Utility of digital images captured after 4 h of incubation on a microbiology laboratory automation system in guiding the work-up of subcultures from positive blood cultures

In recent years, an increasing number of clinical microbiology laboratories have adopted laboratory automation for processing and incubation of specimens submitted for bacterial culture. At our institution, we implemented the Copan WASPLab in 2018 for all cultures, including positive blood cultures. Given that positive blood cultures start with a higher biomass of organisms, the first image capture was set up to occur after 4 h of incubation. In this study, we investigated the utility of this early 4 h image by capturing and calculating the percentage of useful actions taken based on growth identified on the image and the yield of both new identification by MALDI-TOF MS and valid and accurate antimicrobial susceptibility testing (AST) results. We found that while the 4-hour time point provided accurate, early identification and AST results, the overall yield was minimal. From a practical standpoint, this review prompted us to discontinue capture and review of this time point. While our staffing model is likely responsible for this low yield, we hope that our experience would help other laboratories decide how to implement WASPLab workflow for positive blood cultures. Thus, we believe that this information will be of interest to the readers of JCM.