Bacterial species in cord blood and their significance in the context of clinical use.

Approximately 90 % of infants born before 28 full weeks(extremely-preterm-infants) receive erythrocyte transfusions in early life. Umbilical cord blood(UCB) has been investigated as an alternative source for erythrocyte transfusions to preterm neonates. This retrospective study aimed to compile/evaluate spectrum of bacteria groups/species intermittently detected in processed UCB at National-Swedish-Cord blood bank, (NS-CBB) during the years 2008-2020. Consecutive data from the years 2008-2020 were investigated. UCB from healthy newborns born after 37 full weeks of gestation was collected following clamping of cord (1 min) through cannulation of umbilical vein(vaginal-and C-section-deliveries). In total, 5194 cord blood units (UCBUs) that met NS-CBB-guidelines for total nucleated-cell-content(TNC) were manufactured from 8875 collections. Of 5194 UCBUs,77,6 % were from vaginal-and 22,4 % from C-section deliveries.Samples(10 mL) were collected from surplus eryhtrocyte fraction post-processing(n = 5194), transferred into BACT/ALERT® aerobic/anaerobic culture flasks and monitored 10 days using BACT/ALERT®-3D-Microbial-Detection-Systems. Positive samples were subcultured and typed for bacterial groups and/or species. Out of 5194 processed sampled UCB units,186 (3,6 %) were discarded due to positive sterility tests, 92 % were detected in samples from vaginal-deliveries and 8 % from C-section-deliveries. In all,16 different groups of bacteria and 27 species were identified. Common bacterial/groups and species were anaerobe gram-negative rods(n = 28),coagulase-negative-staphylococci(n = 21),gram-positive rods(n = 21),anaerobe-gram-positive cocci(n = 20) and viridans-streptococci(n = 13). Extracted from these results,in positive samples(n = 13) from C-section deliveries, bacteria were found:viridans-streptococci(n = 7),Aerococcus-urinae(n = 1), Staphylococcus lugdunensis(n = 1),other coagulase-negative staphylococci(n = 1) or a mix of aerobic/anaerobic bacteria(n = 3). Our results are in alignment with previously published contamination rates in processed UCBUs. Still, results point towards importance of strict microbial monitoring when manufacturing UCBUs to achieve patient-safe- products for stem-cell transplantation/transfusion.