9 March 2005 - written by BUPA's Health information team What is MRSA?

MRSA is the name given to a group of bacteria that belong to the Staphylococcus aureus (SA) family of bacteria.

Most Staphylococcus aureus bacteria can be treated with medicines called methicillin-type antibiotics.

However, certain types of Staphylococcus aureus bacteria cannot be treated with methicillin-type antibiotics - the bacteria are resistant to these drugs. These are called MRSA bacteria:

M - methicillinR - resistantS - StaphylococcusA - aureus1 How did MRSA become resistant to methicillin-type antibiotics?

Whenever bacteria encounter an antibiotic (such as methicillin) some of the bacteria may be able to survive it. The surviving, methicillin-resistant bacteria can then multiply, potentially producing bacteria with even better resistance.

The chances of resistant bacteria developing have been increased by:1,4

failure to finish full courses of antibiotics, allowing bacteria with some resistance to survive and multiply overuse of antibiotics, meaning that bacteria encounter and survive a wide range of antibiotics

For information on MRSA outside of Alaska, please visit:MRSA-Information for the PublicCampaign to Prevent Antimicrobial Resistance in Healthcare Settings Non-Hospital Healthcare Settings Frequently Asked Questions What is Staphylococcus aureus?

Staphylococcus aureus, often referred to simply as "staph," is a bacteria commonly found on the skin and in the nose of healthy people. Occasionally, staphylococci can get into the body and cause an infection. This infection can be minor (such as pimples, boils, and other skin conditions) or serious and sometimes fatal (such as blood infections or pneumonia). Staph. aureus is a common organism and can be found in the nostrils of up to 30% of persons. Person-to-person transmission is the usual form of spread and occurs through contact with secretions from infected skin lesions, nasal discharge or spread via the hands.

Top of Page What is MRSA?

MRSA are staphylococci that are resistant to the antibiotic, methicillin, and other commonly used antibiotics such as penicillin and cephalosporins. These germs have a unique gene that causes them to be unaffected by all but the highest concentrations of these antibiotics. Therefore, alternate antibiotics must be used to treat persons infected with MRSA. Vancomycin has been the most effective and reliable drug in these cases, but is used intravenously and is not effective for treatment of MRSA when taken by mouth.

Top of Page What is the concern about MRSA?

The increasing frequency of antimicrobial resistance among infectious organisms is of great concern to both medical providers and the general public. Of particular concern is the possibility of spread of multi-drug resistant germs in the community. Since the first reported episode of methicillin resistant Staphylococcus aureus (MRSA) infection in the United States in 19681, the proportion of S. aureus isolates resistant to methicillin causing infections in hospitalized patients has risen significantly from 2% in 19742 to about 40% 1997. Over the past 20 years, infections with MRSA have been limited primarily to patients in hospitals or long-term care facilities. However, recent reports of "community- acquired" MRSA infections raise concern.

These infections, reportedly occur in otherwise healthy, non- hospitalized persons without contact with healthcare personnel or other colonized patients3. A report of MRSA infections leading to four deaths in previously healthy children demonstrated that MRSA infections can be community-acquired in persons with no exposure to the hospital system.4 This raises serious concerns about the possibility of transmission of MRSA outside the healthcare system. If MRSA becomes the most common form of Staphylococcus aureus in a community, it will make treatment of common infections much more difficult.5

Top of Page Staph. aureus and MRSA in Alaska

Infections due to S. aureus have long been common among rural Alaskans. In 1984, a large outbreak of Staph. aureus boils occurred in the village of Kotlik. These were due to a methicillin-sensitive strain. However, in 1996, an Alaska community reported an outbreak of boils caused by S. aureus in healthy persons6. In some of the patients cultures of revealed MRSA. Steam-bathing, a common practice among some Alaska populations, was associated with infection and especially the practices of bathing without sitting on a towel or use of personal soap7. Recent anecdotal reports from clinicians and laboratories in rural and urban Alaska indicate that infections due to MRSA are becoming increasingly common and present significant therapeutic challenges. These reports raise concerns that MRSA infections are more common and widespread that was previously realized.

In August 2000, health care providers in Southwestern Alaska reported an increase in MRSA skin infections among Alaska Natives, many of whom had no previous hospital exposure.8 The Arctic Investigations Program was invited by the Yukon Kuskokwim Health Corporation to conduct an investigation into this outbreak. By evaluating laboratory and medical records we found that large outbreak of community-onset MRSA infections occurred in Southwestern Alaska during 1999 and 2000. Over 80% of culture-confirmed S. aureus infections during this period were MRSA, 84% of MRSA infections involved skin or soft tissue, but more serious or invasive disease was rare.

Unlike a typical hospital-acquired MRSA, isolates from this outbreak were unlikely to be resistant to multiple antimicrobial classes. Patients with MRSA skin infections were more likely to have received an antimicrobial prescription in the 180 days before their infection than patients with methicillin-susceptible Staph. aureus skin infections. Steam bathing was also a factor in this outbreak. MRSA infections were more common among people who used more common steam baths and among persons who used steam baths that were found to be contaminated with MRSA.

These findings indicate a change in the epidemiology of MRSA in rural Alaska and suggest that the emergence of MRSA in this region was not related to spread of a hospital organism. Treatment guidelines were developed that recommend a change in first-line therapy for suspected S. aureus infections away from beta-lactam antimicrobials and to encourage health care providers to consider using treatments other than antibiotics for persons with mild skin infections.