Rapid detection of bacterial contaminants in platelet concentrates using the next generation BACT/ALERT® VIRTUO® Microbial Detection System: improved safety and operational efficiency

Abstract

The BACT/ALERT® 3D Microbial Detection System has been widely adopted for screening platelet concentrates to detect bacterial contamination and reduce the rate of septic transfusion reactions (STRs). Over the past several decades, numerous mitigation strategies have been implemented to reduce contamination and increase sensitivity. An evolution of testing protocols using automated culture systems has shifted from a single aerobic bottle with 4 mL platelet concentrate to an enhanced primary culture protocol using large volume delayed sampling (LVDS) that tests 8–10 mL in both aerobic and anaerobic culture bottles following a 36- to 48-hour delay after collection. Data has shown 7-day LVDS to improve safety and inventory management, and provide positive economic benefit. The BACT/ALERT 3D and next generation BACT/ALERT® VIRTUO® Microbial Detection Systems utilize aerobic and anaerobic culture bottles that have received FDA clearance for testing LVDS that extends shelf-life to 7 days. The systems are also cleared for secondary testing as a safety measure to allow multiple strategies to be used depending on the needs of the blood collection organizations. This review highlights the evolution of bacterial culture protocols and instrumentation that are used for testing platelet concentrates. The BACT/ALERT VIRTUO system incorporates new instrument architecture to improve temperature stability, workflow improvement via automated loading and unloading of bottles, an improved user interface, and an enhanced detection algorithm to shorten times to detection (TTD) of positive cultures. The shortened TTD may decrease the risk of releasing contaminated units with a negative-to-date result. Consolidated validation data and a time and motion study comparing the BACT/ALERT VIRTUO to BACT/ALERT 3D are presented and the improved workflow and overall specificity and sensitivity determined.