Image from MedPageToday

Published: Feb 27, 2014
By Crystal Phend, Senior Staff Writer, MedPage Today

Stethoscopes carried more methicillin-resistant Staphylococcus aureus (MRSA) and other bacteria after a physical exam than most areas of the physician’s hand, a study showed.

MRSA contamination on the stethoscope diaphragm after a single physical exam was higher than that of all areas of the hand except the fingertips (P=0.02 toP<0.001), Didier Pittet, MD, of the University of Geneva Hospitals in Switzerland, and colleagues found.

Fingertips were by far the dirtiest, with a median of 467 total aerobic bacterial colony forming units/25 cm², they reported in the March issue of the Mayo Clinic Proceedings.

But the diaphragm of the stethoscope was more contaminated overall than other areas of the hand, averaging 89 colony forming units/25 cm² versus 37 at the base of the thumb, 34 at the base of the pinkie finger, and 8 on the back of the hand (P=0.004 to P<0.001).

Most stethoscopes don’t get cleaned even once a month, if at all, Pittet’s group noted.

But “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,” they argued.

Edward Septimus, MD, of Texas A&M University in College Station and a member of the on antimicrobial resistance committee of the Infectious Diseases Society of America, agreed.

“If we pay attention to hand hygiene, using an alcohol swab to disinfect the stethoscope between patients should have an impact on reducing a percentage of transmission from patient to patient,” he told MedPage Today.

There’s probably little downside to cleaning stethoscopes, agreed a surgeon who blogs anonymously as Skeptical Scalpel and who has been critical of what he has called a “veritable cottage industry of papers identifying contamination of nearly every inanimate object you can think of.”

However, “most hospitals have a policy of leaving a dedicated stethoscope in the room of each patient with MRSA,” he told MedPage Today. “To me, this renders that whole portion of the study moot.”

Yet for every known MRSA or other multidrug resistant pathogen-infected patient, “there are many more patients on that same patient care unit with undetected colonization — patients who pose a greater risk of spreading these microorganisms than patients known to be colonized or infected and in isolation,” Dennis G. Maki, MD, of the University of Wisconsin School of Medicine and Public Health in Madison, noted in an accompanying editorial.

The bigger issue perhaps was that most of the organisms cultured from the physicians’ dominant hand and stethoscopes weren’t identified in the prospective study of inpatient physical exams of 83 MRSA-colonized patients at a Swiss academic hospital.

“Since skin normally harbors benign bacteria, it is possible that the levels of contamination they found might not pose a risk to most patients,” Skeptical Scalpel said in an email.

Nor was there any attempt to show how significant a factor that transmission was in actual infections, Septimus noted, calling it “the missing link in many of these studies.”

The implications of the study are probably just as much about hand-washing, Skeptical Scalpel suggested.

Maki, though, argued “that it is now time for the use of dedicated stethoscopes with all ICU patients and a case can be made for all hospitalized patients.”

Complaints about poor quality, barely functional stethoscopes for that purpose could be obviated by perhaps using “unique and garish pattern on the tubing (eg, iridescent orange or striped) to deter theft, the major impediment to hospitals purchasing more expensive, high-quality institutional stethoscopes,” he suggested.

Full Story