Comparison of Microorganism Detection, Time to Positivity, and Time-Dependent Shift in Viable Bacterial Count from VersaTREK and BacT/ALERT 3D Blood Culture Systems.

Rapid positive blood culture reporting allows early and appropriate treatment of severe infections to improve patient prognosis. This study evaluated performance of the VersaTREK system with gas pressure detection and tornado stirring method and the conventional BacT/ALERT 3D system. Time to positivity (TTP) of simulated blood cultures without whole blood using 17 ATCC strains was faster with VersaTREK than BacT/ALERT 3D, averaging 6.3 h in aerobic bottles and 12.7 hours in anaerobic bottles. In simulated blood cultures with whole blood using 53 clinical isolates, on average, VersaTREK was faster in aerobic bottles by 6.5 h but slower in anaerobic bottles by 3.8 h. Fifty of 53 simulated blood cultures with whole blood (94%) showed fastest TTP with VersaTREK. TTP of VersaTREK for anaerobic bacteria Bacteroides fragilis and Clostridium perfringens , Helicobacter cinaedi , and Candida glabrata was fast, and viable bacteria numbers in bottles using the Miles and Misra method increased quickly.