Phylogenetic analysis of IncI1 plasmids identified in S. Typhimurium 135@. (A) Maximum likelihood phylogeny of 23 publicly available IncI1 plasmids (listed in Table 4) together with pSTM2 and pSTM7 identified in this study. Key plasmids from these 23 are labeled. The shaded region indicates the clade containing pSTM2 and pSTM7, shown in detail in (B). Bootstrap support for this clade is 88%. (B) Bootstrap values for each branch are 100%, except one node as indicated (99%).