Prevalence of Invasive Bacterial Infections in Well-Appearing, Febrile Infants

Data on invasive bacterial infection (IBI), defined as bacteremia and/or bacterial meningitis, in febrile infants aged <60 days old primarily derive from smaller, dated studies conducted at large, university-affiliated medical centers. Our objective with the current study was to determine current prevalence and epidemiology of IBI from a contemporary, national cohort of well-appearing, febrile infants at university-affiliated and community-based hospitals.

Retrospective review of well-appearing, febrile infants aged 7 to 60 days was performed across 31 community-based and 44 university-affiliated centers from September 2015 to December 2017. Blood and cerebrospinal fluid bacterial culture results were reviewed and categorized by using a priori criteria for pathogenic organisms. Prevalence estimates and subgroup comparisons were made by using descriptive statistics.

A total of 10 618 febrile infants met inclusion criteria; cerebrospinal fluid and blood cultures were tested from 6747 and 10 581 infants, respectively. Overall, meningitis prevalence was 0.4% (95% confidence interval [CI]: 0.2-0.5); bacteremia prevalence was 2.4% (95% CI: 2.1-2.7). Neonates aged 7 to 30 days had significantly higher prevalence of bacteremia, as compared with infants in the second month of life. IBI prevalence did not differ between community-based and university-affiliated hospitals (2.7% [95% CI: 2.3-3.1] vs 2.1% [95% CI: 1.7-2.6]). Escherichia coli and Streptococcus agalactiae were the most commonly identified organisms.

This contemporary study of well-appearing, febrile infants supports previous epidemiological estimates of IBI prevalence and suggests that the prevalence of IBI may be similar among community-based and university-affiliated hospitals. These results can be used to aid future clinical guidelines and prediction tool development.