National Trends of Prevalence of Fluroquinolone Resistance Among Healthcare-Associated Escherichia coli Infections

Abstract

Background: Escherichia coli is the third most common pathogen responsible for healthcare-associated infections (HAIs), but it is increasingly resistant to multiple antibiotics. Antimicrobial susceptibility test (AST) results for fluoroquinolones (FQs) among E. coli implicated in select HAIs are reported to the NHSN surveillance system. Trend analyses in the prevalence of FQ resistance among healthcare-associated E. coli infections reported to NHSN have not been previously assessed. Objective: We investigated the national trends of prevalence of FQ resistance among E. coli HAIs in acute-care hospitals from 2009 through 2018. Method: We analyzed E. coli AST data from central-line–associated bloodstream infections (CLABSIs), catheter-associated urinary tract infections (CAUTIs), and surgical site infections (SSIs) reported to the NHSN between 2009 and 2018. Fluoroquinolone resistance is defined as the number of E. coli isolates that tested resistant or intermediate to at least 1 of 3 quinolones (ciprofloxacin, levofloxacin, and moxifloxacin), divided by number of pathogens tested for susceptibility, multiplied by 100. To evaluate the trends of fluoroquinolone resistance over time, we conducted an interrupted time-series analysis using a generalized linear mixed model with a logistic function. Substantial HAI definitional changes, most consequentially CAUTI in 2015 and a directional incidence change in 2018, were treated as interruptions to the outcome. Regression models adjusted for patient-level (ie, age, gender, HAI type) and facility-level characteristics (ie, facility type, teaching status, number of beds in intensive care units, and average length of stay) were obtained from the NHSN annual hospital surveys. Random-intercept and slope models were evaluated with covariance tests and were included to account for differential baseline fluoroquinolone resistance and trends among reporting facilities. Data were analyzed using SAS with statistical significance defined at alpha = 0.05. Results: During 2009–2018, the number of E. coli isolates with AST results for FQ reported to NHSN (Fig. 1) increased. After adjusting for covariates, fluoroquinolone resistance significantly increased from 2009 through 2015 at an average of 4.2% per year (Fig. 2, β1). There was no significant change in fluoroquinolone resistance from 2015 through 2017 (Fig. 2, β1+ β3). In 2018, there was 6.4% decline in fluoroquinolone resistance compared to 2017 (Fig. 2, β4) Conclusions: An increasing trend of fluoroquinolone resistance from 2009 through 2015 was observed, and fluoroquinolone resistance was stable during 2015–2017. Despite a relatively brief decline in fluoroquinolone resistance in 2018, the absolute change was small (~2%). Sustaining this decline warrants continued efforts in infection prevention and antimicrobial stewardship.

Funding: None

Disclosures: None