Characterization of transfusion-relevant bacteria reference strains in a lyophilized format

Area of Science:

• Microbiology
• Transfusion Medicine
• Food and Drug Safety

Background:

• Current Transfusion-Relevant Bacterial Reference Strains (TRBRS) require ultra-cold storage and manual preparation, limiting their practical application.
• The ISBT Transfusion-Transmitted Infectious Diseases Working Party's Bacterial Subgroup initiated a study to develop a more user-friendly TRBRS format.

Purpose of the Study:

• To validate lyophilised Transfusion-Relevant Bacterial Reference Strains (TRBRS) for enhanced usability in blood safety assessments.
• To evaluate the stability, viability, and robustness of lyophilised TRBRS in interlaboratory studies.

Main Methods:

• Two bacterial strains, Klebsiella pneumoniae and Staphylococcus aureus, were manufactured in a lyophilised format.
• 11 international laboratories assessed the lyophilised bacteria for enumeration, identification, and growth kinetics in platelet concentrates (PCs).

Main Results:

• Lyophilisation did not affect the growth properties of the bacterial strains compared to traditional formats.
• The lyophilised TRBRS allow for direct, low-quantity spiking (approx. 30 bacteria) in PCs for transfusion-relevant experiments.
• The lyophilised format demonstrated long-term stability across temperatures and maintained viability upon direct rehydration in PCs, with 100% of spiked PCs showing bacterial growth in interlaboratory tests.

Conclusions:

• Lyophilised TRBRS offer a user-friendly and stable material for transfusion-related research.
• The improved features of lyophilised TRBRS are expected to increase their utilization in quality control for transfusion safety measures.