Contamination rates in umbilical cord Mesenchymal stromal cell cryopreservation: a report from Vinmec tissue bank

Stromal cells hold immense promise for advancing scientific research and medical innovation. The establishment of a biobank for stem cells, specifically umbilical cord (UC)-derived mesenchymal stromal cells (UCMSCs), is crucial for advancing medical research and regenerative therapies. A biobank provides a centralized and standardized repository of high-quality biological materials, which is essential for researchers and clinicians to explore disease mechanisms, test therapeutic approaches, and develop precision treatments. This study applied microbial testing protocols at Vinmec Hospital, including aerobic and anaerobic culture systems (BacT/ALERT® FA Plus and FN Plus), followed by bacterial identification with the VITEK® 2 Compact system, to ensure contamination-free UCMSC samples suitable for banking. A total of 1,336 UC samples were monitored at three check-points (CPs), including CP1 (UC transfer solution during collection), CP2 (cell washing buffer during isolation), and CP3 (cell culture media at P0 and P1 during expansion). Results showed that 29 cases (2.17 %) were contaminated at CP1, and only four cases (0.299 %) at CP2 showed contamination, which were identified as Candida albicans, Staphylococcus epidermidis, Escherichia coli, and Listeria monocytogenes, and were discarded. No contamination occurred at CP3, ensuring effective control during expansion. These results suggest that contamination primarily occurred during the UC collection and processing stages, while the culture and expansion procedures were not a significant source of microbial risk. Additionally, the careful implementation of these methodologies demonstrates the feasibility of generating a reliable UCMSC biobank, a cornerstone resource for personalized therapies, disease modeling, and drug discovery.