Serious Bacterial Infections in Young Febrile Infants With Positive Urinalysis Results

OBJECTIVE: To determine the prevalence of bacteremia and/or bacterial meningitis in febrile infants <= 60 days of age with positive urinalysis (UA) results. METHODS: Secondary analysis of a prospective observational study of noncritical febrile infants <= 60 days between 2011 and 2019 conducted in the Pediatric Emergency Care Applied Research Network emergency departments. Participants had temperatures >= 38 degrees C and were evaluated with blood cultures and had UAs available for analysis. We report the prevalence of bacteremia and bacterial meningitis in those with and without positive UA results. RESULTS: Among 7180 infants, 1090 (15.2%) had positive UA results. The risk of bacteremia was higher in those with positive versus negative UA results (63/1090 [5.8%] vs 69/6090 [1.1%], difference 4.7% [3.3% to 6.1%]). There was no difference in the prevalence of bacterial meningitis in infants <= 28 days of age with positive versus negative UA results (similar to 1% in both groups). However, among 697 infants aged 29 to 60 days with positive UA results, there were no cases of bacterial meningitis in comparison to 9 of 4153 with negative UA results (0.2%, difference -0.2% [-0.4% to -0.1%]). In addition, there were no cases of bacteremia and/or bacterial meningitis in the 148 infants <= 60 days of age with positive UA results who had the Pediatric Emergency Care Applied Research Network low-risk blood thresholds of absolute neutrophil count <4x10(3) cells/mm(3) and procalcitonin <0.5 ng/mL. CONCLUSIONS: Among noncritical febrile infants <= 60 days of age with positive UA results, there were no cases of bacterial meningitis in those aged 29 to 60 days and no cases of bacteremia and/ or bacterial meningitis in any low-risk infants based on low-risk blood thresholds in both months of life. These findings can guide lumbar puncture use and other clinical decision making.

Automated summary

This study examined the prevalence of bacteremia and bacterial meningitis in febrile infants with positive urinalysis results. The results showed no difference in the prevalence of bacterial meningitis between infants with positive and negative urinalysis results aged 29-60 days. Additionally, low-risk blood thresholds can effectively predict the absence of bacteremia and/or bacterial meningitis in low-risk infants.