One PERFORMANCE OF BC120 SYSTEM IN SIMULATED BLOOD CULTURES: SENSITIVITY AND EFFECTS OF EXPERIMENTAL VARIABLES

Abstract

Bacteremia detection through blood culture is critical for diagnosing infections and guiding appropriate treatment. This study evaluated the performance of the BC120 system from Instituto Hospital de Base do Distrito Federal, comparing it with automated technologies such as Virtuo BacT/Alert, VersaTrek, and BD Bactec. We used aeróbic culture bottles FA and PF from the same lots and ATCC reference strains, ensuring sample consistency. Various sample volumes were tested to assess the time to positivity (TTP) and false positive rates. The results indicated that the BC120 had TTPs comparable to other systems, though slightly higher in some cases. For example, Staphylococcus aureus had a TTP of 12 hours with BC120, compared to 11.4 hours with Virtuo BacT/Alert and 11.8 hours with VersaTrek. The BC120's TTP for Escherichia coli was consistently around 9 hours, regardless of volume. Larger volumes generally increased TTP for Candida albicans but had minimal effect for Enterococcus faecalis. Tests for false positives, including pH variations, indicated that acid and alkaline solutions could impact results, highlighting the need for rigorous sample handling. Sensitivity, specificity, and precision of the BC120 were all 100%, demonstrating its effectiveness in detecting microorganisms without false positives or negatives. In conclusion, the BC120 system proved to be a reliable tool for detecting bacteria and fungi in blood cultures. It matched the performance of leading automated systems, though careful attention to sample handling is crucial to avoid false positives due to pH changes.