In the last few years, the number of eye surgeries for conditions including glaucoma and cataracts has greatly increased and with it, so has the number of potentially blinding intraocular infections.

In a recent study, researchers demonstrate using a mouse model that engineered nanosponges can be employed to protect eyes from infections caused by Enterococcus faecalis. Enterococcus faecalis contain a toxin known as cytolysin, which is found in approximately 50% of isolates that cause post-operative intraocular infections witnessed in the United States.

Details of the research are published in mSphere, an open-access journal of the American Society for Microbiology.
“Toxins are very important in bacterial ocular infections and current therapeutic strategies don’t really address them,” said principal study investigator Michelle Callegan, PhD, James P Luton Endowed Chair in Ophthalmology, Departments of Ophthalmology, Microbiology, and Immunology, University of Oklahoma Health Sciences Center, and the Dean A. McGee Eye Institute, Oklahoma City.

Intraocular infections happen when microorganisms are unintentionally introduced into the eye during, for instance, traumatic eye injuries, eye surgeries for glaucoma or cataracts, or eye injections to treat age-related macular degeneration. E. faecalis belongs to a subset of extremely pathogenic ocular bacterial infections whose pathogenesis is tied to their creation of pore-forming toxins.

Pore-forming toxins, main factors for retinal tissue damage in intraocular infections, comprise around 25% to 30% of bacterial cytotoxic proteins and include Streptococcus pneumonia pneumolysin, Staphylococcus aureus alpha toxin, and E. faecalis cytolysin, to list a few.

If an infection is in the cornea, the toxins from these bacteria will disrupt the epithelium, resulting in an ulcer. If the infection is in the inside of the eye, those toxins will cause disruption of the retina, a nonregenerative tissue which is essential to vision.
Dr. Michelle Callegan, Principal Study Investigator


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