Predictors of Heavy Stethoscope Contamination Following a Physical Examination

BACKGROUND. The degree of bacterial contamination of stethoscopes can vary significantly following a physical examination. OBJECTIVE. To conduct a prospective study to investigate the impact of various environmental and patient characteristics on stethoscope contamination. METHODS. Following a standardized examination, the levels of bacterial contamination of 4 regions of the physicians' hands and 2 sections of the stethoscopes, and the presence of different pathogenic bacteria, were assessed. Predictors of heavy stethoscope contamination were identified through multivariate logistic regression. RESULTS. In total, 392 surfaces were sampled following examination of 56 patients. The microorganisms most frequently recovered from hands and stethoscopes were Enterococcus spp. (29% and 20%, respectively) and Enterobacteriaceae (16% and 7%, respectively). Staphylococcus aureus (either methicillin susceptible or resistant), extended-spectrum beta-lactamase-producing Enterobacteriaceae, and Acinetobacter baumannii were recovered from 4%-9% of the samples from either hands or stethoscopes. There was a correlation between the likelihood of recovering these pathogens from the stethoscopes vs from the physicians' hands (rho= 0.79; P =.04). The level of patient's skin contamination was an independent predictor of contamination of the stethoscope diaphragm (adjusted odds ratio [aOR], 1.001; P=.007) and tube (aOR, 1.001; P=.003). Male sex (aOR, 28.24; P=.01) and reception of a bed bath (aOR, 7.52; P=.048) were also independently associated with heavy tube contamination. CONCLUSIONS. Stethoscope contamination following a single physical examination is not negligible and is associated with the level of contamination of the patient's skin. Prevention of pathogen dissemination is needed.