Clinical Characteristics and Modifiable Factors of Urinary Tract Infections in Infants and Toddlers: A Case-Control Study.

BACKGROUND: To investigate the clinical characteristics and associated factors of urinary tract infections (UTIs) in infants and toddlers from a paediatric urological perspective. METHODS: This single-centre retrospective case-control study included 54 children with UTI and 54 hospital-based unmatched controls treated between January 2023 and December 2025. Perinatal factors, feeding patterns, constipation, clinically relevant external genital abnormalities, diaper changing, and perineal hygiene were compared between groups. Clinical manifestations, pathogens, antimicrobial susceptibility, recurrence, and ultrasound findings were analysed in the UTI group. Firth-corrected logistic regression was used to reduce small-sample estimation bias. RESULTS: The UTI group had higher proportions of low birth weight, non-exclusive breastfeeding, constipation, clinically relevant external genital abnormalities, infrequent diaper changing, and improper perineal hygiene than the control group (all p < 0.05). Multivariate analysis showed that low birth weight, non-exclusive breastfeeding, constipation, and improper perineal hygiene were independently associated with UTI (all p < 0.05). Fever, irritability, poor feeding, and voiding abnormalities were common presentations. Escherichia coli was the predominant pathogen, with high resistance to ampicillin, whereas susceptibility to nitrofurantoin, amikacin, and imipenem exceeded 95%. Ultrasound-detected urinary tract structural abnormalities may be associated with recurrence, but this result should be interpreted cautiously because of the small sample size. CONCLUSIONS: UTIs in infants and toddlers often present with non-specific symptoms; therefore, standardised urine specimen collection combined with comprehensive testing is crucial for early identification. Low birth weight, non-exclusive breastfeeding, constipation, and improper perineal hygiene were associated with UTI, among which feeding pattern, bowel habits, and perineal care are potentially modifiable. For empirical anti-infective therapy, cephalosporins or nitrofurantoin may be preferred. Further imaging evaluation should be individualised, with ultrasonography as the first-line assessment and voiding cystourethrography or dimercaptosuccinic acid scintigraphy reserved for selected children with recurrent febrile UTI, abnormal ultrasound findings, poor treatment response, or suspected renal scarring. Strengthening breastfeeding, constipation management, and perineal care may help reduce UTI occurrence.