Catalase Activity is Critical forProteus mirabilisBiofilm Development, EPS Composition, and Dissemination During Catheter-Associated Urinary Tract Infection

Abstract

Proteus mirabilis is a leading uropathogen of catheter-associated urinary tract infections (CAUTIs), which are among the most common healthcare-associated infections worldwide. A key factor that contributes to P. mirabilis pathogenesis and persistence during CAUTI is the formation of catheter biofilms, which provide increased resistance to antibiotic treatment and host defense mechanisms. Another factor that is important for bacterial persistence during CAUTI is the ability to resist reactive oxygen species (ROS), such as through the action of the catalase enzyme. Potent catalase activity is one of the defining biochemical characteristics of P. mirabilis, and its single catalase gene (katA) was recently identified as a candidate fitness factor for UTI, CAUTI, and bacteremia. Here we show that disruption of katA results in increased ROS levels, increased sensitivity to peroxide, and decreased biofilm biomass. The biomass defect was due to a decrease in extracellular polymeric substances (EPS) production by the ΔkatA mutant, and specifically due to reduced carbohydrate content. Importantly, the biofilm defect resulted in decreased antibiotic resistance in vitro and a colonization defect during experimental CAUTI. The ΔkatA mutant also exhibited decreased fitness in a bacteremia model, supporting a dual role for catalase in P. mirabilis biofilm development and immune evasion.

Redox-mediated inactivation of the transcriptional repressor C3600 makes uropathogenicEscherichia coliexquisitely resistant to reactive chlorine species

“…S3). A recent study reported an interdependence of resistance to ROS, biofilm formation and pathogenicity in Proteus mirabilis, another leading uropathogen (92). Similarly, EAEC adherence to epithelial cells is stimulated by infiltrating neutrophils presumably due to the presence of additional defense mechanisms to oxidative burst, which are therefore considered beneficial for their pathogenicity (93).…”

Metabolic interplay betweenProteus mirabilisandEnterococcus faecalisfacilitates polymicrobial biofilm formation and invasive disease

“…All samples were stored at -20C until end point analysis. Total eDNA was determined using the PicoGreen assay (Invitrogen, MP07581), total carbohydrate was determined by phenol-sulfuric acid method as described previously, and total protein was determined via Pierce BCA protein assay kit (Thermofisher, Cat# 23250), all following the manufacturer's instructions (57,58). For comparison of wild-type and mutant polymicrobial biofilm protein content, biofilms were established in 24-well plates and grown for 24 hours at 37°C, after which three wells were scrapped, pooled, and analyzed as described above.…”

“…Biofilms were established as described above in 24-well plates and incubated for 20 hours at 37°C, with the exception that an entire 24-well plate was used for each inoculum. Compositional analysis was performed as previously described for P. mirabilis (57). Briefly, supernatants were removed and all wells of the entire 24-well plate were gently resuspended into a total volume of 3 mL of sterile Milli-Q water, an aliquot was removed from this total volume to generate the biofilm suspension fraction (BS).…”