Volume 27, Number 1—January 2021
Dispatch
Listeriosis Caused by Persistence of Listeria monocytogenes Serotype 4b Sequence Type 6 in Cheese Production Environment
Figure 2

Figure 2. Minimum-spanning tree based on cgMLST allelic profiles of 34 human Listeria monocytogenes isolates, 1 food isolate, and 5 environmental isolates, Switzerland. Each circle represents an allelic profile based on sequence analysis of 1,701 cgMLST target genes. Values on connecting lines indicate number of allelic differences between 2 strains. Each circle contains the strain identification(s). The food isolate is indicated by a green star, and environmental strains are indicated by blue stars. Outbreak strains are shaded in pink and are shown in comparison with other L. monocytogenes sequence type 6 isolates from Switzerland collected during 2016–2020. cgMLST, core genome multilocus sequence typing.