Clinical Microbiology and Antimicrobial Chemotherapy. 2024; 26(3):384-392
To compare analytical parameters and sensitivity between BACT/ALERT® 3D 60 and Yunon® Labstar 50.
The study included 20 species of clinically significant microorganisms isolated from blood (20 strains for each facultative anaerobic species and 10 strains for each aerobic species). For each strain, individual volumes of the inoculation dose were selected with the control of CFU value. In the case of obtaining a stable CFU value in the range 2–10 per 100 µl of bacterial cell suspension, 100 µl of suspension was inoculated into vials with nutrient media for each analyzer, followed by an analysis of the cultivation time, the presence or absence of a growth signal, and average CFU values. Aliquots of the vials contents were also inoculated onto solid nutrient media to evaluate false positive and false negative results.
It was revealed that the main analytical parameters of both devices were comparable. In addition, for two blood culture systems, the maximum limit value of CFU per sample was set, at which the probability of the growth signal absence from both analyzers significantly increased – 2 CFU per vial. At this value and values below, the analyzers did not detect the growth of microorganisms significantly more often. Also, a comparable median inoculation dose of 5 CFU per vial was established for both devices.
The devices included in the study have comparable analytical parameters and allow to obtain a positive growth signal after inoculating material containing < 10 CFU per vial. However, it is necessary to consider increased probability of a negative result in case of inoculation dose equal to CFU ≤ 2.