Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-3 (of 3 Records) |
Query Trace: Lehman SM[original query] |
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Bacteriophage-mediated control of a two-species biofilm of CAUTI-associated microorganisms in an in vitro urinary catheter model
Lehman SM , Donlan RM . Antimicrob Agents Chemother 2014 59 (2) 1127-37 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 1x103 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. |
Bacteriophages are synergistic with bacterial interference for the prevention of Pseudomonas aeruginosa biofilm formation on urinary catheters
Liao KS , Lehman SM , Tweardy DJ , Donlan RM , Trautner BW . J Appl Microbiol 2012 113 (6) 1530-9 AIMS: We hypothesized that pretreating urinary catheters with benign Escherichia coli HU2117 plus an antipseudomonal bacteriophage (PhiE2005-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. |
Bacteriophage cocktail for the prevention of biofilm formation by Pseudomonas aeruginosa on catheters in an in vitro model system
Fu W , Forster T , Mayer O , Curtin JJ , Lehman SM , Donlan RM . Antimicrob Agents Chemother 2009 54 (1) 397-404 Microorganisms develop biofilms on indwelling medical devices and are associated with device-related infections, resulting in substantial morbidity and mortality. This study investigated the effect of pretreating hydrogel-coated catheters with Pseudomonas aeruginosa bacteriophages on biofilm formation by P. aeruginosa in an in vitro model. Hydrogel-coated catheters were exposed to a 10 log10 PFU ml(-1) lysate of P. aeruginosa phage M4 for 2 hours at 37 degrees C prior to bacterial inoculation. The mean viable biofilm count on untreated catheters was 6.87 log10 CFU cm(-2) after 24 h. Pretreatment of catheters with phage reduced this value to 4.03 log10 CFU cm(-2) (p<0.001). Phage treatment immediately following bacterial inoculation also reduced biofilm viable counts (4.37 log10 CFU cm(-2) reduction, p<0.001). Regrowth of biofilms on phage-treated catheters occurred between 24 and 48 h, but supplemental treatment with phage at 24 h significantly reduced biofilm regrowth (p<0.001). Biofilm isolates resistant to phage M4 were recovered from phage-pretreated catheters. Phage susceptibility profiles of these isolates were used to guide the development of a five-phage cocktail from a larger library of P. aeruginosa phages. Pretreatment of catheters with this cocktail reduced the 48 h mean biofilm cell density by 99.9% (from 7.13 log10 CFU cm(-2) to 4.13 log10 CFU cm(-2), p<0.001), but fewer biofilm isolates were resistant to these phages. These results suggest the potential of applying phages, especially phage cocktails to the surfaces of indwelling medical devices for mitigating biofilm formation by clinically relevant bacteria. |
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