Epi Corner: 2004 review

Epidemiology Corner

April 8, 2005

Methicillin Resistant Staphylococcus aureus (MRSA)

Staphylococcus aureus, often referred to simply as "staph," are bacteria commonly carried on the skin or in the nose of healthy people. In other words, the bacteria are present, but not causing an infection. According to the Centers for Disease Control (CDC), approximately 25% to 30% of the population has staph bacteria in their nose. Only about 1% of people are colonized with Methicillin Resistant Staphylococcus aureus (MRSA). MRSA is a type of Staphylococcus aureus that is resistant to the antibiotic methicillin and other related antibiotics such as oxacillin, penicillin and amoxicillin. Staph bacteria are one of the most common causes of skin infections in the United States.

Staph infections, including MRSA, occur most frequently among persons with weakened immune systems in hospitals or other healthcare facilities such as nursing homes or dialysis centers. These staph infections are considered to be healthcare-associated. Healthcare-associated staph infections may include bedsores, surgical wound infections, meningitis, urinary tract infections, bloodstream infections or pneumonia.

Staph and MRSA can also cause illness in persons outside of hospitals and healthcare facilities. MRSA infections that are acquired by persons who have not been hospitalized or have not had dialysis, surgery, a catheter or another medical procedure within the last year are known as community-associated infections.

According to the CDC, data from a prospective (forward looking) study in 2003, suggests that 12% of MRSA infections may be community-associated. Community-associated staph or MRSA infections are usually skin infections in healthy people that may look like a pimple or boil and can be red, swollen, painful or have pus or other drainage. Rarely, they may cause more serious infections such as pneumonia, bloodstream infections or bone infections which can be fatal.

Community-associated MRSA skin infections are more commonly found among athletes, military recruits, children, men who have sex with men and prisoners. MRSA skin infections can be spread through close skin-to-skin contact, contact with objects or surfaces that have been contaminated with the bacteria or improper care of openings in the skin such as cuts or abrasions. Crowded living conditions and poor hygiene can also play a role in MRSA transmission.

You can protect yourself from infections by practicing good hygiene.

Keep your hands clean by washing thoroughly with soap and water or using an alcohol-based hand sanitizer.
Keep cuts and scrapes clean and covered with a bandage until healed.
Avoid contact with other people’s wounds or bandages.
Avoid sharing personal items such as towels, washcloths or razors.

For more information about MRSA and staph infections, visit the CDC website at http://www.cdc.gov/ncidod/diseases/submenus/sub_mrsa.htm