# P-400. Overdiagnosis and Treatment of Multi-Drug Resistant Urinary Pathogens across a Pediatric Hospital System

## TL;DR

This study examines overdiagnosis of multi-drug resistant urinary tract infections in children, finding that nearly half of treated cases didn't meet national guidelines.

## Contribution

The study identifies overdiagnosis of MDRGN UTIs in pediatrics and highlights antibiotic stewardship opportunities.

## Key findings

- Escherichia coli was the most common MDRGN isolated in urine cultures.
- Nearly half of patients treated for UTIs did not meet national guideline criteria.
- Most E. coli and Klebsiella isolates were extended-spectrum β-lactamase producers.

## Abstract

Increasing antimicrobial resistance in pediatric urinary tract infections (UTI) is an area of concern and overdiagnosis of these infections may lead to unnecessary antibiotic exposure. We describe the characteristics and treatment of multi-drug resistant Gram-negative (MDRGN) UTIs in our pediatric population.

We performed a retrospective review of pediatric patients seen at a pediatric hospital system in 2022 who had a urine culture positive for a MDRGN, which was defined as a Gram negative organisms that are non-susceptible to at least 1 antibiotic in ≥ 3 antibiotic groups. Organisms were considered extended spectrum β-lactamase (ESBL) producers if their resistance profile showed resistant to ceftriaxone or ceftazidime. We determined the proportion of patients treated for a UTI who were overdiagnosed according to AAP clinical practice guidelines. Clinical and microbiologic data was obtained from the electronic medical record. Descriptive statistics and Fisher’s exact were used for analysis.

One hundred and forty-one children had 190 urine cultures positive for a MDRGN. Escherichia coli (128, 67%) and Klebsiella spp. (44, 23%) were isolated most frequently followed by Serratia (7, 4%), Enterobacter (5, 3%), Citrobacter spp. (3, 2%) and one each of Proteus mirabilis, Acinetobacter baumannii, and Morganella morganii. Patients with MDR E. coli compared to all other MDRGNs, were significantly less likely to have neurogenic bowel and bladder (P< 0.001) while there was no observed difference in vesicoureteral reflux (P=0.3) or history of UTI antibiotic prophylaxis (P=0.4). Most patients with a urinalysis had evidence of pyuria (136/171, 80%). Of 190 urine cultures, 159 (84%) had a single organism and 136 (72%) had colony count of > 50,000 CFU/mL. Most of the E. coli (111, 87%) and Klebsiella (42, 95%) isolates were ESBL producers. Of 169 episodes treated as a UTI, 79 (47%) did not meet guideline criteria. Conversely, two patients meeting criteria were not treated.

Escherichia coli was the predominate MDRGN found in urine cultures. Almost half of the patients treated for an infection did not meet UTI definition according to national guidelines, highlighting an opportunity for antibiotic stewardship.

Denver Niles, MD, BioMerieux: Advisor/Consultant