Lead investigator Dr. Didier Pittet, director of the Infection Control Program and WHO Collaborating Centre on Patient Safety, University of Geneva Hospitals in Geneva, Switzerland, and colleagues assessed the level of bacterial contamination on physicians' hands and stethoscopes following a single physical examination.
The study involved 71 patients who were examined 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 were measured for the total number of bacteria present.
The researchers found the stethoscope's diaphragm was more contaminated than all regions of the physician's hand except the fingertips. Furthermore, 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 S.aureus.
"By considering that stethoscopes are used repeatedly over the course of a day, come directly into contact with patients' skin and may harbor several thousands of bacteria -- including MRSA -- collected during a previous physical examination, we consider them as potentially significant vectors of transmission," Pittet said in a statement.
"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."