A. castellanii and P. aeruginosa mutually exacerbate damage to corneal cells during coinfection

Abstract

ABSTRACT Microorganisms that are involved in microbial invasion keratitis infiltrate the cornea and cause eye pain. Despite the administration of antimicrobial treatment, patients with amoebic keratitis develop bacterial coinfections. Pseudomonas aeruginosa infection accounts for 50% of the reported bacterial coinfections in these patients. However, the role of pathogenic bacteria in amoeba-induced corneal damage remains unclear. In our current study, we conducted assays to examine cytopathic effects and observed increased corneal cell damage in the group with secondary P. aeruginosa infections. Imaging revealed that the presence of A. castellanii enhanced the accumulation of P. aeruginosa in areas of cell monolayer leakage. We demonstrated that treatment of P. aeruginosa with amoeba-soluble antigen resulted in higher adhesion ability, increased biofilm formation, and more severe corneal cell damage. Overall, this research significantly contributes to our understanding of the risk of P. aeruginosa coinfection in the progression of Acanthamoeba keratitis. IMPORTANCE At the National Cheng Kung University Hospital, numerous cases of amoebic keratitis had been identified with concurrent bacterial infections. Among these bacterial coinfections, Pseudomonas aeruginosa accounted for 50% of the reported cases. However, the impact of pathogenic bacteria on amoeba-induced corneal damage remains unclear. In our study, we successfully demonstrated that P. aeruginosa accumulated on the Acanthamoeba castellanii surface and caused more severe corneal damage. We also indicated that the exposure of P. aeruginosa to amoeba-soluble antigens enhanced its adhesion ability, promoted biofilm formation, and led to more severe corneal cell damage. These findings significantly contributed to our understanding of the risk associated with P. aeruginosa coinfection in the progression of amoeba keratitis.