Abstract
The 16S rDNA sequences from 15 Leptospiraceae were determined by automated PCR-directed cycle sequencing. Nucleotide comparisons, including those from published sequences for Leptospira canicolaMoulton and Serpulinaspp., were used to construct phylogenetic trees.Serpulina hyodysenteriae and S. innocenswere related to each other but were distinct from the Leptospiraceae comprising Leptospira parva incertae sedis (Turneria parva H), Leptonema illini and Leptonspira spp. The pathogenic and the saprophytic leptospires were distinct and separated from each other.Leptospira inadaioccupied an intermediate position between the two forms. The pathogens formed three groups. Group I was represented by L. interrogans sensu stricto and L. kirschneri, Group II by L. weilii, L. borgpetersenii and L. santarosai, and Group III comprised L. noguchii and L. meyeri. The saprophytic species,L. wolbachiiand L.biflexa sensu stricto shared about 99% sequence similarity. The freshwater isolates were distinct from the marine isolate L. biflexa sensu lato ancona Ancona Porto.