It is well established that poor hand hygiene among healthcare professionals contributes to the spread of bacteria. However a new study has found that your doctor's stethoscope may be more contaminated than parts of their hands.

Swiss scientists set out to assess the level of bacterial contamination on doctors' hands and their stethoscopes following a single physical examination of a patient.

The study involved 71 patients who were examined by three doctors who used sterile gloves and a sterile stethoscope. After each examination, two parts of the stethoscope were tested for bacteria. The two parts were the tube and the diaphragm - the round part of the stethoscope that is placed on the patient.

Four parts of the doctors' hands were also analysed, including the palm and fingertips.

The study found that the stethoscope diaphragms were more contaminated with bacteria than the palms of the doctors' hands. In fact, they were more contaminated with bacteria than all of the parts of the doctors' hands, except for the fingertips.

The tube of the stethoscope was also found to be more contaminated with bacteria than the back of the doctors' hands.

Similar results were recorded when the contamination was due to the hospital superbug, MRSA.

"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," commented the study's lead investigator, Dr Didier Pittet, of the University of Geneva Hospitals.

The team added that from an infection control viewpoint, stethoscopes ‘should be regarded as an extension of the physician's hands and be disinfected after every patient contact'.

Details of these findings are published in the journal, Mayo Clinic Proceedings.