Hosting the Unwanted: Stethoscope Contamination Threat

Aims: Stethoscopes represent a vehicle of bacteria and other microorganisms and may play a role in the spread of health-care associated infections (HAIs). We aimed to evaluate the contamination levels of stethoscopes before and after use of a disinfecting technique (DT).
Study Design: Matched cross-over study.
Place and Duration of Study: The study was conducted in July 2012 and involved three hospitals in Siena Province (Italy). Two were public hospitals with about 750 and 140 beds, and the other was private with 40 beds.
Methodology: We evaluated: i) contamination on 74 shared and non shared stethoscopes; ii) bacterial load before and after use of a DT. Total bacterial count (TBC) at 36ºC and 22ºC, Staphylococcus spp., molds, Enterococcus spp., Pseudomonas spp., Escherichia coli and total coliforms bacteria were evaluated. Mann Whitney and Wilcoxon tests were used for comparisons (p<0.05).
Results: Before DT, 49 stethoscopes were positive for TBC at 36ºC, 48 for TBC at 22ºC, 40 for Staphylococcus spp., 18 for methicillin-resistant Staphylococcus aureus, 33 for coliforms (9 for Escherichia coli), 5 for Enterococcus spp. and 2 for molds. After cleaning, the percentage reduction in CFUs was close at 100% in most comparisons. Shared stethoscopes proved to be less contaminated than non shared ones (p<0.05).
Conclusion: Our results suggest that stethoscopes may be potential vehicles of HAIs. The DT was effective in reducing bacterial contamination.