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2019 OMIG Abstract

Pseudomonas aeruginosaCorneal Perforation Requires the LasR Quorum Sensing Regulator and Can be Prevented by Predatory Bacteria in a Rabbit Model Of Microbial Keratitis

Robert M.Q. Shanks, PhD1, Eric G. Romanowski, MS1, Annie Yan, MS 1, Bryn Brazile, PhD1,
Kira Lathrop, MAMS1, Ian Sigal, PhD1, and Daniel Kadouri, PhD 2
1The Charles T. Campbell Laboratory, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA; 2Department of Oral Biology, Rutgers School of Dental Medicine, Newark, NJ

Purpose: Pseudomonas aeruginosa keratitis (PAK) is a severe ocular infection that can lead to perforation of the cornea. In this study we evaluated the role of bacterial quorum sensing in generating corneal perforation and bacterial proliferation and tested whether co-injection of the predatory bacteria Bdellovibrio bacteriovorus could alter the clinical outcome.

Methods: Rabbit corneas were intrastromally infected with ~2500 CFU of P. aeruginosa strain PA14 or an isogenic lasR mutant, and co-injected with PBS or B. bacteriovorus. After 24 h, eyes were evaluated for clinical signs of infection, a subset was analyzed by OCT, and another subset was homogenized for CFU enumeration.

Results: We observed that 59% of corneas infected by wild-type PA14 presented with a corneal perforation (n=22), whereas 0% of lasR mutant infected corneas perforated (n=12). PA14 infected corneas that were co-infected with B. bacteriovorus did not perforate (4.5%, n=22). The lasR mutant had a proliferation defect with 16-fold fewer bacteria than the wild type per cornea (p<0.01) and B. bacteriovorus reduced corneal P. aeruginosa by 6.5 fold (p<0.01).

Conclusion: These studies indicate a role for bacterial quorum sensing in the ability of P. aeruginosa to proliferate and cause perforation of the rabbit cornea. Additionally, this study suggests that predatory bacteria can reduce the virulence of P. aeruginosa in an ocular infection model.

Disclosure: N


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