Stethoscopes and otoscopes--a potential vector of infection?

• Published in: Family practice 1997-12, Vol.14 (6), p.446-449
• Main Authors: Cohen, H A, Amir, J, Matalon, A, Mayan, R, Beni, S, Barzilai, A
• Format: Article
• Language: English
• Subjects: Community Health Centers; Control; Cross Infection - transmission; Disease Reservoirs; Equipment Contamination; Gram-Positive Bacteria - isolation & purification; Humans; Israel; Methicillin Resistance; Nosocomial infections; Otoscopes - microbiology; Paediatric units; Pediatrics; Sources; Staphylococcus aureus - isolation & purification; Stethoscopes - microbiology
• ISSN: 0263-2136; 1460-2229
• DOI: 10.1093/fampra/14.6.446

We aimed to determine whether stethoscopes and otoscopes used in community paediatric clinics harboured pathogenic micro-organisms, and, if so, which measures could prevent this. Fifty-five stethoscopes belonging to paediatric physicians working in 12 community clinics were sampled for bacterial cultures by two methods: (i) direct impression of the diaphragm and bell section of each stethoscope for 5 seconds onto blood agar plates and a mannitol-salt-agar plate; (ii) swabbing the entire surface of the diaphragm of the stethoscope with a sterile cotton-tipped applicator. Forty-two otoscopes from the same physicians were sampled by rubbing the handles of the otoscopes with cotton-tipped swabs. The plates were incubated at 37 degrees C for 48 hours and examined for colony growth at 24 and 48 hours of incubation. Culture results were recorded as mean numbers of colony-forming units (CFUs). Eight additional stethoscope diaphragms were chosen at random at the participating clinics and cultured as described above. They were then wiped with alcohol swabs (isopropyl alcohol 70%), allowed to air dry for approximately 10 minutes and cultured a second time. All the stethoscopes and 90% of the otoscope handles were colonized by microorganisms. Staphylococci were isolated from 85.4% of the stethoscopes and 83.3% of the otoscopes, with 54.5% and 45.2% respectively being S. Aureus. Methicillin-resistant S. aureus were found in four each of the stethoscopes (7.3%) and otoscopes (9.5%). Cleaning with alcohol reduced the colony count by an average of 96.3%. Fomites can harbour potentially pathogenic bacteria, and with the increasing trend for children with more complex medical problems to be managed in an ambulatory setting, often by physicians who also work in hospitals, there is a real risk of spreading potentially serious infections to such patients. Simple cleansing with alcohol effectively eliminates the bacterial contamination of the fomites, and should be encouraged.