Urine culture findings in well-appearing febrile infants aged 22-90 days with negative urinalysis.

Abstract

To evaluate the appropriateness of the American Academy of Pediatrics' (AAP) recommendation to no longer collect a urine culture (UC) in febrile infants ≥21 days old with negative urinalysis, and to identify predictors for having a positive UC in well-appearing febrile infants aged 22-90 days with a negative urinalysis. This study was a subanalysis of a multicentre retrospective registry, including well-appearing febrile infants aged 22-90 days with a negative urinalysis between 2011 and 2022. We performed a multivariate regression analysis including the following variables: age, sex, duration of fever, maximum temperature, absolute neutrophil count (ANC), and C reactive protein and procalcitonin levels. We included 2391 infants in the study. The UC was positive in 177 (7.4%; 13.5% in males vs 0.6% in females). The main isolated microorganisms were <i>Escherichia coli</i> (83, 46.9%), <i>Enterococcus faecalis</i> (40, 22.6%) and <i>Klebsiella</i> spp (24, 13.6%). Positive UCs were positively associated with male sex (OR 9.0; 95% CI 4.7 to 16.9) and ANC (OR 1.0001; 95% CI 1.00003 to 1.0002). Our findings support the AAP's recommendation to avoid obtaining a UC in female infants aged 22-90 days with a negative urinalysis. Blood tests demonstrated low performance in predicting a positive UC. This finding and the extremely low prevalence of circumcision in our setting suggest that most positive UCs in males with a negative urinalysis are more likely to represent contamination, as noted by the AAP.