P0508 - Frequency of Serious Bacterial Infections in Young Infants with and without Viral Respiratory Infections

Background/Purpose: Conflicting data exist on how viral infections may alter the frequency of serious bacterial infection (SBI: bacteremia, urinary tract infection (UTI), and bacterial meningitis) in febrile infants. We describe the frequency of SBI in young infants with and without documented viral pathogens.

Methods: This was a retrospective cross-sectional study (1/2016-12/2017) in 3 emergency departments (EDs). 0-60-day-old previously healthy infants were included if at least respiratory viral testing and a blood culture was obtained. The frequency of SBI, the primary outcome, was compared among infants with/without respiratory viral infections was calculated via chi-square or Fisher’s exact test.

Results: The median age of the 597-infant cohort was 32 days (interquartile range: 20-45 days); 42% were female. 83% were documented as well appearing in the ED and 72% were admitted. ED triage vitals commonly revealed tachypnea (68%), pyrexia (45%), tachycardia (28%); hypoxemia (5%) was uncommon. 169/597 (28%) had positive viral testing, most commonly RSV (93/169, 55%), parainfluenza (29, 17%), and influenza A (23, 14%). Eight-four infants (14%) had SBI: 8.4% (50) UTI alone, 2.7% (16) bacteremia alone, 1.2% (7) bacteremia + UTI, 1.2% bacteremia + meningitis, and 0.7% (4) meningitis alone. Infants with documented respiratory viral pathogens were less likely to have any SBI (OR: 0.07; 95% CI: 0.02-0.29), UTI (OR 0.2, 95% CI: 0.1-0.6), or bacteremia (OR 0.3, 95% CI: 0.1-0.9) than infants with negative viral testing. There was no difference in meningitis frequency based on viral status (OR 0.4, 95% CI: 0.05-3.1). There was no significant difference the SBI frequency relative to viral infections in 0-28 versus 29-60-day-old infants (p=1).

Conclusion: The frequency of bacteremia and UTI was lower in young infants with respiratory viral infections compared to infants with negative respiratory viral testing.