Background: One of the most prevalent bacterial diseases in children under five is urinary tract infections (UTIs). Due to multidrug resistance, a lack of oral treatment choices, and a higher chance of empirical therapy failure, the growing frequency of extended-spectrum beta-lactamase (ESBL)-producing organisms has become a significant therapeutic issue.

Objective: To study patterns of antibiotic resistance in children under five who have a culture-positive UTI and to find clinical factors linked to ESBL-producing UTIs.

Methods: Over the course of a year, this prospective observational study was carried out in the paediatrics and microbiology departments of a tertiary care teaching hospital. Included were 82 kids with culture-positive UTIs between the ages of one month and five years. Analysis was done on demographic information, clinical presentation, prior antibiotic exposure, recurrent UTI, hospitalisation history, imaging data, urine culture results, and patterns of antimicrobial susceptibility. In accordance with Clinical and Laboratory Standards Institute (CLSI) guidelines, ESBL generation was verified using the combined disc diffusion method. The chi-square test, independent t-test, and multivariable logistic regression were used to evaluate associations.

Results: ESBL-producing organisms were responsible for 29 (35.4%) of the 82 culture-positive UTI cases. Common clinical manifestations were dysuria, vomiting, fever, and poor feeding. ESBL-producing UTI was substantially correlated with prior antibiotic exposure within three months, recurrent UTI, prior hospitalisation, and urinary tract abnormalities. The most common organisms were Escherichia coli and Klebsiella pneumoniae. While meropenem, amikacin, and nitrofurantoin sensitivity was maintained, ESBL isolates demonstrated strong resistance to amoxicillin-clavulanate and third-generation cephalosporins.

Conclusion: A significant percentage of paediatric UTIs in children under five were caused by ESBL-producing organisms. The two main clinical factors were repeated UTIs and prior antibiotic exposure. The necessity of urine culture-based therapy, prudent antibiotic use, and recurring local antimicrobial surveillance is highlighted by high cephalosporin resistance.

KEYWORDS: Paediatrics, Children under Five, Escherichia Coli, Antibiogram, Urinary Tract Infection, ESBL, and Antibiotic Resistance.