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______Bioburden - Biofilm ______
Wound Bed Bioburden A biofilm is an aggregate of microorganisms in which cells are stuck Management: to each other and/or to a surface. These & adherent cells are frequently embedded within a self-produced matrix of March 16, 2016 Elevated extracellular polymeric substance (EPS). Biofilm EPS, which is also referred to as William Tettelbach, MD, FACP, FIDSA Proteases "slime," is a polymeric jumble of DNA, System Medical Director of Wound & proteins and polysaccharides. Hyperbaric Medicine Services
______Bioburden - Biofilm ______Bioburden - Biofilm ______
Formation of a biofilm begins with the attachment of free-floating microorganisms to a surface. These first colonists adhere to the surface initially through weak, reversible van der Waals forces. If not immediately separated from the surface, they can anchor themselves more permanently using cell adhesion structures such as pili.
Exhibits high levels of antibiotic, host, pH and disinfecting resistance. 1000x greater antibiotic resistance than planktonic cells.
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______Bioburden - Biofilm ______Bioburden - Biofilm ______
Hypoxic environment inhibits: Oxidative burst ATP dependent reactions Collagen deposition
______Reduce Bioburden ______Reduce Bioburden ______
Topical Therapy
Bactericidal Noncytotoxic Avoid pressures for emergence of antibiotic resistance, e.g., - Hypochlorous acid - Sodium Hypochlorite - Surfactants / PHMB
WOUNDS 2014;26(12):342-350 Journal of Hospital Infection (1999) 41: 59-70
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______HYPOCHLOROUS ACID DISRUPTS BIOFILM______Bioburden - Biofilm ______
S. aureus biofilms were produced by circulating nutrient broth through Tygon® tubing for 4-12 hours. 5-10 ml of S. aureus culture (108 colony-forming unit [CFU]/ml) was circulated through the tubing. Biofilms were treated with hypochlorous acid for 1, 3, 5, 7, and 10 minutes. After each treatment, 2 cm 2 pieces of tube were cut and neutralized, and bacterial numbers, residual protein, and carbohydrate content measured.
Martin C. Robson, MD . November/December 2014 Today’s Wound Clinic - Volume 8 Issue 9.
______Beyond Bioburden ______Bioburden Elevated Proteases______
Systemic Therapy Proteases: Active infection Enzymes that break down proteins into peptides and amino acids. - e.g., periwound cellulitis Major proteases Critical Colonization - matrix metalloproteinases (MMPs) , e.g., collangenase - serine proteases, e.g., elastase. - Clinical correlation required In general, different wound-related proteases act on extracellular matrix - Wound stalled or increasing in size (ECM) and connective tissue proteins such as collagen, gelatin, proteoglycans and elastin.
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______Roles of Protease in Normal Wound Healing______Protease Activity in Wounds______
There is a burst of protease activity at the start of acute wound healing.
Protease activity typically peaks in 3 days and declines to low levels in 1 week.
Protease Activity - Bacteria/Infection - Treatment Protease-Modulating Dressings ______
Protease activity is the best available biochemical marker Collagen based for predicting poor wound - Targets collagenase healing of both acute and chronic wounds. Calcium alginate Localized bleeding following - Binds & inactivates elastases debridement stimulates influx of alpha-2-macroglobin Silver containing (A2M), a chemical agent that acts as a protease inhibitor, - Displaces zinc ion necessary for MMPs to function 1 thus reducing proteolytic - Decreases bacterial levels potentially reducing host and activity.1, 2 bacterial protease production 2
1. Walker M, Bowler PG, Cochrane CA. In vitro studies to show sequestration of matrix metalloproteinases by silver-containing wound care products. 1. Schultz GS et al, Harding K et al: Wound bed preparation: a systematic approach to wound management. Wound Repair Regen, 2003. 11 (suppl 1): S1 – 28, 2003. Ostomy Wound Manage 2007; 53(9): 18-25. 2. Kainulainen V et al, heparan sulfate proteoglycans, maintain the proteolytic balance of acute wound fluids. J Biol Chem 273 (19): 11563 -11569, 1998. 2. Widgerow,AD. Chronic wound fluid—thinking outside the box. Wound Repair Regen 2011; [Epub ahead of print]
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Thank you for your time
The cost of ineffective wound treatment is estimated to be $20-25 billion annually
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