Comparison of the BacT/Alert and Isolator blood culture systems for recovery of fungi.

The recovery of fungi by the BacT/Alert (Organon Teknika Corporation, Durham, NC) and Isolator (Wampole Laboratories, Cranbury, NJ) blood culture systems was compared by retrospective review of 2,174 matched cultures from 715 patients collected from April 1, 1993 to February 28, 1994. One hundred five isolates were recovered from 44 patients by one or both culture systems. All patients were fungemic with one organism. In all cases of fungemia, collection times for both culture systems were within 6 hours of each other. Of 22 isolates of Candida spp, the Isolator recovered all 22 isolates whereas the BacT/Alert recovered 15 (68.2%) (P < .05). The Isolator detected more isolates of Cryptococcus neoformans (10 of 11) than did the BacT/Alert (7 of 11). All 64 isolates of Histoplasma capsulatum (P < .0001) and 6 isolates of Malassezia furfur (P < .05) were recovered by the Isolator system only. For 20 isolates recovered by both systems for which time to recovery could be determined, the mean time to detection of growth was 2.9 days (range 0-9 days) for the Isolator and 2.1 days (range 0-5 days) for the BacT/Alert. In conclusion, the Isolator blood culture system is superior to BacT/Alert for the detection of fungemia, including fungemias caused by Candida spp, H capsulatum, and M furfur.