680. Bacteriophage as an Adjunct to Bacterial Interference
Session: Poster Abstract Session: Preventing Catheter Associated Infections
Friday, October 21, 2011
Room: Poster Hall B1
Background: Biofilms are integral to the pathogenesis of catheter-associated urinary tract infections, a leading healthcare-associated infection.  In vitro and in vivo, pre-coating urinary catheters with a non-pathogenic Escherichia coli HU2117 biofilm prevented attachment by several uropathogens, but not Pseudomonas aeruginosa. We hypothesized that adding anti-pseudomonal bacteriophage (phage) ΦE2005-24-39 would enhance ability of the E. coli HU2117 biofilm to impede urinary catheter colonization by P. aeruginosa in vitro.

Methods: Silicone catheter segments were exposed to one of four pretreatments (sterile media; E. coli alone; phage alone; E. coli plus phage), inoculated with 105 CFU/mL P. aeruginosa, then incubated for 24 to 72 hours in filter-sterilized human urine. Catheters were processed by rinsing, sonication, and plating for viable counts. Bacterial counts from three 1-cm subsegments of catheters were log-transformed and averaged per catheter. The lytic spectrum of phage ΦE2005-24-39 was tested using the spot test method against a panel of 27 P. aeruginosa clinical urinary isolates collected from a Houston-area hospital.

Results: In 24-hour experiments, catheter pretreatment with E. coli plus phage reduced the P. aeruginosa adherence to catheters from 5.0 X 104 on untreated catheters to 8.0 CFU/cm on pretreated catheters (3-log10 fewer, P < 0.001, ANOVA).  In extended time course experiments, the mean number of P. aeruginosa isolated from E. coli plus phage-pretreated catheters was over 3-log10 lower than that collected from untreated catheters at 24 (15.3 CFU/cm vs. 2.0 X 104 CFU/cm), 48 (2.8 CFU/cm vs. 2.0 X 105 CFU/cm), and 72 hours (38.3 CFU/cm vs. 1.2 X 106 CFU/cm; P < 0.05 for all, ANOVA). Neither E. coli alone nor phage alone decreased P. aeruginosa at any time point.  E. coli numbers were unaffected by phage.  Phage ΦE2005-24-39 lysed 14 of 27 clinical urinary isolates of P. aeruginosa.

Conclusion: The combination of a pre-established biofilm of E. coli HU2117 plus phage was synergistic in preventing catheter colonization by P. aeruginosa. The breadth of phage ΦE2005-24-39’s lytic spectrum in clinical isolates of P. aeruginosa is promising for potential application in clinical settings.


Subject Category: N. Hospital-acquired and surgical infections, infection control, and health outcomes including general public health and health services research

Kershena Liao1, Susan Lehman, Ph.D2, David J. Tweardy, MD1, Rodney Donlan, PhD3 and Barbara W. Trautner, MD, PhD4,5, (1)Medicine, Baylor College of Medicine, Houston, TX, (2)Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, GA, (3)Centers for Disease Control and Prevention, Atlanta,, GA, (4)Department of Veterans Affairs, Health Services Research & Development Center of Excellence, Michael E. DeBakey VA Medical Center, Houston, TX, Houston, TX, (5)Baylor College of Medicine, Houston, TX

Disclosures:

K. Liao, None

S. Lehman, None

D. J. Tweardy, None

R. Donlan, None

B. W. Trautner, None

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