
Phylogeny of relevant bacterial species. The three-letter abbreviations are as follows: eco, Escherichia coli K12 (genbank entry NC_000913); stm, Salmonella typhimurium LT2 (genome.wustl.edu/gsc/bacterial/salmonella.shtml); kpn, Klebsiella pneumoniae MGH78578 (genome.wustl.edu/gsc/Projects/bacterial/klebsiella.shtml); ype,Yersinia pestis CO-92 (www.sanger.ac.uk/Projects/Y_pestis/); vcb, Vibrio cholerae N16961 (genbank NC_002505 and NC_002506); hin, Haemophilus influenzae Rd (genbank NC_000907). The phylogenetic tree is based on 16S ribosomal RNA sequences. H. influenzae is shown only for comparative purposes and was not analyzed in our study.











