A discussion of silver as an antimicrobial agent: alleviating the confusion.

Within the last 3 to 5 years, many silver-based antimicrobial dressings have become available and more are on the way. However, sometimes dressing manufacturers and authors make claims and send messages that conflict with data and conclusions in the literature, creating confusion for clinicians. A literature review of six relevant and frequently discussed topics was conducted. Pre-clinical and clinical study data suggest that: a) bacterial resistance to silver may occur, b) silver dissociation is affected by the test medium used, c) bactericidal activity differences may be a function of the bacterial strain used for testing, d) higher rather than lower levels of silver may be needed because Ag+ binds to proteins and nucleic acids, e) rapid delivery of silver (ie, rate of kill) may be a positive factor when considering prevention of silver resistance and biofilm formation, and f) based on the vast majority of in vivo studies available, silver does not adversely effect viable cells; thus, is not cytototoxic. Continued research into the implications of the data is warranted.