I have a patient who had a failed mesh placement and a panniculectomy and who has developed at least three separate fistulas with a very large amount of output (3-4 L/24 hrs). Any suggestions? I am using an Eakin wound management pouch hooked up to wall suction.
Polishing the Information on Silver
- Wed, 9/3/08 - 10:25am
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- 4185 reads
Dear Editor,
In the interest of upholding Ostomy/Wound Management's goal to provide accurate, balanced continuing medical education, we respectfully request clarifications regarding the article by Dr. Burrell (A scientific perspective on the use of topical silver preparations. In: Bacteria + Pressure Ulcers: The Role of Silver versus Traditional Antimicrobials. Ostomy/Wound Management. 2003;49[5A supp]:19-24) and suggest that the author's past and present affiliations with commercially involved organizations be properly disclosed. We believe the article shows bias toward nanocrystalline technology and does not address topical silver preparations objectively.
Table 1 defines the solubility limits for various forms of silver. It infers that nitrates and nanocrystalline forms provide more silver, but the author fails to disclose that these data refer to solubility in pure water. Consequently, these figures bear no relevance to the availability and antimicrobial efficacy of silver in complex media such as wound fluid.
The only accepted safe and proven antimicrobial species of silver is ionic silver in the form of the monovalent silver cation (Ag+).1,2 Table 2 indicates that nanocrystalline silver provides both Ag+ and Ag0. Ag0 is the chemical symbol for metallic silver for which no evidence of biological or antimicrobial activity exists. Ag0 is generally regarded as being insoluble in water, and the only way that it can get into solution and elicit antimicrobial activity is in the form of the silver ion (Ag+). Also in Table 2, the water concentrations for AgSD (1%) and AgNO3 (0.5%) should read 3,000 micrograms/mL and 3,200 micrograms/mL respectively.
The discussion on the effect of wound fluid on ionic silver levels is limited to dressings containing silver chloride. However, no mention is made of the fact that this same effect will apply to all silver-containing dressings. The concentration of available silver ions is dictated primarily by the solubility limit of silver chloride, which is approximately 1.0micrograms/mL. Ionic silver concentrations in excess of this value (as indicated in Tables 1 and 2) will be rapidly reduced by the formation of inactive silver chloride. Consequently, data showing only solubility and release rates into water are misleading and do not extrapolate to the clinical situation.
Additional confusion is caused by the presentation of traditional static minimum inhibitory concentration (MIC) data based on the exposure of bacteria to single bolus doses of an ionic silver solution at varying concentrations. With the exception of silver nitrate, all the referenced silver-containing products have been designed to provide some level of controlled silver release into a dynamic wound environment over time. Minimum inhibitory concentration tests are not representative of this situation. This is emphasized in Table 2, which shows that AgCMC is bactericidal (100-fold reduction in 30 minutes) yet produces a concentration of less than 1.0 micrograms/mL of ionic silver, which is a substantially lower value than the referenced MIC values. The term oligodynamic is used, but is not applied to the data presented. This term refers to the ability of bacteria to accumulate substances preferentially; it is the number of silver ions absorbed, not the concentration of silver ions in solution that causes bacterial death.3
In Table 2, the use of a 30-minute log reduction assay is of questionable clinical relevance, particularly when many of the referenced dressings are considered to demonstrate antimicrobial activity over a period of days. The conditions and time period of this test are deliberately intended to differentiate nanocrystalline silver from other silver-containing dressings.
References:
Letter
1. Russell AD, Hugo WB. Antimicrobial activity and action of Silver. In: Ellis GP, Luscombe DK (eds). Progress in Medicinal Chemistry, Vol 31. St. Louis, Mo.:Elsevier Science;1994:351-370.
2. Schierholz JM, Wachol-Drewek Z, Lucas LJ, Pulverer G. Activity of silver ions in different media. Zentralblatt fur Bakteriologie. 1998;287:411-420.
3. Lansdown ABG. The role of silver. European Tissue Repair Society: Concepts in Wound Healing. 2002;9:108-111.
Reply
1. McManus AT. 2002. Precautions regarding acquired resistance. Wounds. 2002;14(7 suppl):11S-13S.
2. Ricketts CR, Lowbury EJL, Lawrence JC, Hall M, Wilkins MD. Mechanism of prophylaxis by silver compounds against infection of burns. British Medical Journal. 1970;2:444-446.
