MRSA has been featured in the news and on television programs a great deal recently. MRSA stands for Methicillin-resistant Staphylococcus aureus. This type of bacteria causes “staph” infections that are resistant to treatment with usual antibiotics.
MRSA occurs most frequently among patients who undergo invasive medical procedures or who have weakened immune systems and are being treated in hospitals and healthcare facilities such as nursing homes and dialysis centers. MRSA in healthcare settings commonly causes serious and potentially life threatening infections, such as bloodstream infections, surgical site infections, or pneumonia.
In addition to healthcare associated infections, MRSA can also infect people in the community at large, generally as skin infections that may look like pimples or boils and can be swollen, painful and have draining pus. These skin infections often occur in otherwise healthy people.
Electron micrograph of MRSA bacteria
Electron micrograph depicting a group of MRSA bacteria (CDC/Janice Carr)
How MRSA Spreads in Healthcare Settings
When we talk about the spread of an infection, we talk about sources of infection - where it starts, and the way or ways it spreads - the mode or modes of transmission.
In the case of MRSA, patients who already have an MRSA infection or who carry the bacteria on their bodies but do not have symptoms (colonized) are the most common sources of transmission.

The main mode of transmission to other patients is through human hands, especially healthcare workers' hands. Hands may become contaminated with MRSA bacteria by contact with infected or colonized patients. If appropriate hand hygiene such as washing with soap and water or using an alcohol-based hand sanitizer is not performed, the bacteria can be spread when the healthcare worker touches other patients.
MRSA and the Expensive Results of Antimicrobial Resistance
Along with MRSA, many significant infection-causing bacteria in the world are becoming resistant to the most commonly prescribed antimicrobial treatments. What causes this and what does it mean?
Antimicrobial resistance occurs when bacteria change or adapt in a way that allows them to survive in the presence of antibiotics designed to kill them. In some cases bacteria become so resistant that no available antibiotics are effective against them. At this time, treatment options still exist for healthcare-associated MRSA.
People infected with antibiotic-resistant organisms like MRSA are more likely to have longer and more expensive hospital stays, and may be more likely to die as a result of the infection. When the drug of choice for treating their infection doesn’t work, they require treatment with second- or third-choice medicines that may be less effective, more toxic and more expensive.
So this means that if you or I get an MRSA infection, we may suffer more, and we may pay more for our treatment. Yet American society as a whole suffers more and pays more too because of the increased burden and expense in the healthcare system.
MRSA: a Growing Problem in the Healthcare Setting, But One with a Cure
MRSA is becoming more prevalent in healthcare settings. According to CDC data, the proportion of infections that are antimicrobial resistant has been growing. In 1974, MRSA infections accounted for two percent of the total number of staph infections; in 1995 it was 22%; in 2004 it was 63%.
The good news is that MRSA is preventable. The first step to prevent MRSA, is to prevent healthcare infections in general. Infection control guidelines produced by CDC and the Healthcare Infection Control and Prevention Advisory Committee (HICPAC) are central to the prevention and control of healthcare infections and ultimately, MRSA in healthcare settings. To learn more about infection control guidelines to prevent infections and MRSA go to http://www.cdc.gov/ncidod/dhqp.
CDC welcomes the increased attention and dialogue on the important problem of MRSA in healthcare. CDC, state and local health departments and partners nationwide are collaborating to prevent MRSA infections in healthcare settings. To see what CDC is doing about MRSA go to http://www.cdc.gov/ncidod/dhqp/ar_mrsa_CDCactions.html

Staph infections result when a bacteria called Staphylococcus aureus enters the body through an open cut or break in the skin. They usually produce pus. Minor staph infections include infections of hair follicles after shaving, or sties, which occur when the follicle surrounding the eyelashes causes a sore red bump in the eyelid. Staph infection is also behind most cases of food poisoning and can also lead to more life-threatening conditions, such as toxic shock syndrome, pneumonia, and infections of the heart or blood. Those in hospitals, with weakened immune systems, are especially vulnerable to staph infection but now it has spread into the general population into otherwise healthy individuals.