Hospital-onset antimicrobial resistance increased during COVID-19 pandemic

1. In this retrospective cohort study, the incidence of hospital-onset antimicrobial resistant infections was found to have increased in United States hospitals during the COVID-19 pandemic.

2. Increases in hospital-onset antimicrobial resistance were associated with pre-existing comorbidities, illness severity, and recent antibiotic use, but not hospital factors.

Evidence Rating Level: 2 (Good)

Study Rundown: Antimicrobial resistance (AMR) is a global public health crisis associated with poor health outcomes and significant mortality. In 2022, the U.S. Center for Disease Control and Prevention reported an increasing incidence of AMR across U.S. hospitals during the COVID-19 pandemic, a reversal of several years of pre-pandemic declines in rates of multi-drug resistant infections. Both patients with and without COVID-19 infection were found to be at increased risk of developing antimicrobial-resistant hospital-onset infections, although the mechanisms behind this phenomenon remain unclear. Several potential contributing factors have been posited, including more widespread antibiotic use, breakdown in antibiotic stewardship and infection control protocols due to time and resource constraints, increased instrumentation and invasive procedures, and prolonged hospital stays. Hence, this study was conducted to better characterize the current landscape of AMR in the U.S. This retrospective cohort study investigated the incidence of antimicrobial-resistant infections in U.S. hospitals during and beyond the COVID-19 pandemic, and the factors contributing to AMR increases. The study showed that the incidence of hospital-onset antimicrobial-resistant infections increased in U.S. hospitals during the pandemic, although the overall prevalence of AMR returned to pre-pandemic levels as the pandemic waned. Increases in hospital-onset AMR were strongly associated with pre-existing comorbidities, illness severity, and recent antibiotic use. However, hospital factors such as region, teaching status, and technologic index were not associated with increased AMR. The results of the study were limited by several factors including residual confounding, inability to evaluate the appropriateness of antibiotic regimens, and a lack of generalizability to patient populations outside of U.S. hospitals. Nonetheless, these results highlighted some of the drivers of increased antibiotic resistance during the COVID-19 pandemic.

Click to read the study in AIM

Relevant Reading: Antibiotic resistance associated with the COVID-19 pandemic: a systematic review and meta-analysis

In-Depth [retrospective cohort]: This retrospective cohort study explored the incidence of antimicrobial-resistant infections in U.S. hospitals during and beyond the COVID-19 pandemic, as well as the contributing factors to AMR. Time periods were defined as pre-pandemic (January 2018 to December 2019), peak pandemic (March 2020 to February 2022), and waning pandemic (March to December 2022). The incidence of AMR, including methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), extended-spectrum cephalosporin-resistant Enterobacterales (ECR-E), carbapenem-resistant Enterobacterales (CRE), carbapenem-resistant Acinetobacter (CRA), and carbapenem-resistant Pseudomonas aeruginosa (CR-PA) infections from cultures of any source, was evaluated among 120 continuously reporting hospitals. Antibiotic exposure was estimated using an antibiotic spectrum index (ASI) score derived from antibiotic duration and spectrum. Among 9,955,696 hospitalizations across 243 hospitals between January 2018 and December 2022, 178,579 infection episodes were associated with 1 of the 6 aforementioned AMR phenotypes. MRSA infections were the most common, accounting for 41.3% and 37.2% of community-onset and hospital-onset infections, respectively. Among 120 continuously reporting hospitals, the overall incidence of AMR increased by 6.5% (95% confidence interval [CI], 5.1% to 8.0%) during the pandemic, from 182 to 193 per 10,000 hospitalizations. Antimicrobial-resistant hospital-onset infections increased by 31.5% (95% CI, 27.3% to 35.8%) compared to antimicrobial-resistant community-onset infections, which increased by 0.8% (95% CI, 0.3% to 3.3%) during the pandemic. The rate of hospital-onset AMR remained elevated above baseline even as the pandemic waned (11.6% increase; 95% CI, 6.8% to 16.7%). Cumulative incidence of hospital-associated AMR increased with illness severity, comorbidities, and antibiotic exposure within 3 months as determined by the ASI score. In summary, this study demonstrated increased incidence of hospital-onset AMR in U.S. hospitals during COVID-19 associated with various patient-level characteristics.

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