Detection of Bacteria in Platelet Concentrates Prepared from Spiked Single Donations Using Cultural and Molecular Genetic Methods

Detection of bacteria in platelet concentrates prepared from spiked single donations using cultural and molecular genetic methods

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Bacterial contaminated blood units, especially platelets, can lead to serious transfusion complications. The most severe cases will eventually lead to death. Unfortunately, they account for the second mortality rate behind blood transfusion in the US. Thus the American Association of Blood Banks (AABB) implemented a rule from March 2004 insisting that the blood service should detect and minimize the bacterial contamination in blood units. The severity of the case depend on several aspects such as the type of bacteria present, titer of bacteria, and patient’s immune status. But where do bacteria in these blood units come from? In fact, they either come from a donor with bacterial infection (usually without apparent symptoms), collection procedure (inappropriate disinfection), collection pack (contaminated), or from blood processing procedure (in laboratories). The platelets are of most concern as they are stored in susceptible conditions for bacterial growth. They are usually stored at 22C overnight and pooled from multiple donors as a common practice. However, to meet the rules and regulations of blood banks many studies where conducted and encouraged to understand more about platelets and bacterial contamination. Testing more bacterial species will clarify more how to eliminate them from the products and what is the right measure to take (Hillyer et. al., 2003). Until now many methodologies were invented to detect bacteria and it can be divided to either rapid or culture detection methods. The rapid detection methods include PCR (polymerase chain reaction) which mainly measure the nucleic acids presented. While the cultures usually take a long time to get the results although it is considered as the “gold standard”. The problem with the bacterial detection is that the microorganisms require time to proliferate and to appear in test unlike the viruses (Stormer et. al., 2007).

However, the researchers are trying to overcome this problem and in this edition a German study performed by Stormer and colleagues (2007) focused on how bacteria proliferate in the blood components during storage in different temperatures. The purpose of the study is to consider a detection strategy that minimizes sampling error. Therefore, three main detection methods where used; RT-PCR (Reverse Transcriptase-Polymerase Chain Reaction), cultivation, and automated high-volume extraction method. RT-PCR and the automated high-volume extraction method are used to measure the nucleic acid content of bacteria. While the culture grows the bacterial contaminated blood using automated culture system. In this experiment, whole blood units where spiked with two microorganisms; Staphylococcus