Differences in the pathogenesis of bacteria isolated from contact-lens-induced infiltrative conditions

Purpose: The purpose of this study was to examine the ability of Gram-negat ive bacteria isolated from the noninfectious condition contact-lens-induced acute red eye (CLARE) and infectious microbial keratitis (MK) to infect th e eyes of mice. Methods: One cornea of BALB/c mice was scratched with a needle and 5 x 10(6 ) bacteria applied. Bacterial types used were Pseudomonas aeruginosa, Haemo philus influenzae, Serratia marcescens, Stenotrophomonas moltophilia and Ae romonas hydrophilia. The mice were killed after 1,4 and 24 h and examined b y slit lamp, histology and microbiology. Results: GLARE strains were unable to infect the mouse corneas. The eyes in oculated with the GLARE strains had low levels of polymorphonuclear leucocy tes (PMN) in the stroma. All eyes that had MK contained bacteria and large numbers of PMN after 24 h. Conclusions: The development of GLARE or MK is dependent on the type of bac teria with specific bacterial types being responsible for GLARE or MK.