Methicillin-resistant Staphylococcus aureus (MRSA)


What is MRSA?

Methicillin-resistant Staphylococcus aureus (MRSA) is a type of staph bacteria that is resistant to a number of commonly used antibiotics. Staph bacteria are found all around us and on us and generally do no harm.  Sometimes they can cause infections like boils, and sometimes more serious infections. MRSA is one of the staph bacteria that can cause these infections and can be hard to treat because it is resistant to many antibiotics.

Until recently, most MRSA infections happened in the hospital or long-term care facilities and caused blood stream infections and other serious infections. This has become known as healthcare-associated MRSA, or HA-MRSA.

More recently a newer strain of MRSA has emerged in the community that causes boils, abscesses, and other soft tissue infections that is not linked to previous antibiotic use or hospitalization. It is called community-associated MRSA, or CA-MRSA. The infection often starts out looking like a spider-bite. If this infection isn’t treated it can cause more severe skin infections that may travel to the blood stream and other parts of the body.

Who is at risk for MRSA infection?

Hospital patients, long term care facility residents, those on dialysis, and sick and elderly people are at risk for healthcare associated MRSA. HA-MRSA is found in these settings and can cause infections in those who are exposed.

CA-MRSA occurs because the pus or drainage from MRSA wounds is infectious. Contact with a person’s wound, dirty bandage, or a surface that has been contaminated by wound drainage can lead to infection. Some people in the community are more at risk for CA-MRSA because their activities put them at risk for skin injury or close contact with someone who may be infected. These include athletes and athletic teams, staff and residents of group living facilities, children in daycare, military recruits, first responders, and others. 

How is MRSA treated?

HA-MRSA is treated with intravenous (IV) antibiotics in a healthcare setting. For CA-MRSA, antibiotics are not always needed, but the abscess, boil, or sore can be opened and cleaned out, followed by good wound care. It is important to see your medical provider if you think you have an MRSA infection.

Is MRSA reportable? 

Yes, some MRSA is reportable. In 2008, the State of California made severe staph infections, including MRSA, reportable to local health department. A severe staph infection for purposes of reporting is any case that results in death or admission to an intensive care unit (ICU), of a person who has not been hospitalized or had surgery, dialysis, or residency in a long-term care facility in the past year, and who did not have an indwelling catheter or percutaneous medical device at the time of culture. Providers and facilities treating such cases should report them to the Epidemiology Unit of the County of San Diego at 619-692-8499.

The documents and websites below may be helpful in answering your questions about MRSA and provide more detailed information for specific groups. 

Information for the Public
Information for Health Facilities and Health Professionals
Information for Specific Groups
Other Language Materials
Additional Resources

For more information, contact the Epidemiology Unit 619-692-8499 or send us an e-mail.