Drug-resistant strains of infectious bacteria are hitching a ride into hospitals through an under-appreciated path—the ambulance—according to a sample of 71 Chicago-area emergency response vehicles.
The researchers, led by James Rago of the Lewis University Department of Biology in Romeoville and members of the Orland Fire Protection District in Illinois, obtained samples from 26 sites in 71 ambulances from 34 Chicago area municipalities.
They found at least one isolate of Staphyloccocus aureus in 69% of all ambulances, and 77% showed resistance to at least one antibiotic, and one-third were resistant to two or more.
Ampicillin resistant strains were most common, found in 74% of all isolates, although 70% showed resistance to erythromycin. However, 12 of the samples, from only five of the 71 ambulances, tested positive for methicillin-resistant Staphylococcus aureus, which Rago said was somewhat reassuring.
Rago said that the study should prompt paramedic service personnel to pay more "meticulous attention to proper ambulance cleaning by the prehospital emergency care community."
"Since these surfaces come in contact with human skin quite often, one would expect to find S. aureus, and other similar bacteria, fairly often, regardless of how often the ambulances are disinfected," he said in response to emailed questions.
In a news release, Rago said the study's results indicate that first responders in general "are doing a good job of protecting their patients. The research is significant because improper cleaning of these surfaces could be a cause for concern due to the frequency with which emergency medical technicians may touch infected surfaces during patient care, the prevalence of open wounds among burn victims, and the fact that these patients go directly to the hospital where they come in contact with patients with compromised immune systems who are vulnerable to infections."
How often should ambulances be cleaned?
"The more, the better, within reason of course," Rago said in an email. "I would hope that consistent application of existing techniques would continue, and where appropriate, new and better techniques would be incorporated. But as I said in the article, a conscientious and consistent approach to what’s already in place is usually reasonably sufficient to protect both the members of the EMT community, and the general public as a whole."
"Given the frequency with which both patients and emergency care personnel contact various surfaces in ambulances, it should come as no surprise that almost 70% of ambulances yielded at least one S. aureus isolate," the authors wrote.