Novel automated microbial screening of platelet concentrates

Abstract

The recovery of bacteria and the speed of detection of microbial growth in platelet concentrates (PC) were studied, comparing a novel automated blood culture system (BacT/Alert) with two traditional methods. Full‐scale experiments were performed with a total of 33 units of PC (average content 320 × 109 platelets per unit) obtained from pooled buffy coats. Six strains known as possible PC contaminants were tested: S. epidermidis, S. aureus, P. aeruginosa, B. cereus, E. aerogenes, and S. sanguis. Using an inoculum of 50–98 bacteria/ml, bacterial contamination was detected in all of 11 PCs on 132 sampling occasions. With a small inoculum (0.3–9 bacteria/ml), the bacterial contamination was detected in all PCs in which abundant growth appeared, but failed to be detected in some instances where the bacterial content was very small. All of 11 uninoculated PC controls were negative. With the automated method the time for detection of a culture‐positive PC was 6–16 h, clearly shorter than with the two manual‐visual systems. The new system provides a rapid, reliable, and labour‐saving method for screening of bacterial contamination in PCs. This would increase safety particularly if the present 5‐day shelf life were extended.

Studies of One Invasive and Two Noninvasive Methods for Detection of Bacterial Contamination of Platelet Concentrates

“…In the second set of experiments the contribution to pC02 from the platelets was strongly reduced, as compared to the The BacT/Alert technique that we have tested previously [2] and used as control in this study, sensitively and rapidly detected the bacterial contamination in the PCs. This seems to be a very promising possibility to improve the safety of PCs with respect to bacterial contamination.…”

“…The 22 negative samples were obtained from those PCs which contained very low concentrations of bacteria, and this sample volume was obviously too small to detect them safely. The conclusion was that the rate of detection of bacterial contamination was very high [2]. None of the noninoculated PC units tested positive.…”

“…Streptococcus sanguis Sample of 4 ml and 0.5 ml were drawn from the PCs at various intervals for inoculation in BacT/Alert aerobic cul ture bottles for pediatric use [2], Samples were also drawn for blood gas analyses and pH (ABL 300 Blood Gas Analyzer, Radiometer, Co penhagen, Denmark) and quantitative bacterial culture (colony count). (2) Bacteria were inoculated into PCs, 4 PC units with each tested strain: one strain each of S. epidermidis and Escherichia coli.…”

“…However, traditional methods for blood culture are relatively slow which is a clearcut disadvantage in the case of PCs, since their shelf life is relatively short. A new method for blood culture, the BacT/Alert technique (Organon Technika, Belgium), has recently been found by us to be very suitable for PC screening with respect to sensi tivity as well as speed of detection of even small concentra tions of bacteria [2], This method eliminates some of the disadvantages mentioned, but it is expensive and requires sampling from the PC. We have compared the three possi bilities.…”

Serious bacterial complications from blood components — how do they occur?

“…Several methods for the detection of bacterial contamination in platelet concentrates have been presented in recent years. New automated methods for bacterial culture based on the capacity of the bacteria to form carbon dioxide have been demonstrated sufficiently sensitive and rapid ( Gong et al ., 1994 ) and have been applied for routine use in some countries.…”