Controlled clinical comparison of three commercial blood culture systems

In a controlled clinical comparison, three commercial blood culture systems - the standard aerobic BacT/Alert bottle (STD), the aerobic BacT/Alert FAN bottle (FAN) and the Isolator system (ISO; Wampole Laboratories, USA) were compared for their ability to detect aerobic and facultatively anaerobic m icroorganisms. A total of 945 BacT/Alert (STD and FAN) blood culture sets w ere compared. Of these, 110 blood culture sets (11.6%) yielded growth of 11 6 clinically significant bacterial and fungal isolates. Microorganisms were recovered from 10.7% (101/945) of the FAN bottles compared to 8.9% (84/945 ) of the STD bottles. Of the significant isolates, 78 (67.2%) were recovere d by both bottles, 29 (25%) by the FAN bottle only and nine (7.8%) by the S TD bottle only (P < 0.01). Along with 56.1% (530/945) of BacT/Alert blood c ulture sets, a concomitant ISO tube was obtained. Of the triple (STD+FAN+IS O) blood culture sets, 54 (10.2%) yielded growth of 59 clinically relevant isolates. Microorganisms were detected in 9.1% (48/530) of the FAN bottles, 8.3% (44/530) of the STD bottles and 4% (21/530) of the ISO tubes (P < 0.0 01). Overall, the BacT/Alert system detected more clinically significant mi croorganisms than the ISO tube; the STD and the FAN bottle each recovered s ignificantly more staphylococci (P < 0.01 and P < 0.001, respectively) and gramnegative rods (P < 0.01, both). In conclusion, the BacT/Alert FAN bottl e performed better than the BacT/Alert STD battle; both BacT/Alert bottles, however, were superior to the ISO tube in terms of recovery of clinically significant microorganisms, including gram-positive and gram-negative bacte ria.