RESUMO
BACKGROUND: Aseptic technique and cold storage of blood can reduce the incidence of transfusion-associated infections. But, none of these precautions eliminates the potential of drawing contaminated blood from an asymptomatic carrier with psychrophilic organisms such as Yersinia enterocolitica. We evaluated the ability of WBC-reduction filters to prevent the growth of bacteria in packed RBCs that are artificially inoculated with Y. enterocolitica. METHODS: Twenty units of packed RBCs donated from 20 healthy individuals were divided into 4 groups. Group A and B were inoculated with 10 CFU/mL of Y. enterocolitica and group C and D were inoculated with 100 CFU/mL of Y.enterocolitica. After 24 hours of cold storage, group A and C were filtered through WBC-reduction filter (Sepacell R 500A: Asai medical, Japan) and returned them to storage. Group B and D served as unfiltered controls. We collected blood weekly from day 1 to day 35 of storage. Bacterial growths were compared between 4 groups. RESULTS: The prefiltration WBC count was 8,880/ L (SD 1464.2/ L, n=20). After filtration residual WBC count was 210/ L (SD 99.8/ L, n=10). All cases of group B & D (10 & 100 CFU/mL inoculation without filtration) showed growth over 105 CFU/mL after 3 weeks storage. But in filtered groups, only 1/5 (20%) of group C (100 CFU/mL inoculation with filtration) and 4/5 (80%) of group A (10 CFU/mL inoculation with filtration) showed growth over 105 CFU/mL after 3 weeks. CONCLUSIONS: The use of WBC-reduction filter have ability to reduce the risk of transfusion transmitted bacteremia in packed RBCs.