A Single Multilocus Sequence Typing (MLST) Scheme for Seven Pathogenic Leptospira Species

Siriphan Boonsilp,Sharon J Peacock,Rudy A Hartskeerl,Matthew T G Holden,Brian G Spratt,Edward J Feil,Cuicai Zhang,Lee D Smythe,Nobuo Koizumi,David M Aanensen,Alex R Hoffmaster,Janjira Thaipadungpanit,Premjit Amornchai,Narisara Chantratita,Vanaporn Wuthiekanun,M S Bailey ,Nicholas P J Day ,Renee L Galloway ,Scott B Craig ,Xingran Jiang ,Kyle R Taylor

doi:10.1371/journal.pntd.0001954

Abstract

BackgroundThe 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 FindingsWe 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.ConclusionThe 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.

Highlights

Leptospirosis is a global zoonosis caused by pathogenic members of the Leptospira genus [1,2,3,4,5]
The new multilocus sequence typing (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
Leptospirosis can be caused by 8 pathogenic Leptospira species [6,7,8], one of which (L. alstonii) is very rarely isolated with only two strains deposited in reference collections to date

Summary

Introduction

Leptospirosis is a global zoonosis caused by pathogenic members of the Leptospira genus [1,2,3,4,5]. These are maintained by chronic carrier mammalian hosts (e.g. rats and dogs), and are typically transmitted to humans via water contaminated with urine or by direct contact with reservoir hosts [1,2,3,4,5]. Leptospirosis can be caused by 8 pathogenic Leptospira species [6,7,8], one of which (L. alstonii) is very rarely isolated with only two strains deposited in reference collections to date. Our aim was to broaden the utility of this scheme to incorporate a total of seven pathogenic species

Objectives

Methods

Results

Discussion

Conclusion