Figure 1.

Minimum spanning tree based on the core genome allele profile of OXA-244-producing Escherichia coli ST38 outbreak isolates (n = 12) from Western Norway and isolates from other regions in Norway in 2020 (n = 7)

OXA: oxacillinase; MLST: multilocus sequence typing; ST: sequence type.

Each isolate is represented by a circle coloured according to the hospital involved in the outbreak or region. The number of core genome MLST allele differences between isolates is indicated with a number along the connecting lines between circles. Circles containing > 1 isolate indicate no core genome MLST allele differences. Grey shading show clusters of isolates with a core genome MLST allele difference below the cluster threshold (≤ 10 allele differences).