Bacterial proliferation is comparable in red blood cell concentrates stored in DEHT/PAGGSM and DEHP/SAGM containers

The European Union's ban on the use of di(2-ethylhexyl) phthalate (DEHP) in medical devices will take effect in 2030. DEHP is a plasticizer in polyvinyl chloride blood bags that helps stabilize the red blood cell membrane during hypothermic red blood cell concentrate (RBCC) storage. Recent studies have shown that RBCCs have acceptable in vitro quality after storage in DEHP-free containers (e.g., plasticized with di(2-ethylhexyl) terephthalate [DEHT] and stored in phosphate-adenine-glucose-guanosine-saline-mannitol [PAGGSM] additive solution). To complement quality data, in this study, we compared bacterial growth in RBCCs stored in either DEHT/PAGGSM or DEHP/saline-adenine-glucose-mannitol (SAGM).

Paired ABO-matched whole blood units were collected into DEHT/PAGGSM sets, pooled and split into one DEHT/PAGGSM and one DEHP/SAGM bag set. RBCCs were produced using a top/bottom buffy coat process, tested for baseline in vitro quality and sterility, and spiked with Yersinia enterocolitica, Serratia liquefaciens and Listeria monocytogenes (~10² CFU/mL) and Cutibacterium acnes (~10³ CFU/mL) (N = 3). RBCCs were stored at 1-6°C for 43 days and sampled weekly for bacterial enumeration. Bacterial counts were compared between DEHP/SAGM and DEHT/PAGGSM RBCCs over 43 days of storage.

For Y. enterocolitica, S. liquefaciens and C. acnes, no differences in survival/growth between DEHP/SAGM and DEHT/PAGGSM RBCCs were observed. Y. enterocolitica and S. liquefaciens grew to 10⁸-10⁹ CFU/mL by day 14, while C. acnes remained at 10³ CFU/mL until day 43. L. monocytogenes counts declined in DEHT/PAGGSM compared to DEHP/SAGM RBCC on days 0-7, but bacterial loads were similar (~10⁷ CFU/mL) in both bags by day 43.

These results suggest that the bacterial safety risk of RBCCs is not increased in DEHT/PAGGSM containers.