title: Canadian experience with detection of bacterial contamination in apheresis platelets.
abstract: BACKGROUND
  In Canada, both blood suppliers, Héma-Québec (HQ) and Canadian Blood Services (CBS), implemented bacterial testing in apheresis platelets (PLTs) with an automated microbial detection system (BacT/ALERT, bioMérieux).
  
  
  METHODS
  Validation of the BacT/ALERT Classic and 3D systems involved apheresis PLT spiking with different bacteria at concentrations of 10 and 10(2) colony-forming units per mL. As of February 2006, more than 95 percent of apheresis PLTs were screened for bacterial contamination at HQ and CBS. Between 3.5 and 10 mL of PLTs is inoculated into BacT/ALERT aerobic culture bottles followed by incubation for a maximum of 7 days.
  
  
  RESULTS
  During the validation studies, all bacteria were detected at all concentrations and volumes tested. Upon implementation of bacterial screening, the percentage of initial positive samples at CBS and HQ was 0.09 and 0.07 percent, respectively. The rate of indeterminate cultures was significantly higher at CBS than at HQ, whereas the rates for true-positive, false-positive, and false-negative results did not differ significantly. Six confirmed-positive cultures, including three coagulase-negative staphylococci and three Enterobacteriaceae species, were detected and PLT units contaminated with these bacteria were not transfused. The rate of true-positive cultures was significantly lower than that reported by other blood operators. Unfortunately, failed detection of two contaminated units resulted in septic transfusion reactions.
  
  
  CONCLUSIONS
  Bacterial screening of apheresis PLTs in Canada was successfully implemented, and transfusion of contaminated units was prevented. Rapid bacterial detection systems that could be used before transfusion, however, may further reduce the risk of transfusion reactions.
authors.affiliation: Canadian Blood Services, Ottawa, Ontario, Canada. sandra.ramirez@bloodservices.ca
authors.forename: Sandra
authors.initials: S
authors.lastname: Ramírez-Arcos
authors.forename: Craig
authors.initials: C
authors.lastname: Jenkins
authors.forename: Jocelyne
authors.initials: J
authors.lastname: Dion
authors.forename: France
authors.initials: F
authors.lastname: Bernier
authors.forename: Gilles
authors.initials: G
authors.lastname: Delage
authors.forename: Mindy
authors.initials: M
authors.lastname: Goldman
mesh_terms: D001431:Bacteriological Techniques / Q000379:methods*; D001769:Blood / Q000382:microbiology*; D001800:Blood Specimen Collection / Q000379:methods; D002170:Canada; D015169:Colony Count, Microbial; D006801:Humans; D017713:Platelet Transfusion / Q000009:adverse effects; D010983:Plateletpheresis