PowerPoint Presentation
Bugs, Drugs & Silver Bullets
Lindsay Kalan, PhD
PCN West
May 28, 2015
This is a picture of a multi-drug resistant psuedomonasa isolated from a wound and growing as a biofilm.
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Faculty/Presenter Disclosure
Faculty: Dr. Lindsay Kalan
Relationships with commercial interests:
Other: Employee of Exciton Technologies Inc. (Manufacturer of Exsalt Wound Dressings)
This program has received in-kind support from Exciton Technologies in the form of clinical information tools and literature.
Potential for conflict(s) of interest:
Dr. Lindsay Kalan has received salary from Exciton whose product(s) will being discussed in this program.
Exciton Technologies Inc develops and benefits from the sale of a product that will be discussed in this program: Exsalt SD7 and T7 Wound Dressings with Ag Oxysalts.
There is a potential for bias in slides 40-44. This has been mitigated by providing full references, referring to scientific names and providing materials/methods and raw data for experimental results.
This slide must be visually presented to the audience AND verbalized by the speaker.
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Disclosure of Commercial Support
This program has received in-kind support from Exciton Technologies in the form of clinical information tools and literature.
Potential for conflict(s) of interest:
Dr. Lindsay Kalan has received salary from Exciton whose product(s) will being discussed in this program.
Exciton Technologies Inc develops and benefits from the sale of a product that will be discussed in this program: Exsalt SD7 and T7 Wound Dressings with Ag Oxysalts.
This slide must be visually presented to the audience AND verbalized by the speaker.
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Mitigating Potential Bias
There is a potential for bias in slides 40-44. This has been mitigated by providing full references, referring to scientific names and providing materials/methods and raw data for experimental results.
This slide must be visually presented to the audience AND verbalized by the speaker.
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Learning Objectives
Antibiotic Resistance and Wound Infection
Biofilms 101
Biofilms in chronic wounds
The use of silver as a topical antimicrobial
Applying antibiotic stewardship and new research knowledge to clinical methodology and practice
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For the education, list world leaders in silver dressings and the type of silver they utilize.
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The Cost of a Wound
$ 3.9 Billion CND/year more than care for stroke
30-50% of all health care involves wounds
In the US >$25 Billion USD/year1
30% of DPN cost go towards wounds ($10B/yr)
Additional $35-45B/yr spent on SSI2
Dont include indirect and intangible costs associated with quality of life and society as a whole
1Sen et al. 2009. Human Skin Wounds: A Major Snowballing Threat to Public Health and the Economy
2Scott, R.D. 2009. The Direct Medical Cost of Hospital Acquired Infection in US Hospitals and the Benefits of Prevention
87% of DFU are infected.
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Antibiotic Resistance
In 2013 - 23 million antibiotic Rx were written in Canada
45% respiratory, 16% upper respiratory, 14% UTI, 10% ear, 20% other
Many of these infections may not have required antibiotic therapy (eg. virus)
The CDC estimates >$20B in excess health care costs
>$35B in other societal costs and >8 million additional hospital days
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No ESKAPE
http//www.sciencephoto.commedia11428enlarge
http://phil.cdc.gov/phil/home.asp
Staphylococcus aureus
Klebsiella pneumoniae
Acinetobacter baumannii
Pseudomonas aeruginosa
Enterobacter spp.
Enterococcus faecium
Plus: Totally drug resistant TB, C. difficile, N. gonorrhoeae and more
VRE
MRSA/VRSA
CRE
CRE
MDRPA
MDRAB
The Infectious Disease Society of America has recognized these pathogens as the most dangerous in the treatment of ongoing bacterial infections.
ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species; clockwise from top centre) are considered the greatest threat in the hospital setting due to their significant presence (responsible for more than 40% of infections in intensive care units) and their exceptional ability to evade the lethal effects of antibiotics.
Generally these pathogens infect opportunistically via open wounds, catheters, breathing tubes. As such they are the causes of respiratory tract infections and urinary tract infections
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Why is this happening?
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Q. Where do antibiotics come from?
A. Bacteria
http://microbewiki.kenyon.edu/index.php/Streptomyces
Environmental microbes make antibiotics and have self resistance which can be transferred to pathogens
Alexander Flemings Nobel Laureate Speech
He defined the term antibiotic as a chemical agent produced by one microorganism to destroy another microorganism
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The Antibiotic Resistome
Introduce concept of resistome. Antibiotic resistance genes are ubiquitous. They are found in the organisms that produce the antibiotic as protection mechanisms, they are found in clinical pathogens, they are found in the environment in organisms that neither produce the antibiotic or cause infection. Finally, we see this idea of precursor genes that could be future indicators of resistance, as there is reason to believe resistance genes have evolved from genes involved in basic cellular processes.
