From Dr. Mercola (_http://articles.mercola.com/sites/articles/archive/2013/07/03/antibiotics-colloidal-silver.aspx)
Colloidal Silver Dramatically Boosts Effectiveness of Antibiotics
The use of silver in the battle against pathogenic bacteria goes way back into antiquity. Hippocrates was one of the first to describe its antimicrobial properties in 400 B.C. Over the past few years, several studies have demonstrated the fact that silver is indeed one of the most effective agents in the battle against antibiotic-resistant super pathogens. Yet conventional medicine has largely dismissed such claims, relegating colloidal silver to the "woo-woo" section of medical myth.
They may be inclined to change their tune however, in light of the latest research which shows that low doses of silver can make antibiotics up to 1,000 times more effective, and may even allow an antibiotic to successfully combat otherwise antibiotic-resistant bacteria. As reported by Medical News Today:13
"...[N]ot only did silver boost the ability of a broad range of commonly used antibiotics so as to stop mice dying of otherwise lethal infections, but it made at least one resistant bacterium succumb to antibiotics again. The addition of silver also broadened the effect of vancomycin, an antibiotic that is usually only effective at killing Gram-positive bacteria like Staph and Strep; aided by silver it killed Gram-negative bacteria such as those that cause food poisoning and dangerous hospital-acquired infections."
For example, by adding a small amount of silver to the antibiotic, a powerful synergism occurred, and a urinary tract infection caused by tetracycline-resistant E. coli was successfully eradicated. Silver also helped save the lives of 90 percent of mice suffering with a life-threatening abdominal inflammation by adding it to the antibiotic vanomycin. In the group receiving vanomycin only, a mere 10 percent survived. The researchers discovered two mechanisms that help explain how silver can boost the effectiveness of an antibiotic:
Silver interferes with the bacteria's metabolism, increasing production of reactive oxygen species (ROS); products of normal oxygen consuming metabolic processes in your body that, in excess, can damage cell membranes and DNA. Many antibiotics are believed to kill bacteria by producing ROS compounds, and here, the researchers found that adding a small amount of silver boosted the antibiotic's ability to kill anywhere from 10 and 1,000 times more bacteria
Silver makes the bacteria's cell membrane more permeable. This may explain the beneficial effect of silver on gram-negative bacteria, the cells of which are often impenetrable to antibiotics due to the molecular size of the drugs