Phylogenetic tree for five rhesus monkey H. cinaedi isolates (31111, 30365, 30527, 30314, and 30327) and selected other Helicobacter species based on 16S rRNA sequences. The scale bar represents a 1% difference in nucleotide sequence, as determined by measuring the lengths of horizontal lines and connecting any two species. GenBank accession numbers for comparision species were as previously described (28).