title: Microbial contamination of hematopoietic progenitor and other regenerative cells used in transplantation and regenerative medicine.
abstract: BACKGROUND
  Microbial contamination of hematopoietic progenitor cells (HPCs) and other regenerative cells used in transplantation and regenerative medicine can occur during collection and after in vitro manipulation, including purging, cryopreservation, thawing, and infusion.
  
  
  METHODS
  Microbiologic culture findings on consecutive HPCs and other cell preparations at a single institution derived from peripheral blood, marrow, cord blood, and mesenchymal stromal cells during all phases of manipulation were retrospectively examined from 2005 through 2011. Results were classified as confirmed positive, false positive, and indeterminate.
  
  
  RESULTS
  During the 6-year surveillance period, 365 patients underwent 912 procedures involving HPC or other cell-based transfusion. True positive microbial contamination was found in five of 663 (0.8%) peripheral blood and two of 34 (5.9%) marrow preparations (p = 0.04), while no contamination was found in 118 preparations from other sources. True-positive microbial contaminants included coagulase-negative staphylococci in autologous HPC products derived from peripheral blood from two patients with asymptomatic central venous catheter infections at time of apheresis and Propionibacterium acnes in one apheresis and two marrow products. Organism loads were low in all cases (≤500 colony-forming units/mL), and no adverse sequelae occurred in four patients that received contaminated products.
  
  
  CONCLUSIONS
  The incidence of microbial contamination of progenitor cell products in our institution over a 6-year period was low (0.8% overall), with contaminants originating from infected central venous catheters or from skin flora. All contaminants were bacterial species of low virulence, present in low titers and, if transfused, did not result in adverse reactions.
authors: Departments of Pathology and Medicine and Case Comprehensive Cancer Center, Case Western Reserve University and University Hospitals Case Medical Center, Cleveland, Ohio.
authors: Michael R
authors: MR
authors: Jacobs
authors: Caryn E
authors: CE
authors: Good
authors: Robert M
authors: RM
authors: Fox
authors: Katharine P
authors: KP
authors: Roman
authors: Hillard M
authors: HM
authors: Lazarus
mesh_terms: D001419:Bacteria / Q000302:isolation & purification*; D001781:Blood Component Removal; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000382:microbiology*; D006801:Humans; D044968:Regenerative Medicine; D012189:Retrospective Studies