Blog | Tuesday, March 4, 2014

QD: News Every Day--Stethoscopes can be as dirty as clinicians' hands


Physicians interested in eliminating vectors for MRSA transmission are running out of things that don’t get contaminated during the work day. Researchers assessed the level of bacterial contamination on physicians’ hands and stethoscopes following a single physical examination and found the tools were as dirty as the hands.

In this study, researchers at the University of Geneva Hospitals examined 71 patients seen by 1 of 3 physicians using sterile gloves and a sterile stethoscope. After a standardized physical examination, 4 regions of the physician’s gloved or ungloved dominant hand, back, fingertips, and thenar and hypothenar eminences, and 2 sections of the stethoscopes, the tube and diaphragm, were pressed onto selective and nonselective media. Total aerobic colony counts (ACCs) and total methicillin-resistant Staphylococcus aureus (MRSA) colony-forming unit (CFU) counts were assessed.

Results appeared in the March issue of Mayo Clinic Proceedings.

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. Similar results were observed when contamination was due to MRSA.

Specifically, median total ACCs were 467 for fingertips, 37 for the thenar eminence, 34 for the hypothenar eminence, 8 for the hand dorsum, 89 for the stethoscope diaphragm, and 18 for the tube. Contamination level of the diaphragm was lower than the contamination level of the fingertips (P<0.001) but higher than the contamination level of the thenar eminence (P=0.0004). The MRSA contamination level of the diaphragm was higher than the MRSA contamination level of the thenar eminence (7 CFUs/25 cm2 vs. 4 CFUs/25 cm2; P=0.004).

The correlation analysis for both total ACCs and MRSA CFU counts revealed that the contamination level of the diaphragm was associated with the contamination level of the fingertips (Spearman’s rank correlation coefficient, r=0.80; P<0.001 and r=0.76; P<0.001, respectively). Similarly, the contamination level of the stethoscope tube increased with the increase in the contamination level of the fingertips for both total ACCs (r=0.56; P<0.001) and MRSA CFU (r=0.59; P<0.001). “This observation suggests that the patient’s skin and immediate surroundings are the common denominators and determinants of both physicians’ hands and stethoscope contamination,” researchers wrote.

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, the authors noted.

Clinicians generally don’t clean their stethoscopes, the authors noted.

“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. Thus, failing to disinfect stethoscopes could constitute a serious patient safety issue akin to omitting hand hygiene. Hence, 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.”