Prevalence of methicillin-resistant Staphylococcus aureus in ambulances in southern Maine

To determine whether methicillin-resistant Staphylococcus aureus (MRSA) could be found in ambulances in a predominantly rural state.

Samples were obtained from specified areas in 51 ambulances in southern Maine. These samples were tested on mannitol salt agar containing 4 microg/mL oxacillin. Resulting colonies were gram-stained and tested for the presence of catalase and coagulase.

Of the 51 ambulances tested, 25 (49%) had at least one area positive for MRSA contamination.

A significant number of ambulances operating in southern Maine have MRSA contamination, and ambulances may represent an important reservoir for the transmission of potentially serious infections to patients and EMS personnel. There was no statistical difference between the service types (fire-based vs. non-fire-based) or annual call volume. There was, however, a statistically significant lower rate of contamination in services that provided paid, 24-hour coverage versus those that did not.