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Clinical Pathogens
Precursor Genes
Resistance Genes
Producers
Environmental Organisms
Antibiotic Resistance is Natural
Bacteria in these caves have been isolated for an estimated 4 million years
They are on average resistant to 3-4 clinically used antibiotics
Sealed from the surface for 4 million years. Some resistant to 14 different antibiotics.
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Glycopeptide Antibiotics
Front-line treatment for serious Gram-positive infection (MRSA)
Two used clinically vancomycin and teicoplanin
Three second-generation televancin (2009), oritovancin, dalbavancin (2014)
All have the same primary mechanism of action
Resistance exists for all
Use glycopeptides as an example of this.
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How Old is it?
Probe DNA extracted from permafrost cores for resistance genes
6 permafrost soil cores from eastern Beringia (Yukon)
25.3ky (stadial)
80-90ky (interstadial)
740ky (interglacial)
DCosta et al. 2011. Nature
Resistance mechanism consistent with contemporary (VRE) clinical pathogens discovered
Explain that we probed DNA, found a full length ORF for vanA. Had is synthesized and looked at structure and enzyme activity compared to contemporary vanAs
Spiked outside with GFP expressing E. coli to ensure no outside contamination. Able to get a full length open reading frame of the vanA which resulted in 4 unique sequences with high identity to modern VanAs (
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Resistance is Widespread and Diverse
VRE vanA
VRE vanB
S. coelicolor
A. balhimycina
S. toyocaensis
P. apiarius PA-B2B
S
R
H
A
X
Y
Z
S
R
H
B
X
W
Y
K
S
R
H
ASc
X
J
K
H
ASt
X
S
R
murF
S
R
H
APa
X
Y
Z
W
S
R
H
ABh
X
ABh
Clinical Pathogens
Producers
Environ-mental
VVE
H
A
X
Y
Z
VVE strains have recently been isolated from patients across Canada. They have high level resistance that evolves after vancomycin administration and include wound isolates
VVE Normally a deletion in vanRS results in sensitivity because the cluster is turned off. In these strains a reversion was occurring under selective pressure (ie. treatment). Additional rearrangements in the region upstream HAX allows for expression of the cluster and restoration of constitutive resistance.
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Why is this important?
Number of Antimicrobial NDA = 1
Stewardship and alternate infection control strategies are of equal importance to new drug discovery
No new antibiotics, resistance rising
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We have a lot left to learn
On June 26, 2000 the first draft of the human genome was sequenced the project started in 1990
2001
Canadian microbiologist Dr. Julien Davies quickly pointed out: Our existence is dependent on bacterial speciesliving in and on us!
Microbiologist Dr. Joshua Lederberg coins the term microbiome
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We have 10x more bacterial cells than human cells in our bodies that contribute to our health and homeostasis
Today we can sequence a genome in days.
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Considerations
Antibiotics and subsequent resistance are natural phenomena
Microbes can adapt quickly
Antibiotics impact the healthy microbiome and select for resistance in human pathogens
Alternate strategies are desperately needed
So Why am I here?
What does this have to do with wound care?
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The Microbial Influence on Healing
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Colonization
Contamination
Critical Colonization
Infection
Wounds become chronic and stuck in an inflamed state
Haemostasis
Inflammation
Proliferation
Remodeling
Increasing clinical problems
Vigilance required
Intervention required
Note: Localized infection may or may not be accompanied by the classical signs and symptoms of inflammation
-clinical signs both visual and olfactory (smell)
Culturing yields 60% of human infections involve biofilms
In these cases the biofilm provides for a constant inoculation of the infectious organism. The result is cycles of infection.
VLU Polymicrobial Biofilm?
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T=0
D1
W1
W2
W3
W4
T=0
W2
W3
D1
43 yr old male with a recurring chronic leg wound (5-8 yrs).
Liver disease, PVD
Prior to study was dressed with nanocrystalline Ag
Bacterial Genera: >35
At onset: >80% S. aureus
W4: Reduced to 23% relative abundance in tissue swabs
Within one week there were improvements to wound measurements. As the wound started to close there is an overall increase in diversity which is consistent with literature and shift towards healthy microbiota/skin. S 24 hrs was 14% streptococcus and primarily betaproteobacteria (comamonadaceae). By week 4 he had 23% saureus, 20% caulobacter (alphaproteobacteria), 40% betaproteobacteria, + low abundance other stuff in swabs. Debridement at week 4 was 93% saureus.
