Wound Care #3

Front 1

Describe the Planktonic Model of bacteria

Back 1

Bacteria are relatively free-floating hydrophillic

There is minimal glycocalyx (protects bacteria by allowing it to attach to certain surfaces

Bacteria are susceptible to antibacterial agents such as antibiotics

This knowledge of antibiotic activity is based on planktonic bacteria--but most bacteria dont live this way they live in Biofilms

Front 2

Rough description of biofilms

Back 2

Bacteria attach to a surface & colonize--communicating with each other & forming biofilm in a wound making the wound more resistant to drugs

Front 3

Further description of biofilms

Back 3

1. Interacting communities of microorganisms bound to solid surface
-Occur at a given population density (Quorum) --or the minimum amt of bacteria necessary to make a biofilm

2. Coating of glycocalyx protect them and make them less vulnerable
-Enhancing drug resistance
-May even turn body's own defenses against it --such as fibrin?

3. May work synergistically to optimize replication
-Anerobes working with aerobes
-Different resistances of different organsisms
-Anerobic microbes and aerobic microbes convey resistance to each other & each live & are less affected by different drugs

Front 4

What is a good way to txt biofilms

Back 4

Aggressive debridement

Front 5

What is an example of a biofilm

Back 5

Dental Plaque : mainly streptococci

Colonizes fissures in and contact points bt the teeth

Dietary sucrose utilized to form the glycocalyx and assist adhesion to the tooth

Within this microbial biofilm by-products are trapped including acids that destroy the tooth enamel and dentin

How do we treat plaque--brushing and plaque pick= debridement

Front 6

What 2 characteristics do biofilms have that make them so resistant

Back 6

Tenacious survival
-Appear resistant to neutrophils
-They are affected by drug treatment but they "outlive" the course of the drug

Aggressive Virulence
-Some bacteria can slough off and restart infection after abx have ended

Glycocalyx blocks antibacterial compounds & secretes factors that help block PMN's (neutrophils)

Front 7

Are biofilms more destructive?

Back 7

Wounds with biofilm dont necessarily look any worse but their very difficult to close/heal

Wound also isnt necessarily becoming more lethal

Front 8

Describe mechansim progression of biofilm tolerance

Back 8

1. Slow penetration of Abx drug
2. Stress response by biofilm
-When biofilm is stressed they increase replication of bacteria to fight stress response

3. Altered microenvironment

4. Persisters are strong microbes that survive during antibiotic involvement & replicate after Abx have run their course

Front 9

Biofilm based wound care

Back 9

1. Debridement--frequent and aggressive

2. Selective biocides
-Silver, Iodosorb, Hydrofera blue

3. Antibiofilm agents
-Lactoferrin (binds to Fe- so bacteria cannot get enough Fe- to survive), Xylitol, Farnasol
-Plant products, fatty acid gel

4. Antibiotics
-Adjunct
-Use strong and long (high dose for a long time)

Assume biofilm in any chronic wound

Front 10

In depth look at polarity on the skin and what cells are affected when with specific polarity

Back 10

Different cells do respond differently to different polarities, and in THEORY, this could make a big difference regarding which pole to apply to a wound in a given phase of healing. For example, fibroblasts and keratinocytes seem to migrate to the cathode, while neutrophils move to the anode. The data on macrophages is equivocal. So, in the acute inflammatory phase, you might want to promote neutrophil action with the anodal stim.

However, you also need to remember that MOST studies indicate that the anti-bacterial effects of stim are associated with cathodal stim. So, you would want to use that first in any infected wound. Once you got the infection clear, you could switch to anodal stim, but you might not want to keep it there once the inflammatory phase was finished. Also recall that many empirical studies suggest that the polarity should be switched every 1-3 days or when you notice a plateau in progress with a given polarity. I am not sure there is any definitive answer for why this is. As a bit of bald speculation, one might say that normally healing wounds show an abrupt switch in skin voltage from negative to positive, so alternating polarities may be a way of continually "re-starting" the healing signal in a poorly healing wound