Stethoscopes: A Potential Source of Nosocomial Infections

Francis Marie C. Africa-Purino, Emmanuel Edwin R. Dy, Remedios F. Coronel
Department of Infectious Diseases and Tropical Medicine, Division of Medicine, Santo Tomas University Hospital, Espana, Manila
Phil J Microbiol Infect Dis 2000; 29(2):9-13

Nosocomial infections remain a significant hazard for hospitalized patients. Stethoscopes because of their universal use by medical professionals, can be a potential source of nosocomial infections. This study was undertaken to determine the stethoscope-cleaning practices among medical health providers at the Infectious Ward of the Santo
Tomas University Hospital; to show whether the stethoscope is a potential source of nosocomial infection; and to compare the effectiveness of common antiseptics (i.e. soap and water, 70% isopropyl alcohol and hypochlorous acid in solution) in disinfecting stethoscopes.
Health care providers were asked how often they clean their stethoscopes and what is their cleansing agent of choice. Cultures were then obtained from the diaphragm of 30 randomly chosen stethoscopes, after disinfecting with soap and water, 70% isopropyl alcohol or hypochlorous acid in solution. The transmissibility of human skin flora to the
diaphragm of disinfected stethoscopes was also determined.
Results show that 63.3% of health care providers (19 of 30) cleaned their stethoscope a week to a year prior to the survey with 16.7% (5 of 30) doing it monthly and 47% (14 of 30) doing it once yearly while 36.7% (11 of 30) had never cleaned their stethoscopes. There is a trend showing that residents seem to practice disinfection of their
stethoscopes more frequently than the other groups surveyed. Alcohol was the preferred agent for cleaning. Fifty seven of the disinfected stethoscopes’ diaphragms (17 of 30) that were placed on patient's chest grew Staphylococcus aureus.
Cleaning of the stethoscope with soap and water, 70% isopropyl alcohol or hypochlorous acid in solution resulted in the disinfection of the stethoscope sampled.
Our results confirm that stethoscopes can be a potential source of infection. This contamination can be greatly reduced by cleansing with soap and water, 70% isopropyl alcohol or hypochlorous acid in solution. We recommend the disinfection of stethoscopes regularly.