Intra-ocular Predation of Fluoroquinolone-ResistantPseudomonas aeruginosaandSerratia marcescensby Predatory Bacteria

Abstract

AbstractEndogenous endophthalmitis caused by Gram-negative bacteria is an intra-ocular infection that can rapidly progress to irreversible loss of vision. While most endophthalmitis isolates are susceptible to antibiotic therapy, the emergence of resistant bacteria necessitates alternative approaches to combat intraocular bacterial proliferation. In this study the ability of predatory bacteria to limit intraocular growth ofPseudomonas aeruginosa, Serratia marcescens, andStaphylococcus aureuswas evaluated in a New Zealand White rabbit endophthalmitis prevention model. Predatory bacteriaBdellovibrio bacteriovorusandMicavibrio aeruginosavoruswere able to reduce proliferation of keratitis isolates ofP. aeruginosaandS. marcescens. However, it was not able to significantly reduceS. aureus, which is not a productive prey for these predatory bacteria, suggesting that the inhibitory effect onP. aeruginosarequires active predation rather than an antimicrobial immune response. Similarly, UV-inactivatedB. bacteriovoruswere unable to prevent proliferation ofP. aeruginosa. Together, these data suggestin vivopredation of Gram-negative bacteria within the intra-ocular environment.