Clinical profile and outcome of urinary tract infections caused by extended- Spectrum beta-lactamase-producing escherichia coli: a retrospective Observational study from intensive care units of a tertiary care teaching Hospital in south india

Abstract

Objective: The objective of the study is to compare the clinical profile, antimicrobial susceptibility pattern, severity indicators, and outcomes of urinary tract infections (UTIs) caused by extended-spectrum beta-lactamase (ESBL)-producing and non-ESBL-producing Escherichia coli among critically ill patients admitted to intensive care units (ICUs). Methods: This retrospective observational study was conducted in a tertiary care teaching hospital over a three-year period and included 1237 culture-confirmed E. coli UTI isolates from ICU patients. Patients were categorized into ESBL and non-ESBL groups based on phenotypic ESBL detection. Demographic variables, clinical presentation, comorbidities, complications, antimicrobial susceptibility, ICU stay, Acute Physiology and Chronic Health Evaluation (APACHE IV) and Sequential Organ Failure Assessment (SOFA) scores, and clinical outcomes were analyzed. Results: Among 1237 isolates, 742 (60.0%) were ESBL producers and 495 (40.0%) were non-ESBL producers. ESBL infections were associated with higher complication rates, including renal failure (58.0%), septic shock (18.0%), and multi-organ dysfunction syndrome (10.0%). Mean ICU stay was significantly longer in the ESBL group than in the non-ESBL group (5.1 vs. 3.6 days; p<0.01). Mortality was higher among ESBL patients than among non-ESBL patients (12.4% vs. 6.8%), with an absolute risk difference of 5.5% (95% confidence interval: 2.3–8.8%). APACHE IV and SOFA scores showed good mortality prediction, with area under the curve values of 0.82 and 0.79, respectively. Carbapenems showed the highest sensitivity among ESBL isolates. Conclusion: ESBL-producing E. coli UTIs in ICU patients are associated with increased morbidity, prolonged ICU stay, higher complication rates, and greater mortality. Early identification, appropriate empirical therapy, severity-based risk stratification, and antimicrobial stewardship are essential to improve clinical outcomes.