A Meta-analysis of the Rates of Listeria monocytogenes and Enterococcus in Febrile Infants

CONTEXT: A change in the epidemiology of pathogens causing serious bacterial infection (SBI) has been noted since original recommendations were made for the empirical antibiotic choices for young infants with fever. OBJECTIVE: To assess the prevalence of SBI caused by Listeria monocytogenes and Enterococcus species. DATA SOURCES: A literature search was conducted on keywords related to SBI, L. monocytogenes, and Enterococcus spp. infections. STUDY SELECTION: Eligible studies were those conducted in the United States and published between January 1998 and June 2014 focusing on SBI in infants ≤90 days of age. DATA EXTRACTION: The rates of urinary tract infection, bacteremia, and meningitis for each pathogen were recorded for each study. Meta-analysis was performed to calculate the prevalence for each pathogen in a random effects model with 0.5 continuity correction added to studies with zero events. RESULTS: Sixteen studies were included. A total of 20 703 blood cultures were included, with weighted prevalences for L. monocytogenes and Enterococcus spp. bacteremia of 0.03% and 0.09%, respectively. A total of 13 775 cerebrospinal fluid cultures were included with event rates (unweighted prevalences) for L. monocytogenes and Enterococcus spp. meningitis of 0.02% and 0.03%, respectively. A total of 18 283 urine cultures were included, with no cases of L. monocytogenes and a weighted prevalence for Enterococcus spp. urinary tract infection of 0.28%. LIMITATIONS: There may have been reporting bias or incomplete retrieval or inadvertent exclusion of relevant studies. CONCLUSIONS: SBI caused by L. monocytogenes and Enterococcus spp. in febrile infants is rare, and therefore clinicians may consider a change in empirical antibiotic choices.