Risk factors for cefazolin-resistant febrile urinary tract infection in children.

Background: Febrile urinary tract infection (fUTI) is a common bacterial infection among children. This study investigated the risk factors for fUTI caused by cefazolin-resistant bacteria in children.

Methods: The medical records of patients with fUTI hospitalized between April 2014 and March 2020 were retrospectively analyzed. The patients were divided into two groups based on the cefazolin susceptibility of the infection-causing bacteria: cefazolin-resistant and cefazolin-susceptible groups.

Results: The records of 80 patients were evaluated. The median age was 5.0 months (range 0.5-119.4 months). Cefazolin-susceptible bacteria were detected in 60 patients (75.0%). Significant differences were noted between the cefazolin-resistant and cefazolin-susceptible groups regarding UTI-related antimicrobial prophylaxis and recurrence of UTI within 3 months (P = 0.0318 and P = 0.00876, respectively). However, no significant differences were observed between these two groups regarding renal anomalies, or UTI history. Logistic regression analysis revealed that the recurrence of UTI within 3 months was an independent, significant risk factor for cefazolin-resistant fUTI (odds ratio 3.81, 95% confidence interval: 1.07-13.5, P = 0.0388). Six patients who were empirically treated with antibiotics ineffective against the infection-causing bacteria recovered from fever before these antibiotics were switched to those effective against the infection-causing bacteria.

Conclusions: In children, a recurrence of UTI within 3 months is a risk factor for fUTI caused by cefazolin-resistant bacteria. Recognizing these risk factors before initiating fUTI treatment in children may support treatment with narrower-spectrum antibiotics, such as first-generation cephalosporins (e.g., cefazolin).