SEP 02, 2015 7:30 AM PDT

Keynote: The Science of Biofilm Control with Antimicrobial Agents

Speaker

Abstract

This presentation will discuss fundamental physical, chemical, and biological concepts important to understanding control of detrimental biofilms. Four phenomena that are important in the action of antimicrobial agents against a biofilm will be examined: diffusion, hydrodynamics, physiology, and the genetic basis of biofilm tolerance. Direct microscopic observation of facile diffusion of a fluorophore-tagged antibiotic into biofilm is contrasted with failure of hydrogen peroxide, a much smaller molecule, to penetrate. These seemingly contradictory observations can be reconciled by recognizing that penetration of antimicrobials into biofilms is governed by the balance of reaction and diffusion. Time-lapse imaging of biofilms subjected to antimicrobial treatments reveals that in many cases these treatments do not remove the biofilm. In instances where removal is observed it is clear that forces applied by the flowing fluid are an important component of the removal process. Oxygen and nutrient concentration gradients within biofilms lead to stratified patterns of anabolic activity. For example, microelectrode technology demonstrates the presence of anoxic niches in biofilms exposed to aerated medium. Staining techniques reveal that the same biofilm can harbor, in distinct spatial niches, growing and dormant cells. Variation in the physiological activity is accompanied by alterations in susceptibility to antimicrobials. More specifically, patterns of gene expression within biofilms in response to local environmental chemistry are hypothesized to contribute to protection from antimicrobial agents. As an illustrative example, a transcriptomic and mutant susceptibility analysis is presented. The biofilm transcriptome is found to be enriched for genes associated with oxygen limitation and stationary phase growth. Mutants in regulatory genes associated with the response to growth arrest or hypoxia exhibit diminished tolerance to an antibiotic when grown as biofilms. These analyses suggest a model in which overlapping starvation and stress responses control the expression of multiple genes that are activated in mature biofilms and contribute to biofilm antimicrobial tolerance. The biofilm defense against biocides and antibiotic is multifactorial and so requires integrated and interdisciplinary science. Learning Objectives - Explain two general mechanisms of biofilm protection from antimicrobial agents - Contrast killing and removal processes in biofilms - Discuss fundamental phenomena important in the interaction of an antimicrobial agent with biofilm


Show Resources
You May Also Like
FEB 15, 2023 7:00 AM PST
FEB 15, 2023 7:00 AM PST
Date: February 15, 2023 Time: 7:00am (PST), 10:00pm (EST), 4:00pm (CET) While not all microscopy samples can fluoresce, all can scatter light, and this scattered light can be imaged. This ha...
AUG 24, 2022 7:00 AM PDT
AUG 24, 2022 7:00 AM PDT
Date: August 24, 2022 Time: 7:00am (PDT), 10:00pm (EDT), 4:00pm (CEST) Light field microscopy was first introduced in 2006, and allows users to capture the 4D light field within the microsco...
OCT 12, 2022 9:00 AM PDT
C.E. CREDITS
OCT 12, 2022 9:00 AM PDT
Date: October 12, 2022 Time: 9:00am (PDT), 12:00pm (EDT), 6:00pm (CEST) The microbiome of every food product is incredibly diverse and can include everything from innocuous background flora...
OCT 13, 2022 9:00 AM +08
OCT 13, 2022 9:00 AM +08
First Broadcast: Date: October 12, 2022 Time: 8:00am PDT, 11:00am EDT Second Broadcast: Date: October 12, 2022 Time: 9:00am SGT The new Embedded CryoSPARC Live, now fully integrated with t...
AUG 10, 2022 10:00 AM PDT
AUG 10, 2022 10:00 AM PDT
Date: August 10, 2022 Time: 10:00am PDT, 1:00pm EDT The global pandemic has increased focus and scrutiny on molecular diagnostic assay development, resulting in a need for assays that provid...
NOV 09, 2022 8:00 AM PST
C.E. CREDITS
NOV 09, 2022 8:00 AM PST
Date: November 09, 2022 Time: 8:00am (PST), 11:00am (EST), 5:00pm (CET) The field of cell and gene therapy is rapidly growing. In particular, the use of lentiviruses in CAR-T applications is...
SEP 02, 2015 7:30 AM PDT

Keynote: The Science of Biofilm Control with Antimicrobial Agents



Show Resources
Loading Comments...
Show Resources