Febrile Urinary Tract Infection in Infants Less Than 3 Months of Age.

INTRODUCTION: Urinary tract infection (UTI) is the leading cause of bacterial infection in infants younger than 3 months of age with fever without a source. OBJECTIVE: The objective of the study was to analyze the characteristics of emergency department presentations of febrile infants younger than 3 months of age with a UTI and identify risk factors for invasive bacterial infection (IBI) secondary to UTI. METHODS: This was a secondary analysis of a prospective observational registry that includes infants younger than 3 months with fever without a source managed at a pediatric emergency department between 2003 and 2019. RESULTS: Of the 2850 patients included, 592 (20.8%) were diagnosed with a UTI (524, 88.5%, for Escherichia coli ). Infants with UTIs showed significant clinical differences when compared with those not diagnosed with a bacterial infection: patients with a UTI were more likely to have a history of renal/urological problems (8.3% vs. 3.5%), temperature ≥39ºC (38.3% vs. 29%) and poor feeding (13% vs. 8.7%). Yet, nearly half (285 of the 592, 48.1%) of the infants with febrile UTIs had none of these 3 risk factors. Thirty-six infants (6.1%) had a secondary IBI. We identified the following independent risk factors for secondary IBI: infants younger than 1 month of age, parent-reported irritability, procalcitonin >0.5 ng/mL, and C-reactive protein >60 mg/L. CONCLUSIONS: History and physical examination do not allow us to safely rule out a UTI among young febrile infants. Age, parent-reported irritability, and biomarkers are useful in identifying patients at increased risk of secondary IBI.

Rate of invasive bacterial infection in recently vaccinated young infants with fever without source.

OBJECTIVE: To compare the rates of invasive bacterial infection (IBI) (bacterial pathogen in blood or cerebrospinal fluid) and urinary tract infection (UTI) in febrile infants between 42 and 90 days of age who had and had not been vaccinated in the previous 48 hours. DESIGN: Observational study; secondary analysis of a prospective registry-based cohort study. SETTING: Paediatric emergency department. PATIENTS: Infants 42-90 days of age with fever without source seen between 2010 and 2021. MAIN OUTCOME MEASURES: Rates of IBI (bacterial pathogen in blood or cerebrospinal fluid) and UTI (urine culture obtained by an aseptic method yielding growth of ≥10 000 cfu/mL with associated leucocyturia). RESULTS: We included 1522 infants, including 185 (12.2%) vaccinated in the previous 48 hours. Overall, 19 (1.25%) were diagnosed with an IBI and 282 (18.5%) with a UTI. No recently immunised infants were diagnosed with an IBI (vs 19, 1.4% of those not recently immunised, p=0.2). The UTI rate was higher in infants not recently immunised (20.1% vs 7.0%, p<0.01; OR: 3.3 (1.9-5.9)). CONCLUSIONS: Although the rate of UTI in recently immunised infants 42-90 days old with fever without a source is lower than in those not recently immunised, recommending screening for UTI seems appropriate. If the lower rate of IBI among recently immunised well-appearing infants is confirmed, the recommendation to systematically perform blood tests in these infants should be reconsidered.

Impact of the Step-by-Step on febrile infants.

OBJECTIVE: To evaluate the impact of introducing the Step-by-Step approach on care quality in young febrile infants. DESIGN: Observational study including infants ≤90 days old with fever without source seen in a paediatric emergency department 5 years before (n=1222) and after (n=1151) its introduction. Quality of care was evaluated in terms of adherence to recommendations, resource use and safety. RESULTS: Adherence: percentages of infants undergoing both urine and blood tests and infants <15 days old receiving full sepsis evaluation increased (84.7% vs 91.0% and 23.9% vs 63.3%, respectively; p<0.01). Resource use: lumbar puncture and admission rates decreased (24.1% vs 18.7% and 43.6% vs 38.3%, respectively; p<0.01), while the rate of antibiotic therapy increased (30.2% vs 43.2%; p<0.01). SAFETY: the invasive bacterial infection rate among infants managed as outpatients was unchanged (0.7% vs 0.3%; p=0.24). CONCLUSION: The introduction of the Step-by-Step increased the quality of care provided to young febrile infants.