COMPARISON OF BACT ALERT WITH SIGNAL BLOOD CULTURE SYSTEM/

The BacT/Alert (Organon Teknika Corp., Durham, N,C,) is an automated b lood culture system, It is based on the detection of CO2 by means of a colorimetric sensor internally attached to the bottom of culture bott les, The aerobic and anaerobic media of this system were compared with one bottle of the Signal system (Oxoid Ltd., Hampshire, United Kingdo m), At bedside, 20 ml of blood was drawn from each adult patient, The two BacT/Alert bottles were inoculated with 5 ml of blood each; the Si gnal bottle was inoculated with 10 ml, A total of 5,284 sets (2,483 pa tients; 2.1 cultures per patient) consisting of three bottles each wer e evaluated, of which 781 sets (14.8%) revealed microorganisms (n = 89 2); 642 of these were considered to be pathogenic, Significantly more (P < 0.0001) pathogens were isolated from the two BacT/Alert bottles t ogether (n = 584) than from the single Signal bottle (n = 515), Escher ichia coli (P = 0.007), gram-negative bacteria other than members of t he family Enterobacteriaceae or Pseudomonas spp, (P = 0.006), and yeas ts (P = 0.02) were isolated more often from both or either BacT/Alert bottle, Comparing the systems in terms of 388 different organisms per septic episode, the difference between BacT/Alert and Signal was signi ficant for the total number of septicemia cases (P = 0.003), More cont aminants grew in the BacT/Alert system (173 versus 116; P = 0.0001), F alse-positive indications were more frequent in the BacT/Alert system, 198 (3.7%) aerobic bottles and 57 (1.1%) anaerobic bottles, than in t he Signal bottles, 24 (0.5%) bottles, Pathogens could be detected sign ificantly earlier (P < 0.0001) in the BacT/Alert system than in the Si gnal system, The BacT/Alert instrument with two bottles allowed earlie r detection as well as the isolation of more microorganisms than the m anual, one-bottle Signal system,