Characteristics of children with first febrile urinary tract infection caused by Staphylococcus species.

Staphylococci are uncommon causes of febrile urinary tract infections (UTIs) in children and are often dismissed as contaminants in urine cultures. Data on their clinical significance in pediatric febrile UTIs are scarce. This study aimed to characterize the clinical features of children treated for a first febrile staphylococcal UTI at Hôpital Universitaire des Enfants Reine Fabiola (HUDERF) in Brussels. We performed a retrospective observational study including children aged < 16 years diagnosed with a first febrile staphylococcal UTI between January 2010 and December 2023. Twenty-five children were included; 56% had no prior history of febrile UTI. The male-to-female ratio was 3.2. At admission, median age was 6.5 years (interquartile range [IQR] 2.6-7.9), median temperature 39 °C (IQR 38.5-39.5), and median C-reactive protein level 31.6 mg/L (IQR 7.2-66.9). Congenital anomalies of the kidney and urinary tract (CAKUT) were present in 84% of cases, with vesicoureteral reflux (VUR) in 57%. Identified species included Staphylococcus epidermidis (44%), S. aureus (28%), S. saprophyticus (16%), S. haemolyticus (8%), and S. hominis (4%). S. epidermidis was mainly associated with VUR, whereas S. aureus was associated with obstructive uropathies and severe complications. S. saprophyticus was predominantly identified in girls without anatomical predisposition. UTI recurrence was observed in 20%, exclusively in boys with CAKUT. Conclusions: Although rare, staphylococci may cause febrile UTIs in children, particularly in those with underlying urinary tract anomalies. Such isolates should not be systematically considered contaminants and warrant careful clinical investigation.