Bacteria elimination from plasma by methylene blue/light treatment using a DEHP-free bag system

Background

Di-ethyl-hexyl-phthalate (DEHP) is currently one of the major plasticizers used in blood bags. Due to its endocrine disrupting properties European regulators decided to ban its use in medical devices. Although, the final sunset date is not yet clear, DEHP-free blood bags will be essential in Europe within the next years. The bacteria elimination capacity by Methylene blue (MB)/light treatment of plasma using the DEHP-free version of the THERAFLEX MB-plasma system (Macopharma) was investigated.

Methods

Relevance of the THERAFLEX MB-plasma procedure steps (leukocyte depletion (Plasmaflex filtration), MB/light treatment, removal of MB and photoproducts (Blueflex filtration)) were examined for their impact on elimination of two different bacteria species (Klebsiella pneumoniae and Brevundimonas diminuta). Leukodepleted plasma was prepared from whole blood using standard blood banking technology (containing DEHP). Plasma units (n=3 for each bacteria strain) were spiked with bacteria suspension (≈ 106 CFU/mL). MB/light treatment was done according to the manufacturer"s instructions (120 J/cm², Macotronic B2 illumination device) with the DEHP-free THERAFLEX MB-Plasma system PROSDV1. Bacteria titer was determined by plating on agar plates.

Results

Samples were taken after spiking, Plasmaflex filtration, illumination and Blueflex filtration and the log10 reduction was calculated. K. pneumoniae was reduced by ≥ 5.7 log steps by filtration through the Plasmaflex filter. A reduction factor of at least 5.9 log steps was achieved by the entire process. B. diminuta was reduced by ≥ 2.2 log steps by Plasmaflex filtration. A further reduction below the limit of detection was achieved by subsequent irradiation and Blueflex filtration so that an overall reduction factor of at least 4.7 log steps was achieved for the entire process.

Conclusion

In the current study it could be demonstrated that bacteria species Klebsiella pneumoniae and Brevundimonas diminuta were efficiently removed from plasma by using the THERAFLEX MB-Plasma System PROSDV1 (non-DEHP). Due to a higher spiking concentration log reduction factors achieved in this study are even higher than formerly published for DEHP-containing THERAFLEX MB-Plasma systems.

Offenlegung Interessenkonflikt:

Study was sponsored by Macopharma Productions (CS).