University-wide, Talks & Lectures, Open to the Public
8 Dec 2021
Zoom Webcast

The Approaching Zero Seminar Series: Characterizing Biofilms on Intravascular Catheters as Microbial Communities

Rodney Donlan, Centers for Disease Control

Abstract

Intravascular catheters (IC) are indwelling medical devices used for administering fluids, medications, parenteral nutrition, and blood products; to monitor hemodynamic status; and to provide hemodialysis. Use of intravascular catheters in patient care may be associated with increased risk of central line associated bloodstream infections (CLABSI), and antimicrobial resistance. Microorganisms originating from the patient’s microbiome (skin, oral, gastrointestinal tract), the environment, contaminated catheter hubs or needleless connectors, or from hematogenous seeding may colonize the catheter to develop a biofilm. Biofilms are sessile microbial communities composed of microbial cells and an extracellular matrix (termed extracellular polymeric substance or EPS), that may contain specific polysaccharides, proteins, and extracellular DNA. Microbial attachment to the catheter will be influenced by the physical and chemical characteristics of the catheter surface, the composition of the host-produced “conditioning film”, composition and fluid dynamics of the aqueous medium in the catheter, and properties of the microbial cell surface. The anatomical site of catheter insertion may also influence biofilm formation because the catheter insertion site has been reported to affect the composition of catheter or needleless connector microbial communities. The microorganisms comprising IC biofilms are diverse and the microbial communities on these devices may be polymicrobic, containing multiple taxa. Microbial communities may be characterized with respect to the microbial diversity, the ways that member organisms interact, levels of organization, temporal progression, and resilience or stability. Recent studies have utilized culture-independent methods, based on amplification of the 16S rRNA gene from IC biofilm samples to provide evidence that these biofilm microbial communities may be highly diverse, containing many organisms that have not previously been detected using traditional culture methods. Microorganisms in the IC biofilm interact with one another, the substratum, and the host environment to produce a structure (the biofilm EPS) which is critical in the adhesion, dispersal, tolerance to antimicrobial agents, and the spread of antimicrobial resistance genes. The host environment may also influence biofilm structure. Catheters coated with antimicrobial or anti-biofilm agents can reduce but not prevent microbial attachment and biofilm formation for short periods of time. Novel technologies are needed and should be evaluated in animal model systems or in clinical studies using methods that accurately quantify microbial attachment to the catheter surface.

Biography

Dr. Rodney Donlan is the Team Leader for the Biofilm and Water Quality Applied Research Team in the Division of Healthcare Quality Promotion at the Centers for Disease Control and Prevention in Atlanta, GA. He joined the CDC in 1998 as a research microbiologist to create the Biofilm Laboratory in the Division of Healthcare Quality Promotion. The Biofilm Laboratory performs applied public health research to investigate the role of microbial biofilms in healthcare-associated infections and antimicrobial resistance and evaluate new methods for their detection and control. He has mentored many students and fellows since joining CDC and has developed numerous research collaborations with industrial partners and academic centers. Prior to joining CDC he was employed by Calgon Corporation as a Research Associate and by Philadelphia Suburban Water Company as Supervisor of Laboratories and Technical Services. He is board certified in microbiology by ASCP, a Registered Microbiologist, a life member of the American Water Works Association, and a member of the American Society for Microbiology since 1976. He received his B.S. and M.S. degrees from Virginia Tech and his Ph.D. from Drexel University.

 

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