ASSESSMENT OF 3 AUTOMATED BLOOD CULTURING SYSTEMS BIO-ARGOS, BACT ALERT AND BACTEC NR-860/

In 1991 and 1992, three automated blood culturing systems were auccess ively assessed (<< Diagnostics Pasteur >> Bio Argos : 1 120 Vials, << Organon Teknika >> BacT/Alert : 1 400 vials and << Becton Dickinson >> bactec NR-860 : 2 146 standard vials 6 and 7 and 2 360 resin vials 26 and 27), and compared with the conventional system (C) (Roche aerobic BHI-S Liquoid, and Diagnostics Pasteur anaerobic prereduced Shaedler) . Duplicate blood cultures were collected in various hospital services . They were processed over a 7-day period by the automated instruments and were incubated for 10 days using conventional techniques. The per centage of positivity (clinically significant results) obtained with t he automated instruments was similar to that obtained with conventiona l techniques. Bio Argos : 3.4 p. cent vs 3.8 p. cent with C, BacT/Aler t : 3.9 p. cent vs 3.5 p. cent, Bactec standard 6 and 7 vials 5.6 p. c ent vs 6.4 p. cent, and resin 26 and 27 4.2 p. cent vs 3.1 p. cent. A better sensitivity was found with Bactec resin 26 and 27 vials when co mpared to C for Staphylococcus aureus (22 p. cent of S. aureus strains were isolated only with resin vials 26 and 27). False positives were as follow : 0.36 p. cent for BacT/Alert, 2.1 p. cent for Bio Argos and 3.5 p. cent for Bactec. The fastest detection rate was observed with the instrument which shakes the vials continuously (BacT/Alert) : 73.6 p. cent of positive vials were detected on the day the vials were rec eived at the laboratory. Ninety-four percent of the Bactec resin 26 an d 27 positive vials, 90.6 p. cent of the BacT/Alert positive vials, 84 p. cent of the Bactec 6 and 7 positive vials and 73.7 p. cent of the Bio Argos positive vials were detected within twenty-four hours.