How often are our stethoscopes contaminated?

The 2 minute update looks at a study asking how common is bacterial contamination on our stethoscopes.

30 clinicians were involved, primarily hospitalists and residents. Researchers asked how often they cleaned their stethoscopes, and then took cultures before cleaning, after cleaning, and after a single patient encounter after cleaning.

Cleaning was pretty simple, they just used a regular paper towel and standard hand sanitizer, wiping the stethoscope for 2-3 seconds, and allowing it to dry.

A stethoscope was considered regularly cleaned if the practitioner reported cleaning it at least 3 times a day. A stethoscope was classified as contaminated if the swab grew 3 or more bacterial colonies.

Only 20% of the practitioners reported cleaning their stethoscopes at least 3 times per day. If they did that, 17% were contaminated. But 58% of stethoscopes that were not regularly cleaned were contaminated, and the difference is statistically significant. Overall, 50% of stethoscopes were contaminated prior to cleaning. After cleaning, none of the stethoscopes were contaminated. But after a single patient encounter, over 36% were contaminated.

We do not have data on infections, but it seems quite likely that regularly cleaning stethoscopes would prevent some infections, especially for immunocompromised patients. This clearly shows that we should clean our stethoscopes more often. How often are patients being infected by contaminated stethoscopes? Probably more often than we realize.

Personally, I use the hand sanitizer every time I leave a patient’s room. And years ago I got into the habit of rubbing the hand sanitizer on my stethoscope after I rub the sanitizer over my hands. It really takes no time at all, since I’m walking back to the charting area while I do that.

Reference: Dressler et al. Hospital Physicians' Stethoscopes: Bacterial Contamination After a Simple Cleaning Protocol. Cureus 15:e37061