Physicians' Stethoscopes Hoard Bacterial Contamination

A new study confirms that stethoscope contamination is not trivial, and is comparable to the contamination level of healthcare workers' fingertips, the hand region most implicated in microbial cross-transmission.

Researchers at University of Geneva Hospitals (Switzerland) conducted a structured prospective study between January 1, 2009, and May 31, 2009, involving 83 inpatients. After a standardized physical examination, four regions of the physician’s gloved or ungloved dominant hand (the back, fingertips, and thenar and hypothenar eminences) and two sections of the stethoscopes (the tube and diaphragm) were pressed onto selective and nonselective media; in all, 489 surfaces were sampled. Total aerobic colony counts (ACCs) and total methicillin-resistant Staphylococcus aureus (MRSA) colony-forming unit (CFU) counts were assessed.

The results showed that the stethoscope's diaphragm contained contamination levels that were lower than the contamination level of the fingertips, but higher than the contamination level of the thenar eminence. 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 MRSA after examining MRSA-colonized patients. The study was published in the March 2014 issue of Mayo Clinic Proceedings.

“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 collected during a previous physical examination, we consider them as potentially significant vectors of transmission,” concluded lead author Pittet, MD, MS, director of the infection control program at University of Geneva Hospitals. “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.”

Related Links:
University of Geneva Hospitals