In the United States, nearly 100,000 people die annually from hospital-acquired infections (HAIs) in the acute care setting, and when nursing homes are included, the number of annual deaths linked to HAIs soars to over 400,000. Approximately 1.7 million HAIs occur annually in United States hospitals, resulting in costs estimated at up to $147 billion.(1,2) The CDC reports that 72,000 hospital patients with HAIs died during their hospitalization in 2015. Similarly, in Europe, HAIs cause 16 million extra days of hospitalization and 37,000 attributable deaths, and associated costs of about 7 billion euros per year.(2) Indirect costs, such as costs of litigation and plaintiffs’ verdicts, are also present. While it can be difficult to identify the causative source of an HAI, CDC guidelines state that “the stethoscope can be contaminated and spread disease.” Not surprisingly, a facility or hospital can be held liable for an HAI when hygiene measures were not performed.(3)

Pathogens from the practitioner’s hands are spread to the stethoscope, which functions as a “third hand” in the spread of disease. Efforts have been undertaken to combat this tragedy, mostly by hand hygiene initiatives, but the stethoscope worn around necks, thrust in pockets, and touched by unwashed hands, has been largely ignored. The stethoscope, the most frequently used medical instrument with over 5.5 billion annual auscultations in the United States alone, is a ubiquitous and valuable clinical tool. Looking just at cardiology, examples include presence of an S3 heart sound, which is highly predictive of left ventricular dysfunction, pericarditis without effusion, and pulmonary hypertension. More than 30% of HAIs are avoidable through stethoscope hygiene, hand hygiene, and particularly, simultaneous stethoscope and hand hygiene.(4,5) However, the vast majority of stethoscopes are contaminated and harbor staphylococcus aureus, pseudomonas aeruginosa, vancomycin-resistant enterococci, clostridium difficile and other pathogens.(6-15)

It was once thought that stethoscopes could be cleaned with isopropyl alcohol or isopropyl alcohol wipes, but no longer. Studies show that stethoscopes maintain significant rates of pathogen colonization after alcohol use. There is also evidence of pathogenic resistance to alcohol, while some pathogens are simply unaffected by alcohol.(16-22) Current stethoscope manufacturer recommendations to clean with alcohol or alcohol wipes, or clean only the diaphragm of the stethoscope and ignore the earpieces and tubing, are dramatically flawed. Pathogens causing disease are found on the diaphragm, earpieces, and tubing.(28-30) Concerns over degradation of earpieces and tubing due to stethoscope hygiene are misplaced because earpieces and tubing degrade slowly anyway. Cracks arise due to aging and exposure to human sweat. PVC material used to make some stethoscopes reacts to human skin, oils, and follicles, making them hard and resulting in cracks. Cracks arise from cleaning with alcohol. Hand sanitizers have additives that affect parts of the stethoscope. Solvents used in the hospital contribute to cracking.(31) An overwhelming number of medical publications report the sad reality that any form or extent of stethoscope self-cleaning is ineffectual, inconsistent, and almost never happens.(20-27)

Ultraviolet light emitted by light emitting diodes (LEDs) is a proven method of stethoscope disinfection.(32) The radiation with the most germicidal effect is represented by UV-C (200-280 nm). LEDs allow you to select the frequencies of interest to capture their effects on various species of microbes.(33)

References

1. https://www.infectioncontroltoday.com/view/keeping-the-stethoscope-the-clinician-s-third-hand-clean.

2. Wenzel R.P., Thompson R.L., Landry S.M., Russell B.S., Miller P.J., Ponce de Leon S., Miller G.B., Jr. Hospital-acquired infections in intensive care unit patients: An overview with emphasis on epidemics. Infect. Control. 1983;4:371–375. doi: 10.1017/S0195941700059774. 

3. B.A. Barnes, Negligence, medical malpractice, vicarious liability, or patient responsibility: who should pay when a patient contracts MRSA from a healthcare facility? Indiana Health Law Rev. (2010).

4. Messina G., Rosadini D., Burgassi S., Messina D., Nante N., Tani M., Cevenini G. Tanning the bugs—A pilot study of an innovative approach to stethoscope disinfection. J. Hosp. Infect. 2017;95:228–230. doi: 10.1016/j.jhin.2016.12.005.

5. Healthcare-associated infections data portal. Centers for Disease Control and Prevention website. https://www.cdc.gov/hai/data/portal/index.html. Accessed January 27, 2020.

6. O’Flaherty N., Fenelon L. The stethoscope and healthcare-associated infection: A snake in the grass or innocent bystander? J. Hosp. Infect. 2015;91:1–7.

7. Boulée D, Kalra S, Haddock A, Johnson TD, Peacock WF. Contemporary stethoscope cleaning practices: What we haven't learned in 150 years. Am J Infect Control. 2019 Mar;47(3):238-242. doi: 10.1016/j.ajic.2018.08.005. Epub 2018 Nov 2.

8. Longtin Y, Schneider A, Tschopp C, et al. Contamination of stethoscopes and physicians’ hands after a physical examination. Mayo Clin Proc 2014;89:291–299.

