Detection of bacterial contamination of platelet components: six years' experience with the BacT/ALERT system

BACKGROUND: Hemovigilance has shown that bacteria cause more fatalities than other infections together. Surveillance for detection of bacteria in platelets (PLTs) was initiated. Concomitantly, the storage period for PLTs was extended from 5 to 7 days to reduce cost. STUDY DESIGN AND METHODS: Analysis was performed of all cases of a positive signal in a screening procedure for contaminated PLTs taking into account results of confirmative cultures and results of culture from blood components including bacteria strains. Records were assessed from patients transfused with blood components issued before the screening culture became positive. RESULTS: Samples were collected from 22,057 PLT units. An initial reaction was seen in 84 (0.38%). Growth was confirmed in 70 of these. Of the associated PLT units, 26 had been issued or outdated at the time when the culture was found to be reactive, in 27 bacteria were found, and in 17 cultures were negative. The bacteria found were mainly from normal skin flora. Sixty-six patients received 75 blood components issued before the screening system alarmed. None of these patients had a transfusion reaction reported. The outdating fell to less than 5 percent. CONCLUSION: A screening system for detection of bacterial contamination was implemented without increase in cost owing to extension of storage time to 7 days. Transfusion of several contaminated blood components was prevented.