Blood Volume Required for Detection of Low Levels and Ultralow Levels of Organisms Responsible for Neonatal Bacteremia by Use of Bactec Peds Plus/F, Plus Aerobic/F Medium, and the BD Bactec FX System: anIn VitroStudy

We used an in vitro technique to investigate blood volumes required to detect bacteremia and fungemia with low concentrations of an organism. At 1 to 10 CFU/ml, Escherichia coli, Staphylococcus epidermidis, Staphylococcus aureus, Listeria monocytogenes, Candida albicans, and Candida parapsilosis isolates were detected in volumes as low as 0.5 ml. Detection of Streptococcus agalactiae and detection of bacteremia at <1 CFU/ml were unreliable.