Re: Degree of the Hazards of Silver-Containing Dressings on MRSA-Infected Wounds in Sprague-Dawley and Streptozotocin-Induced Diabetic Rats

The April 2015 article, “Degree of the Hazards of Silver-Containing Dressings on MRSA-Infected Wounds in Sprague-Dawley and Streptozotocin-Induced Diabetic Rats,” (Wounds 2015;27(4):95-102). appears to contain a significant factual error. The article text states several times that the level of GOT (AST) at day 15 in the Sprague-Dawley rats was significantly higher in the P (PolyMem Silver) group than it was in the B (Betadine control) group, which would suggest that the use of PolyMem Silver may contribute to liver dysfunction. However, the data presented in the article should lead to the exact opposite conclusion, because the GOT (AST) levels at day 15 for the Sprague-Dawley rats shown in both Figure 2 and Table 2 are far lower (not higher) in the PolyMem group (127.7 ± 19.9) than they are in the Betadine control group (172.3 ± 14.0). In fact, across all of the tests presented, PolyMem Silver dressings appeared to be liver protective.

This is what one would logically expect, because PolyMem Silver’s antimicrobial benefits do not rely upon depositing silver into the wound bed. Instead, components in PolyMem Silver break the bonds between the slough and the wound bed and pull wound contaminants into and onto the dressings, where microbes are killed by the locked-in silver. This continuous wound cleansing system is rendered less useful when dressings are changed on a rigid schedule, as they were in this study, rather than allowing dressing change frequency to vary based upon the amount of wound exudate. In 2007, independent researchers Burd and coauthors,¹ wrote, “it [PolyMem Silver] appears to be ‘locking up’ the silver in the dressing. This is potentially a very good feature of a silver-based dressing where the bacterial ‘‘kill zone’’ is in the dressing rather than in the wound, thus avoiding the ‘‘collateral’’ damage to the healthy cells within the wound.¹

Sincerely,

Linda Benskin, PhD, RN, SRN (Ghana), CWCN, CWS, DAPWCA
Clinical Research & Education Liaison, and Charity Liaison
Ferris Mfg. Corp, Fort Worth, TX

We would like to address the issues raised by Dr. Linda Benskin concerning our article, “Degree of the Hazards of Silver-Containing Dressings on MRSA-Infected Wounds in Sprague-Dawley and Streptozotocin-Induced Diabetic Rats,” (Wounds 2015;27(4):95-102).

Dr. Benskin suggested the article text states the exact opposite conclusion when the GOT (AST) levels at day 15 for the Sprague-Dawley (SD) rats shown in both Figure 2 and Table 2 are checked. We agree with her concerns that 15days after wounding for the SD rats, the GOT level was higher in the Betadine group than in other groups, and the PolyMem Silver group was significantly lower than the Betadine group (Dunnett’s test, P < 0.005).

With regard to the proposed reference, Burd and colleagues¹ wrote that silver dressing products can be categorized as silver-delivery dressings (eg, Acticoat, Smith and Nephew, St. Petersburg, FL; and Urgotul SSD, Urgo Medical, Shepshed-Loughborough, UK) and silver-containing dressings (eg, Aquacel Ag, ConvaTec, Bristol-Myers Squibb, Skillman, NJ; Biatain Aq, formerly Contreet Foam, Coloplast, Minneapolis, MN; and PolyMem Silver, Ferris Mfg Corp, Fort Worth, TX). PolyMem Silver has high absorptive capacities and can “lock up” the silver content. Silver-containing dressings showed the least cytotoxicity to both cultured keratinocytes and fibroblasts and released a much lesser amount of silver into the culture medium over time. The potential cytotoxicity of silver dressing depends on the nature of the dressing, its affinity for moisture as well as the silver composition. The mechanism involved in serum-promoted silver release is yet unknown, but the presence of sodium and chloride has an effect on silver dissociation generally.¹

Hence, the results of our study should be corrected to reflect that the GOT levels at day 15 for SD rats as shown in Figure 2 and Table 2 are significantly lower in the PolyMem group than in the Betadine group.  We thank you for your kind words.

With kind regards,

Young Koo Lee, MD, PhD,
Corresponding Author
Department of Orthopaedic Surgery
Bucheon Hospital, College of Medicine, Soonchunhyang University
Gyeonggi-Do, Republic of Korea

The Editor and Publisher regretfully retract the study Dr. Benskin addresses due to a faulty study design.