Stethoscopes should be disinfected after each use because they pick up bacteria from a patient’s skin, a study has found.
The researchers from the University of Geneva assessed the level of bacterial contamination on physicians' hands and stethoscopes following a single physical examination.
Their findings, published in the March issue of Mayo Clinic Proceedings, revealed that stethoscopes had as many bacteria on them as the palms of doctors' hands, and only doctors' fingertips had more.
Cleaning stethoscopes regularly would cut down on transmission of bacteria, the researchers said.
Dr Didier Pittet, Director of the Infection Control Program and WHO Collaborating Centre on Patient Safety, University of Geneva Hospitals, said: "By considering that stethoscopes are used repeatedly over the course of a day, come directly into contact with patients' skin, and may harbour several thousands of bacteria (including MRSA) collected during a previous physical examination, we consider them as potentially significant vectors of transmission.
"From infection control and patient safety perspectives, the stethoscope should be regarded as an extension of the physician's hands and be disinfected after every patient contact."
A total of 71 patients were examined for the study by one of three physicians using sterile gloves and a sterile stethoscope. After they completed the examination, two parts of the stethoscope (the tube and diaphragm) and four regions of the physician's hands (back, fingertips, and thenar and hypothenar eminences) were measured for the total number of bacteria present.
The stethoscope's diaphragm was more contaminated than all regions of the physician's hand except the fingertips. Further, the tube of the stethoscope was more heavily contaminated than the back of the physician's hand. Similar results were observed when contamination was due to methicillin-resistant Staphylococcus aureus (MRSA) after examining MRSA-colonised patients.