WHO/BS/2015.2269 Collaborative Study to Enlarge the First WHO Repository of Platelet Transfusion-Relevant Bacterial Reference Strains

Overview

Bacterial contamination of platelet concentrates (PCs) remains a persistent problem in transfusion [1, 2, 3, 4 and 8]. For method validation and for assessment of blood safety measures it is crucial to use bacterial strains that are able to proliferate in blood components, e.g. in PCs under usual storage conditions [5, 6].

Four bacterial strains were adopted by ECBS in 2010 as the 1st WHO International Reference Repository of Platelet Transfusion Relevant Bacterial Reference Strains: Staphylococcus epidermidis PEI-B-P-06, Streptococcus pyogenes PEI-B-P-20, Escherichia coli PEI-B-P-19 and Klebsiella pneumoniae PEI-B-P-08. [7] The committee requested detailed instructions for use, which were provided by PEI in February 2011. The four bacterial strains have been cultivated and distributed by the Paul-Ehrlich-Institut since 2014 (PEI code number 8483/13).

This study was coordinated by the Paul Ehrlich Institut (PEI) in cooperation with the ISBT Working Party Transfusion Transmitted Infectious Diseases (WP-TTID), Subgroup on Bacteria. Eleven further bacterial candidate strains were evaluated together with the already established strains in an international study under routine conditions, which means the simulation of bacterial contamination during blood donation by low bacterial cell count spiking (< 1 Colony Forming Unit per milliliter) directly into PC-bags and determination of their ability to proliferate in PC from multiple donors. Bacterial counts were performed at days 2, 4 and 7 after inoculation to assess the bacterial growth kinetics.