Rapid detection of positive blood cultures with the BACTEC NR-660 does not require first-day subculturing.
An analysis of blood culture data was performed to determine whether subculturing within the first 24 h of incubation decreased the time to detection of positive blood cultures when compared with the routine use of the BACTEC NR-660 system (Johnston Laboratories, Inc., Towson, Md.). During a 9-month period (June 1985 to February 1986), 17,913 blood cultures were received in our laboratory, of which 1,463 (8.2%) became positive. Of the positive cultures, 97% were detected with equal or greater rapidity by the NR-660 system than by visual inspection and first-day blind subculturing. There were 37 delayed positive cultures from which only one isolate (0.07%) was not eventually detected by the NR-660 system. Coagulase-negative staphylococcus was the most frequent isolate among the delayed positive cultures, but only 3 of 15 isolates were known to be clinically significant isolates. The longest delay in detection by the NR-660 system was 6 days for one isolate of Cryptococcus neoformans and one isolate of Klebsiella pneumoniae. Although subculturing may decrease the time to detection of a few cultures, the majority of positive blood cultures were detected faster or with equal speed by the NR-660 system. When the data were evaluated, routine use of the NR-660 system was sufficient for the detection of positive blood cultures and was cost-effective.
Levi
M H
MH
Department of Pathology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York 10467.
Gialanella
P
P
Motyl
M R
MR
McKitrick
J C
JC
D001419:Bacteria / Q000254:growth & development / Q000302:isolation & purification*; D001420:Bacteria, Aerobic / Q000302:isolation & purification; D001421:Bacteria, Anaerobic / Q000302:isolation & purification; D001424:Bacterial Infections / Q000097:blood*; D001431:Bacteriological Techniques; D001769:Blood; D003470:Culture Media; D006801:Humans
D003470:Culture Media