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Listed below are 3 categories of Studies for Silverlon^® Products. Please click on the category of interest to view the study in which you are interested in. If you would like to view or print the entire study page in a separate Browser Window, please click here

Silverlon^® Antimicrobial Studies

1. USP Antimicrobial Preservative Effectiveness

The USP Antimicrobial Preservative Effectiveness Test determines protection that Silverlon^® fabric provides to microbial contamination.  Study was performed by North American Science Association Inc.

Method
Duplicate 20 g portions of the test article in 200 ml of saline (SC) were separately inoculated with the appropriate amount of suspension to achieve an approximate population of 10⁵ -10⁶  cells per g of test article. Inoculated sample aliquots were held 20-25^oC throughout the course of the study.   Using various dilution blanks and Tryptic Soy Agar (TSA) and Sabourauds Dextrose Agar (SDA) for plating, total plate counts were performed on each sample at 0,7,14,21 and 28 days after inoculation. The SDA plates were incubated at 20-25^oC for 5 days.  The TSA plates were incubated at 30-35^oC for 3 days.

Results

	S aureus ATCC9027	P. aeruginosa ATCC8739	E. coli ATCC6538	C. albicans ATCC10231	A. niger ATCC16404
Organisms per Gram of Silverlon	1.5 x 105	1.9 x 105	2.6 x 105	4.8x 105	1.2 x 105
After 7 Days	<10	3.5 x 101	<10	<10	4.0 x 101
After 14 Days	0	0	0	0	0
After 21 Days	0	0	0	0	0
After 28 Days	0	0	0	0	0

Interpretation Under the conditions of this study, Silverlon^® was effective in the product examined up to 28 days.

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2. Antimicrobial Activity-Dynamic Test of Surfaces ASTM E 2149

The Antimicrobial Activity-Dynamic Test of Surfaces ASTM E 2149 determines the effectiveness of Silverlon^® as a bactericidal antimicrobial.  Study was performed by North American Science Association Inc.

Method
The antimicrobial activity of the Silverlon^® Wound Contact Dressing 4x4 was evaluated by the Antimicrobial Activity Dynamic Test of Surfaces ASTM E2149 for 10⁶ CFU/ml of Pseudomonas aeuroginosa ATCC 9027 and Staphylococcus aureus (MRSA). Plate counts are performed at zero time of inoculation and after 1/2 hours, 1 hour, 2 hour and 4 hours of incubation at 37⁰C.

Test Article:	Silverlon®
Test Organism:	Staphyloccous aureus (MRSA)  ATCC 33591
	Pseudomonas aeruginosa    ATCC 9027
Sample Size:	2.00 +/- 0.01 g
Pre-Wet Medium:	Sterile Deionized Water
Neutralizer:	Letheen Broth
Target Inoculum Level:	(1-2) x 105  CFU/0.1 ml
Inoculum Concentration:	S. aureus  =  3 x 106  CFU/ml
	P. aeruginosa  =  3 x 106 CFU/ml
Test Date:	2/21/02

Bacterial Species	Time
	0 Hour	0.5 Hour	1 Hour	1.5 Hour	2 Hour	4.0 Hour
Staphylococcus aureus MRSA ATCC 33591	1,500,000 CFU/ml	210,000 CFU/ml	3,400 CFU/ml	2,500 CFU/ml	120 CFU/ml	0 CFU/ml
Pseudomonas aeruginosa ATCC 9027	2,400,000 CFU/ml	0 CFU/ml	0 CFU/ml	0 CFU/ml	0 CFU/ml	0 CFU/ml

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3. Assessment of Antibacterial Finishes on Textile Materials
AATCC Test Method 100 (24 hours)

The Assessment of Antibacterial Finishes on Textile Materials Method 100 determines whether the antimicrobial agent applied to a medical device or textile is effective toward inhibiting bacterial growth. Study was performed by North American Science Association Inc. 

Method
A 4.8 cm disc of Silverlon^® is inoculated with 1.2 x 10⁵ CFU of S. aureus and P. aeruginosa.  Plate counts are performed at zero time of inoculation and after 24 hours of incubation at 37⁰C. 

