New York, Feb 28 (IANS): What is more contaminated in hospitals, doctors' hands or his stethoscope? Research indicates towards the latter.

Although healthcare workers' hands are the main source of bacterial transmission in hospitals, physicians' stethoscopes appear to play a role.

"Stethoscopes are used repeatedly and come directly into contact with patients' skin. These may harbour several thousands of bacteria. We consider them as potentially significant vectors of transmission," said Didier Pittet, director of infection control programme and World Health Organisation (WHO) centre on patient safety at Geneva University Hospitals (HUG).

The stethoscope should be regarded as an extension of the physician's hands and be disinfected after every patient contact, he noted.

To explore this, investigators at Geneva University Hospitals assessed the level of bacterial contamination on physicians' hands and stethoscopes following a single physical examination.

In this study, 71 patients 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 (back, fingertips, and thenar and hypothenar eminences) were measured for 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.

This work is the first to compare directly the level of contamination of physicians' hands and stethoscopes.

Physicians must be aware of the need to disinfect their stethoscope after each use, suggested the study that appeared in the journal Mayo Clinic Proceedings.