Cyclic Di-GMP Signaling Contributes to Pseudomonas aeruginosa-Mediated Catheter-Associated Urinary Tract Infection

Bis-(3′-5′) cyclic dimeric GMP (c-di-GMP) controls the lifestyle transition between the sessile and motile states in many Gram-negative bacteria, including the opportunistic human pathogenPseudomonas aeruginosa . Under laboratory conditions, high concentrations of c-di-GMP decrease motility and promote biofilm formation, while low concentrations of c-di-GMP promote motility and decease biofilm formation. Here we sought to determine the contribution of c-di-GMP signaling to biofilm formation duringP. aeruginosa -mediated catheter-associated urinary tract infection (CAUTI). Using a murine CAUTI model, a decrease in CFU was detected in the bladders and kidneys of mice infected with strains overexpressing the phosphodiesterases (PDEs) encoded byPA3947 andPA2133 compared to those infected with wild-typeP. aeruginosa . Conversely, overexpression of the diguanylate cyclases (DGCs) encoded byPA3702 andPA1107 increased the number of bacteria in bladder and significantly increased dissemination of bacteria to the kidneys compared to wild-type infection. To determine which of the DGCs and PDEs contribute to c-di-GMP signaling during infection, a panel of PA14 in-frame deletion mutants lacking DGCs and PDEs were tested in the CAUTI model. Results from these infections revealed five mutants, three containing GGDEF domains (ΔPA14_26970 , ΔPA14_72420 , and ΔsiaD ) and two containing dual GGDEF-EAL domains (ΔmorA and ΔPA14_07500 ), with decreased colonization of the bladder and dissemination to the kidneys. These results indicate that c-di-GMP signaling influencesP. aeruginosa -mediated biofilms during CAUTI.IMPORTANCE Biofilm-based infections are an important cause of nosocomial infections, since they resist the immune response and traditional antibiotic treatment. Cyclic di-GMP (c-di-GMP) is a second messenger that promotes biofilm formation in many Gram-negative pathogens, includingPseudomonas aeruginosa . Here we determined the contribution of c-di-GMP signaling to catheter-associated urinary tract infection (CAUTI), an animal model of biofilm-based infection.P. aeruginosa with elevated levels of c-di-GMP during the initial infection produces an increased bacterial burden in the bladder and kidneys. Conversely, low concentrations of c-di-GMP decreased the bacterial burden in the bladder and kidneys. We screened a library of mutants with mutations in genes regulating c-di-GMP signaling and found several mutants that altered colonization of the urinary tract. This study implicates c-di-GMP signaling during CAUTI.