Clinical comparison of two commercial blood culture systems

A prospective, volume-controlled comparison of the BacT/Alert FAN (Organon Teknika, USA) and Vital (bioMérieux, France) blood culture systems was performed in a university hospital during a period of 11 months. Twenty to 40 ml of blood drawn from an adult patient was distributed equally between a BacT/Alert FAN and a Vital blood culture set, both consisting of an aerobic and an anaerobic bottle. Bottles were weighed prior to use and after incubation to calculate the blood volume. A compliant pair of aerobic, or anaerobic, bottles of a blood culture was defined as follows: blood volumes were 4-11 ml and the blood volumes in the two bottles differed by < or =20%. From 120 compliant pairs of aerobic bottles, 135 organisms were recovered, of which 78 were isolated in both bottles, 44 in the BacT/Alert FAN bottle only and 13 in the Vital bottle only (P<0.0005). In particular, aerobic BacT/Alert FAN bottles yielded more members of the family Enterobacteriaceae (P<0.01). The BacT/Alert FAN system also performed significantly better when comparing anaerobic bottles, and the yield was greater during septic episodes. Both culture systems were similar regarding detection time, recovery during antimicrobial therapy, and the occurrence of false-positive and false-negative bottles. The overall performance of the BacT/Alert FAN system was better than that of the Vital system.