Comparison of Novel Blood Culture System DL-Bt112TM with BacT/Alert 3DTM by Using Clinical Samples

Blood cultures are the main diagnostic laboratory tool to detect bloodstream infections. Many clinical microbiology laboratories utilize automated blood culture systems to isolate infectious agents from blood samples. The diagnostic performance and time-to-detection values of the novel automated blood culture system, DLBt112TM (DL), was compared with BacT/Alert 3DTM (B3D) in this prospective comparative study with clinical samples.

A total of 356 blood culture sets (178 sets for each system) were evaluated over a 6-month period in a university hospital. Two sets of blood culture samples (one for DL and one for B3D) were drawn from intensive care unit patients who were suspected to have bloodstream infections. BacT/ALERT FA FAN® Aerobic/Anaerobic blood culture bottles for B3D and FAN adult anaerobic/aerobic blood culture bottles for DL were used. The Vitek® 2 automated system was used for identification of the isolated bacteria.

We evaluated 178 sets from 105 patients consisting of 712 blood culture bottles in total. In total, 294 negative bottles and 47 positive bottles were detected by both systems. Recovery rate of the B3D (96.7%) was significantly higher than that of DL (79.0) (p < 0.05). We determined significant differences between DL and B3D in terms of time-to-detection values for gram negatives (p = 0.006) and contaminants (p = 0.048). Overall, B3D had shorter time-to-detection mean values.

The recovery rate of DL was unfavorably low and time-to-detection values for DL were significantly higher than that of B3D. This might result from the ingredients of the culture bottles since the detection technologies of the systems were similar.