MRSA Overview

Methicillin-resistant Staphylococcus aureus (MRSA) is a type of bacteria that is resistant to certain antibiotics. These antibiotics include methicillin and other more common antibiotics such as oxacillin, penicillin and amoxicillin. Staph infections, including MRSA, occur most frequently among persons in hospitals and healthcare facilities (such as nursing homes and dialysis centers) who have weakened immune systems.

MRSA infections that occur in otherwise healthy people who have not been recently (within the past year) hospitalized or had a medical procedure (such as dialysis, surgery, catheters) are known as community-associated (CA)-MRSA infections. These infections are usually skin infections, such as abscesses, boils, and other pus-filled lesions.

The estimated number of people developing a serious MRSA infection (i.e., invasive) in 2005 was about 94,360; this is higher than estimates using other methods.

Serious MRSA disease is still predominantly related to exposures to healthcare delivery:

• About 85% of all invasive MRSA infections were associated with healthcare, and of those, about two-thirds occurred outside of the hospital, while about one third occurred during hospitalization.
• About 14% of all the infections occurred in persons without obvious exposures to healthcare.

Although the rates of disease varied between the geographically diverse sites participating in the surveillance, overall rates of disease were consistently highest among older persons (age >65), Blacks, and males.

Evaluation of the pathogens causing these infections confirmed that most of the strains associated with these serious MRSA infections were caused by strains traditionally associated with healthcare. However, the strains traditionally associated with transmission in the community are now being identified in healthcare.

Handwashing has been identified as the best prevention against MRSA.

Source: Centers for Disease Control and Prevention