Microorganisms from a patient or their environment may colonize indwelling urinary catheters, forming biofilm communities on catheter surfaces and increasing patient morbidity and mortality.
This study investigated the effect of pre-treating hydrogel-coated silicone catheters with mixtures of Pseudomonas aeruginosa and Proteus mirabilis bacteriophages on the development of single- and two-species biofilms in a multi-day, continuous-flow in vitro model using artificial urine. Novel phages were purified from sewage, characterized, and screened for their ability to reduce biofilm development by clinical isolates of their respective hosts. Screening data showed that Artificial Urine Medium (AUM) is a valid substitute for human urine for the purpose of evaluating uropathogen biofilm control by these bacteriophages. Defined phage cocktails targeting each of P. aeruginosa and P. mirabilis were designed based on biofilm inhibition screens. Hydrogel-coated catheters were pre-treated with one or both cocktails and challenged with approximately 1×103 CFU/mL of the corresponding pathogen(s). Biofilm growth on catheter surfaces in AUM was monitored over 72 to 96 h. Phage pre-treatment reduced P. aeruginosa biofilm counts by 4 log10CFU/cm2 (p≤ 0.01) and P. mirabilis biofilm counts by > 2 log10 CFU/cm2 (p ≤ 0.01) over 48 h. The presence of P. mirabilis was always associated with an increase in lumen pH from 7.5 to 9.5, and with eventual blockage of the reactor lines. Results of this study suggest that pretreatment of a hydrogel urinary catheter with a phage cocktail can significantly reduce mixed species biofilm formation by clinically relevant bacteria.
Lehman SM, Donlan RM. Are you the author?
Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, GA, 30333.
Reference: Antimicrob Agents Chemother. 2014 Dec 8. pii: AAC.03786-14.