Emergence of Extended-Spectrum β-Lactamase-Producing Pathogens in Community-Acquired Urinary Tract Infections Among Infants at a Pediatric Emergency Department.

BACKGROUND:Extended-spectrum β-lactamase (ESBL)-producing pathogens are common among adults and are associated with extended and multiple hospitalizations. They cause urinary tract infections (UTIs) among children with known risk factors such as urinary tract abnormalities and antimicrobial prophylaxis. The emergence of UTIs caused by ESBL-producing organisms among infants has not been well characterized. OBJECTIVE:We sought to describe the incidence and current clinical management of infants who were diagnosed with UTIs caused by ESBL-producing organisms at a pediatric emergency department (ED). In addition, we sought to describe risk factors associated with inpatient hospitalization for UTIs caused by ESBL-producing organisms. METHODS:We retrospectively identified infants who were treated in the ED from 2013 to 2017 and who had positive urinalyses and urine cultures positive for greater than 50,000 colony-forming unit per milliliter of a single ESBL-producing urinary pathogen. We abstracted details of clinical management and known previous risk factors, including prior neonatal intensive care unit hospitalization stay, prior UTI caused by an ESBL-producing organism, and known urologic abnormalities. RESULTS:Forty-five UTIs caused by ESBL-producing organisms occurred in 43 patients (mean age of 5.9 months and 59% female)-ESBL Escherichia coli represented the majority (42/45). The incidence of UTIs caused by ESBL-producing organisms ranged from 0.9% to 4.5% during the 5-year study period. The 13 patients (26%) admitted from the ED were significantly younger than discharged patients (1.9 vs 6.7 months, P = 0.016) and more likely to have had prior neonatal intensive care unit hospitalizations (50% vs 15.6%, P = 0.0456). Of the 33 visits (77%) resulting in initial outpatient management, 5 were followed by readmission for parenteral antibiotic treatment. Of those who were readmitted, 40% (n = 2) were afebrile at the time of admission. The remainder (28/33) completed outpatient oral antibiotic courses guided by susceptibilities. Two patients (4%) had negative repeat urine cultures despite in vitro resistance to initial antibiotic coverage. CONCLUSIONS:Extended spectrum β-lactamase-producing organisms are an increasing cause of UTIs in infants presenting at a pediatric ED, and outpatient management may be reasonable for infants older than 2 months.