Relationship between bacterial load, species virulence, and transfusion reaction with transfusion of bacterially contaminated platelets

Abstract

Background. Bacterial contamination is currently the major infectious hazard of platelet transfusion, but associations between bacterial species and quantity and transfusion reactions have not been characterized. Methods. Patients receiving platelets from July 1991 through December 2006 were observed using active surveillance by quantitative culture of platelets at the time of issue or passive surveillance by investigation of clinical reactions in patients and culture of implicated units. Patient reactions were classified by type and severity and were correlated with bacterial species and number. Endotoxin content of gram-negative contaminants was determined by limulus lysate assay. Results. Fifty-two bacterially contaminated platelet units were detected (50 by active and 2 by passive surveillance). Rates of bacterial contamination and septic transfusion reactions were 32.0-fold and 10.6-fold higher, respectively, as determined by active versus passive surveillance (P 90% of contaminants. Conclusions. Active surveillance detected 32-fold more bacterially contaminated platelet units and 10.6-fold more septic reactions than did passive surveillance, and virulent species and bacterial counts of ≥105 colony-forming units/mL were associated with more-severe transfusion reactions. Improved detection methods or use of pathogen inactivation technology are needed to eliminate this problem. © 2008 by the Infectious Diseases Society of America. All rights reserved.