Direct microbiota profiling of apheresis-associated products for microbiological insights in cell therapy

Cellular therapies require rigorous prevention of bacterial contamination during cell collection, manufacturing, and infusion. We characterized 16 S rRNA profiles in blood-derived specimens obtained during leukapheresis. Leukapheresis donors provided five specimen types: buffy coats (BCs), whole-blood plasma (WBP), apheresis plasma stored at room temperature for 24 h (AP24) and 72 h (AP72), and saliva. Species-level identification was performed using next-generation sequencing-based 16 S rRNA analysis and a database-weighted method. In total, 40 samples from eight donors were analyzed. Plasma specimens (WBP, AP24, and AP72) exhibited higher alpha diversity than saliva (Shannon index, p < 0.05). Beta diversity analysis identified three distinct clusters corresponding to BC, plasma specimens, and saliva (permutational multivariate analysis of variance, p = 0.001). Streptococcus oralis subsp. tigurinus was predominant across all specimens types, Bifidobacterium kashiwanohense predominated in blood-derived specimens, and Enhydrobacter aerosaccus was observed exclusively in plasma specimens. Skin swab culture performed before and after venipuncture site disinfection exhibited no bacterial growth post-disinfection, suggesting that skin-derived carryover is unlikely to fully explain the detected microbial DNA signals. This study provides microbial DNA profiles of various blood-derived specimens obtained during leukapheresis. These findings provide preliminary reference information that may assist interpretation of molecular microbial signals in cellular therapy manufacturing.