# Biotype Determines Survival of Yersinia enterocolitica in Red Blood Cell Concentrates

## TL;DR

This study shows that different types of Yersinia enterocolitica bacteria survive and grow differently in blood cell storage, with some growing more than others.

## Contribution

The study reveals that bioserotype influences Y. enterocolitica survival and growth in RBC concentrates and links this to iron metabolism gene diversity.

## Key findings

- Y. enterocolitica bioserotype 1B/O:8 (Ye8) showed the highest growth in RBC concentrates after 28 days.
- Isolates varied in serum sensitivity, with some becoming more or less sensitive over time.
- Iron metabolism gene content and variants may affect bacterial growth in RBC.

## Abstract

Red blood cell (RBC) concentrates remain at risk of bacterial contamination during cold storage. Although infrequent, Yersinia enterocolitica poses a significant blood safety risk. This study aimed to assess Y. enterocolitica bioserotype growth in RBC concentrates, serum sensitivity, and genetic diversity including iron metabolism genes. Ten Y. enterocolitica isolates from bioserotypes 1A, 1B/O:8, 4/O:3, and 2/O:9 were incubated in RBC concentrates and counted on days 3, 7, 14, 21, and 28. After incubation, the isolates were tested in human serum (NHS). Eight genomes were sequenced, analyzed using cgMLST, and screened for iron metabolism genes. The isolates formed two clusters, with 186dz (1A) and Ye8 (1B/O:8) as singletons. After 28 days in the RBC concentrates, the bacterial counts ranged from 1.98 × 10⁵ to 1.2 × 10⁹ CFU/mL, with Ye8 (1B/O:8) achieving the highest growth and one 4/O:3 isolate showing the lowest. All isolates survived 15–30 min in NHS, but the 28s isolate did not survive at 60 min. Serum sensitivity increased in two isolates, decreased in three, and remained unchanged in five. Isolates contained 27–42 iron metabolism genes with multiple allelic variants. The iron metabolism gene content or variants may influence the growth of Y. enterocolitica in RBC.