Sterility Testing of Stem Cell Products by Broad-Range Bacterial 16S Ribosomal DNA Polymerase Chain Reaction.

OBJECTIVE To evaluate broad-range 16S ribosomal DNA (rDNA) polymerase chain reaction (PCR) as a rapid screening tool to detect bacterial contamination of stem-cell products. METHODS We performed the evaluation using whole blood spiked with serially diluted bacterial-type strains. Detection sensitivity was defined as the bacterial concentration for which all replicates were positive at each concentration (100% detection). We tested the sterility of 29 bags of autologous peripheral blood stem cell (PBSC) products harvested at our facility using the 16S rDNA PCR method. RESULTS The detection sensitivity of 16S rDNA PCR in spiked whole blood was 10¹ to 10² colony-forming units (CFU) per mL, depending on the bacterial strain. We detected no amplified 16S rDNA among the PBSCs we used in this study. The BacT/ALERT automated bacterial culture system that we used also showed no positive signals in any of the PBSCs tested. CONCLUSIONS Our data indicate that bacterial 16S rDNA PCR is a useful alternative for rapid sterility testing, not only for blood products used in transfusion medicine but also for stem-cell products used in regenerative medicine.