Phylogenetic analysis of RtxA1 in the RTX gene cluster of L. hongkongensis. The tree was constructed by neighbor joining method using Kimura's correction and bootstrap values calculated from 1000 trees. One thousand and eighty-seven amino acid positions were included in the analysis. The scale bars indicate the estimated number of substitutions per 20 amino acids. All names and accession numbers are given as cited in the GenBank database.