Stethoscopes are More Contaminated than Physicians’ Hands

A latest study reveals that not only medical personnels' hands but stethoscopes are also a source of infection as they transmit bacteria.

Stethoscopes, considered an extension of the physician's hands, are found to be more heavily contaminated by bacteria than the palms of a doctors' hand ( as opposed to fingertips). This is the first study to evaluate the level of contamination present on the hands of the physician and the stethoscope present around the physician's neck.

The investigation was led by researchers at the University of Geneva Hospitals and suggests that hands of hospital workers are still the main source of contamination and extra care should be taken to see that this risk is cut down. They emphasize that stethoscopes should b sterilized after every examination.

As a part of the investigation, one out of three physicians examined 71 patients using sterile gloves as well as a sterile stethoscope. At the end of the examination, the two parts of the stethoscope, mainly the tube and the diaphragm as well the four regions of the physician's hands (back, fingertips and thenar and hypothenar eminences) were examined. The researchers measured the total number of bacteria harboring in these regions.

The researchers noticed that the diaphragm of the stethoscope was highly contaminated compared to other regions of the physician's hand except for the fingertips. The tube of the stethoscope was also more contaminated compared to the back of the hand.

When the researchers checked for the levels of MRSA contamination (meticillin-resistant staphylococcus aureus) in particular, they noticed the same results. The stethoscopes were more highly infected than the hand.

"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. 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," said lead investigator Didier Pittet, MD, MS, Director of the Infection Control Program, University of Geneva Hospitals.

The study claims that more research is needed to understand how the stethoscope can be sterilized and also how long does a bacteria survive on a stethoscope and how it is being transmitted to the patients, according to BBC reports.

"Germs are acquired from the patient's skin in contact with the stethoscope, the same way hands usually get colonized with the patient's germs.  It's clear cleaning hands with alcohol-based gel is most important to prevent cross contamination with bacteria. But if your hands are clean and your stethoscope is not, it's counterproductive," said Pittet, who is also the Director at WHO Collaborating Centre on Patient Safety.

The study provides sufficient evidence that physicians should consider the importance of regularly cleaning the stethoscope and contamination of tools should not be ignored.

The study appears in Mayo Clinic Proceedings.