IAFC On Scene: August 15, 2010
Methicillin-resistant Staphylococcus aureus (MRSA) was first identified in the 1960s, and in the last 10 years, it has become a major pathogen. MRSA can be transmitted from any inanimate object (formites) to a person as well as person to person. Because of this, patient-to-firefighter and firefighter-to-firefighter transfers have become an increasing concern.
MRSA has also been isolated from razors, towels, gym equipment, bar soap, mops and a variety of medical equipment. MRSA colonization—the presence of the bacteria, but no signs of illness or infection—is a known risk factor for future MRSA infections. Other known risk factors for MRSA infections in the community at large include previous antibiotic therapy, extensive hospital stays, surgery, living in a long-term care facility, kidney dialysis, the presence of invasive medical devices and interaction with people infected with MRSA.
Unfortunately, community-acquired (CA) MRSA infections are on the rise, and outbreaks of skin and soft-tissue infections have occurred among healthy firefighters with no health-care exposure or known classical risk factors. Some risk factors associated with CA-MRSA outbreaks include:
– Shared personal care products
– Frequent skin-to-skin contact
– Skin abrasions
– Crowded living conditions
– Treating people with MRSA infections
In today’s environment, it’s likely that firefighters and paramedics will treat patients with current or past MRSA infections or who are currently colonized with MRSA. A recent Tucson, Ariz., study sampled commonly touched sites at nine fire-related occupational and training facilities. Of 160 sites sampled, 6.9% were MRSA-contaminated.
In that study, the couches with soft, porous material had the highest percentages of MRSA contamination while no MRSA was found on the surfaces of their ambulances or fire trucks. In contrast, a 2010 study found 49% of ambulances in southern Maine were contaminated with MRSA.
There was no statistical difference between fire-based vs. non-fire-based ambulances 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 didn’t.
A recent yearlong study of two Northwest fire stations from two different fire districts was conducted by Dr. Roberts (one of the authors) and colleagues at the School of Public Health at the University of Washington in Seattle. The study isolated MRSA from 44 (4.2%) of 1,060 samples examined and included USA300 and hospital-like (HA) MRSA isolates.
USA300: Genetically related isolates which causes >90% of common CA-MRSA infections in the USA; infects people with no risk factors in the community and is now found in the hospital.
MRSA was isolated from samples taken from the inside and outside surfaces of fire apparatus (medic/aide rigs, engines and trucks) as well as specific equipment and equipment bags, fire-station garage floors, water coolers, computer keyboards, kitchen appliances, phones, TV remote controls, cloth chairs, desks, bathroom and gym surfaces, washing machines and fire-protection clothing. The same strains of MRSA were found in both the dirty apparatus sections and the clean living quarters.
A recent study from Children’s Hospital Los Angeles suggests MRSA can survive on some nonporous surfaces up to eight weeks following contamination—and skin transmission takes only three seconds. In addition, the presence of organic matter generally increases the survival of pathogenic bacteria fomites. Surfaces visibly soiled provide the perfect medium for the possibility of increased exposure to surviving pathogens, causing a higher probability of exposure to MRSA than a cleaned surface.
In the community at large, 25-35% of the population is colonized with S. aureus and 0-2% with MRSA. As part of the University of Washington study, nasal colonization was examined in 40 firefighters within one of the fire districts. In this small sample, 22.5% of the personnel were colonized with MRSA and 10% colonized with Staphylococcus aureus. The majority of the nasal MRSA/S. aureus isolates were genetically related to the environmental fire station MRSA strains, suggesting transmission between personnel and environmental surfaces may be occurring.
The University of Washington MRSA grant was funded by Washington State Safety & Health Investment Projects.
To reduce the levels of MRSA contamination, the recommendations derived from the University of Washington study included the following:
– Use cleaners/disinfectants that are EPA-registered for MRSA
– Daily clean each of the following:
– fire apparatus and medic/aid car interiors with appropriate disinfection products
– kitchen area, including appliances
– all apparatus floors
– all fire station floors
– Weekly cleaning of mop heads and sponges with disinfectant
– Station uniforms cleaned and left at the station
– Discontinue placing feet on furniture
– When buying new furniture make sure it is easily cleanable surface and eliminate cloth fabrics
Skin rashes and/or infections, which do not improve within 2-3 days with topical over the counter antibiotics, should be seen by a clinician.
Personnel with repeated MRSA infections should discuss with their doctor decolonization of fire personnel and potentially family members.
Record keeping should be done to determine if any one station is having a cluster of MRSA infections, which would require additional protocols to reduce spread between personnel from continuing.
Marilyn C. Roberts, PhD, is a professor in the School of Public Health, University of Washington. Her current research includes identification of MRSA on environmental surfaces and how to reduce contamination levels of these surfaces. Kim C. Favorite is the Occupational Health & Fitness Coordinator for the Seattle Fire Department. She’s a member of the IAFC’s Safety, Health and Survival Section and has been a technical advisor for the Fire Service Joint Labor-Management Wellness-Fitness Initiative since 1996.