Cu versus Ag as Antimicrobial
In response to questions regarding antimicrobial efficacy copper vs silver, I will describe a figure and a table from a peer reviewed published paper in 2009 ( https://www.amcopper.com/copper-versus-silver). This paper compares the antimicrobial efficacy of two commercial silver-containing coatings versus six commercial copper alloys.
This paper discusses test results showing the effects of temperature and humidity on antimicrobial response of two commercial silver-containing coatings and six copper alloys, after methicillin resistant Staphylococcus aureus (MRSA), a "Super Bug" that causes serious hospital-acquired infections was place on their surfaces.
The figure shows a 7 log (~10,000,000 times) reduction in reduction in live bacteria on a 99.9%Cu alloy in 80 minutes but no meaningful reduction in the two silver containing coatings at 400 minutes. Stainless steel (S304) served as the experimental control and also showed no meaningful reduction since it has no efficacy.
The table shows the log reductions observer on six copper alloys and one silver containing coating at temperatures of 35C and 20C and relative humidity levels of >90RH% and ~20RH to 22RH.
The conclusion is that copper displays good antimicrobial efficacy under all humidity and temperature test conditions but silver only works at very high humidity levels, which are not typically found in indoor settings.
Harold T. Michels,
Consultant, Formerly Senior Vice President, Copper Development Association. Retired from Copper Dev Assoc in 2014 & Inco Ltd. in 1998.Manhasset NY,email@example.com
------------------------------Harold MichelsConsultant, Formerly Senior Vice President, Copper Development AssociationRetires from Copper Dev Assoc in 2014 & Inco Ltd. in 1998Manhasset NY(516) 627-5335------------------------------
There was clinical trial conducted by CODELCO, Chilean copper mining company, in a Pediatric Intensive Care Unit. Prior to that, a study was conducted the CDA in the ICUs of three hospitals. The results of the US study showed that the infection rate was reduced by a statically significant 58% in the rooms where six copper components were installed, versus the typical rooms. The six copper components were the :
To view the paper, Salgado, et. al., Copper Surfaces Reduce the Rate of Healthcare Acquired Infections in the Intensive Care Unit, go to: www.amcopper/infections
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