Abstract

Bacterial transmission is the major cause of microbe associated morbidity and
mortality in transfusion recipients. In these studies initially the actual clinical
impact was assessed and bacterial contamination rate determined in blood
components. Until the late 1990 s, no effective intervention had been introduced
in the UK to reduce the transmission of bacteria by transfusion. Three strategies
were developed: improved donor arm disinfection, diversion of the first 20ml of
donated blood and bacterial screen testing of platelet concentrates. These
interventions have now been implemented by the National Blood Service (NBS)
and other blood services worldwide.
Improved donor arm disinfection was shown to be 10 times more efficient than
existing practice and reduced bacterial contamination in whole blood by 57% and
reduced clinically apparent transmissions by 65% (from 17 to 6 cases per million).
Diversion reduced contamination in whole blood by 47% and clinically apparent
transmissions from platelet concentrates by 76% (from 21 to 5 cases per million)
and 100% in red cell units (previously 0.3 cases per million). BacT/ALERT was
adapted for screen testing platelet concentrates and is now used routinely for shelf
life extension. Pall eBDS was developed and enhanced by the National
Bacteriology Laboratory of the NBS on a collaborative basis for the same
purposes. These studies provided data which facilitated Certificate European
marking and Food and Drug Administration approval for both systems. Both
systems have now been implemented throughout the world and are market
leaders. Scansystem (a rapid assay) was investigated, but was not considered
suitable for routine use. Screen testing of all NBS platelet concentrates is now
under consideration by the service.
The studies undertaken have made a significant contribution to knowledge and
have helped improve blood transfusion practice worldwide. Practicable and cost
effective interventions supported by scientifically robust data have resulted in a
marked reduction in transfusion-transmitted bacterial reactions, thereby improving
the safety of the blood supply.