Molecular characterization of microbial contaminants isolated from Umbilical Cord Blood Units for transplant

Abstract

Disposal of Umbilical Cord Blood Units due to microbial contamination is a major problem in Cord Blood Banks worldwide as it reduces the number of units available for transplantation. Additionally, economic losses are generated as result of resources and infrastructure used to obtain such units. Umbilical Cord Blood Units that showed initial microbial contamination were subject to strains isolation, identification, and characterization by sequencing the 16S rRNA gene and Enterobacterial Repetitive Intergenic Consensus (ERIC-PCR). Moreover, tests of antimicrobial resistance/sensitivity and phenotypic activities that may play an important role in microbial infection were performed. Microbial contamination was detected in 120 Umbilical Cord Blood Units (2.31%) in the period from 2003 to 2013. The most frequently isolated strains were Enterococcus faecium, followed by Staphylococcus epidermidis, Escherichia coli, Enterococcus faecalis, Staphylococcus haemoliticus, Klebsiella pneumoniae, Enterococcus durans, Lactobacillus helveticus, Enterococcus hiriae and Roseomonas genomospecies 5. The ERIC-PCR assays revealed a wide genetic diversity in some strains although belonging to the same genus and specie, indicating different sources of contamination. Broad-spectrum penicillins, third generation cephalosporins, aminoglycosides, and fluoroquinolones showed lower inhibitory activity on the tested strains. All strains were proteolytic, 67.69% were amylase-positive, 27.6% hemolysis-positive, and 34.71% nuclease-positive. The most common sources of contamination were: vaginal flora, digestive tract, and skin flora, highlighting the need for staff training in good manufacturing practices in collection SCU since all contaminants identified are part of the microbial flora of the donors. Implications and consequences in the therapeutic use of Umbilical Cord Blood Units for transplantation contaminated by multiresistant bacteria in immunocompromised patients are discussed.

Contamination Rate of Cryopreserved Umbilical Cord Blood Is Inversely Correlated with Volume of Sample Collected and Is also Dependent on Delivery Mode

“… 13 These results of contamination rates in this study are well within the range of those values reported in the literature (0.9%-8.6%). 18 , 39-44 …”

“… 14-16 Bacterial contamination of human blood products is another challenge as it occurs quite frequently and it is observed that bacteria developed resistance, which can be life-threatening, especially in immune-compromised patients. 17 , 18 Therefore, sterility testing is mandatory according to the guideline standards to prevent transplantation transmitted bacterial infections causing severe transfusion-associated sepsis in immune-suppressed patients. 19 , 20 …”

Development of a proof of principle for universal neutralization of antibiotics in cord blood by‐products used for sterility testing

“…Microbial contamination of umbilical cord blood (CB) hematopoietic stem cell products can occur at different points during collection in hospital obstetric units or during processing at the cord blood bank, and could represent a serious safety risk for immunocompromised transplantation patients. The incidence of contaminated CB varies widely between centers with skin and vaginal flora organisms representing the majority of contaminants isolated from CB . As required by cellular therapy accrediting organizations, cell therapy products must be tested for microbial contamination…”

“…The incidence of contaminated CB varies widely between centers with skin and vaginal flora organisms representing the majority of contaminants isolated from CB. [1][2][3][4][5] As required by cellular therapy accrediting organizations, cell therapy products must be tested for microbial contamination. 6,7 Sterility testing of CB units manufactured at Canadian Blood Services' Cord Blood Bank is performed using the (BacT/ALERT 3D system).…”

“…From the 1 Canadian Blood Services Centre for Innovation, Product and Process Development; and 2 Canadian Blood Services' Cord Blood Bank, Ottawa, Ontario. obtained during cesarean section deliveries, with donors undergoing prophylactic antibiotic therapy.…”