Antimicrobial Resistance Trends of Escherichia coli Isolates from Outpatient and Inpatient Urinary Infections over a 20-Year Period

Antimicrobial resistance is a worldwide problem, and resistance in Enterobacteriaceae, particularly Escherichia coli and Klebsiella pneumoniae, is a critical threat to human health. Inappropriate and unnecessary use of antibiotics in human health care is the most common cause for the development and spread of antimicrobial resistance. In this work, we retrospectively analyzed the antimicrobial data of E. coli strains isolated from midstream urinary samples over a 20-year period (2000-2019). The aim was to provide useful information to clinicians to prescribe a more appropriate empirical antibiotic therapy. A total of 30,955 unique E. coli isolates from positive midstream urine samples of inpatients (1,198) and outpatients (29,757) were collected. Except for carbapenems, over time all the antibiotics tested showed increasing resistance rates in both groups (p < 0.0001). On the other hand, fosfomycin and nitrofurantoin presented significant decreasing trends in resistance rate (p < 0.05). There were significant increases in extended-spectrum β-lactamases- and multidrug resistance positive isolates starting in 2000 (p < 0.0001), with similar results in both groups. Ciprofloxacin, gentamicin, trimethoprim/sulfamethoxazole, and third-generation cephalosporin resistances significantly increased with increasing age (p < 0.0001). Collectively, E. coli resistance rates severely increased during the study period, except for fosfomycin and nitrofurantoin. The need of monitoring studies about antibiotic nonsusceptibilities at local and regional levels are necessary to enhance the focus on antimicrobial stewardship, to reduce antimicrobial consumption and to detect alarming resistance mechanisms.