Test Article:                                         Silverlon^®

Test Organism :                                    Staphylococcus aureus     ATCC 6538
                                                         Pseudomonas aeruginosa   ATCC 9027
Sample Size:                                        48 mm diameter disk
Pre-Wet Medium:                                  Sterile Deionized Water
Neutralizer:                                          Letheen Broth
Target Inoculum Level:                          (1-2) x 10⁵  CFU/0.1 ml
Inoculum Concentration:                        S. aureus  =   1.3 x 10⁵   CFU/0.1 ml
                                                        P. aeruginosa   =   3.2 x 10⁵ CFU/0.1 ml
Test Date:                                                                   5/26/98

Results

	Results (CFU/ml)
Sample I.D.	Zero Contact Time		24-hour Contact Time		Percent Reduction
1	S. aureus	P. aeruginosa	S. aureus	P. aeruginosa	S. aureus	P. aeruginosa
2	1.4 x 105	2.7 x 105	<1.0 x 102	<1.0 x 102	99.93	99.97

Interpretation
The antimicrobial agent, silver, applied to the textile surface was shown to be effective in inhibiting  S. aureus and P. aeruginosa  99.93 and 99.97 respectively.

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3. Assessment of Antibacterial Finishes on Textile Materials
AATCC Test Method 100 (4 hours)

The Assessment of Antibacterial Finishes on Textile Materials Method 100 determines whether the antimicrobial agent applied to a medical device or textile is effective toward inhibiting bacterial growth. Study was performed by North American Science Association Inc.

Method
A 4.8 cm disc of Silverlon^® is inoculated with 1.2 x 10⁶ CFU of Staphylococcus areus ATCC 6538, Pseudomonas aeruginosa ATCC 9027, Enterococcus faecalis (VRE) ATCC 51575 and Staphyloccous aureus  ATCC 33591. Plate counts are performed at zero time of inoculation and at 30 minutes, 2 hours and 4 hours after incubation at 37⁰C. 

Interpretation
Interpreting this data in terms of long reduction, the difference between the initial bacterial concentration and the bacterial concentration in CFU/ml at ½ hour, 2 hours and 4 hours is calculated an summarized in the following table.

4. Dow Corning Corporate Test Method 0923

The Dow Corning Corporate Test Method determines whether the antimicrobial agent applied to a medical device or textile is effective toward inhibiting bacterial growth. Study was performed by North American Science Association Inc.

Method
Antimicrobial activity of Silverlon^® was evaluated by shaking a sample in 1.0 – 2.0 c 10⁴ CFU/ml of Staphylococcus aureus, ATCC 6538 and Pseudomonas aeruginosa, ATCC 9027 suspensions for one hour contact time.  The suspension was diluted before and after contact to determine bacterial counts. Study was preformed by North American Science Association Inc.

Test Article:                                         Silverlon^®
Sample Size:                                         0.75 ⁺  0.01 g
Target Inoculum Level:                           (1-2) x 10⁴  CFU/ml
Test Date:                                            5/26/98

Interpretation
The antimicrobial agent, silver, applied to nylon was shown to be effective toward inhibiting bacterial growth.  The plate counts obtained before and after shaking show a 99.9% effectiveness in the reduction of bacteria. 

5. Kirby Bauer Standard Antimicrobial Susceptibility Test

The Kirby Bauer Standard Antimicrobial Susceptibility Test determines whether the antimicrobial agent applied to a medical device or textile is effective toward inhibiting bacterial growth. Study was performed by North American Science Association Inc.

Method
Antimicrobial activity of Silverlon^® was evaluated by taking a broth culture of the selected organisms.  The broth is inoculated onto the surface of a Mueller-Hinton agar plate in three different directions. The test sample centered on the agar surface and incubated at 25 – 37⁰C for 16 – 18 hours.

