Background:
The available
Leptospira
multilocus sequence typing (MLST) scheme supported by a MLST website is limited to
L. interrogans
and
L. kirschneri
. Our aim was to broaden the utility of this scheme to incorporate a total of seven pathogenic
species.
Methodology and Findings:
We modified the existing scheme by replacing one of the seven MLST loci (
fadD
was changed
to
caiB
), as the former gene did not appear to be present in some pathogenic species. Comparison of the original and
modified schemes using data for
L. interrogans
and
L. kirschneri
demonstrated that the discriminatory power of the two
schemes was not significantly different. The modified scheme was used to further characterize 325 isolates (L. alexanderi [n = 5], L. borgpetersenii
[n = 34], L. interrogans [n = 222], L. kirschneri [n = 29], L. noguchii [n = 9], L. santarosai [n = 10], and L.weilii [n = 16]). Phylogenetic analysis using concatenated sequences of the 7 loci demonstrated that each species
corresponded to a discrete clade, and that no strains were misclassified at the species level. Comparison between genotype and serovar was possible for 254 isolates. Of the 31 sequence types (STs) represented by at least two isolates, 18 STs included isolates assigned to two or three different serovars. Conversely, 14 serovars were identified that contained between 2 to 10 different STs. New observations were made on the global phylogeography of
Leptospira spp., and the utility of MLST in making associations between human disease and specific maintenance hosts was demonstrated.
Conclusion:
The new MLST scheme, supported by an updated MLST website, allows the characterization and species assignment of isolates of the seven major pathogenic species associated with leptospirosis.