Comparison of New and Old BacT/Alert Aerobic Bottles for Detection of Candida spp.

Abstract

PurposeA new version of aerobic blood culture media has been developed for the BacT/Alert (bioMerieux) blood culture system. We evaluated the TTD and yeast cell counts in positive blood cultures for each Candida spp. according to changes in media. MethodsIsolates from defibrinated horse blood were inoculated into three types of bottles: the old version of FA Plus (Old FA Plus), New FA Plus, and FN Plus. All bottles were incubated in the BacT/Alert Virtuo blood culture system. The TTD was monitored for each bottle, and yeast cell counts were performed immediately after testing positive, determined via the plate count method. Clinical retrospective data of the candidemia samples before and after aerobic bottle change also were analyzed. ResultsThe mean TTD was 51.2 hours in the Old FA Plus bottles versus 19.5 hours in the New FA Plus bottles (P < 0.001) for Candida glabrata, and standard and clinical strains showed similar results. C. albicans (27.6 to 25.1 hours) and C. guilliermondii (28.8 to 27.3 hours) had shorter TTDs. However, C. auris (25.6 to 28.1 hours) had a longer TTD in the New FA Plus bottle. The retrospective clinical analysis showed a significant decrease in TTD (45.0 to 19.4 hours) for C. glabrata, which is consistent with our simulated study. ConclusionThis study shows that the TTD of C. glabrata was markedly reduced in the New FA Plus bottle due to the optimized growth performance. The reduction of TTD enables faster detection and therapeutic approach for C. glabrata infections.