Venous arterial disease? Venous pulmonary disease
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Microbial composition in wound swabs
Corynebacterium sp.S8-1S8-2S8-3S8-4S8-5S8-60.04364447276202610.00.0003016591251885370.00.00.00211608222490931Paenibacillus sp.S8-1S8-2S8-3S8-4S8-5S8-60.02994584262503980.00.0007541478129713420.0003859141341051610.0009099181073703360.0123941958887545S. aureusS8-1S8-2S8-3S8-4S8-5S8-60.8388021662949980.02135374697824330.8096530920060330.3908345393150020.6712920837124660.234280532043531Streptococcus sp.S8-1S8-2S8-3S8-4S8-5S8-60.03775087607518320.1424254633360190.1298642533936650.6057887120115770.05197907188353050.00574365175332527Finegoldia sp.S8-1S8-2S8-3S8-4S8-5S8-60.002070723160242110.0006043513295729250.004524886877828059.64785335262904E-50.000568698817106460.0Peptoniphilus sp.S8-1S8-2S8-3S8-4S8-5S8-60.01497292131251990.00.003469079939668170.0002894356005788710.00.0Family CaulobacteraceaeS8-1S8-2S8-3S8-4S8-5S8-60.001752150366358710.1259065269943590.01085972850678730.001350699469368070.06380800727934480.204050785973398Family BradyrhizobiaceaeS8-1S8-2S8-3S8-4S8-5S8-60.0003185727938834020.004230459307010470.0007541478129713420.00.002161055505004550.00755743651753325Family RhodospirillaceaeS8-1S8-2S8-3S8-4S8-5S8-60.00.003424657534246570.00.00.00.0Sphingomonas sp.S8-1S8-2S8-3S8-4S8-5S8-60.0003185727938834020.01933924254633360.0003016591251885370.00.01057779799818020.0256952841596131Family BurkholderialesS8-1S8-2S8-3S8-4S8-5S8-60.001433577572475310.0646655922643030.002714932126696830.00.007961783439490440.0377871825876663Family ComamonadaceaeS8-1S8-2S8-3S8-4S8-5S8-60.006690028671551450.1712328767123290.00814479638009059.64785335262904E-50.05721110100090990.178657799274486Curvibacter sp.S8-1S8-2S8-3S8-4S8-5S8-60.006690028671551450.1706285253827560.01357466063348429.64785335262904E-50.06289808917197450.17503022974607 Family ComamonadaceaeS8-1S8-2S8-3S8-4S8-5S8-60.006690028671551450.2512087026591460.007843137254901960.00.05527752502274790.107920193470375
Relative abundance (%) per sample
Biofilms in Wounds
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Wound biofilms are often not detected.
They are intrinsically antibiotic resistant but can be caused by multi-drug resistant organisms
They may be caused by previously unknown pathogens or skin commensals (more research is needed)
Depending on the wound systemic antibiotics may not even reach the site of infection and have collateral damage to beneficial microbes
The biofilm acts as a continual source of re-inoculation
Duplantier and van Hoek. 2013. Front. Immunol. Doi:10.3389/fimmu.2013.00143
Where do we go from here? focus on wound care
Start testing antimicrobials against biofilm populations
Try other antimicrobials: metals are showing promise at eradicating biofilms and persister cells:
Antibiotics are directed toward a handful of targets, cells may not grow, but they dont die
Persister cells are not as susceptible
Multidrug resistance easily developed
Metals have multiple targets in the cell (non-specific biocides)
Biofilm tolerance is time dependent
VS
Metals
Antibiotics
Antimicrobial Silver
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Phoenicians Water purification
Hippocrates healing and anti-disease
Silver sutures and foil used in surgery
Golden Era of Antibiotic Discovery
Emergence of antibiotic resistance
1000 BCE
400 BCE
1500-1895
1940-70
1980-now
1900-20
Widespread use of silver in medicine
Resurgence of silver usage
Silver used in surgery from the 1500s Ambrose Pare and later William Halsted used silver sutures and silver foil for surgical wounds. Go through timeline. Lead into use of silver in wounds.. This is important because.. Next slide.
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Silver has many targets
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OUT
IN
Gram (-)
Gram (+)
SH
Ag+
Ag+
Ag+
Ag+
Morones-Ramirez et al. 2013. Sci. Trans. Med
As a reminder, the mechanism of action of silver ions is by scavenging electrons from the bacterial cell. I like to think of electrons as the currency of a cell, driving biochemical reactions and metabolism to generate energy and go about daily business. In this way, silver ions act as an oxidizing agent.
James Collins lab at MIT published a really nice paper in 2013 detailing specific pathways that are most susceptible. This study, and most in the literature use silver nitrate as a source of silver 1+ ions.
Binding thiol groups causing protein misfolding
Misfolded proteins are translocated to the outer-membrane
Disrupt iron homeostasis including Fe-S clusters
Causes an increase in intracellular Fe2+
Stimulate superoxide production driving Fenton chemistry
Interrupt the TCA cycle driving ROS production
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Basic Redox Chemistry
e-
e-
e-
e-
Reducing Agent
Oxidizing Agent
Red gains electrons, becoming reduced
Blue loses electrons, becoming oxidized
Oxidized
Oxidized
Reduced
Reduced
Propensity to reduce, i.e. opposite of oxidation. The addition of electrons to a compound, while oxidation is the removal of them.
