MULTICENTER COMPARISON OF BACTEC-9050 AND BACTEC-9240 BLOOD CULTURE SYSTEMS

The overall recovery of organisms and time to detection with the BACTE C 9050 and BACTEC 9240 systems were compared in a multicenter evaluati on. In the first phase of the study, a total of 4,383 compliant aerobi c (Plus Aerobic/F) blood culture sets were processed. There was no sig nificant difference in the recovery of individual groups of organisms with the two systems, with the exception of Streptococcus pneumoniae w hich was isolated more frequently with BACTEC 9050, False-positive sig nals occurred more often with BACTEC 9240 (58 cultures) than with BACT EC 9050 (43 cultures), but false-negative cultures were uncommon with both systems (3 cultures for each system). Time to detection of positi ve cultures of clinically significant organisms was essentially the sa me with both instruments, In the second phase of the study, 2,431 comp liant anaerobic (Plus Anaerobic/F) blood culture sets were processed. There was no significant difference in the recovery of organisms with BACTEC 9050 compared,vith BACTEC 9240, Significantly (P < 0.03) more f alse-positive signals occurred with BACTEC 9240 (15 cultures) than wit h BACTEC 9050 (4 cultures). Likewise, more false-negative cultures occ urred with BACTEC 9240 (11 cultures) than with BACTEC 9050 (8 cultures ). Time to detection of positive cultures of clinically significant or ganisms was essentially the same with both systems with the exception of anaerobes (N = 10), which were recovered earlier (P < 0.01) with BA CTEC 9240 (35.0 h) than with BACTEC 9050 (61.4 h).