Urinary tract infections in young infants with a normal urine dipstick.

Aim: To assess missed urinary tract infections (UTI) in febrile infants ≤2 months when adhering to recent guidelines suggesting not to send a urine culture with a negative dipstick. Methods: A retrospective cohort study of 308 infants ≤2 months with a positive urine culture admitted in 2013–2023, divided into subgroups without exposure to urine dipstick results: 'urosepsis' (UTI with bacteraemia), 'UTI' (positive urine culture, elevated inflammatory markers, no other cause of fever) and 'bacteriuria' (positive urine culture, not meeting the above‐mentioned criteria). After retrieving the dipstick results, the 'missed UTI' group (UTI+ negative dipstick) was described. Results: A negative dipstick was found in 2/20 (10%), 32/127 (25%) and 126/161 (78%) of infants with 'urosepsis', 'UTI' and 'bacteriuria', respectively. In the 'missed UTI' group (n = 34), there were more non‐Escherichia coli UTI (68% vs. 9% with positive dipstick, p < 0.001), and lower inflammatory markers (leukocytes 15.5 vs. 17.2 k/μL, p = 0.007, C‐reactive protein 21 vs. 58 mg/L, p < 0.001). Three infants had high‐grade vesicoureteral reflux (VUR) and renal scarring. Conclusions: There is a non‐negligible rate of infants ≤2 months with UTI and without pyuria, including those with urosepsis, VUR and renal scarring. We suggest obtaining a urine culture regardless of dipstick results. [ABSTRACT FROM AUTHOR]