Use prior slides as an example of serial oxidation
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Silver Science: Redox Potential
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Reduction potential
(+) potential (V)
= need for electrons
oxidation
All silver species are different
Potential to take electrons
ReactionReduction Potential (V)Ag3+ + e Ag2++ 1.80Ag2+ + e Ag++ 1.98Ag2O + 2H+ + 2e 2Ag0 + 2H2O+ 1.17Ag+ + e Ag0+ 0.80Ag2SO4 + 2 e- 2Ag + SO42-+ 0.64Ag2O + H2O + 2e 2Ag0 + 2OH-+ 0.34AgCl + e Ag0 + Cl+ 0.22Reactivity
Because silver ions are an oxidizing agent that means they participate in redox reactions. A review of reduction potentials, the higher the potential the stronger the affinity for electrons. If we look at this chart of reduction potentials silver 1+ sits here at 0.8 whereas silver in the 2+ and 3+ oxidation states have reduction potentials close to 2. For reference, hydrogen peroxide has a similar reduction potential. This means that different chemistry is accessible to Ag2+ or 3+ ions compared with Ag1+. Higher oxidation states of silver are therefore more reactive and unstable because of the need to fill their electron shells. However, we are able to stabilize these ions with oxygen as silver oxysalts.
Highlight Ag20 and the OH increase
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AgCl
Very insoluble (1.9mg/L) and stable ie. does not react with water
Ag+(aq) + Cl-(aq) AgCl(s)
Light exposure causes degradation to metallic silver (no activity) and chlorine.
Mostly used in photography
Ag2O formed by surface oxidation of Ag metal
Releases Ag+
Ag2O(s) + H2O(aq) Ag(OH)2-(aq)
OH- causes pH spike = pain
High [Ag] needed for efficacy
O2
O2
O2
Ag
Ag
Ag2O
Ag2O
Ag Found Commonly in Dressings
Ag7NO11
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Ag+, Ag2+, Ag3+
Here you are seeing silver oxysalt crystals. They are stable until they come into contact with an aqueous environment like a wound where they begin to degrade and release silver in the 1+, 2+ and 3+ state. The inset is a picture of the crystals after exposure to water, you can see that it looks fuzzy as it begins to degrade and release silver into the fluid. So now that the chemistry lesson is over, Im sure everyone is wondering do they actually kill bacteria?
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Adapted from the respective product documentation/marketing materials
Spina, Carla J., Lischuk, David, Motta, Glenda, Silver Dressings 101: Silver Science
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Silver TypeOxidation StateSilver in Dressing (mg Ag/100 cm2)Silver Release (4h in SWF)Silver Oxysalts Ag3+, Ag2+, Ag1+40107Metallic Silver, Silver (I) Oxide Ag1+, Ag016028Metallic SilverAg1+, Ag04405Silver Na H Zr Phosphate Ag1+2104Silver Sulfate Ag1+12018Silver Chloride Ag1+1228Silver Wound Dressings how to choose?
And taking a closer look at silver dressings available on the market, it is clear to see that there are not only many options for silver wound dressings, but indeed, many types of silver within those dressings. Each type of silver offering different oxidation states, different concentrations of silver and therefore different release profiles in a simulated wound fluid.
Refer to the CIT
Silver Availability
Explain how silver release (solubility) influence bioactivity. Notice difference between silver sulfate and oxysalts. Same release but different activity because of oxidation state. Wanted to examine this more closely. Surprisingly there werent any comprehensive studies looking at the differences in antimicrobial efficacy of difference silver compounds and formulations. Most of the work is done on wound dressings, in different physical formats, concentrations and quite frankly poorly designed studies. I wanted to go right to the basics and look at pure compounds for things as simple as MIC.
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Efficacy of Silver Dressings
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Adapted from Seth et al. 2015. Wound Repair and Regeneration DOI: 10.1111/wrr.12232
106 cfu/mL
72 hrs., 250 rpm, 37C
Rinse gauze 3X with sterile saline
Simulated Wound Fluid
+/- Nutrient Agar
Treatment (4 hrs)
SEM - S. aureus biofilm on gauze fibers
10 M
1 M
10 M
10 M
SEM P. aeruginosa biofilm on gauze fibers
20 M
10 M
200 M
200 M
Need a more clniically relevant model. We adpated a model by which biofilms are grown on standard cotton gauze fibers. Essentiall explain assay and results.
After 24 hrs the counts were below the limit of detection for both dressings.
We repeated this assay but incubated the treatments on a nutrient agar plate instead of saline and next slide
BC= Benzalkonium Chloride
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Not all Silver Bullets are the Same
AgCl
4 hr exposure on complex media
4 hr exposure in saline
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In Vitro In Vivo Efficacy
Burn Wound Inoculated with P. aeruginosa
Ask Questions!
What was the test method?
What was being measured?
What kind of environment was the dressing tested in?
