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A Health Care Professional’s Perspective on a Silver Compound

Fresh Views on Silver

A Health Care Professional’s Perspective on a Silver Compound

Index: Ostomy Wound Manage. 2017;63(12):12,14.

Background

When I began my training at Crawford (Doylestown, PA), I was introduced to a new portfolio of products. Two contain a novel silver compound, Ag Oxysalts, whose mechanism of action (MOA) challenged my knowledge about silver in wound care practice. To learn more, I assessed them as I would any product.

I find it intuitive to start with some basic objective questions and considerations. These general questions and their answers lead me to a more comprehensive evaluation plan. For example, I ask, “Does this product have similar indications for use as products I am currently using in my practice?” If the answer is yes, I address more indepth considerations before deciding to use the new product. Ag Oxysalts is an example of a product for which it is important to critically evaluate the MOA.

Elemental silver in the Ag0 format is a stable molecule and is relatively nonreactive. However, through technology developments in the 1990s, elemental silver was modified to ionic silver, a more reactive version and the only form of antimicrobial silver. This technology provided a way for silver compounds to be delivered in dressings and broken down into ions when exposed to wound fluid or an aqueous solution. The ions are an Ag1+ electron format and can kill bacteria by rupturing the cell wall, inhibiting vital enzymes, destroying cells using silver-free radicals, or interacting with the bacteria’s DNA. The MOA of newly engineered Ag Oxysalts (Ag7NO11) technology makes highly oxidative states of silver ions (Ag1+, Ag2+, Ag3+) available; thus, the silver is more powerful and can work faster while using a fraction of the amount of silver compared to other ionic silver formats1,2 (see Figure 1). 

After my review of the MOA, I developed questions that would help me analyze the value of this new technology. These questions are based on my experiences using silver dressings in clinical practice and teaching the antimicrobial properties of silver in pre- and post-professional coursework. Because of the historical challenges regarding the use of silver dressings in the literature, my questions were related to cytotoxicity and healthy tissue, resistance of microbes to silver, and the ability to disrupt a biofilm, not just planktonic bacteria.

Is this technology cytotoxic to healthy tissue and will it impair healing?

Thomason et al3 presented in vivo and in vitro data to support use of the Ag Oxysalts technology without impaired healing or cytotoxicity. Improved healing was demonstrated by significant decreases in wound area and increased epithelialization in full-thickness mouse wound models when the Ag Oxysalts technology was compared to a nonantimicrobial control. There also was evidence that treatment with Ag Oxysalts promoted wound healing and accelerated closure in human keratinocyte scratch wounds compared to untreated control scratch wounds.

Is there bacterial resistance to this technology?

Bacteria have been around for millennia and have made some extraordinary adaptations to environment and in response to repeated exposure to lethal substances. This adaptive ability is evidenced among all the multidrug-resistant (MDR) bacteria known today. Using a time-kill analysis, Kalan et al1 found that a panel of MDR pathogens isolated from wound specimens remained susceptible to Ag7NO11 over a period of 7 days, even with repeated inoculations of 1 × 106 CFU/mL to the dressing.1 Finley et al4 found that both Klebsiella pneumonia (SRKP) and Enterobacter cloacae (SREC) expressing silver-resistant genes were highly resistant to 7 of 9 silver dressings; silver oxysalt dressing  was among the silver dressings to which the SRKP and SREC remained sensitive.

Does this technology effectively disrupt biofilms?

Dressings that contain higher oxidative states of silver (Ag1+, Ag2+, Ag3+) with Ag Oxysalts were found to be more effective against planktonic bacteria and bacteria within wound biofilms than another Ag1+ dressing.5 Mature Pseudomonas aeruginosa biofilms in a porcine ex vivo model were found to have statistically significantly less bacteria (P <.05) than the control 24 hours after application of Ag Oxysalts (see Figures 2, 3, and 4).

Conclusion

As an HCP and educator who has evaluated many wound care products, it is my conclusion that the unique chemical qualities of the Ag Oxysalts compound allow it to perform as an effective antimicrobial, disrupting biofilm and improving wound healing processes without cytotoxicity and with minimal to no bacterial resistance. My evaluation of the MOA, published peer-reviewed literature, and first-hand recommendations from other trusted HCPs have encouraged me to use this product in my clinical practice. 

Disclosure

Fresh Views on Silver is made possible through the support of Crawford Healthcare, Doylestown, PA. The opinions and statements of the clinicians providing Fresh Views on Silver are specific to the respective authors and not necessarily those of Crawford Healthcare, OWM, or HMP. This article was not subject to the Ostomy Wound Management peer-review process.