The dirty (and dangerous) truth about doctors' stethoscopes

Cleaning stethoscopes between patients is good infection control practice. (NIAID)

While stethoscopes can transmit the same germs as unclean hands, none of the doctors in a recent study bothered to clean them between patients.

And that was the case even after an educational intervention about the importance of stethoscope hygiene in preventing infections: Zero doctors wiped off the stethoscope between patient encounters, according to a study published in the July issue of the American Journal of Infection Control, the journal of the Association for Professionals in Infection Control and Epidemiology (APIC).

The team of doctors from Yale University School of Medicine and the department of medicine at Veterans Affairs Connecticut Healthcare System in West Haven, Connecticut, anticipated a poor result based on the low rates of stethoscope hygiene reported in other studies, but were still surprised no one disinfected their stethoscope.

The bad results were especially confounding because the institution checks second-year medical students’ compliance in an evaluation that demonstrates competency in performing a complete history and physical.

Infection control guidelines from the Centers for Disease Control and Prevention also say reusable medical equipment, such as stethoscopes, must undergo disinfection between patients.

“Stethoscopes are used repeatedly throughout the day and become contaminated after each patient exposure, so they must be treated as potential vectors of transmission. Failing to disinfect stethoscopes could constitute a serious patient safety issue similar to ignoring hand hygiene,” said APIC President Linda Greene, RN, in an announcement.

The doctors undertook a quality improvement pilot project in which they observed stethoscope hygiene, using alcohol swabs or gel or disinfectant wipes, at the start of a 4-week rotation for medical students, resident physicians and attending physicians at a tertiary care academic teaching hospital. No one bothered with stethoscope hygiene. They also observed for hand hygiene, via alcohol gel or soap and water.

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The team then educated clinicians about the importance of stethoscope hygiene between patient encounters, set the expectation that they follow the procedure and hinted they might monitor clinicians during a follow-up phase. Despite the effort, the physicians failed to clean their stethoscopes. 

The study authors said the project demonstrates that standard education may not be the answer to the problem and consistent efforts may be necessary to change culture and habits.

Hand hygiene has traditionally received much more attention than stethoscope hygiene, but the authors said microbiology data show that contamination of a stethoscope after a single patient exam is comparable to that of a physician’s dominant hand. Potential pathogens cultured from stethoscopes include Staphylococcus aureus, Pseudomonas aeruginosa, Clostridium difficile and vancomycin-resistant enterococci. And a recent Swiss study found that stethoscopes were capable of transmitting potentially resistant bacteria, including methicillin-resistant Staphylococcus aureus (MRSA).