3. Spacciapoli P, Buxton D, Rothstein D, Friden P. Antimicrobial activity of silver nitrate against periodontal pathogens. Journal of Periodontal Research. 2001;36:108-113.
4. Schierholz JM, Wachol-Drewe, Z, Lucas LJ, Pulverer G. Activity of silver ions in different media. Zentralblatt fur.Bakteriologie. 1998;287:411-420.
5. Lansdown ABG. The role of silver. European Tissue Repair Society: Concepts in Wound Healing. 2002;9:108-111.
6. Fan FF-R, Bard AJ. Chemical and electrochemical, gravimetric, and microscopic studies on antimicrobial silver films. Journal of Physical Chemistry B. 2002;106(2):279-287.
7. Yin HQ, Langford R, Burrell RE. Comparative evaluation of the antimicrobial activity of Acticoat Antimicrobial Barrier Dressing. J Burn Care Rehabil. 1999;20:195-200.
8. Wright JB, Hansen DL, Burrell RE. The comparative efficacy of two antimicrobial barrier dressings: in vitro examination of two controlled release silver dressings. Wounds. 1998;10(6):179-188.
9. Thomas S, McCubbin P. A comparison of the antimicrobial effects of four silver containing dressings on three organisms. Journal of Wound Care. 2003;12(3):101-106.
10. Wright JB, Lam K, Hansen DL, Burrell RE. Wound management in an era of increasing bacterial antibiotic resistance: a role for topical silver treatment. Am J Infect Control. 1998;26:572-577.
11. Wright JB, Lam K, Burrell E. Efficacy of topical silver against fungal burn wound pathogens. Am J Infect Control. 1999;27:344-350.
12. Burrell RE, Wright JB, Heggers JP, Davis GJ. Efficacy of silver coated dressings as barriers in a rodent burn sepsis model. Wounds. 1999;11(4):64-71.
13. Olson ME, Wright JB, Lam K, Burrell RE. 2000. Healing of donor sites covered with silver coated dressings. Eur J Surg. 2000;166:486-489.
14. Tredget EE, Shankowsky HA, Groeneveld A, Burrell RE. A matched-pair, randomized study evaluating the efficacy and safety of Acticoat Silver-Coated Dressing for the treatment of burn wounds. J Burn Care Rehabil. 1998;19:531-537.
15. Wright JB, Lam K, Buret AG, Olson ME, Burrell RE. Early healing events in a porcine model of contaminated wounds: impact of nanocrystalline silver on matrix metalloproteinases, cellular apoptosis and wound healing. Wound Repair and Regeneration. 2002;10:141-151.
16. Kirsner R, Orsted H, Wright JB. Matrix metalloproteinases in normal and impaired wound healing: a potential role of nanocrystalline silver. Wounds. 2001;13:4S-12S.
17. Paddock HN, Schultz GS, Perrin KJ, Moldawer LL, Wright B, Mozingo DW. Clinical assessment of silver-coated antimicrobial dressing on MMPs and cytokine levels in non-healing wounds. Annual Meeting Wound Healing Society. Baltimore, Md. May 28 to June 1, 2002.
18. Stratton CW, Cooksey RC. Susceptibility Tests: Special Tests. In: Manual of Clinical Microbiology, 5th ed. ASM, Washington, DC;1991.
19. Barry AL, Craig WA, Nadler H, Reller LB, Sanders CC, Swenson JM. Methods for Determining Bactericidal Activity of Antimicrobial Agents. Approved Guideline. NCCLS document M26-A (ISBN 1-56238-384-1);1999.
20. Jackson GG, Riff LJ. Pseudomonas bacteremia: pharmacologic and other bases for failure of treatment with gentamicin. J Infect Dis. 1971;124:S185-S191.
21. Schierholz JM, Rump AFE, Pulverer G. Drug delivery concepts for efficacious prevention of foreign body infections. Zentralblatt fur Bakteriologie. 1996;284:390-401.
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