Optimizing blood culture practices in pediatric immunocompromised patients: evaluation of media types and blood culture volume.
BACKGROUND
The optimal use of blood cultures to determine the etiology of febrile episodes in neutropenic children has not been well-defined.


METHODS
Single volume blood cultures using the Pediatric ISOLATOR System (ISO), were compared with variable, weight-based culture volumes using the BACTEC 9240 Culture System (BAC). Additionally the value of routinely inoculating the BACTEC MYCO/F LYTIC culture vial (MFL) as well as the BACTEC AEROBIC/F culture vial (AF) was examined.


RESULTS
A total of 2620 cultures had both ISO and BAC inoculated; 182 cultures were positive (7.0% of cultures); 97.8% of positive cultures were detected by the BAC (AF and/or MFL) vs.46.2% detected by the ISO. The advantage of the BAC over the ISO was statistically significant for overall recovery of isolates and bloodstream infections, including most individual organism categories. There were only two instances (one each of histoplasmosis and candidemia) in which a blood stream infection was detected by ISO only. All the isolates judged to be contaminants were recovered by BAC only. AF detected significantly more coagulase-negative Staphylococcus spp. than the MFL. Of the isolates 16%, representing 14% of the bloodstream infections (including Gram-negative infections), were detected by the MFL only. Infections were detected more quickly by BAC than by ISO (P < 0.0001). Among the BAC media types, AF was faster than MFL (P < 0.0001).


CONCLUSIONS
Optimal yield of blood cultures in immunocompromised pediatric patients included the use of BAC with a weight-based, graduated volume of culture inoculation and routine use of both AF and MFL.
Gaur
Aditya  H
A
Department of Infectious Diseases, St. Jude Children's Research Hospital, University of Tennessee Health Science Center, 332 N. Lauderdale Street, Memphis, TN 38105-2794, USA.
Giannini
Mary Anne
MA
Flynn
Patricia M
PM
Boudreaux
Jan W
JW
Mestemacher
Mark A
MA
Shenep
Jerry L
JL
Hayden
Randall T
RT
D016470:Bacteremia / Q000097:blood* / Q000382:microbiology; D001431:Bacteriological Techniques; D003470:Culture Media; D005260:Female; D006090:Gram-Negative Bacteria / Q000302:isolation & purification*; D006094:Gram-Positive Bacteria / Q000302:isolation & purification*; D006801:Humans; D016867:Immunocompromised Host; D008297:Male; D010372:Pediatrics; D011336:Probability; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric
D003470:Culture Media