650 - Clinical Performance Evaluation of Virtuo Blood Culture System in a Tertiary Care Hospital

Background: Bloodstream infections are a major cause of morbidity and mortality. BACT/ALERT VIRTUO (VIRTUO) blood culture system is an automated, closed system used with resin-containing media which may enhance the growth of microorganisms. Our objective was to assess the real-world performance of the VIRTUO system.

Methods: We retrospectively reviewed all blood cultures performed between January-December 2018 (VersaTREK) and January-December 2019 (VIRTUO) at a 1250-bed academic medical center. Blood culture positivity rates, contamination rates, and time from collection to arrival in the laboratory were compared pre- versus post-VIRTUO implementation. Contamination was defined as a single blood culture with common skin microbiota.

Results: A total of 101803 blood cultures were performed during the study period: 48969 (48.1%) were processed with VersaTREK system and 52834 (51.9%) with VIRTUO system. A decreased median time from collection until arrival to the laboratory was seen post-implementation (2.0 pre- vs. 0.8 hours post-implementation, p< 0.001). The positivity rate increased from 3987 (8.1%) pre-implementation to 6141 (11.6%) post-implementation (p < 0.001) (Table and Figure). Staphylococcus aureus was the most frequently isolated species for both periods and had higher recovery rate with the VIRTUO system (717 (1.5%) pre- vs. 1764 (3.3%) post-implementation, p< 0.001). Higher recovery rate was also noted for other Staphylococcus spp. in the post-implementation period (985 (2.0%) pre- vs. 1644 (3.1%) post-implementation, p< 0.001). No difference in the organism recovery rate was noted for Streptococcus spp., Enterococcus faecium, E. faecalis, Pseudomonas aeruginosa, Enterobacterales, and Candida spp. The inpatient contamination rate was higher post-implementation (1.5% pre- vs. 1.9% post-implementation, p < 0.001).Comparison of blood culture positivity rate pre- vs. post-implementation, by culture location
Daily positivity rate for blood cultures processed at BJH during the study period


Conclusion: The VIRTUO system showed a higher rate of positive blood cultures compared to the VersaTREK system primarily from a higher detection of Staphylococcus spp. Further studies are needed to assess whether an increased rate of positive blood cultures is associated with changes in management and clinical outcomes.