The fate of bacteria introduced into whole blood from which platelet concentrates were prepared and stored at 22 or 4C.

Bacteria were intentionally introduced into units of whole blood. Platelet concentrates (PC) which were made from these units were stored at either room temperature (22 C) or at 4 C. In order to isolate small numbers of bacteria from a PC (i.e., 1 to 10 organisms per ml), substantial contamination (42 to 125 organisms per ml) of the whole blood was required. If the PC were stored at room temperature, all organisms except Pseudomonas aeruginosa, which was apparently killed, grew out of control within 48 hours. Storage of PC at 4 C resulted in the general maintenance of bacterial numbers. Since gross contamination of PC has only occasionally been reported, we conclude that past reports of modest contamination of platelet concentrates are primarily sampling artifacts.