Stethoscopes Hold More Bacteria Than Physicians' Hands
A physician’s stethoscope contains more bacteria than most parts of his or her hands, according to the results of a recent study. This is the first study to compare the levels of contamination on stethoscopes with the levels of contamination on physicians' hands.
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“Bacterial colonization, assessed by quantitative culture techniques, was as high on the membrane of the stethoscope as that of the fingertips of physicians, and much higher than the colonization of other parts of the hands,” said senior author Didier Pittet, MD, MS, Infection Control Program and WHO Collaborating Centre on Patient Safety, University of Geneva Hospitals, and Faculty of Medicine, University of Geneva, Geneva, Switzerland.
To establish the dynamics of bacterial colonization on physicians’ stethoscopes, compare the contamination level of physicians’ hands and stethoscopes, and assess the potential risk of cross-transmission of bacterial pathogens associated with stethoscope use, researchers conducted a prospective 5-month study with 83 participants, some of whom were colonized with methicillin-resistant Staphylococcus aureus (MRSA).
All patients underwent a standard physical examination, after which the hand dorsum, fingertip, thenar eminence, and hypothenar eminence regions of the examining physician’s hand and the tube and diaphragm of the stethoscope that was used during the examination were sampled and assessed for total aerobic colony counts (ACCs) and total MRSA colony-forming unit (CFU) counts.
The median total ACCs were highest for the physicians’ fingertips (467 CFUs/25 cm2) and the stethoscope diaphragm (89 CFUs/25 cm2) compared with the thenar eminence (37 CFUs/25 cm2), hypothenar eminence (34 CFUs/25 cm2), hand dorsum (8 CFUs/25 cm2), and stethoscope tube (18 CFUs/25 cm2). Similarly, the median MRSA contamination levels were highest for the fingertips (12 CFUs/25 cm2) and the stethoscope diaphragm (7 CFUs/25 cm2) compared with the thenar eminence (4 CFUs/25 cm2), hypothenar eminence (2 CFUs/25 cm2), hand dorsum (0 CFUs/25 cm2), and stethoscope tube (0 CFUs/25 cm2).
In addition, “There was a close correlation between the intensity of bacterial colonization on fingertips and the membrane of the stethoscope, for both commensal flora and multi-resistant pathogens, such as MRSA,” said Pittet.
According to the discussion, it is generally recognized that stethoscopes are not disinfected regularly.
These study findings are significant in that they may change clinical practice, according to Pittet.
“The same as hands should be cleaned according to the ‘My 5 Moments for Hand Hygiene’ during patient care, and in particular immediately after a contact with a patient, stethoscopes should be cleaned or disinfected immediately after each use at the end of a physical examination,” he said.
This study was published in Mayo Clinic Proceedings.
-Meredith Edwards White
Longtin Y, Schneider A, Tschopp C, et al. Contamination of stethoscopes and physicians' hands after a physical examination. Mayo Clin Proc. 2014 Mar;89(3):291-9. doi: 10.1016/j.mayocp.2013.11.016.