43 The Prevalence of Serious Bacterial Infections in Infants less than 90 Days with and without Features of a Viral Infection: A Retrospective Cohort Study

Primary Subject area Emergency Medicine - Paediatric Background Prior studies suggest the prevalence of serious bacterial infections (SBI) (i.e., urinary tract infection [UTI], bacteremia, or meningitis) is lower in infants with a viral infection compared to those with fever without a source (FWS) (2-3% vs. 10-15%). Objectives To determine the difference in proportion of SBI in infants with and without clinical features of a viral infection. Design/Methods A retrospective cohort study was done on a consecutive sample of infants ≤ 90 days seen at a pediatric ED over a 5-year period ending August 30, 2019. Eligible subjects had rectal temperatures ≥ 38°C, and had ≥ 1 screening test for SBI (urine, blood and/or cerebrospinal fluid cultures). Excluded were infants who received antibiotics in the past 7 days, had congenital anomalies, required intensive care, or were preterm. We defined a clinical viral infection as > 1 clinical features of a respiratory viral infection (new-onset sneezing, cough, rhinorrhea, or shortness of breath). UTI was defined as per American Academy of Pediatrics guidelines. Results We screened 7021 charts and 885 (12%) were eligible. Of these, 498 (56%) had a clinical viral infection and 387 (44%) did not. Blood and urine cultures were collected from 860 (97%) infants and 308 (35%) had a lumbar puncture. Overall, 84 (10%) infants had an SBI: 76 (9%) UTI, 6 (0.7%) isolated bacteremia, and 2 (0.2%) meningitis. Among those with clinical viral infection, 23 (5%) had SBI, compared to 61 (16%) without viral infection (risk difference [RD] 11%, 95% CI [7%, 15%]). Both cases of meningitis occurred in infants ≤28 days and without any viral symptoms. A logistic regression was done to ascertain the effects of clinical viral infection, known risk factors for sepsis, age ≤ 28 days, or a temperature ≥ 39°C on the likelihood of SBI. Of the 4 predictors, only clinical viral infection and the presence of known risk factors for sepsis were significantly associated with SBI (odds ratio [OR] 0.3, 95% CI [0.17, 0.48] and 2.5, 95% CI [1.4, 4.5], respectively). Proportions of contaminated blood culture and urine culture were 5% (95% CI [4%, 7%]) and 14% (95% CI [12%, 17%]), respectively. Conclusion SBI prevalence in infants without features of a viral infection on assessment is triple that of infants with viral symptoms. Contaminant blood and urine cultures are folds higher than true pathological cultures. Future research is needed to identify infants at low risk of SBI without invasive testing.