While the use of various metals for their anti-microbial properties is not a new concept, a recent study published in the American Journal of Infection Control is pointing to the potential hygiene benefit of of copper as a primary metal in stethoscopes. The full text of the study, Antimicrobial copper alloys decreased bacteria on stethoscope surfaces, describes the methodology used to examine the effect of copper on stethoscope bacterial loads. Stethoscopes are well known to be carriers of bacteria between patients. Unfortunately, we healthcare staff may be the direct cause of an infection if these factors are not taken into account and addressed.
The authors conducted their study in a pediatric emergency room and an adult medical intensive care unit. (Both of these are excellent environments to encounter bacteria) The study involved the use of retail variant of the 3M Littmann Master Cardiology stethoscope, and a second custom designed copy of the Master Cardiology which was made from primarily copper alloys. This included replacing the PVC diaphragm with a copper variant based on what is described in the full-text. In total 21 medical providers were issued with the stethoscopes used in the study.
What resulted from the data was evidence that supports the use of copper as an alloy in stethoscopes. There was a 91% reduction in bacterial load found on the copper variant. There are clearly some limitations to the study (small sample size, individual cleaning efforts by users were not monitored, etc), and further studies will be needed to demonstrate longevity of this research. Regardless of this there is clearly a potential for patient care areas to benefit from the use of copper in equipment such as stethoscopes. Rolling this out as an industry standard would require some buy-in from manufacturers given the impact this would have on device prices, durability, etc.