Bacterial contamination of donated blood

Bacterial contamination of blood remains a rare but important cause of illn ess and death following blood transfusion, accounting for about 10% of tran sfusion-associated mortality. In red cell preparations, which are stored at 4 degreesC, the organisms usually implicated are Yersinia enterocolitica, Pseudomonas fluorescens and other organisms which can multiply at 4 degrees C. Contamination of red cell units is thought to arise from donor bacteraem ia, skin contamination and environmental contamination. In platelet prepara tions, which are stored at 20-24 degreesC, the organisms most commonly foun d are skin commensals such as Staphylococcus epidermidis, and contamination at the time of donation is the major mechanism. Universally adopted preven tive measures include strict aseptic technique and the use of closed system for blood processing and storage. Other measures directed against specific problems have been considered but are not known to be effective. The conse quences of transfusion of components in which bacteria have grown can range from mild febrile reactions to septic shock and death. Detection of bacter ial contamination before transfusion is a problem because it has to be done close to the time of transfusion, rather than immediately after donation, and is not feasible as routine practice with current technologies. Investig ation of febrile transfusion reactions should include culture of suspect un its. (C) 2000 Lippincott Williams & Wilkins.