Health-care associated infections (HAI) are a major cause of potentially preventable morbidity, mortality, and medical cost. Reducing spread of nosocomial pathogens (including via fomite transmission) is an important means of decreasing infectious complications. Study objectives were to 1) determine levels of bacterial colonization present on physician stethoscopes and 2) compare effectiveness of two waterless hand sanitizer products in reducing stethoscope bacterial counts.
100 study subjects (medical students, residents, and staff) at Walter Reed National Military Medical Center were randomly assigned to stethoscope disinfection with 62.5% ethyl alcohol foam or 63% isopropyl alcohol gel. Each participant completed a survey including demographics and stethoscope use habits. A total of 200 paired pre- and post-disinfection samples from each subject’s stethoscope were collected for microbial analysis. Samples were cultured on selective media to identify specific organisms. Descriptive statistics were used to analyze baseline bacterial levels, and Fisher’s exact test to compare effectiveness of the two hand sanitizers in reducing bacterial counts.
Data from all 100 participants were included in initial analysis of bacterial colonization. 39/100 stethoscopes had no bacteria present at baseline and were excluded from further analysis. 61/100 stethoscopes grew at least one potentially pathogenic Gram positive organism (MRSA, MSSA, or VRE). No Clostridium difficile and rare Gram-negative organisms were identified. Of the 61 stethoscopes with baseline colonization, 21/33 (63%) had no residual bacterial growth after cleaning with ethyl alcohol foam, while 24/28 (86%) had no growth after cleaning with isopropyl alcohol gel (p = 0.079).
A majority (61%) of stethoscopes were found to have bacterial colonization with potentially pathogenic Gram-positive cocci. Though no statistically significant difference between the two hand sanitizers was observed, there was a trend toward greater effectiveness of the isopropyl alcohol gel product compared to the ethyl alcohol foam at reducing stethoscope bacterial counts.
J. Danko, None
D. Tribble, None
C. Decker, None