The detection of positive blood cultures by the AccuMed ESP-384 system: the clinical significance of three-day testing.

A total of 805 positive blood cultures obtained over a 4-month period during 1997 by the AccuMed ESP-384 system were evaluated and compared with 471 positive blood cultures obtained during 1989. Of the 805 microorganisms isolated in 5-day culture and testing by the ESP-384, 671 (83.4%) were detected within the first 2 days and 758 (94.2%) within 3 days. There were 47 (5.7%) microorganisms detected in culture Days 4 and 5 from 42 patients and review of the medical records from these patients demonstrated that no significant changes in clinical management were instituted as a result of detection and identification of these isolates. These 47 organisms were considered to be zero to equivocal clinical relevance. These data suggest that a 3-day routine blood culture incubation protocol with the ESP-384 system may be sufficient when considering detection rate, clinical relevance, and cost-effectiveness. The microbial spectrum and relative frequencies in this study were found to be similar to those of positive blood cultures obtained during 1989.