Aseptic Stethoscope Barriers Prevent C difficile Transmission In Vitro

W Frank Peacock; Sarathi Kalra; Rajiv S Vasudevan; Francesca Torriani

doi:10.1016/j.mayocpiqo.2020.10.002

Aseptic Stethoscope Barriers Prevent C difficile Transmission In Vitro

Mayo Clin Proc Innov Qual Outcomes. 2021 Jan 13;5(1):103-108. doi: 10.1016/j.mayocpiqo.2020.10.002. eCollection 2021 Feb.

Authors

W Frank Peacock¹, Sarathi Kalra², Rajiv S Vasudevan³, Francesca Torriani³

Affiliations

¹ Department of Emergency Medicine, Baylor College of Medicine, Houston, TX.
² Department of Emergency Medicine, University of South Alabama, Mobile, AL.
³ Department of Medicine, University of California San Diego School of Medicine, San Diego, CA.

Abstract

Objective: To evaluate whether Clostridioides (formerly Clostridium) difficile-contaminated stethoscope diaphragms remained aseptic by the placement of an aseptic diaphragm barrier.

Methods: On November 1, 2019, fresh cultures of C difficile were diluted to 10⁷ colony-forming units (CFU)/mL and used to inoculate 16 stethoscope diaphragms; 8 had an aseptic diaphragm barrier applied and 8 served as nonbarrier controls. Contaminated stethoscopes were anaerobically incubated, then swabbed at 15 and 30 minutes, 2 and 4 hours, and 1, 2, 3, and 7 days after inoculation and subsequently plated onto blood, chocolate, and cycloserine-cefoxitin fructose agar. Plates were incubated for 48 hours and on November 9, 2019, the resulting colonies were manually counted. Statistical analyses (RStudio, version 1.0.153) used analysis of variance with post hoc Tukey honestly significant difference.

Results: Overall, mean colony count was 33 CFU on stethoscopes without barriers vs zero on those with barriers (P≤.05). Growth was greatest at 48 hours, with colony counts as high as 160 CFU. The presence of the barrier resulted in no growth in 100% of stethoscope diaphragms for up to 1 week.

Conclusion: We found that stethoscope diaphragm barriers provide an aseptic patient contact point, thus reducing the potential for transmission of C difficile during the physical examination. In critical care environments, in which many hospitals use acoustically inferior disposable stethoscopes, the option of a disposable aseptic stethoscope barrier may allow high-quality auscultation while reducing the potential for pathogen transmission.

Keywords: CCFA, cycloserine-cefoxitin fructose agar; CDI, Clostridioides (formerly Clostridium) difficile infection; CFU, colony-forming unit; MDRO, multidrug resistant organism; VRE, vancomycin-resistant Enterococcus.