Systemic inflammatory response syndrome in pediatric urinary tract infections associated with urolithiasis: a retrospective study of risk factors, pathogens, and antimicrobial resistance at two tertiary hospitals

Urinary tract infections (UTIs) in children with urinary calculi are frequently caused by multidrug-resistant organisms and may rapidly progress to systemic inflammatory response syndrome (SIRS). Early diagnosis is challenging due to nonspecific symptoms, especially in younger children. This study aims to identify the risk factors for SIRS and characterize pathogen distribution and antimicrobial resistance patterns in pediatric stone-related UTIs. We retrospectively analyzed 198 pediatric patients with culture-positive urinary calculi treated at two tertiary hospitals from January 2017 to December 2024. Bacterial identification and antimicrobial susceptibility profiling were performed using the VITEK 2 automated system (bioMérieux, France) in accordance with Clinical and Laboratory Standards Institute (CLSI) guidelines. Patients were categorized into SIRS and non-SIRS groups according to clinical criteria, and logistic regression was performed to identify risk factors for SIRS. The median age was 66 months, and 61.11% were male. The majority of cases involved multiple stones (61.62%) and small stones (93.94%); 14.67% were lower urinary tract stones and 22.22% had urinary tract malformations. Multivariable analysis identified three factors associated with SIRS: recurrent UTIs (OR = 4.95, 95% CI: 2.20–11.13), urinary tract malformations (OR = 2.78, 95% CI: 1.21–6.42), and elevated SIRI (OR = 2.33, 95% CI: 1.41–3.85). The predominant pathogens were Escherichia coli (23.23%), Enterococcus faecium (14.14%), Enterococcus faecalis (14.14%), and Klebsiella pneumoniae (9.60%). Gram-negative bacteria accounted for 61.11% of isolates with non-Escherichia coli strains comprising 76.77%. The most common bacteria were Escherichia coli in girls (32.47%), compared with Enterococcus faecalis in boys (20.66%). Over 70% of Escherichia coli isolates produced ESBLs and 67.39% of isolates were multidrug-resistant; resistance to multiple cephalosporins exceeded 67%, while susceptibility to piperacillin/tazobactam, meropenem, and imipenem was fully preserved. Recurrent UTIs, urinary tract malformations, and elevated SIRI values enable early risk stratification for SIRS, while the distinct and resistant pathogen profile mandates a shift from conventional empiric therapy to precision management. Not applicable.