MICROBIOLOGIC CONTAMINATION OF PERIPHERAL-BLOOD STEM-CELL AUTOGRAFTS

We have determined the incidence and clinical significance of positive microbiologic cultures in a series of 290 peripheral blood stem cell concentrates in 95 patients undergoing multiple apheresis procedures f or autologous stem cell rescue. Specimens for bacterial cultures were obtained after processing of the autografts just prior to freezing. Th e incidence of microbial contamination was 4.5% (n = 13). The predomin ant pathogenic microorganism cultured was coagulase-negative Staphyloc occus (n = 11). From 8 patients with contaminated leukapheresis produc ts 6 underwent autologous stem cell transplantation. Five patients rec eived 1-5 culture-positive stem cell concentrates without serious sequ elae, whereas the sixth patient was autografted with noncontaminated l eukapheresis products, 1 concentrate contaminated with Aspergillus fum igatus being not reinfused. No microorganism present in the stem cell autograft was recovered in vivo in the posttransplantation period, alt hough fever as a sign of infection occurred in all but 1 patient. Peri pheral blood stem cell collection and ex vivo processing for cryoprese rvation may result in microbiologic contamination. However, our data s how that infusion of contaminated stem cell autografts does not play a significant role as a source for infections in the clinical setting o f autologous stem cell rescue.