New In Vitro Study Data Shows Importance of Dressing Conformability to Action of Silver-Containing Wound Dressing

Wound Dressing Killed More Bacteria Beneath Dressing than Other Tested Silver-Containing Foam Dressings (1)

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Apr 18, 2010, 08:00 ET

ORLANDO, Fla., April 18 /PRNewswire/ -- ConvaTec, a world-leading developer and marketer of innovative medical technologies for community and hospital care, today announced new in vitro study results in which a Hydrofiber® dressing containing ionic silver was observed to conform more closely to a porcine tissue surface in a shallow wound model than did certain silver-containing foam dressings following hydration. In the in vitro study the Hydrofiber® dressing containing ionic silver killed more bacteria (Pseudomonas aeruginosa and Staphylococcus aureus) beneath the dressing than any of the tested silver-containing foam dressings. In addition, the Hydrofiber® dressing containing ionic silver was observed to not allow the spread of bacteria beyond the edge of the simulated wound. These data were presented at the 23rd Annual Symposium on Advanced Wound Care and Wound Healing Society (SAWC/WHS) in Orlando, Florida.

Chronic wounds are often made up of many types of bacteria from external sources such as the surrounding skin, gut and mouth. A wound that will not heal is an excellent environment for bacteria to colonize. Colonizing bacteria can often lead to difficult-to-treat infections. It is important that a wound dressing conforms well to the wound's unique topography to ensure that an antimicrobial agent comes into the most contact with the threatening bacteria.

In the in vitro study, models were utilized that enabled both visualization of the conformability of silver-containing dressings with a simulated wound tissue and measurement of the antimicrobial activity of the dressings in a simulated shallow wound microbial model. The percentage of growth for each bacterium was measured for Hydrofiber® dressing containing ionic silver and three silver-containing foam dressings (Foam A-C). Mean results of three replicated tests, measured by growth beneath the dressing, were as follows: the Hydrofiber® dressing containing ionic silver had 0.4% growth when inoculated with S. sureus and 9.0% with P. aeruginosa; Foam A had 25.7% growth when inoculated with S. aureus and 100% with P. aeruginosa; Foam B had 16.7% growth when inoculated with S. aureus and 97.8% with P. aeruginosa; and Foam C had 24.6% growth when inoculated with S. aureus and 95.8% wit P. aeruginosa.(1)

About Staphylococcus aureus

Staphylococcus aureus (S. aureus) is a common bacterium found on the skin and in the noses of up to 25% of healthy people and animals. Staphylococcus aureus is important because it has the ability to make seven different toxins that are frequently responsible for food poisoning. (2)

About Pseudomonas aeruginosa

The versatile "blue-green pus bacteria" that opportunistically infects people, especially those who are immunocompromised. Pseudomonas rarely causes infection in healthy individuals but it is a major cause of hospital acquired (nosocomial) infections. It tends to infect people with immunodeficiency or burns and those with indwelling catheters or on respirators. Infection with pseudomonas can lead to urinary tract infections, sepsis (blood stream infection), pneumonia, pharyngitis, and many other medical problems.(3)

About Hydrofiber® Technology

Dressings with Hydrofiber® Technology gel on contact with fluid, providing clinicians and patients with substantial wound care benefits. This unique gelling action enables the dressings to lock in exudate and its harmful components*(4,5,6).

About ConvaTec

ConvaTec is a leading developer and marketer of innovative medical technologies that have helped improve the lives of millions of people worldwide. With four key business divisions – Ostomy Care, Wound Therapeutics, Continence and Critical Care and Infusion Devices – ConvaTec products support health care professionals from the hospital to the community health setting. From its headquarters in Skillman, New Jersey, the company oversees more than 8,000 employees in over 90 countries serving consumers and their health care professionals on six continents. For more information, please visit www.convatec.com.

* As demonstrated in vitro

Hydrofiber is a registered trademark of ConvaTec Inc.

(1) Bowler P, et.al. The Importance of Dressing Conformability to Antimicrobial Action of Silver-Containing Wound Dressings: In Vitro Studies. Poster Presented at: 23rd Annual Symposium on Advanced Wound Care and Wound Healing Society Meeting; April 17-20, 2010; Orlando, FL.

(2) Disease listing page. Centers for Disease Control and Prevention Web site. http://www.cdc.gov/ncidod/dbmd/diseaseinfo/staphylococcus_food_g.htm Accessed April 12, 2010.

(3) Pseudomonas infection information page. Healthline.com Web site. http://www.healthline.com/galecontent/pseudomonas-infections/2 Accessed April 12, 2010.

(4) Walker M, Hobot JA, Newman GR, Bowler PG. Scanning electron microscopic examination of bacterial immobilisation in a carboxymethylcellulose (Aquacel) and alginate dressings. Biomaterials.2003;24:883-890.

(5) Waring MJ, Parsons D. Physico-chemical characterisation of carboxymethylated spun cellulose fibres. Biomaterials.2001;22:903-912.

(6) Walker M, Bowler PG, Cochrane CA. In vitro studies to show sequestration of matrix metalloproteinases by silver containing would care products. Ostomy Wound Manage.2007;53(9):18-25.