Harnessing microbial-derived metabolites in the urinary tract to prevent infection induced catheter encrustation.

Abstract

Proteus mirabilis is a predominant cause of catheter associated urinary tract infection (CAUTI), and a key virulence factor is its urease enzyme which can increase urine pH and form urinary stones, causing catheter blockage and facilitating bacteremia. The only FDA approved urease inhibitor, acetohydroxamic acid (AHA), has side effects that limit its clinical use, necessitating new approaches to target urease activity. We previously discovered that common urinary tract colonizers modulate P. mirabilis urease activity via secreted small molecules. In this study, we conduct a metabolomics analysis of six modulatory bacterial species to reveal urease-dampening metabolites. Of 31 candidate metabolites, seven reproducibly decrease P. mirabilis urease activity. All seven metabolites dampen urease activity in other urease-positive bacterial species, suggesting conserved targets. Six of the metabolites act via mixed inhibition of the urease enzyme. One metabolite, D-imidazole lactate, exhibits a non-competitive mechanism of urease inhibition along with antimicrobial activity and repression of the urease operon in P. mirabilis. Metabolite combinations with AHA demonstrate synergistic activity and prevent catheter encrustation in an in vitro model for CAUTI. Prophylactic use of urease dampening metabolites with AHA could improve the efficacy of antimicrobial treatment against catheter biofilms.