2023 - Yersinia isolates

Summary

The Enteric Reference Laboratory (ERL) typed a total of 974 Yersinia isolates in 2023 including 5 Y. pseudotuberculosis with the remainder typed as Y. enterocolitica. The most common type for Y. enterocolitica was biotype 2/3 serotype O:9 with 659/969 (68.0%) isolates confirmed. This is similar to previous years where this serotype accounted for 71.1% in 2022, 62.7% in 2021, and 55.9% in 2020 with evidence of a possible plateau following a yearly increase. Biotype 1A and biotype 4 serotype O:3 with 200 and 89 isolates out of the 659 total Y. enterocolitica identified, respectively (20.6% and 9.2%). Biotype 1A had a similar trend to the biotype 2/3 serotype O:9 with 17.1% of Y. enterocolitica isolates typed in 2022, 17.34% in 2021, and 23.9% in 2020. This coincides with a downward trend in identifications of Y. pseudotuberculosis with 13 in 2020, 10 in 2021, and 9 in 2022. It is unclear how this relates to culture independent testing with some manufacturer’s panels able to detect Y. pseudotuberculosis and enterocolitica while others only detect enterocolitica.

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