What is the type and quantity of silver?
Are there other components that reduce bioburden or keep the wound bed healthy?
What is the construction of the dressing?
Explain data and how relevant it is.
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Clinical Case Study #1
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T= D4
W1
W2
W3
72 yr old male with a recurring DFU
Type II diabetic, renal failure, overweight, immunocomprimised
Insulin, steroids, anticoagulants, oral hypoglycemics
Prior to study was dressed with nanocrystalline Ag
Dressing was changed 2x weekly at home
Bacterial Genera : >50
At onset: High abundance of Staphyloccocus sp. and Paenibacillus sp. W3: Staphylococcus sp. reduced to 50% by day 4 (picture not shown)
Data is still preliminary and still in process of analyzing.
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Microbial composition in wound swabs
Actinomyces sp.S7-2S7-3S7-4S7-50.00.00.01899659035557720.0231788079470199Corynebacterium sp.S7-2S7-3S7-4S7-50.00.001200480192076830.004870920603994150.0231788079470199Paenibacillus sp.S7-2S7-3S7-4S7-50.7283802333562110.0007202881152460980.02362396492937160.086644591611479Macrococcus sp.S7-2S7-3S7-4S7-50.06850549073438570.00.001461276181198250.0Staphylococcus sp.S7-2S7-3S7-4S7-50.1885295126973230.00144057623049220.001461276181198250.0S. aureusS7-2S7-3S7-4S7-50.00.0002400960384153660.02532878714076960.0132450331125828Anaerococcus sp.S7-2S7-3S7-4S7-50.00.00.2118850462737460.241721854304636Finegoldia sp.S7-2S7-3S7-4S7-50.00.00.2211397954213350.189293598233996Helcococcus sp.S7-2S7-3S7-4S7-50.00.00.3957622990745250.322295805739514Peptoniphilus sp.S7-2S7-3S7-4S7-50.00.00.07038480272771550.0607064017660044Caulobacteraceae familyS7-2S7-3S7-4S7-50.0005576527110501030.1906362545018010.004383828543594740.00386313465783664Sphingobium sp.S7-2S7-3S7-4S7-58.57927247769389E-50.01320528211284510.00.0Burkholderiales orderS7-2S7-3S7-4S7-50.0003860672614962250.06698679471788710.0002435460301997080.00551876379690949Comamonadaceae familyS7-2S7-3S7-4S7-50.004461221688400820.2513805522208880.003653190452995610.0022075055187638Curvibacter sp.S7-2S7-3S7-4S7-50.003345916266300620.2391356542617050.0007306380905991230.00275938189845475Roseateles sp.S7-2S7-3S7-4S7-50.004675703500343170.1800720288115250.005358012664393570.00386313465783664
Relative abundance (%) per sample
Clinical Case Study #2
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66 yr old male with a recurring DFU (several yrs)
Type II diabetic , diabetic neuropathy, metabolic disorder, poor perfusion, overweight
Osteomyelitis and awaiting tendon surgery
T=0
W2
W4
W1
W3
T=0
W1
W2
W4
D1
W3
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Microbial composition in wound swabs
Staphylococcus sp.S5-1S5-2S5-3S5-4S5-5S5-60.002655035084392190.00.0003344481605351179.38350380031905E-50.0008425487098472880.00225443753210433S. aureusS5-1S5-2S5-3S5-4S5-5S5-60.04911814906125540.4112874779541450.5722408026755850.05386131181383130.04560294892048450.0480851549569088Streptococcus spS5-1S5-2S5-3S5-4S5-5S5-60.8511283899108670.4566137566137570.3784280936454850.5487473022426570.9046866771985260.940614120198619Anaerococcus spS5-1S5-2S5-3S5-4S5-5S5-60.01232694860610660.0005291005291005290.001672240802675580.03650182978324110.006003159557661930.00025683465555619Finegoldia spS5-1S5-2S5-3S5-4S5-5S5-60.004361843352930020.000176366843033510.001170568561872910.006756122736229710.004212743549236440.00025683465555619Helococcus sp.S5-1S5-2S5-3S5-4S5-5S5-60.002655035084392190.00370370370370370.003344481605351170.01604579149854560.002948920484465510.000114148735802751Peptoniphilus sp.S5-1S5-2S5-3S5-4S5-5S5-60.001327517542196090.001058201058201060.001003344481605350.008820493572299890.003159557661927330.000114148735802751Allobaculums sp.S5-1S5-2S5-3S5-4S5-5S5-60.000189645363170870.00.00.00.02.85371839506877E-5Caulobacteraceae sp.S5-1S5-2S5-3S5-4S5-5S5-60.00.00.00.00.0004212743549236440.000228297471605502H. parainfluenzaeS5-1S5-2S5-3S5-4S5-5S5-60.0732031101839560.1261022927689590.0401337792642140.324106221263020.0307530279094260.0032532389703784
Relative abundance (%) per sample
Wound size over time
T=0W1W2W3W40.480.80.50.880.91
Wound Size (cm2)
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Silver Wound Dressings
Silver dressing on the market today have different types of silver.
