Increasing Incidence of Extended-Spectrum β-Lactamase-Producing Escherichia coli in Community Hospitals throughout the Southeastern United States

Abstract

OBJECTIVE To describe the epidemiology of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBL-EC) and Klebsiella pneumoniae (ESBL-KP) infections DESIGN Retrospective cohort SETTING Inpatient care at community hospitals PATIENTS All patients with ESBL-EC or ESBL-KP infections METHODS ESBL-EC and ESBL-KP infections from 26 community hospitals were prospectively entered into a centralized database from January 2009 to December 2014. RESULTS A total of 925 infections caused by ESBL-EC (10.5 infections per 100,000 patient days) and 463 infections caused by ESBL-KP (5.3 infections per 100,000 patient days) were identified during 8,791,243 patient days of surveillance. The incidence of ESBL-EC infections increased from 5.28 to 10.5 patients per 100,000 patient days during the study period (P=.006). The number of community hospitals with ESBL-EC infections increased from 17 (65%) in 2009 to 20 (77%) in 2014. The median ESBL-EC infection rates among individual hospitals with ≥1 ESBL-EC infection increased from 11.1 infections/100,000 patient days (range, 2.2-33.9 days) in 2009 to 22.1 infections per 100,000 patient days (range, 0.66-134 days) in 2014 (P=.05). The incidence of ESBL-KP infections remained constant over the study period (P=.14). Community-associated and healthcare-associated ESBL-EC infections trended upward (P=.006 and P=.02, respectively), while hospital-onset infections remained stable (P=.07). ESBL-EC infections were more common in females (54% vs 44%, P<.001) and Caucasians (50% vs 40%, P<.0001), and were more likely to be isolated from the urinary tract (61% vs 52%, P<.0001) than ESBL-KP infections. CONCLUSIONS The incidence of ESBL-EC infection has increased in community hospitals throughout the southeastern United States, while the incidence of ESBL-KP infection has remained stable. Community- and healthcare-associated ESBL-EC infections are driving the upward trend. Infect. Control Hosp. Epidemiol. 2015;37(1):49-54.

FIGURE 1

Rate of extended-spectrum β-lactamase–producing E. coli (ESBL-EC) (A) and extended-spectrum β-lactamase–producing K. pneumoniae (ESBL-KP) (B) infections in 26 community hospitals throughout the southeastern United States by year. The mean rate of ESBL-EC and ESBL-KP infections per 100,000 patient days per year, along with the 95% confidence intervals (CI), are noted here. The trend lines and 95% CI were constructed using Poisson regression while controlling for clustering by hospital.

FIGURE 2

Rate of extended-spectrum β-lactamase–producing E. coli (ESBL-EC) (A) and extended-spectrum β-lactamase–producing K. pneumoniae (ESBL-KP) (B) infections in 26 community hospitals throughout the southeastern United States by year, stratified by infection type. Infection types include hospital onset (HO), healthcare associated (HCA), and community associated (CA). The mean rate of ESBL-EC and ESBL-KP infections per 100,000 patient days per year are noted here. Trend lines were constructed using Poisson regression while controlling for clustering by hospital.