Epidemiology of Bacteremia in Febrile Infants in the United States

BACKGROUND: Fever in infants is a common clinical dilemma. The objective of this study was to present data from hospital systems across the northeast, southeast, mid-west, and western United States to identify the pathogens causing bacteremia in febrile infants admitted to general care units.

METHODS: This was a retrospective review of positive blood culture results in febrile infants aged ≤90 days admitted to a general care unit across 6 hospital systems. Data were collected from January 1, 2006 through December 31, 2012 from emergency departments and general inpatient units. Cultures from ICUs, central lines, or infants who had complex comorbidities were excluded, as were repeat cultures positive for the same bacteria. Common contaminants were considered pathogens if they were treated as such.

RESULTS: We identified 181 cases of bacteremia in 177 infants. The most common pathogen was Escherichia coli (42%), followed by group B Streptococcus (23%). Streptococcus pneumoniae was more likely in older infants (P = .01). Non-low-risk bacteremic infants were more likely to have E coli or group B Streptococcus than low-risk bacteremic infants. We identified no cases of Listeria monocytogenes. Variation between sites was minimal.

CONCLUSIONS: This is the largest and most geographically diverse study to date examining the epidemiology of bacteremia in infants. We suggest E coli is the most common cause of bacteremia in previously healthy febrile infants admitted to a general inpatient unit. We identified no cases of L monocytogenes and question whether empirical therapy remains necessary for this pathogen.