Test Organisms:                                    Staphylococcus aureus  ATCC 33591 (MRSA)
                                                          Staphylococcus aureus ATCC 6538
                                                          Pseudomonas aeruginosa  ATCC 9027
                                                          Enterococcus faecalis  ATCC 51575 (VRE)

Sample size:                                         20mm square

Test Conditions:                                    Incubated at 35^oC – 37^oC for 16 to 24 hours

Date Received:                                      5-26-98

Results

Interpretation
The Kirby Bauer Standard Antimicrobial Susceptibility Test reveals excellent antimicrobial activity of Silverlon^® against four very common wound pathogens: S. aureus  ATCC 33591, S. aureus  ATCC 6538, P. aeruginosa  ATCC 9027, E. faecalis ATCC 51575.  Two of the bacterial species [Staphylococcus aureus ATCC 33591 (MRSA), and Enterococcus faecalis ATCC 51575 (VRE)] have multiple antibiotic resistance.

1.  Sigler T, Patterson GK, Loehne HB, Sawyer A, Johnson P, Farmer M

The Use of Negative Pressure Therapy and Elemental Silver Contact Layer* in Increasing the Survivability of split-Thickness Skin Grafts

Presented at the 16^th Annual Clinical Symposium on Advances in Skin and Wound Care September 20-23, 2001.

Problem: Difficulty in securing split thickness skin grafts (STSG) to concave or convex surfaces is a vexing problem.  Traditional bolster type dressings of gauze left for long periods can also have infectious complications with associated graft loss.

Rationale: To improve on existing dressings for adhering STSG to prepared granulation beds, and to incorporate an antimicrobial function to decrease infectious complications.

Methodology: We present our first five patients in an on going trial utilizing both a new silver dressing *and negative pressure therapy (NPT).  Initially each patient’s wound was treated with NPT and once a sufficient granulation base was achieved the patient under went STSG.  The fresh STSG was covered with a non-stick wound veil and then elemental silver coated contact layer.  NPT is performed with 400 micron porous foam at 50 – 75 mm Hg for five days.

Results: 4 of 5 (80%) STSG were successful.  One graft (20%) failed secondary to patient compliance issues with keeping the NPT machine turned on.  This caused the graft to shear off.   Of the four successful grafts all had 100% take despite prior positive cultures.

Conclusion: The combination of NPT and elemental silver contact dressings* represents an exciting new method of securing STSG’s in colonized wounds.  Patient education and compliance in this more sophisticated method are issues to be addressed.

2.   Carl Van Gils, MS, DPM, The Foot and Ankle Institute, St. George, UT; LeeAnn Stark MS, APRN, CFNP, CWOCN, and Brenda Forbes RN BSN CDE

The combined benefit of negative pressure therapy, elemental silver contact layer and bilayered living skin equivalent in the treatment of chronic hard to heal lower extremity wounds.

Presented at Symposium on Advanced Wound Care April 27-30, 2002 Baltimore MD.

Problem: Closure of chronic wounds is often more challenging due to existing co-morbidities.  Complicating factors deter wound healing and encourage resistance to typically reliable wound healing techniques. For example (L.S.E.) may be prone to failure if heavy wound exudate cannot be well controlled. These hard to heal wounds invite further complications Ie: infection, pain, disability, and amputation.

Rationale: To accelerate the wound healing process in chronic hard to heal wounds and to decrease pain, infection, and wound exudate.

Methodology: Six patients with co-morbidities including chronic steroid use, poor healing potential, MRSA , pain and vascular disease were chosen.  Initially (N.P.T) at 75-100 mm Hg was combined with an elemental silver-coated contact dressing for an average of 14 days.  Once a sufficient granulation wound base was achieved, the patient underwent L.S.E placement.  (N.P.T.) at 125mm Hg continues for an additional 6-7 days over the silver contact dressing and the (L.S.E.).

Results: 6 of 6 patients were successful in achieving wound closure or marked improvement in wound size, decreased pain, and decreased infection.

Conclusion: The combination of N.P.T, elemental silver contact dressing, and L.S.E. in colonized hard to heal chronic wounds produces an accelerated wound healing potential.

1. Silverlon^® Wound Contact and Wound Pad Dressing Ionic Silver Release In Tryptic Soy Broth

Ionic Silver Release from the 4 x 4 Silverlon^® Wound Contact Dressing and the 4 x 4 Silverlon^® Wound Pad Dressing measured by inductively coupled plasma spectroscopy released in tryptic soy broth at 37^oC.  Study performed August 2001 by Dr. David Marx, University of Scranton, Scranton PA.