Culture-Independent Microbiological Analysis of Foley Urinary Catheter Biofilms

Daniel N Frank,Shandra S Wilson,Norman R Pace,Allison L St Amand,Adam J Ratner

doi:10.1371/journal.pone.0007811

Abstract

BackgroundPrevention of catheter-associated urinary tract infection (CAUTI), a leading cause of nosocomial disease, is complicated by the propensity of bacteria to form biofilms on indwelling medical devices [1], [2], [3], [4], [5].Methodology/Principal FindingsTo better understand the microbial diversity of these communities, we report the results of a culture-independent bacterial survey of Foley urinary catheters obtained from patients following total prostatectomy. Two patient subsets were analyzed, based on treatment or no treatment with systemic fluoroquinolone antibiotics during convalescence. Results indicate the presence of diverse polymicrobial assemblages that were most commonly observed in patients who did not receive systemic antibiotics. The communities typically contained both Gram-positive and Gram-negative microorganisms that included multiple potential pathogens.Conclusion/SignificancePrevention and treatment of CAUTI must take into consideration the possible polymicrobial nature of any particular infection.

Highlights

Nosocomial urinary tract infections associated with catheterization occur in more than 1 million U.S patients each year [4,6,7]
Microscopic observations show that catheter biofilm-associated bacteria form polymicrobial microcolonies that are embedded within an amorphous, protective extracellular matrix [5,9,10,11,12]
Treatment is complicated by the resistance of biofilm-associated microorganisms to antibiotics that are otherwise effective in treating cells in the planktonic state [9]

Summary

Introduction

Nosocomial urinary tract infections associated with catheterization occur in more than 1 million U.S patients each year [4,6,7]. Diverse microbial species have been identified from catheter biofilms by microbiological culture [5,13,14,15]. Nickel et al [10] reported that multiple morphological types were observed to colonize Foley urinary catheters, only a small fraction of the attendant microorganisms could be detected by traditional microbiological culture. Biomass was removed from the internal cavities and external catheter surfaces by forcefully scraping material from each location into a microcentrifuge tube with a sterile scalpel (Materials and Methods).

Results

Conclusion