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Epidemiology and Recent Trends in Methicillin-resistant and in Methicillin-susceptible Staphylococcus Aureus Bloodstream Infections — United States

Athena P. Kourtis; Kelly Hatfield; James Baggs; Yi Mu; Isaac See; Erin Epson; Joelle Nadle; Marion A. Kainer; Ghinwa Dumyati; Susan Petit; Susan M. Ray; Emerging Infections Program MRSA author group: David Ham; Catherine Capers; Heather Ewing; Nicole Coffin; L. Clifford McDonald; John Jernigan; Denise Cardo


Morbidity and Mortality Weekly Report. 2019;68(9):214-219. 

In This Article

Abstract and Introduction


Introduction: Staphylococcus aureus is one of the most common pathogens in health care facilities and in the community, and can cause invasive infections, sepsis, and death. Despite progress in preventing methicillin-resistant S. aureus (MRSA) infections in health care settings, assessment of the problem in both health care and community settings is needed. Further, the epidemiology of methicillin-susceptible S. aureus (MSSA) infections is not well described at the national level.

Methods: Data from the Emerging Infections Program (EIP) MRSA population surveillance (2005–2016) and from the Premier and Cerner Electronic Health Record databases (2012–2017) were analyzed to describe trends in incidence of hospital-onset and community-onset MRSA and MSSA bloodstream infections and to estimate the overall incidence of S. aureus bloodstream infections in the United States and associated in-hospital mortality.

Results: In 2017, an estimated 119,247 S. aureus bloodstream infections with 19,832 associated deaths occurred. During 2005–2012 rates of hospital-onset MRSA bloodstream infection decreased by 17.1% annually, but the decline slowed during 2013–2016. Community-onset MRSA declined less markedly (6.9% annually during 2005–2016), mostly related to declines in health care–associated infections. Hospital-onset MSSA has not significantly changed (p = 0.11), and community-onset MSSA infections have slightly increased (3.9% per year, p<0.0001) from 2012 to 2017.

Conclusions and Implications for Public Health Practice: Despite reductions in incidence of MRSA bloodstream infections since 2005, S. aureus infections account for significant morbidity and mortality in the United States. To reduce the incidence of these infections further, health care facilities should take steps to fully implement CDC recommendations for prevention of device- and procedure-associated infections and for interruption of transmission. New and novel prevention strategies are also needed.


Staphylococcus aureus is a major cause of community- and health care–associated infections,[1] ranging from superficial skin and soft tissue infections (SSTI) to invasive infections, sepsis, and death. Methicillin-resistant S. aureus (MRSA) has long been recognized as a pathogen associated with health care settings; however, in the 1990s, community-associated MRSA infections, causing mostly SSTI, emerged in the United States.[2] Substantial progress has been achieved in preventing MRSA bloodstream infections in U.S. health care facilities[3–5] after widespread introduction of enhanced infection control efforts in acute-care hospitals.

Although the rates of hospital-onset MRSA bloodstream infections have substantially decreased, evidence from the National Healthcare Safety Network (NHSN) and from the Emerging Infections Program (EIP) surveillance system suggests that the decline might have slowed in more recent years;[4,6] the United States is not on track to meet the 2020 goal of the Healthcare-Associated Infection National Action Plan of a 50% reduction in hospital-onset MRSA bloodstream infections from the 2015 baseline.[7] Moreover, to protect patients, expanded efforts are needed to prevent methicillin-susceptible S. aureus (MSSA), which causes approximately half of all health care–associated S. aureus infections.[8] There is little information on the current epidemiology of MSSA infections in the United States, and available data might not be nationally representative.[9–11]

A critical assessment of recent trends and incidence of both MRSA and MSSA invasive disease in the United States is crucial to informing public health policy and formulating a framework of approaches to further prevent S. aureus infections. In this report, recent data from the EIP population surveillance and two large electronic health record (EHR) data sets from over 400 U.S. acute care hospitals were used to update estimates of MRSA and MSSA bloodstream infections, and to estimate associated in-hospital mortality.