Although studies have illustrated the importance of stethoscope hygiene and guidelines have been established, healthcare professionals rarely comply.

Infection control guidelines from the Centers for Disease Control and Prevention (CDC) state that reusable medical equipment, such as stethoscopes, must undergo disinfection between patients. Potential pathogens cultured from stethoscopes include Staphylococcus aureus, Pseudomonas aeruginosa, Clostridium difficile and vancomycin-resistant enterococci.

The risk of cross-transmission of bacteria through healthcare workers' hands has been studied extensively. But research looking at the contamination via stethoscopes is more recent.

In a Swiss study, researchers compared the contamination level of physicians' hands and stethoscopes and explored the risk of cross-transmission of microorganisms through the use of stethoscopes. After a standardized physical examination, four regions of the physician's gloved or ungloved dominant hand and two sections of the stethoscopes were pressed onto selective and nonselective media; 489 surfaces were sampled.

Total aerobic colony counts and total methicillin-resistant Staphylococcus aureus (MRSA) colony-forming unit counts were assessed. They found that stethoscopes were capable of transmitting potentially resistant bacteria, including MRSA.

These results provided strong evidence of the potential for stethoscope-mediated transmission of microorganisms and the need to systematically disinfect stethoscopes after each use.

Another study confirmed that stethoscopes used in emergency practice are often contaminated with staphylococci and are therefore a potential vector of infection. Researchers showed that cleaning the stethoscope diaphragm resulted in immediate reduction in the bacterial count by 94 percent with alcohol swabs, 90 percent with nonionic detergent, and 75 percent with antiseptic soap.

A new report in the American Journal of Infection Control shows that only 4.6 percent of trainees at three academic medical centers over an 11-month period used stethoscope hygiene. Researchers implemented a pilot project at a tertiary care Department of Veterans Affairs hospital consisting of provider education, reminder flyers and provision of cleaning supplies at the start of clinical rotations for house staff, medical students and attending physicians.

The researchers recorded baseline observations of stethoscope hygiene (alcohol swabs, alcohol gel or disinfectant wipes) and hand hygiene (alcohol gel or soap and water) between patients during the first week of a four-week period. Hand sanitizer dispensers were located in the hallways.

The intervention phase consisted of an interactive 11-slide presentation about stethoscope hygiene at intern report, resident report with attendings present, and nursing staff meetings on the wards. The point that either alcohol swabs or hand sanitizer were acceptable and equivalent (excluding Clostridium difficile) was emphasized, as was the expectation for stethoscope hygiene between each encounter for medical students, resident physicians and attending physicians.

Hand hygiene rates did not change significantly with rates between 58 percent and 63 percent, while stethoscope hygiene remained at zero. Although the researchers anticipated low stethoscope hygiene rates, they were surprised that no one performed stethoscope hygiene, despite the fact that it was on the checklist for second-year medical students' final evaluation demonstrating competency in performing a complete history and physical at the institution.

Failure to disinfect stethoscopes could be as serious as ignoring hand hygiene, and healthcare providers are rarely performing stethoscope hygiene between patients. The question remains: How can we change this?

Standard education may not be the answer to the problem. The implementation of stethoscope hygiene may need more consistent efforts to change behavior, such as consistent hygiene initiatives and increased accountability.