Evaluation of Zhuhai DL Biotech's BT24 automated blood culture system

Introduction: For the microbiological diagnosis of bacteremia and fungemia, it is essential to use automated blood culture systems that guarantee good performance in the detection of microorganisms. We evaluated the BT24 system for blood cultures by comparing it with the BACTEC™ FX system in detection of positive spiked blood cultures (BC) and bottles, subsequent growth of the microorganism, and time to detection (TTD).

Methods: The parallel analysis of both systems was performed with 160 strains of 31 different species, each inoculated under the same conditions and simultaneously in six blood culture bottles. The Chi-square test was used for comparison per BC and per bottle detection. Wilconxon test and Student's t-test were used for comparison of TTDs.

Results: Overall, the following BC (aerobic bottle+anaerobic bottle) were detected as positive: 160/160 (100%) in BACTEC FX and 158/160 (98.7%) in BT24 (P=.31). Furthermore, the following pediatric blood cultures (1 single bottle, aerobic) were also detected: 159/160 (99.4%) in BACTEC FX and 156/160 (97.5%) in BT24 (P=.17). TTDs were longer with BT24 system than with BACTEC FX system, especially for Staphylococcus aureus strains.

Conclusions: We consider the BT24 system with good performance and specificity comparable to the reference system, but inferior in TTD.