Use of a solid-phase fluorescent cytometric technique for the detection of bacteria in platelet concentrates

Blood services worldwide are now striving to reduce the risk of transmission of bacteria by transfusion. The BacT/ALERT microbial detection system (bioMerieux, Basingstoke, Hants, UK) is currently regarded as the 'gold standard' for bacterial screening of platelet concentrates. The BacT/ALERT is a culture system and will not generate an 'instant' (within 2 h) determination. We report on the Scansystem (Hemosystem, Marseille, France), a solid-phase fluorescent cytometric technique, which enables the rapid detection of bacteria (within 90 min) in platelet concentrates. The study was performed in two parts - one involving the routine screening of platelet concentrates and the other determining the sensitivity of the system. In both arms of the study, the BacT/ALERT was used for comparative purposes. In total, 900 platelet concentrates were screened (63 apheresis and 837 buffy coat pooled). No bacteria were detected in any of the platelet concentrates tested by means of either the Scansystem or the BacT/ALERT. The sensitivity of the Scansystem was in the order of 10(3) cfu mL(-1). Escherichia coli and Staphylococcus aureus were detected by using the Scansystem at 1 cfu mL(-1). The BacT/ALERT detected all organisms tested (n = 6) at 1 cfu mL(-1). The Scansystem offers a sensitive alternative technology to bacterial culture, with the benefit of a rapid test time.