Most products offer Ag0 or Ag1+
New products offer Ag2+ & Ag3+
Silver Dressings are Used To:
Prevent - where there is a high risk of infection in:
Contaminated wounds
Partial- or full-thickness burns
Large and/or deep wounds
Reduced healing because of patient-related factors
Restore Wound Balance - where there is increased bioburden:
local infection
local infection that is associated with a widespread (systemic) infection
And amid all the options of silver dressings available on the market today, it is important to know that those dressing contain different types of silver and those types of silver have very different chemical properties, each playing a significant role in how the dressing as a whole, manages bioburden.
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Additional Considerations
Infected wounds may require additional interventions such as systemic antibiotics (oral or intravenous), dressing selection to support moisture balance and debridement of necrotic tissue.
The wound management team, including the patient, must have clearly identified endpoints (goals or outcomes) with rationale for all decisions related to wound care.
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Keeping in mind that it is also important for clinicians to recognize that topical therapies may be only one part of a complete treatment plan and all members of the team must be on the same page to ensure a collaborative treatment plan is in place and appropriate for a particular patient.
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Summary
Systemic antibiotics might not be effective even in the absence of a resistant microbe Antibiotic stewardship is critical
Many if not all chronic wounds have a multi-species biofilm established with intrinsic antibiotic resistant
The patient may have co-morbidities significantly impacting healing
We still have a lot to learn about the influence of microbes on healing pathways
The wound team is multi-disciplinary
Innovative treatment strategies start with you
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You might not see the biofilm
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Instrumental Policy & Clinical Practice Documentation
Wound Infection in Clinical Practice An International Consensus (2008) http://www.woundsinternational.com/clinical-guidelines/wound-infection-in-clinical-practice-an-international-consensus
International Consensus - Appropriate Use of Silver Dressings in Wounds (2012) http://www.woundsinternational.com/clinical-guidelines/international-consensus-appropriate-use-of-silver-dressings-in-wounds
A Closer Look at Silver A Clinical Information Tool (CIT) to help you to help you choose the right silver wound dressing for your patient (2013) https://www.scribd.com/doc/261794917/Clinical-Information-Tool-a-Closer-Look-at-Silver
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Based upon published consensus materials and personal interactions with the wound care community we have built an understanding of what and when silver wound care dressings are needed. Instrumental consensus documents and clinical information tools are challenging clinicians to re-examine clinical practice of wound care and the use of antimicrobial silvers in treatment
Thank-You
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The Canadian Wound Care Community
Michele Suitor
Jane Ratay
Marlene Varga
Dr. David Keast
Heather Orsted (and eQuadra Solutions team)
Collaborators
Dr. Andrew Myles
Dr. Raymond Turner
Dr. Joe Lemire
Dr. Ben Willing
Dr. Mi Zhou
Westview Health Center Wound Clinic
Alberta Provincial Microbiology Lab
Exciton Technologies Inc.
Steven Miller
Deanna Pepin
Dr. Imran Ul-Haq
Karen Cuvelier
Melanie Ussyk
Rod Precht
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Questions and Discussion
50
Supplementary
51
What about Biofilms?
52
Ag can exist with different oxidation states and aqueous availability
Ag2+/3+ has antimicrobial and antibiofilm activity at lower concentrations than Ag1+ in vitro
Planktonic populations of I) E.coli (JM109), II) P. aeruginosa (PAO1), and III) S.aureus (ATCC 25923)
24h established biofilms grown for 24h in SWF and then treated with varying concentrations of Ag compounds for 24h. n 4 SD. v
What we found explain
Focus on equivalent silver concentrations and the signifcant difference between oxysalts and
10 uM = 1 ppm
40uM = 4.3 ppm
246 uM = 28 ppm
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50 patients, mixed etiology wounds
25 men and 25 women
Median/Avg. Age = 67 years
range 33-95 years
Median wound duration 3.5 months
Range, 2 days to 24 months
Wound treatment with exsalt SD7 weekly, minimum 4 weeks, with BWAT wound scores, analogue pain scale, and cost analysis.
Spina, C.J., Lischuk, D.L, CE Mark Technical File: Scientific and Clinical Report. Exciton Technologies Inc., December 2011, In Support of European Regulatory Submission
Wound statistics for the 49 patients enrolled in the multi-site study evaluating novel silver oxysalts wound dressing. Statistics Chronic(n=44)Non-Chronic (n=5)Mean age (years SD) 64 2074 16Median age (years [range]) 65 [95]79 [38]Mean wound duration (months SD) 3.7 4.90.5 0.3Median wound duration (weeks [range]) 2.0 [24.0]0.5 [0.7]Mean BWAT at Start ( SD) 35 826 5Median BWAT at Start [range] 33. [31]25 [14]Mean BWAT at End ( SD) 19 1219 40Median BWAT at End [range] 9.2. [0.4]9 [1]53
Clinical Performance
To further support our scientific knowledge, in-vivo research was initiated by way of clinical case studies. In one of our studies, a series of 50 patients with mixed chronic and acute wounds was evaluated with exsalt dressings weekly over a minimum of 4 weeks or at the instruction of the physician.
