Sydney Cord Blood Bank, Sydney Children's Hospital, Randwick, NSW, Australia; University of New South Wales, Sydney, NSW, Australia; BMT Laboratory, SEALS, Prince of Wales Hospital, Randwick, NSW, Australia; Division of Microbiology, SydPath, St. Vincent's Hospital, Darlinghurst, NSW, Australia.
Transfusion. 2014 Mar;54(3):532-40. doi: 10.1111/trf.12323. Epub 2013 Jun 30.
Cord blood units (CBUs) are associated with significant risk of exposure to microbial contamination during collection and processing; however, the survival of bacteria within a CBU is poorly understood. This study aimed to determine whether contaminating organisms in CBU survive the cryopreservation, frozen storage, and subsequent thawing conditions before infusion.
A total of 134 CBUs rejected from banking due to known contamination were thawed and rescreened using blood culture bottles (BacT/ALERT, bioMérieux). An additional 61 fresh CBUs were deliberately spiked with a range of microbial organisms and evaluated both before freeze and after thaw.
Microbial contaminants were detected after thaw in 63% of stored contaminated CBUs and 85% of spiked CBUs. Postthaw organism detection in spiked cord blood (CB) was higher in adult culture bottles (80%) than pediatric culture bottles (61%). Twenty percent of spiked organisms, particularly Bacillus subtilis, Escherichia coli, Clostridium sporogenes, and Propionibacterium acnes, were not detected in prefreeze samples but were detectable after thaw.
This study demonstrates that the majority of contaminating organisms isolated in a prefreeze sample of CB have the ability to survive cryopreservation, frozen storage, and thawing. Further, CBUs reported as microbial free may contain microbial contamination, which could result in transplantation of contaminated CB and be potentially deleterious to a patient.
脐带血单位（CBU）在采集和处理过程中存在着受到微生物污染的重大风险；然而，CBU 内细菌的存活情况还不太清楚。本研究旨在确定污染的生物体是否能在冷冻保存、冷冻储存以及随后的输注解冻条件下存活下来。
共有 134 份因已知污染而被银行拒收的 CBU 被解冻并使用血液培养瓶（BacT/ALERT，bioMérieux）重新进行筛查。另外 61 份新鲜的 CBU 被故意混入一系列微生物，并在冷冻前和解冻后进行评估。
在储存的污染 CBU 中有 63%和在污染的 CBU 中有 85%在解冻后检测到微生物污染物。在解冻后的成人培养瓶（80%）中检测到的污染 CB 中的病原体检测率高于儿科培养瓶（61%）。20%的污染病原体，特别是枯草芽孢杆菌、大肠杆菌、梭状芽孢杆菌和痤疮丙酸杆菌，在冷冻前样本中未被检测到，但在解冻后可被检测到。
本研究表明，在 CBU 的冷冻前样本中分离出的大多数污染生物体具有在冷冻保存、冷冻储存和解冻后存活的能力。此外，报告为无微生物的 CBU 可能含有微生物污染，这可能导致受污染的 CBU 被移植，并对患者产生潜在的有害影响。
