IMPORTANCE: Antimicrobial resistance is a major public health problem in the US. Estimating national rates of antimicrobial-resistant infections commonly associated with health care can aid in targeted public health efforts. OBJECTIVE: To determine the national incidence rates of 6 pathogens over time: methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus spp (VRE), extended-spectrum cephalosporin-resistant Escherichia coli and Klebsiella spp (excluding Klebsiella aerogenes) (ESCR-EK), carbapenem-resistant Enterobacterales (CRE), carbapenem-resistant Acinetobacter spp (CRAsp), and multidrug-resistant (MDR) Pseudomonas aeruginosa. DESIGN, SETTING, AND PARTICIPANTS: This cohort study used data from 2012 to 2022 on inpatient hospitalizations, clinical cultures, and facility-level characteristics. Hospital-months were included in the dynamic cohort if the hospital reported at least 1 culture with microbial growth accompanied by antimicrobial susceptibility testing (AST) results in the month. Data from the PINC-AI and Becton Dickinson Insights databases were used, and cases were defined as incident nonsurveillance cultures yielding an organism of interest with sufficient AST results for a phenotype of interest. Data were collected from January 2012 to December 2022 and analyzed from April 2023 to June 2024. EXPOSURE: Inpatient hospitalizations with a discharge date in an included hospital month. MAIN OUTCOMES AND MEASURES: National annual antimicrobial-resistant cases per 10 000 hospitalizations were obtained using weights based on facility-level characteristics. Cases were defined as community-onset if collected on or before day 3 of hospitalization and hospital-onset if obtained on day 4 or later. RESULTS: This study cohort included 332 to 606 hospitals per year between 2012 to 2022 and 7 158 139 cultures. Antimicrobial-resistant pathogens accounted for an estimated 569 749 (95% CI, 475 949-663 548) cases and 179.6 (95% CI, 163.1-196.1) cases per 10 000 hospitalizations in 2022. Of these cases, 77% (437 657; 95% CI, 364 529-510 785) were community-onset and 23% (132 092; 95% CI, 108 241-155 943) were hospital-onset. MRSA (44% [251 854; 95% CI, 209 558-294 150]) and ESCR-EK (35% [200 884; 95% CI, 163 692-238 077]) made up the largest proportions of total infections in 2022, respectively. Rates of hospital-onset MRSA, VRE, CRE, CRAsp, and MDR P aeruginosa had periods of decline from 2012 to 2019; however, all pathogens experienced an increase in hospital-onset rates in 2020 and 2021. Community-onset ESCR-EK rates increased from 2012 to 2022, while community-onset rates of MRSA, VRE, and MDR P aeruginosa declined. CONCLUSIONS AND RELEVANCE: While antimicrobial resistance rates have experienced uneven declines in the US from 2012 to 2022, the burden of resistance remains substantial. These findings suggest that more effective strategies to reduce antimicrobial resistance are needed.

IMPORTANCE: Characterizing the scale and factors associated with hospital-onset SARS-CoV-2 infections could help inform hospital and public health policies regarding prevention and surveillance needs for these infections. OBJECTIVE: To evaluate associations of hospital-onset SARS-CoV-2 infection rates with different periods of the COVID-19 pandemic, hospital characteristics, and testing practices. DESIGN, SETTING, AND PARTICIPANTS: This cohort study of US hospitals reporting SARS-CoV-2 testing data in the PINC AI Healthcare Database COVID-19 special release files was conducted from July 2020 through June 2022. Data were collected from hospitals that reported at least 1 SARS-CoV-2 reverse transcription-polymerase chain reaction or antigen test during hospitalizations discharged that month. For each hospital-month where the hospital reported sufficient data, all hospitalizations discharged in that month were included in the cohort. SARS-CoV-2 viral tests and results reported in the microbiology files for all hospitalizations in the study period by discharge month were identified. Data analysis was conducted from September 2022 to March 2023. EXPOSURE: Hospitalizations discharged in an included hospital-month. MAIN OUTCOMES AND MEASURES: Multivariable generalized estimating equation negative-binomial regression models were used to assess associations of monthly rates of hospital-onset SARS-CoV-2 infections per 1000 patient-days (defined as a first positive SARS-CoV-2 test during after hospitalization day 7) with the phase of the pandemic (defined as the predominant SARS-CoV-2 variant in circulation), admission testing rates, and hospital characteristics (hospital bed size, teaching status, urban vs rural designation, Census region, and patient distribution variables). RESULTS: A total of 5687 hospital-months from 288 distinct hospitals were included, which contributed 4 421 268 hospitalization records. Among 171 564 hospitalizations with a positive SARS-CoV-2 test, 7591 (4.4%) were found to be hospital onset and 6455 (3.8%) were indeterminate onset. The mean monthly hospital-onset infection rate per 1000 patient-days was 0.27 (95 CI, 0.26-0.29). Hospital-onset infections occurred in 2217 of 5687 hospital-months (39.0%). The monthly percentage of discharged patients tested for SARS-CoV-2 at admission varied; 1673 hospital-months (29.4%) had less than 25% of hospitalizations tested at admission; 2199 hospital-months (38.7%) had 25% to 50% of all hospitalizations tested, and 1815 hospital months (31.9%) had more than 50% of all hospitalizations tested at admission. Postadmission testing rates and community-onset infection rates increased with admission testing rates. In multivariable models restricted to hospital-months testing at least 25% of hospitalizations at admission, a 10% increase in community-onset SARS-CoV-2 infection rate was associated with a 178% increase in the hospital-onset infection rate (rate ratio, 2.78; 95% CI, 2.52-3.07). Additionally, the phase of the COVID-19 pandemic, the admission testing rate, Census region, and bed size were all significantly associated with hospital-onset SARS-CoV-2 infection rates. CONCLUSIONS AND RELEVANCE: In this cohort study of hospitals reporting SARS-CoV-2 infections, there was an increase of hospital-onset SARS-CoV-2 infections when community-onset infections were higher, indicating a need for ongoing and enhanced surveillance and prevention efforts to reduce in-hospital transmission of SARS-CoV-2 infections, particularly when community-incidence of SARS-CoV-2 infections is high.