Introduction
Clostridioides difficile (C. diff) is a gram-positive anaerobic bacillus that produces spores and presently represents a significant health threat. Studies show that C. diff infections can be contracted in the health care setting and require continued epidemiological monitoring.Reference Lessa, Gould and McDonald1 In addition to nosocomial infection, C. diff infection can also result from exposure to antibiotics as described by Kazakova, et al.Reference Kazakova, Baggs and McDonald2 Infection with C. diff causes clinical manifestations ranging from nausea and diarrhea to life-threatening colitis and even death, and the spores of C. diff are known to persist on common surfaces for extended periods of time and have been isolated from medical equipment.Reference Balsells, Filipescu and Kyaw3 Prior research by Gibson has also revealed that ambulances serve as potential reservoirs of pathogenic bacteriaReference Gibson4 and Emergency Medical Service (EMS) professionals may face challenges with disinfection of the patient compartment of ambulances as well as medical equipment due to a lack of universal disinfection protocols. The purpose of this study is to assess prehospital monitor/defibrillator equipment for contamination with C. diff. Monitor/defibrillators are used in the prehospital setting for performing defibrillation as well as obtaining vital signs, such as electrocardiogram (ECG) rhythm, non-invasive blood pressure, and pulse oximetry. Monitoring equipment used in the prehospital environment is often reused and must be thoroughly disinfected prior to reuse to avoid cross-contamination.
Materials and Methods
A large EMS station was selected for the study and serviced a municipality in Alabama (USA) with a population of approximately 200,000 residents. On March 22, 2019, samples were obtained from 20 Lifepak 15 monitor/defibrillators (Physio-Control; Redmond, Washington USA) located at the EMS station. Surface samples were collected from three areas of each Lifepak 15 monitor-defibrillator: the patient side of the blood pressure cuff, fingertip pulse oximeter sensor, and right arm monitor lead. The total samples collected were 60 (n = 60). Sterile wooden cotton-tipped applicators (Dynarex; Orangeburg, New York USA; Cat. # 4304) were saturated in an isotonic 0.85% Sodium Chloride solution (Hardy Diagnostics; Santa Maria, California USA; Cat. # K58), followed by a uniform surface sampling of each area. Immediately following surface sampling, the applicator was immersed in Banana Broth solution, rotated, scored at the midpoint, and released into a C. diff Banana Broth vial (Hardy Diagnostics; Cat. # K226). The vials were tightly sealed to promote an anaerobic environment and promptly transported to the laboratory for incubation. A total of 60 samples (n = 60) were incubated at 36°C for 72 hours. Following incubation, each Banana Broth vial was then inspected for a colorimetric change. A colorimetric change from red to yellow was considered a positive indication for the presence of C. diff. Each vial was examined, a positive or negative result determined, the data entered into a spreadsheet, and the frequency of positive results reported.
Results
A colorimetric change indicative of C. diff contamination was observed in 75% of the blood pressure cuffs (15 of 20), 95% of fingertip pulse oximeter sensors (19 of 20), and 100% of ECG right arm monitor lead samples (20 of 20) from the prehospital monitor/defibrillators.
Discussion
Prehospital monitor/defibrillators and other medical equipment may represent a significant reservoir of C. diff and other pathogenic bacteria. C. diff produces spores which are resistant to both chemical and physical disinfection, which necessitates that medical equipment undergo a thorough disinfection process following patient care to avoid cross-contamination. However, prehospital monitor/defibrillators and other medical equipment contain electronic components which are often sensitive to liquids, extreme temperatures, and harsh chemicals. Thus, conventional disinfection methods implemented in the prehospital setting may be inadequate. Disposable monitoring equipment are manufactured commercially and may offer a suitable alternative to reusable equipment with the benefit of reducing the chance of cross-contamination. The reason for wide-spread contamination of prehospital monitor/defibrillators could be attributed to the introduction of C. diff on the fingertips during routine hygiene practices following defecation then subsequent contamination of monitoring equipment during the monitoring procedure by the health care provider or the patient. This is especially true of the fingertip pulse oximetry sensors, which are in direct contact with the patient’s digits throughout monitoring.
Study Limitations
The limitations of this study were that it was a single site sampling and confirmatory testing was not performed on the vials.
Conclusion
Prehospital monitor/defibrillators and other medical equipment may act as a fomite. Thorough disinfection of reusable equipment or use of disposable supplies may help to avoid risk of cross-contamination.
Acknowledgements
The authors express gratitude to the EMS personnel for their assistance at the station where the study was conducted, members of the Calhoun Community College Biological Sciences Research Group, Matthew Gibson for his review of the manuscript prior to submission, and Daniel and Lori Gibson for their continued support.
Conflicts of interest/funding
The authors have not declared a specific grant for this research from any funding agency in the public, commercial, or not-for-profit sectors. No conflicts of interest declared.
Author Contributions
The authors acquired and analyzed the data. CVG, JES, and GDC wrote the first draft. Revisions were made, and the final draft was prepared and submitted.
