A large and robust clade grouped 27 strains from human origin and corresponded to the major clonal complex MSCC4/eBCC4. The clade corresponding to eBCC1 contained 23 strains from different origins. In this clade, the relationships between environmental and clinical strains could not be established

due to the weak robustness of the branching order. Figure 2 ML trees based on concatenated check details PCI32765 sequences of the seven housekeeping gene fragments. Position of the artificial root (black circle) corresponded to branching of the out-group (B. suis 1330T) included in the analysis but not shown on the tree. Horizontal lines are scales for genetic distance. Numbers given at the nodes are support values estimated with 100 bootstrap replicates. Only bootstrap values >50% are indicated. For better visualization of the tree, bootstrap values are shown at the terminal nodes. The scale bar indicates the number of substitutions per nucleotide position. The clonal complexes MSCC and eBCC determined by Minimum Spanning and eBurst, respectively are indicated by Baf-A1 molecular weight vertical bold bars. Blue: clinical strains; green: environmental strains. (*) indicated major conflicting phylogenetic positions between the seven genes-based tree and the

trpE-based tree in Fig 3. The sequences of each of the seven loci were used in the ML analysis of congruence where each ML tree was compared to the ML tree reconstructed from the seven concatenated sequences. We observed conflicting topologies regarding the tree based on concatenated sequences suggesting recombination events, particularly for the aroC- and omp25-based trees (data acetylcholine not shown). The dnak-, recA- and rpoB-based trees were more congruent. They affiliated the isolates to only 2 to 3 large clades but they failed to establish relationships inside the clades. However, the combination

of the 3 markers gave a tree showing polymorphism inside each clade. Particularly, the strains belonging to eBCC1 and MSCC4/eBCC4 formed two independent robust lineages (data not shown). The gap- and trpE-based trees were globally congruent with the tree based on concatenated sequences. The gene trpE appeared to be a good marker for studying the phylogenetic relationships among isolates in the species O. anthropi (Fig. 3). Figure 3 ML trees based on the trpE gene fragment. Position of the artificial root (black circle) corresponded to branching of the out-group (B. suis 1330T) included in the analysis but not shown on the tree. Horizontal lines are scales for genetic distance. Numbers given at the nodes are support values estimated with 100 bootstrap replicates. Only bootstrap values >50% are indicated. For better visualization of the tree, bootstrap values are shown at the terminal nodes. The scale bar indicates the number of substitutions per nucleotide position. The clonal complexes MSCC and eBCC determined by Minimum Spanning and eBurst, respectively are indicated by vertical bold bars.