Trends in Incidence and Epidemiology of Methicillin-Resistant Bacteremia, Six Emerging Infections Program Surveillance Sites, 2005-2022.

BACKGROUND

The impact of the coronavirus disease 2019 (COVID-19) pandemic on methicillin-resistant (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; < .001) reversed during 2016-2019 (APC, +5.9; < .001). Hospital-onset incidence did not change significantly during 2014-2019 (APC, -1.5; = .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; < .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; < .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.