Some storage characteristics of platelet concentrates contaminated with pseudomonas aeruginosa

The present work investigates the effects of contamination with Pseudomonas aeruginosa on some properties of platelet concentrates, i.e. the ability to transmit light, swirling and the degree of platelet activation and cell lysis. 20 pairs of platelet concentrates were studied over a 7 day period. On day 1, one of the concentrates was inoculated with Pseudomonas aeruginosa, while the other served as an identical non-contaminated control. In the contaminated concentrates, swirling and release of platelet factor 4 and lactate dehydrogenase were analysed on day 1, day 2 and day 3; bacterial counts were performed on day 2 and day 3, and on day 7 all these variables were determined in both concentrates. After the 7 day storage period, bacterial growth was found in 13/16 of the contaminated platelet concentrates; all these preparations displayed transmission changes and at least one deviating biochemical parameter. On day 3 all contaminated concentrates had unimpaired swirling, 15/20 had bacterial growth and 10/20 light transmission changes. The study demonstrates that light transmission monitoring on day 3 offers significant advantage (p < 0.05) compared to the visual estimation of swirling. The results also show that the optical method often fails to identify contaminated concentrates during early storage.