Title: Longitudinal analysis of community-onset bacteremia due to ESBL-producing E. coli, K. oxytoca, K. pneumoniae, and P. mirabilis (2016-2024)
Authors: Raveena Patel, Laura Leigh Stoudenmire, Bryan P. White, Cong Cheng, Xianyan Chen, Daniel B. Chastain
Background:
Bacteremia caused by extended-spectrum β-lactamase (ESBL)-producing Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, and Proteus mirabilis is increasingly prevalent, limiting treatment options and worsening patient outcomes. While prompt carbapenem therapy can reduce mortality in these infections, understanding temporal trends and patient-level risk factors is crucial for guiding empiric treatment and minimizing unnecessary carbapenem use. However, specific clinical information regarding these ESBL-producing organisms as a cause of community-onset bacteremia remains limited. This study investigates the evolving epidemiology of community-onset ESBL-producing bacteremia from 2016 to 2024.
Methods:
This retrospective cohort study included adult patients (≥18 years) presenting to Phoebe Putney Health System in Albany, Georgia, from January 2016 through November 2024 with community-onset bacteremia caused by ESBL-producing E. coli, K. pneumoniae, K. oxytoca, or P. mirabilis, defined by non-susceptibility to ceftriaxone according to antimicrobial susceptibility testing results. Cases were included if the first positive blood culture was obtained during emergency department evaluation or within 48 hours of hospitalization. Patients with polymicrobial bacteremia, incomplete medical records, or transfer from another facility were excluded. Only one isolate per patient per year was included to avoid duplication. Clinical data were extracted from electronic health records using REDCap and included demographics, comorbidities, prior healthcare and antibiotic exposures, infection source, and severity of illness. Descriptive statistics and linear regression analysis were utilized to analyze data.
Results:
A total of 127 cases of community-onset ESBL-producing E. coli, K. pneumoniae, K. oxytoca, or P. mirabilis bacteremia were identified. E. coli was the most frequent isolate (83.4%, 106/127), followed by K. oxytoca (11.8%, 15/127). The median age of the cohort was 67 years (IQR 58-77), with a majority being female (56.7%) and identifying as African American or Black (52.8%). The median Charlson Comorbidity Index was 5 (IQR 3-7). Most patients presented from home (77.8%) with a urinary source of infection (66.9%). Few patients (14.2%) had a prior history of ESBL-producing organisms in cultures within the preceding 1 year. Antibiotic use was reported in 37.0% and 61.4% of patients within the prior 30 and 90 days, respectively. Similarly, 39.4% and 60.6% had a hospitalization within the prior 90 days and 1 year, respectively. The overall prevalence of ESBL-producing isolates increased significantly from 6.8% in 2016 to 15.5% in 2024 (p=0.008), representing an approximate annual increase of 1%. This upward trend may be attributed to multiple factors, including high comorbidity burden among patients (median Charlson Comorbidity Index, 5 [IQR, 3-7]) and recent healthcare or antibiotic exposure.
Conclusion:
This longitudinal analysis revealed a significant increase in the prevalence of ESBL bacteremia from 2016 to 2024. A majority of the risk factors analyzed in this study were not statistically significant in explaining the rise of ESBL Bacteremia. Our study suggests that other factors were not analyzed in this study which could be contributing to the rise of ESBL bacteremia. Further investigation is needed to identify and understand other potential factors that may be contributing to the rise of the prevalence of ESBL bacteremia.
Correspondence:
rapatel@phoebehealth.com
