Bacterial screening of platelet components by National Health Service Blood and Transplant, an effective risk reduction measure

Abstract

The implementation of bacterial screening of PLT components with the NHSBT BacT/ALERT protocol was an effective risk reduction measure and increased the safety of the blood supply.

Microbiological Screening of Platelet Concentrates in Europe

“…Due to adhesion of bacterial cells to the inner surface of the platelet bags, a sampling error is very likely [48]. Similar findings are reported for S. aureus isolates, which escaped from the screening process despite late sampling [17]. To this end, S. aureus can form aggregates by direct interaction with platelets [49].…”

“…This benefit has been confirmed by several reports [11, 18, 39, 40]. For instance, a study from NHS Blood and Transplant showed that 66% of all confirmed positive results were only detected in anaerobic culture bottles, whereas 8% were positive in an aerobic and 26% in both bottle types [17]. It should, however, be noted that if both bottles are removed as soon as one of both is flagged as positive, it is unknown whether the second bottle would have led to a positive signal afterwards.…”

“…For instance, culture-based screening reduced the number of contaminated PC to 5.4 per million compared to 16.3 before routine screening was introduced in the UK. Focusing on adverse transfusion reactions, the number even decreased by 90% [17]. Moreover, no fatalities were reported since the implementation of culture-based screening.…”

“…Moreover, some bacteria particularly from the enteric flora show even a faster detection time in anaerobic bottles compared to aerobic conditions [16]. A negative aspect connected to the anaerobic culture is the relatively high rate of false-positive alarms leading to a withdrawal of non-contaminated PC [17]. Furthermore, the clinical relevance of anaerobic pathogens as contaminants in platelets is still under debate.…”

Implications of the US Food and Drug Administration draft guidance for mitigating septic reactions from platelet transfusions

“…9 In the United States, samples for culture are taken at 24 to 30 hours after collection (vs 36-48 hours in the United Kingdom). In the United States, samples are typically 8 mL in aerobic culture and from the primary platelet bag, which then may be split into 1 to 3 platelet products, whereas the United Kingdom uses 8 mL in aerobic and anaerobic culture for each product.…”