Does the low prevalence of bacterial contamination in random platelet concentrates justify the use of preventive measures?

DOI: 10.5581/1516-8484.20130056 Despite the growing advancement of transfusion medicine, bacterial contamination of blood components still represents a serious risk to recipients and is currently the leading cause of adverse effects(1) and the second leading cause of death related to blood transfusions(2). It is estimated that the risk of sepsis related to platelet transfusions is 1:12.000, with a mortality rate of 26%. The rates are further increased when transfusions of platelet concentrates are obtained from multiple donors(3). Currently the Ordinance no 1353 of June 13, 2011 is in force in Brazil; this regulation determines that 75% or more of blood products must comply with the established quality and sterility standards(4). Given the importance of microbiological control in blood banks, the present study aimed to analyze the prevalence of positive bacterial cultures in random platelet concentrates (RPC) obtained in the period from November 2010 to April 2011 in the Instituto Pasquini de Hemoterapia e Hematologia in Curitiba, Brazil. A retrospective observational study was conducted of 409 reports of bacterial cultures on RPC, which represented a total of 3183 donations. It is recommended that a patient requiring a platelet transfusion receives one unit for every 10 kg body weight. The Instituto Pasquini has standardized eight units of RPC for all patients except for surgical and pediatric patients. The material is prepared in a laminar flow hood with prior irradiation of germicidal light for 15 minutes. After, the eight units of RPC are transferred to a 600 mL pouch, from which 10 mL are removed for blood cultures (BacT / Alert ® 3D, bioMérieux, USA) using a previously validated method(5). A culture in January 2011 was positive (Table 1), showing a growth of coagulasenegative Staphylococcus. This represented 1.25% of the cultures performed in January 2011 and 0.24% in the period from November 2010 to April 2011. As at least one unit of this pool was contaminated, this represents 0.15% of random platelet donors of January, and is thus well within the parameters established by Ordinance no 1353 for the sterility of blood components(4) which determines a level of sterility higher than 75%.