427. Trends in Hospital-onset Escherichia coli Infections Resistant to Fluoroquinolones and Extended-spectrum Cephalosporins, 2012-2020

BACKGROUND: Inpatient and outpatient fluoroquinolone (FQ) use has decreased substantially in the last decade; however, the impact of this trend on FQ resistance is less clear. During this period, extended-spectrum β-lactamase (ESBL) Escherichia coli infections have increased. We examined hospital-onset (HO) E. coli clinical culture trends and resistance patterns among hospitalized adult patients in the United States. METHODS: We measured the incidence of positive clinical cultures from inpatient encounters in a cohort of hospitals submitting data to the Premier Healthcare Database from 2012-2020. We included E. coli cultures with susceptibility testing to FQs or extended-spectrum cephalosporins (ESC). ESC resistance was defined as non-susceptibility to cefotaxime, ceftriaxone, ceftazidime, or cefepime and FQ resistance as resistance to ciprofloxacin, levofloxacin, or moxifloxacin. Co-resistance was defined as both ESC and FQ resistance in the same E. coli isolate. Isolates were classified as FQ resistant only (and not ESC), ESC resistant only (and not FQ), co-resistant, or neither FQ nor ESC resistant. RESULTS: The overall proportion of HO E. coli with any FQ resistance decreased 12.3% (from 36.7% in 2012 to 32.2% in 2020). The proportion of HO E. coli with only FQ resistance decreased by 39.8% (from 27.9% in 2012 to 16.8% in 2020); the proportion with only ESC resistance increased by 112.5% (from 2.4% to 5.1%), and co-resistance increased by 75.0% (from 8.8% to 15.4%) (Figure). [Figure: see text] CONCLUSION: These results suggest that declining FQ use has been accompanied by declining FQ resistance in E. coli. Increases in FQ and ESC co-resistance may be due to factors including increases in the use of non-FQ antibiotics such as cephalosporins and increased transmission of E. coli strains such as ST131 in which co-resistance is prevalent. Antibiotic stewardship across multiple antibiotic classes combined with infection control measures are likely necessary to reduce multidrug resistant E. coli infections. DISCLOSURES: All Authors: No reported disclosures.