9. Schneider A, Tschopp C, Longtin Y, et al. Predictors of stethoscope contamination following a standardized physical exam. BMC Proc 2011;5:304

10. Guinto CH, Bottone EJ, Raffalli JT, Montecalvo MA, Wormser GP. Evaluation of dedicated stethoscopes as a potential source of nosocomial pathogens. Am J Infect Control 2002;30:499–502.

11. Queiroz JRA, Melo IO, Santos Calado GH, Cavalcanti LRC, Sobrinho CRW. Identification and resistance profile of bacteria isolated on stethoscopes by healthcare professionals: systematic review. Am J Infect Control 2021;49: 229–237.

12. Tschopp C, Schneider A, Longtin Y, Renzi G, Schrenzel J, Pittet D. Predictors of heavy stethoscope contamination following a physical examination. Infect Control Hosp Epidemiol 2016;37:673–679.

13. Marinella M, Pierson C, Chenoweth C. The stethoscope: a potential source of nosocomial infection? Arch Intern Med 1997;157:786–790.

14. Vasudevan RS. Observation of stethoscope sanitation practices in an ED setting. Am J Infect Control 2019;47:234−237.

15. Holleck JL, Merchant N, Lin S, Gupta S. Can education influence stethoscope hygiene? Am J Infect Control 2017;45:811–812.

16. Parmar RC, Valvi CC, Sira P,et al. A prospective, randomised, double-blind study of comparative efficacy of immediate versus daily cleaning of stethoscope using 66% ethyl alcohol. Indian J Med Sci 2004;58:423–430.

17. Russell A, Secrest J, Schreeder C. Stethoscopes as a source of hospital acquired methicillin-resistant Staphylococcus aureus. J Perianesth Nurs 2012;27:82–87.

18. Zachary KC, Bayne PS, Morrison VJ, Ford DS, Silver LC, Hooper DC. Contamination of gowns, gloves, and stethoscopes with vancomycin-resistant enterococci. Infect Control Hosp Epidemiol 2001;22:560–564.

19. Favero MS, Bond WW. Chemical disinfection of medical and surgical materials. In: Block SS, ed. Disinfection, Sterilization, and Preservation. Philadelphia: Lippincott Williams & Wilkins; 2001:881–917.

20. Pidot SJ, Gao W, Buultjens AH, et al. Increasing tolerance of hospital Enterococcus faecium to handwash alcohols. Sci Transl Med 2018;10(452): eaar6115.

21. Wilcox MH, Fawley WN. Hospital disinfectants and spore formation by Clostridium difficile. Lancet 2000;356:1324.

22. Jabbar U, Leischner J, Kasper D, et al. Effectiveness of alcohol-based hand rubs for removal of Clostridium difficile spores from hands. Infect Control Hosp Epidemiol 2010;31:565–570.

23. Alali SA, Shrestha E, Kansakar AR, Parekh A, Dadkhah S, Peacock WF. Community hospital stethoscope cleaning practices and contamination rates. Am J Infect Control 2020;48:1365−1369.

24. Nunez S, Moreno A, Green K, Villar J. The stethoscope in the ED: a vector of infection? Epidemiol Infect 2000;124:233–237.

25. Smith, ML. Mathewson JJ, Ulert IA, Scerpell EG, Ericsson CD. Contaminated stethoscopes revisited. Arch Int Med 1996;156:82–84.

26. Muniz J, Sethi RKV, Zaghi J, Ziniel SI, Sandora TJ. Predictors of stethoscope disinfection among pediatric healthcare providers Am J Infect Control 2012;40:922–925.

27. Saunders C, Hryhorskyj L, Skinner J. Factors influencing stethoscope cleanliness among clinical medical students. J Hosp Infect 2013;84:242–244.

28. Cohen SR, McCormack DJ, Youkhana A, Wall R. Bacterial colonization of stethoscopes and the effect of cleaning. J Hosp Infect. 2003;55(3):236–7.

29. Tang PH, Worster A, Srigley JA, Main CL. Examination of staphylococcal stethoscope contamination in the emergency department (pilot) study (EXSSCITED pilot study). CJEM. 2011;13(4):239–44.

30. Longtin Y, Schneider A, Tschopp C, Renzi G, Gayet-Ageron A, Schrenzel J, et al. Contamination of stethoscopes and physicians’ hands after a physical examination. Mayo Clin Proc. 2014;89(3):291 9. https://doi.org/10.1016/j.mayocp.2013.11.016. 

31. https://ultrascopes.com/blogs/news/why-does-my-stethoscope-tubing-crack#:~:text=Stethoscopes%20could%20crack%20from%20over,huge%20cracks%20on%20the%20tube.

32. Messina, G.; Burgassi, S.; Messina, D.; Montagnani, V.; Cevenini, G. A new UV-LED device for automatic disinfection of stethoscope membranes. Am. J. Infect. Control 2015,43, e61–e66.

33. Pyrek KM (2015) Understanding the Essential of Germicidal UV Light- Infection Control Today.