Although the therapeutic goal of antimicrobial dressings is to provide a protective barrier and to control the bacterial burden levels in the wound environment. It is important to properly assess the progression of wound healing and key signs of infection and bacterial balance to accurately evaluate the performance of these dressings. Therefore in this study, periodic wound assessment in addition to pain assessment and cost analysis was completed to determine the impact of silver oxysalt wound dressings on these diverse wounds.
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Day 0
Day 6
Day 16
patients entered (4 week) study with
chronic (non-healing) wounds
93% of patients perceived a reduction in pain (with no pain reported upon dressing application)
98% of wounds had a decrease in wound exudate
25% of wounds healed within the 4 week evaluation
48% cost savings observed over standard of care
Conclusion:
Higher oxidation state silver (in Exsalt wound dressing) is effective for chronic and critically colonized wounds.
Data on file - GMA Multi-Site Study
Multi-Center Clinical Evaluation
Mixed Etiology Case Series
20 Patient case series*
10 Chronic Leg Ulcers
10 Chronic Foot Ulcers
Positive outcomes
Size in 16 out of 20 stalled chronic wounds
Decrease in cumulative pain scores
Patricia Coutts, Grace Modelski, Laurie Goodman, Judy Ryan, R. Gary Sibbald M.D.
* 20 out of 30 total patients analyzed to date
Chronic Wound Case Series
6 Patient case series*
Mixed etiology
Localized infection or at risk of infection
Exsalt SD7 applied twice weekly for four weeks
Positive outcomes
Reducing wound size: 52.3 cm2 to 34.1 cm2
Visual improvement in bacterial burden
Decrease in exudate
Symptom# ImprovedPain6Oedema6Stalled Healing5Malodor5Bakeer M, Vair A, Keast D, Evaluation of Silver-impregnated Dressings in a Clinical Setting: Observations on Efficacy and Practicality, CAWC 2012
Microbial Ecology of Wounds
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V1
Swab
Debridement
V2
Week1
Week2
Week3
Week4
Dressing Change
V3
V4
V5
V6
Day 1
T=0
INCLUSION AND EXCLUSION CRITERIAInclusionExclusionAge >17 yrsSystemic antibiotics in previous 2 weeksChronic non-healing wound > 6 wkKnown skin sensitivity Requires at least weekly careParticipation in another studyV1
Westview Health Center, Stony Plain, AB
Debride wound collect
Swab surface of wound
Extract total DNA
Amplify 16S rDNA gene
NGS 454 platform
Briefly the study is.
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Diabetic Foot Ulcer
58
November, 2013: Started on Acticoat Flex
December, 2013: Switched to promogram
January, 2014: Restarted on Acticoat Flex because wound got worse
Mid Jan, 2014: Promogram added to Flex
February 12, 2014 - Started on Exsalt
March 13, 2014 Beginning to Epithelialize
Feb. 20, 2014
exsalt cut to size, foam secondary dressing
Bacterial Genera : >10
High proportion of streptococcus on all visits. From tissue swabs 92% relevant abundance from T=0 (before exsalt application) to 41% relative abundance on week 4 of exsalt treatment.
Note: Debridement samples have an inverse correlation to streptococcus (assuming dead slough). DNA analysis does not indicate live/dead cells.
Patient suffers from: Type I diabetes; morbidly obese; CAD; PVD, Diab neuropathy,
Both SD7 and T7 were used on this wound.
Patient 3
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Infected Surgical Wound
59
Exsalt SD7 fan-folded and packed into wound.
Week One: the wound decreased 70% in size.
Week Three: switched to T7 for packing
Secondary dressing changed according to level of exudate
Patient 2: Morbidly Obese, Hypertension, Depression, Anemia
Non-adherence to treatment plan, immunocompromised and poor lifestyle choices
Treatment in clinic began November 5, 2013, on exsalt February, 2014 had a hole in bowel and required surgery.
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Right Flank
60
Prior to study treated with Hydrofera Blue
Treated with exsalt T7 and secured with film (eg. Tegaderm)
Healed before week 2 visit.
