Bacteriophages are synergistic with bacterial interference for the prevention of Pseudomonas aeruginosa biofilm formation on urinary catheters.

AIMS

We hypothesized that pretreating urinary catheters with benign Escherichia coli HU2117 plus an antipseudomonal bacteriophage (ΦE2005-A) would prevent Pseudomonas aeruginosa biofilm formation on catheters--a pivotal event in the pathogenesis of catheter-associated urinary tract infection (CAUTI).

METHODS AND RESULTS

Silicone catheter segments were exposed to one of four pretreatments (sterile media; E. coli alone; phage alone; E. coli plus phage), inoculated with P. aeruginosa and then incubated up to 72 h in human urine before rinsing and sonicating to recover adherent bacteria. Pseudomonas aeruginosa adherence to catheters was almost 4 log(10) units lower when pretreated with E. coli plus phage compared to no pretreatment (P < 0.001) in 24-h experiments and more than 3 log(10) units lower in 72-h experiments (P < 0.05). Neither E. coli nor phage alone generated significant decreases.

CONCLUSIONS

The combination of phages with a pre-established biofilm of E. coli HU2117 was synergistic in preventing catheter colonization by P. aeruginosa.

SIGNIFICANCE AND IMPACT OF THE STUDY

We describe a synergistic protection against colonization of urinary catheters by a common uropathogen. Escherichia coli-coated catheters are in clinical trials; adding phage may offer additional benefit.