Recent studies using the gene-editing platform Crispr-Cas9 allows scientists to take a closer look at how silver poisons pathogens. The research has led to insights into how new antimicrobials can be developed.
The antimicrobial properties of silver can be traced back to the time of the Phonecians, when water was stored in silver coated bottles to discourage contamination. Later people added silver discs to milk bottles in order to keep milk fresh. Silver, as silver nitrate, was once even used as drops added to newborn’s eyes to prevent the transmission of the bacteria that causes gonorrhea.
With the era of antibiotics the use of silver waned. However, with the rise of antibiotic resistance interest in silver has increased of antibiotic-resistant strains such as CA-MRSA and HA-MRSA, the flesh-eating bacteria. This interest has been partly driven by the use of more adbanced laboratory techniques.
An example of this is Dr. Joe Lemire and his team at the University of Calgary. The researchers recently presented on the application of silver in modern antimicrobials at the American Society for Biochemistry and Molecular Biology annual meeting during the Experimental Biology 2017 meeting, which took place in April 2017 in Chicago.
In an interview, Dr. Lemire explains the aim of his research, stating the goal is “to deliver the relevant scientific evidence that would aid policymakers in developing guidelines for when and how silver could be used in the clinic to combat and control infectious pathogens.”
Researchers have established, for example, that the antimicrobial action of silver is proportional to the amount of bioactive silver ions released and the availability of these ions to interact with bacterial or fungal cell membranes. In addition, silver can help in the fight against drug-resistant bacteria by easing large antibiotic molecules through the microbes’ outer coating.
With this Dr. Lemire thinks knowing more about silver toxicity will allow for new silver-based antimicrobial therapies to be developed. For this, the researchers are using the gene editing method Crispr-Cas9 to screen for and then to delete genes that allow certain bacterial species to resist silver’s antimicrobial properties. With this it should be possible to add silver to hundreds of commercial products.
