Centers for Disease Control and Prevention

Antimicrobial Resistance Threats Report

Methicillin-resistantStaphylococcus aureus

Threat Level: SERIOUS

In the United States in 2023:

CDC changed methodologies and data sources to produce the most comprehensive AR Threats Report to date. Direct comparison of this threat's data to previous reports is not recommended.

What you need to know

Staphylococcus aureus (S. aureus) bacteria normally live on the skin of many people and animals. Many people carry S. aureus bacteria, and for most people, they do not cause problems. Most S. aureus infections are mild skin infections. However, S. aureus bacteria can also cause severe and even deadly infections in almost any body site, including the blood, lungs, bones, and skin and soft tissues.

Methicillin-resistant S. aureus (MRSA) bacteria are a type of S. aureus that can be resistant to several antibiotics and can cause difficult-to-treat infections. MRSA can spread and cause infections in healthcare facilities and the community. About 40–50% of S. aureus infections in hospitals are due to MRSA. The risk of MRSA infection increases for people who have been hospitalized or live in nursing homes, have a lot of skin-to-skin contact with others (such as in contact sports), or live or work in crowded places (such as prisons, military barracks, and homeless shelters). Fortunately, in recent years several antibiotics have become available that expand treatment options for people with MRSA infections.

Methicillin-resistant Staphylococcus aureus data

In 2023, there were an estimated 220,997 cases of methicillin-resistant Staphylococcus aureus (MRSA) in hospitalized patients and 7,499 people who died due to their MRSA infection. CDC estimates that MRSA cases were responsible for more than $1.55 billion in healthcare costs in 2023. Despite declines in MRSA bloodstream infections during the last two decades, MRSA bacteria continue to be a serious threat in healthcare and community settings.

Number of methicillin-resistant Staphylococcus aureus (MRSA) cases in hospitalized patients (N=220,997) by location of onset and specimen type in 2023 in the U.S.

In 2023, 16% of MRSA cases in hospitalized patients were hospital-onset, and 84% were community-onset. Hospital-onset cases occur when specimens (samples) taken from patients on or after day four of hospitalization test positive for MRSA. Community-onset cases occur when specimens taken from patients immediately before or within the first three days of hospitalization test positive for MRSA. Community-onset cases may be in patients with recent healthcare exposure prior to their hospitalization, including nursing home residents.

Eighteen percent of hospital-onset MRSA cases and 21% of community-onset MRSA cases were invasive. Invasive cases mean MRSA bacteria are found in normally sterile (free from germs) body sites, such as blood or cerebrospinal fluid. Non-invasive cases mean MRSA bacteria are found in non-sterile sites, such as the urinary tract, the respiratory tract, or wounds.

Most reported MRSA cases are non-invasive. Non-invasive infections can be mild or severe, and some non-invasive infections, like pneumonia, can be deadly. Invasive infections are very serious and can be deadly, often resulting in significant healthcare needs, antibiotic use, and an increased risk for sepsis (the body's extreme response to infection). Despite years of progress, MRSA bacteria are still a major cause of serious infections both inside and outside the hospital.

For the first time, data from the National Healthcare Safety Network (NHSN) Antimicrobial Use and Resistance Module were used to estimate the burden of MRSA as shown in the figure above.

For the figure below, data from a complementary surveillance platform, the CDC Emerging Infections Program (EIP), were used to show past trends in MRSA. EIP surveillance for MRSA bloodstream infection (bacteremia) is active, laboratory- and population-based, which means that public health staff work continuously with clinical laboratories and seek to identify every MRSA bloodstream infection in people who live in selected counties and states. For this analysis, data from 17 counties in six states were included.

Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia incidence per 100,000 population by epidemiologic classification and year

Previously published data from CDC's Emerging Infections Program, shown in the figure above, indicate overall rates of MRSA bloodstream infections declined about 50% over almost two decades of monitoring. Most of these declines occurred between 2005 and 2016 in healthcare-associated community-onset MRSA bloodstream infections. Hospital-onset MRSA bloodstream infections declined from 2005 to 2013, plateaued starting in 2014, and increased during the COVID-19 pandemic. The community-associated MRSA bloodstream infection rate increased from 2016 to 2019 but decreased during the COVID-19 pandemic, possibly due to decreased social interactions and crowding [1].

An MRSA bloodstream infection is classified as hospital-onset if the specimen (sample) that tested positive for MRSA was collected on or after day four of hospitalization. Otherwise, if the patient had at least one healthcare exposure (for example hospitalization, surgery, dialysis, or long-term care facility residence) within the previous year or a central venous catheter within the previous two days before the culture was collected, the MRSA bloodstream infection was categorized as healthcare-associated community-onset. MRSA bloodstream infections that were not categorized as hospital-onset or healthcare-associated community-onset were categorized as community-associated.

Continued close monitoring of MRSA cases and use of infection prevention and control measures in both community and healthcare settings is critical.

Nile's Story

Nile's Story

In this video, Ty and Carole Moss tell the tragic story of losing their son, Nile, to a MRSA infection that developed into sepsis.

Many people are unaware of and unprepared for life-threatening, life-changing infections from bacteria like methicillin-resistant Staphylococcus aureus (MRSA). This was the situation for Ty and Carole Moss when their son, Nile Moss, contracted a deadly MRSA infection in a local hospital.
When he was 15, Nile visited a local hospital for an annual series of medical tests. Within 48 hours, he developed a high fever and flu-like symptoms.
Nile was admitted to the hospital but died the next morning. His parents later learned that Nile had a MRSA infection that led to sepsis (the body's extreme response to an infection). Multiple doctors had missed the signs of sepsis, delaying appropriate treatment until it was too late.
Nile's parents founded Nile's Project, which helps educate the public about preventable healthcare-associated infections and the threat of drug-resistant infections. CDC partners with Nile's Project to increase transparency in health care, build health education and awareness campaigns, and make health care safer by sharing useful facts and solutions.

How CDC combats methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus resources

Illustration of Methicillin-resistant Staphylococcus aureus