The rate of microbial contamination of hematopoietic progenitor cell products from peripheral blood is low. In this study, we investigated the prevalence of positive blood cultures of hematopoietic progenitor cells from peripheral blood in a hemotherapy service. Of a total of 618 samples taken during the period from 2000 to 2007, 26 (4.2%) were contaminated by bacteria. Staphylococcus coagulase-negative was the predominant bacterium isolated in blood cultures. Pre- and post-infusion antibiotic therapy was established depending on the microorganism and antibiogram, whereas in five out of twelve contaminated infusions, no antibiotics were administered prophylactically. Febrile episodes were observed in seven patients (58%), while five (42%) did not suffer from fever. Of the twelve contaminated infusions performed, six (50%) of the samples had positive blood cultures after thawing, while the others (50%) were negative. This is due to the bactericidal properties of DMSO, phagocytosis-active cells and the extremely low temperatures during cryopreservation. Authors have reported success in the procedure after the infusion of contaminated products with minimal clinical consequences.
Blood; hematopoietic stem cell transplantation; quality control; reference standards