Day 10: Wound healed
Fragile skin, wound caused by cell phone rubbing against leg
Patient 4: Burn at 3 years of age-caused kidney crystalization and thus kidney stones, has had many lithotrypsies, hemachromatosis 2ndary polycythemia
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Non-Healing VLU
61
Day 0, pre- exsalt application
Day 1 Jan 28, 2014
Week 2
Week 4
December 4, 2013: Started on Aquacel Ag + Mepilex
December 12, 2013: NU-GEL + Alldress
December 19, 2013: Biopsy taken, NU-GEL, calcium alginate, Alldress
January, 2014: Mepilex Ag and coban wrap
Wound fully healed on next follow up visit
Bacterial Genera: >25
Before treatment: Mostly betaproteobacteria (Comamonadaceae)
W4: Mainly Allobaculum and Caulobacter (associated with skin).
Patient 1 was on other silver dressings for 8 weeks before switching to exsalt.. Healed within 4 weeks.
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Foot Wound - PVD
62
Day 0, pre- exsalt application
Day 2
Week 2 - Healed
Patient comments: Wound less painful and happy with improvement
Dressing treated with Inadine (iodine antimicrobial) prior to exsalt study)
Patient 6
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Recurring Cellulitis
63
Patient had an infection to the lower leg, after treatment with exsalt a notable improvement to periwound skin was observed (breakdown was occurring).
Patient 9: Cannot do visit 2 because of compression wrap. small area noted to crease anteriorly at ankle and foot. Mepilex lite to both feet. Infection to lower leg as breakdown(periwound worse), odor to lower leg to be assessed by dr. june 4. healing rate is 26.7 % since 20/may; dr. said no antibiotics on june 4, periwound is better exsalt lightly packed, ichthopaste to calf wound.
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Incisional Hernia skin graft
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Pre-study: Hypergranulation, dressed with Biatain Ag
Purulent discharge ceased by week 2
Exsalt packed into undermining and dressed center of wound
Week 3
Week 4
Week 2
Day 0
Patient 10: pain tender with packing in undermining. One large piece to undermining, one small to edge of undermining, one small to center of graft. Prior to visit on Biatain Ag nothing to debride on visit 3 . Hypergranulation until day 3 then just granulation tissue, wound is starting to look healithier.
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Recurrent Venous Stasis Ulcer failed graft
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Week 1
Day 0
Week 2
Week 4
Pre-study: On Acticoat flex
Wound measurements improving
Increase of granulation
Continued improvement, wound eventually closed
Patient 13: What happened unti now? was on acticoat flex prior to study and stopped oral antibitics 5 days earlier (may 21) on visit 3 SD7 was fenestrated to allow exudate through stinging a short time; wound measurements improved on visit 4 and 5 hypergranulation occuring so switched to T7 pain on debriding and cleaning; some hypergranulation now follow up? wound improvments Completed study now was exsalt still on the last week? wound healed august 11, outcomes completed. Wound shrunk by 50%
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Fistula infection 1 month post surgery
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Day 0
Week 4
Day 0 - 1 month post surgery. Wound epithelializing by week 2, healed by week 4.
Patient 14; 74 yr old F
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Recurrent VLU
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Day 0
Week 1
Week 2
Week 3
Week 4
Patient 15: failed graft site
Not sure the outcome here. The wound actually increased in size but might be the case of getting worse before getting better.
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Questions?
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68
O O
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NH
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HO
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Cl
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Vancomycin Teicoplanin
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Dalbavancin Telavancin
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Penicillin Streptomycin
Ag7NO11
Nanocrystall
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10
20
30
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200400600
4 hr silver release into RO H2OSi
lver
rele
ase
(ppm
) ppm Ag+/dressing
ppm Ag+/mg Ag(s)
A
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7
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0 24 48 72 96 120 144 168 1920
100
200
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500
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Time (hrs)
Silv
er re
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Cumulative Ag+ Release from Ag7NO11
024487296120144168192
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Time (hrs)
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Ag Oxysalts Wound DressingHF Ag/BC/EDTAHF AgNegative
************
*
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****
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Porcine Burn Biofilm Model
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AgNO3
Ag2SO4 Ag2O
Ag Oxysa
lts0
10
20
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4050
450
850
1250
Con
c. o
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al [
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Minimum Biofilm Eradication Concentration Established Biofilms - 24 hr Treatment
E.coliP.aeruginosa
S.aureus*
****
*
*
*
A
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A
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C
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Minimum Biofilm Eradication Concentration
Established Biofilms - 24 hr Treatment
E.coli
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*
*
*
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*
*
*
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AgNO3
Ag2SO4 Ag2O
AgOxysa
lts0
20
40
60
80
500
1000
1500
2000
Con
c. o
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al [
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Minimum Biocidal Concentration4 hr exposure to Ag
E.coliP.aeruginosa
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****
***
A
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A
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C
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Minimum Biocidal Concentration
4 hr exposure to Ag
E.coli
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S.aureus
****
****
****
**
*
Wound Scores
27
29
31
33
02468
Time (weeks)
Avg. BWAT Score
Pain
26
30
34
38
42
02468
Time (weeks)
Cumulative Pain Scores