This product can also be purchased with the following package(s): 2003 Cytergy Courseware Subscription, Biofilm Science in Healthcare and Medicine 2003.

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More information about this product:

• Product Description
• Outline
• Author Biography

Also available with purchase of this courseware:

• Downloadable print copy of presentation slides (Adobe PDF)
• Glossary of key terms
• Bibliography of related publications
• List of online resources
• Technical support from instructor (at a discounted consulting rate available only through Cytergy)

Microbial biofilms are notoriously resistant to killing by antimicrobials and antibiotics. In addition to contributing to significant problems in industrial environments where control of biofouling is critical for process performance and water quality, biofilm resistance provides great challenges to medical practitioners and pharmaceutical developers when biofilms are responsible for chronic infections.

A variety of mechanisms are responsible for this resistance, including slow penetration, altered microenvironment, stress response, and persistence. Each of these mechanisms are discussed in detail.

Despite the challenges that biofilms pose, innovative strategies are available to control biofilms and mediate chronic infections. These strategies are presented in light of new science that comprises the leading edge of biofilm control practice and technology.

Length: 51 Minutes

Part 1: Introduction and Background

Goal: Illustrate that microorganisms in biofilms are difficult to control with conventional antimicrobial agents.

• Example of biofilm reduced susceptibility: glutaraldehyde
• Example of biofilm reduced susceptibility: tobramycin

Part 2: Mechanisms of Antimicrobial Resistance in Biofilms

Goal: Outline four hypothesized mechanisms that protect microorganisms in biofilms from killing.

• Slow penetration hypothesis
• van Leeuwenhoek quote regarding penetration in dental plaque
• Schematic diagram of microelectrode apparatus for measuring penetration
• Hydrogen peroxide penetration measurements
• Hydrogen peroxide penetration in a catalase-negative mutant biofilm
• Colony biofilms
• Picture of a colony biofilm
• Scheme for measuring penetration in colony biofilms
• Antibiotic penetration in colony biofilm – experimental data
• Summary of penetration mechanism – reaction-diffusion interaction
• Visual confirmation of antibiotic penetration – TEMS (near membrane)
• Visual confirmation of antibiotic penetration – TEMS (near air interface)
• Altered microenvironment hypothesis
• Oxygen concentration profiles
• Pattern of growth in colony biofilm – 1st method
• Pattern of growth in colony biofilm – 2nd method
• Pattern of growth in glass capillary biofilm - A
• Pattern of growth in glass capillary biofilm - B
• Pattern of growth in glass capillary biofilm - C
• Pattern of growth in glass capillary biofilm - D
• Summary of altered microenvironment mechanism – physiological heterogeneity
• Stress response hypothesis
• Catalase induction example 2D gels of antibiotic-treated biofilm
• Overall summary of four mechanisms
• Implications for controlling biofilms with antimicrobials

Part 3: Alternative strategies for controlling biofilms

Goal: Present several approaches that might be used for controlling biofilms in the future.

• Overview of options for microbial control
• Stop attachment option
• The non-stick surface and the old model of bacterial attachment
• How bacteria really stick
• Ways to stop attachment
• A mucin-protected surface
• An antimicrobial surface
• Stop growth option
• Biological pretreatment diagram
• Biological pretreatment example – Fleming and Griebe
• Biological pretreatment example – Wend et al
• Block matrix synthesis option
• Structure of alginate
• Images of alginate acetylation mutant
• Images of biofilm treated with clarithromycin
• Disrupt communication option
• Picture of furanone-containing polymer
• Promote detachment option
• Stoodley movie
• Summary of options for microbial control

Dr. Stewart is a professor of chemical engineering at Montana State University in Bozeman, Montana. He received his B.S. (1982) from Rice University, and M.S. (1985) and Ph.D (1988) degrees from Stanford University, all in chemical engineering. After finishing his doctoral studies, he was a NATO postdoctoral fellow at the Institut Jacques Monod in Paris, France and a senior chemical engineer at Bechtel Environmental in San Francisco, California. He joined the faculty of Chemical Engineering at Montana State in 1991 where he also serves as Deputy Director of the Center for Biofilm Engineering. Dr. Stewart research focuses on the control of detrimental microbial biofilms. He has authored or co-authored more than 75 technical publications and has directed projects for eleven industrial sponsors. He is the recipient of an NSF Career Award and has been honored at Montana State University with both of that institution’s top faculty awards for excellence in research and scholarship.

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