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Updated: Sep 19, 2025
Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus MRSA
Published on: February 9, 2011
Trends in Incidence and Epidemiology of Methicillin-Resistant Staphylococcus aureus Bacteremia, Six Emerging
Holly M Biggs1, Rongxia Li1, Kelly A Jackson1
1Division of Healthcare Quality Promotion, National Center for Emerging and Zoonotic Infectious Diseases, US Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
Background:
The impact of the coronavirus disease 2019 (COVID-19) pandemic on methicillin-resistant Staphylococcus aureus (MRSA) bacteremia incidence compared with prepandemic trends is unknown.
Methods:
Active laboratory- and population-based surveillance identified incident MRSA blood isolates among surveillance area residents in 6 continuously reporting sites during 2005-2022. Annual incidence per 100 000 census population was stratified by epidemiologic classification (hospital-onset, community-associated, health care-associated community-onset). Joinpoint with Poisson regression was used to determine incidence trend segments and annual percent change (APC; 2005-2019) and predicted incidence (2020-2022). Recent COVID-19 was a positive severe acute respiratory syndrome coronavirus 2 viral test ≤30 days before incident MRSA culture.
Results:
Overall declines in MRSA bacteremia incidence during 2005-2016 (APC, -7.1; P < .001) reversed during 2016-2019 (APC, +5.9; P < .001). Hospital-onset incidence did not change significantly during 2014-2019 (APC, -1.5; P = .32), but during 2020-2022 it was higher than during 2016-2019 and significantly higher than predicted in 2021. Health care-associated community-onset incidence increased during 2017-2019 (APC, +8.4; P < .001); 2021 incidence was the lowest observed during 2005-2022, although it was not significantly lower than predicted. Community-associated incidence was increasing prepandemic (APC, +8.4; P < .001), but during 2020-2022 it was lower than predicted. During 2020-2022, the proportion of cases with recent COVID-19 was highest among hospital-onset infections (18%-22%); 2021 hospital-onset incidence excluding these cases fell within the predicted range.
Conclusions:
Previous declines in MRSA bacteremia incidence had ended before the COVID-19 pandemic. During 2020-2022, patients with recent COVID-19 contributed substantially to increases in hospital-onset MRSA bacteremia, suggesting a need for robust infection prevention in this population. Reversal of prepandemic increases in health care-associated community-onset and community-associated infections during the pandemic could be related to COVID-19 mitigation measures.
Insights
Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia incidence declined before COVID-19, then increased, particularly hospital-onset cases. Patients with recent COVID-19 significantly contributed to this rise, highlighting infection prevention needs.
Area of Science:
- Infectious Diseases
- Epidemiology
- Public Health
Background:
- The impact of the COVID-19 pandemic on methicillin-resistant Staphylococcus aureus (MRSA) bacteremia incidence remains unclear.
- Understanding these trends is crucial for public health strategies and infection control.
Purpose of the Study:
- To analyze the incidence of MRSA bacteremia during the COVID-19 pandemic compared to prepandemic trends.
- To investigate the contribution of patients with recent COVID-19 to MRSA bacteremia rates.
- To assess changes in different epidemiological classifications of MRSA bacteremia.
Main Methods:
- Utilized active laboratory and population-based surveillance data from 6 sites (2005-2022).
- Calculated annual MRSA bacteremia incidence per 100,000 population, stratified by onset type (hospital, community-associated, health care-associated community-onset).
- Employed joinpoint regression to analyze incidence trends and predict 2020-2022 incidence, considering recent COVID-19 status.
Main Results:
- MRSA bacteremia incidence declined from 2005-2016 but reversed with an increase from 2016-2019.
- Hospital-onset MRSA bacteremia increased during 2020-2022, significantly higher than predicted, with 18-22% of cases having recent COVID-19.
- Community-associated and health care-associated community-onset MRSA bacteremia trends showed complex changes, with some decreases during the pandemic potentially linked to mitigation measures.
Conclusions:
- Prepandemic declines in MRSA bacteremia had ceased; the COVID-19 pandemic exacerbated increases, especially in hospital-onset cases.
- Patients with recent COVID-19 were a significant factor in rising hospital-onset MRSA bacteremia, underscoring the need for targeted infection prevention.
- Observed reversals in community-associated MRSA trends may be attributed to COVID-19 mitigation strategies.
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