User:Wdford/silver

Silver compounds in the treatment of external infections

In World War I, before the advent of antibiotics, silver compounds were used to prevent and treat infections. Silver compounds continue to be used in external preparations as antiseptics, including silver nitrate, which can be used to prevent conjunctivitis in newborn babies and to treat certain skin conditions, such as corns and warts.

Herbert Slavin, M.D. director of the Institute of Advanced Medicine and member of the Committee for the Responsible Use of Silver in Health, states that ionic silver “is clearly recognized to be highly effective against essentially every other class of pathogen”, and that “The fact that ionic silver is effective against a very broad range of bacteria is well established”. Laboratory studies at the Biochemical Materials Research and Development Center of Jiaxing College, China, have shown that silver-containing alginate fibres provide a sustained release of silver ions when in contact with wound exudates, and are “highly effective against bacteria”. A study administered by the Hull York Medical School found that an antimicrobial barrier dressing containing silver provided “a highly effective and reliable barrier to the spread of MRSA into the wider hospital.”

According to Atiyeh et al. (2007), "The gold standard in topical burn treatment is silver sulfadiazine (Ag-SD), a useful antibacterial agent for burn wound treatment". They do note however that silver-impregnated dressings do sometimes result in a slower healing process. Silver sulfadiazine cream (SSD Cream) replaced colloidal silver as the most common delivery system for using silver on the surface of burn wounds to control infection in the 1970s.

More recently, dressings incorporating nanocrystalline silver or activated silver-impregnated substances have become available, which deliver higher concentrations of the active silver ion. As of 2006, more "than 10 dressings containing pure silver" were available. In particular, silver is being used with alginate, a naturally occurring biopolymer derived from seaweed, in a range of products designed to prevent infections as part of wound management procedures, particularly applicable to burn victims.

Wound dressings containing silver are increasing in importance due to the increase of antibiotic-resistant bacteria, which has imposed clinical limits on the use of antibiotics. Chopra states that topical silver is regaining popularity in the management of open wounds, “due largely to the spread of methicillin-resistant Staphylococcus aureus and the resultant reduction in first-line antibiotic prescribing”. Chopra also expresses the concern that “There is a need for silver MIC levels and breakpoints to be developed and standardized.” He does however conclude that “Some silver-based dressings appear to provide an effective alternative to antibiotics in the management of wound infection.” Silver has proven antimicrobial activity that includes antibiotic-resistant bacteria. It has a broad spectrum of antimicrobial activity, with minimal toxicity toward mammalian cells at low concentrations, and has a less likely tendency than antibiotics to induce resistance due to its activity at multiple bacterial target sites.

However, some sources still hold that the evidence for the effectiveness of silver-treated dressings is mixed, as the evidence is marred by the poor quality of the trials used to assess these products. Consequently a major systematic review by the Cochrane Collaboration found insufficient evidence to recommend the use of silver-treated dressings to treat infected wounds.

An article from the National Center for Complementary and Alternative Medicine points out that silver nitrate and silver sulfadiazine can have negative side effects, and that they must be applied to the body externally and not taken internally. According to Lansdown, the risk expected due to clinical exposure to silver is "minimal", as only chronic ingestion or inhalation of silver preparations leads to an accumulation of silver in the human body that can cause argyria, argyrosis (accumulation of silver in the eye) and other conditions.

Silver-based products are contra-indicated for people who are allergic to silver.