Next time you visit the doctor, ask her to wash her hands AND her stethoscope.

Hand washing has gotten plenty of well-deserved attention as a tool against the spread of infection in doctor’s offices, hospitals, and other health-care settings. But the trusty stethoscope, which touches patients almost as often as doctors’ hands but gets washed far less often, can harbor dangerous bacteria, according to new research.

The diaphragm of a stethoscope (the round piece that’s placed against your skin), can collect antibiotic-resistant bacteria, picking up more germs during a patient visit than any part of the doctor’s hands except for the fingertips, according to the study by Swiss researchers published yesterday in the journal Mayo Clinic Proceedings.

The tube of the stethoscope also can get dirty with bacteria.

Sterilizing a stethoscope after each patient, as the researchers did, is recommended, but few doctors do so, Didier Pittet, the study’s lead author, told Smithsonian magazine.

“Physicians forget to clean their hands quite frequently, even in the best places,” he told the magazine. “When they forget to clean their hands, they certainly forget to disinfect their stethoscope. And from my experience, even those who are really good models of hand hygiene likely forget to clean their stethoscopes most of the time.”

The study didn’t demonstrate that patients actually got sick from cross-contamination, but the potential is certainly there.

Preventing the spread of infection has become a top priority for hospitals, particularly given the rise of antibiotic-resistant “superbugs” such as MRSA. In addition to equipment, health care providers are also targeting their clothing in the fight against bacteria, including the traditional white coat.

At any given time, about one out of every 20 patients has an infection related to hospital care, according to the U.S. Centers for Disease Control and Prevention.