Key takeaways:
- At the end of a shift, 67.6% of EMS clinicians and 60% of ambulances harbored clinically important pathogens.
- A researcher said it was “surprising” so many clinician uniforms showed contamination.
A Duke University study showed that more than half of emergency medical service ambulances and about two-thirds of EMS clinicians harbor clinically important bacteria before and after work shifts.
The study confirmed the researchers’ expectations regarding high vehicle contamination while uncovering an unexpected trend of bacterial loads on clinicians, Diego Schaps, MD, MPH, a resident physician at Duke University Medical Center and former EMS ambulance clinician, told Healio.
Data derived from Schaps D, et al. Prehosp Emerg Care. 2026;doi:10.1080/10903127.2026.2681882.
“We anticipated there would be a high degree of ambulance contamination,” Schaps said. “It was surprising that so many EMS clinician uniforms were contaminated with clinically important pathogens (CIPs) before even starting their shifts.”
The prospective observational study collected 941 samples from 27 EMS clinicians and 20 ambulances. The vehicles and staff belonged to two central North Carolina agencies: a rural county 911 service and nonemergency medical transport agency.
Testing revealed that 63.1% of EMS clinicians carried at least one CIP before starting their shift, which rose to 67.6% by shift’s end. CIP contamination in the ambulances remained identical at 60% before and after shifts, according to the research.
Overall, 18.5% of samples from various locations from the ambulances and EMS clinicians harbored at least one CIP. Methicillin-susceptible Staphylococcus aureus (MSSA) was the most common (12.8%), followed by MRSA (4.6%) and vancomycin-resistant Enterococcus (3%). Clostridioides difficile was isolated from 0.1% of samples.
The study reported higher contamination in emergency 911 ambulances vs. those used for medical transport.
The researchers classified sampling locations into three categories: patient-facing surfaces, clinician-facing surfaces and EMS clinicians.
Patient-facing surfaces included samples from the blood pressure cuff, pulse oximeter, stretcher handles and electrocardiogram wires. Clinician-facing surfaces comprised the monitor/defibrillator handle, oxygen flow knob, EMS seat/bench, radio microphone, laptop keyboard, steering wheel, push handle on the stretcher, ceiling grab handle and countertop.
EMS clinician samples consisted of bilateral boots, shirt torso, pants and a single left nostril swab, which was included to evaluate whether clinician colonization with MRSA or MSSA is a potential link to contamination within the ambulance.
In the study, Schaps and colleagues noted that workers “were expected to disinfect high-use surfaces between calls and perform a terminal disinfection at the end of each shift, during which all surfaces were disinfected and floors were cleaned.” But “it is challenging” to ensure that the patient-facing surfaces have been thoroughly decontaminated between caring for different patients, Schaps said.
“EMS teams are working really hard to take care of patients and must be supported in their decontamination work. There is only so much time in a shift. This area is ripe for potential innovation to protect both patients and EMS clinicians from pathogens,” he said.
The motivation behind the study, Schaps said, was his days working as an ambulance emergency medical technician before going to medical school.
“I would take care of emergency patients and more stable transport patients,” he said, “and I was surprised by the differences that each hospital and EMS system had in their infection prevention and disinfection policies. I wondered whether these differences could be opportunities for improvement.”
After the study, Schaps said the results “got us thinking” about advocating for the health of both patients and clinicians in an EMS ambulance setting. Schaps and colleagues noted in the study that previous research has shown an association between EMS contamination and patient infections.
“Our group has been working to understand potential pathogen transmission in the medical transport environment better as we suspect there are many opportunities here for innovation and improving patient outcomes and protecting our EMS clinicians,” he said.
For more information:
Diego Schaps, MD, MPH, can be reached at infectiousdisease@healio.com.
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