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Updated: May 2, 2026
Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus MRSA
Published on: February 10, 2011
Invasive methicillin-resistant Staphylococcus aureus infections in the United States
R Monina Klevens1, Melissa A Morrison, Joelle Nadle
1Division of Healthcare Quality Promotion, Centers for Disease Control and Prevention, Atlanta, Georgia, USA. rmk2@cdc.gov
Context:
As the epidemiology of infections with methicillin-resistant Staphylococcus aureus (MRSA) changes, accurate information on the scope and magnitude of MRSA infections in the US population is needed.
Objectives:
To describe the incidence and distribution of invasive MRSA disease in 9 US communities and to estimate the burden of invasive MRSA infections in the United States in 2005.
Design And Setting:
Active, population-based surveillance for invasive MRSA in 9 sites participating in the Active Bacterial Core surveillance (ABCs)/Emerging Infections Program Network from July 2004 through December 2005. Reports of MRSA were investigated and classified as either health care-associated (either hospital-onset or community-onset) or community-associated (patients without established health care risk factors for MRSA).
Main Outcome Measures:
Incidence rates and estimated number of invasive MRSA infections and in-hospital deaths among patients with MRSA in the United States in 2005; interval estimates of incidence excluding 1 site that appeared to be an outlier with the highest incidence; molecular characterization of infecting strains.
Results:
There were 8987 observed cases of invasive MRSA reported during the surveillance period. Most MRSA infections were health care-associated: 5250 (58.4%) were community-onset infections, 2389 (26.6%) were hospital-onset infections; 1234 (13.7%) were community-associated infections, and 114 (1.3%) could not be classified. In 2005, the standardized incidence rate of invasive MRSA was 31.8 per 100,000 (interval estimate, 24.4-35.2). Incidence rates were highest among persons 65 years and older (127.7 per 100,000; interval estimate, 92.6-156.9), blacks (66.5 per 100,000; interval estimate, 43.5-63.1), and males (37.5 per 100,000; interval estimate, 26.8-39.5). There were 1598 in-hospital deaths among patients with MRSA infection during the surveillance period. In 2005, the standardized mortality rate was 6.3 per 100,000 (interval estimate, 3.3-7.5). Molecular testing identified strains historically associated with community-associated disease outbreaks recovered from cultures in both hospital-onset and community-onset health care-associated infections in all surveillance areas.
Conclusions:
Invasive MRSA infection affects certain populations disproportionately. It is a major public health problem primarily related to health care but no longer confined to intensive care units, acute care hospitals, or any health care institution.
Insights
Invasive methicillin-resistant Staphylococcus aureus (MRSA) infections are a significant public health concern, disproportionately affecting older adults, Black individuals, and males. These infections are largely healthcare-associated but are increasingly found outside traditional hospital settings.
Area of Science:
- Infectious Diseases
- Epidemiology
- Public Health
Background:
- Accurate data on the scope of methicillin-resistant Staphylococcus aureus (MRSA) infections in the US is crucial due to evolving epidemiology.
- Understanding the burden of invasive MRSA is essential for public health strategies.
Purpose of the Study:
- To determine the incidence and distribution of invasive MRSA disease across 9 US communities.
- To estimate the overall burden of invasive MRSA infections in the United States for the year 2005.
Main Methods:
- Population-based surveillance of invasive MRSA was conducted in 9 US sites from July 2004 to December 2005.
- MRSA cases were investigated and categorized as healthcare-associated (hospital-onset or community-onset) or community-associated.
- Incidence rates, mortality rates, and molecular characterization of MRSA strains were analyzed.
Main Results:
- A total of 8987 invasive MRSA cases were reported. The majority were healthcare-associated (85%), with 58.4% community-onset and 26.6% hospital-onset.
- The standardized incidence rate of invasive MRSA in 2005 was 31.8 per 100,000 population.
- Incidence was highest in individuals aged 65+, Black individuals, and males. The standardized mortality rate was 6.3 per 100,000.
Conclusions:
- Invasive MRSA infections disproportionately impact specific populations, highlighting health disparities.
- MRSA remains a major public health issue, primarily linked to healthcare settings but extending beyond traditional confines.
- Molecular analysis revealed the presence of community-associated MRSA strains in healthcare-associated infections across all surveillance areas.
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