacillus and other forms of severe bacterial endophthalmitis.


Clinicians and researchers have attributed the virulence of B. cereus and other virulent endophthalmitis pathogens to toxin production. For Bacillus however, toxins are not the complete story. Bacillus is also motile, and migrates throughout the eye in a short period of time, inciting an explosive intraocular inflammatory response in its wake. This inflammatory response is likely the result of breakdown of the protective blood ocular barrier in response to infection, the triggers of which are presently being investigated. In addition, during infection, retinal architecture collapses and retinal function drops precipitously.


We hypothesize that either Bacillus or its toxins (or both) target specific cells in the retina that are involved in protection by the blood ocular barrier (retinal pigment epithelial [RPE] cells) or retinal function itself (Muller cells, photoreceptor cells), leading to the detrimental effects observed during infection.


Since the ultimate goal of therapy is to kill offending organisms, arrest inflammation, and preserve organ function, an important goal is to develop more effective therapeutic regimens, with newer antibiotics, anti-inflammatory agents, and/or novel drugs that target bacteria- and host-derived virulence factors in order to prevent blindness. 

Current Lab Personnel:

Roger Astley, Research Technician, Pathogenesis of Endophthalmitis
Phillip Coburn, Ph. D., Assistant Professor of Research, Ocular Bacterial Pathogenesis
Md Huzzatul Mursalin, Graduate Student

Selected Publications: