Utility of anaerobic blood cultures in a pediatric emergency department.
OBJECTIVE
To determine the frequency with which clinically significant bacterial pathogens are isolated only from the anaerobic blood culture medium in children evaluated for bacteremia and to describe the clinical features associated with these positive cultures.


METHODS
Retrospective review of all blood cultures received from the emergency department in the microbiology laboratory. Clinically significant pathogens were defined as microorganisms that rarely are considered to be contaminants or microorganisms that are recovered from multiple blood cultures or sites from the same individual. Charts of all patients with positive anaerobic cultures for clinically significant pathogens in the presence of negative aerobic cultures were reviewed. The setting was an urban tertiary care pediatric emergency department.


RESULTS
2675 paired blood cultures were performed between January 1, 1998 and December 31, 2000. Growth of a bacterial organism occurred in 595 of the paired samples. Two hundred seventy-eight were clinically significant pathogens. One hundred sixty-two (58.3%) were present in both the aerobic and anaerobic mediums, 85 (30.6%) were only in the aerobic medium, and 31 (11.2%) were only in the anaerobic medium. Most patients with growth only in the anaerobic medium had underlying conditions (ie, central venous line, immunocompromised, congenital heart disease, liver disease, age < 3 months). No obligate anaerobic organisms were detected.


CONCLUSIONS
In a pediatric emergency department setting, almost all pathogenic bacteria were isolated from aerobic culture mediums in otherwise healthy children. The yield of routinely performed anaerobic blood cultures is low. In previously healthy children, it may be optimal to inoculate the entire blood volume obtained into the aerobic medium.
Freedman
Stephen B
SB
Division of Pediatric Emergency Medicine, Children's Memorial Hospital, Chicago, IL 60614, USA. s-freedman@md.northwestern.edu
Roosevelt
Genie E
GE
D000293:Adolescent; D000332:Aerobiosis; D000693:Anaerobiosis; D001421:Bacteria, Anaerobic / Q000302:isolation & purification*; D001424:Bacterial Infections / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology*; D001431:Bacteriological Techniques / Q000706:statistics & numerical data; D001769:Blood / Q000382:microbiology*; D002641:Chicago / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003470:Culture Media; D003955:Diagnostic Tests, Routine / Q000706:statistics & numerical data*; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D004866:Equipment Contamination; D006776:Hospitals, Pediatric / Q000706:statistics & numerical data*; D006786:Hospitals, Urban / Q000706:statistics & numerical data*; D006801:Humans; D007223:Infant; D012189:Retrospective Studies; D016037:Single-Blind Method
D003470:Culture Media