TRANSFUSION TRANSMITTED BACTERIAL-INFECTION (TTBI)

We have experimentally studied the effect of the presence of leukocytes in newly collected blood on the survival of different bacterial species. The following conclusions can be drawn: (1) Leukocytes have a clearcut protective effect which is, however, not equally strong with all bacterial species. S. epidermidis and E. coli were cleared from the blood by leukocytes, while S. aureus had a greater capacity to withstand the phagocytic action. (2) Optimum effect was reached after several hours, in some experiments not until after 24 h. Thus a certain time of action seems optimal for the leukocytes. (3) Some Gram-negative species were killed by plasma factors. (4) Propionibacterium species (anaerobic) did not grow, probably because of the oxygen containing environment. (5) Yersinia enterocolitica disappeared temporarily from the blood in the presence of leukocytes, but reappeared later during storage, most likely because of the disintegration of the leukocytes. If these were removed from the blood 5 h after inoculation of the bacteria, the units remained sterile. (6) The presence of leukocytes remaining in the whole blood for some time after blood collection has a potent clearing effect on contaminating bacteria. If the leukocytes remain in the blood, however, those bacteria species that are not killed intracellularly will be released when the leukocytes disintegrate, and may subsequently grow.