Reassessment of MLST schemes for Leptospira spp. typing worldwide

Leptospirosis is a neglected zoonosis of global importance. Several multilocus sequence typing (MLST) methods have been developed for Leptospira spp., the causative agent of leptospirosis. In this study we reassessed the most commonly used MLST schemes in a set of worldwide isolates, in order to select the loci that achieve the maximum power of discrimination for typing Leptospira spp. Global eBURST algorithm was used to detect clonal complexes among STs and phylogenetic relationships among concatenated and individual sequences were inferred through maximum likelihood (ML) analysis. The evaluation of 12 loci combined to type a subset of strains rendered 57 different STs. Seven of these loci were selected into a final scheme upon studying the number of alleles and polymorphisms, the typing efficiency, the discriminatory power and the ratio dN/dS per nucleotide site for each locus. This new 7-locus scheme was applied to a wider collection of worldwide strains. The ML tree constructed from concatenated sequences of the 7 loci identified 6 major clusters corresponding to 6 Leptospira species. Global eBURST established 8 CCs, which showed that genotypes were clearly related by geographic origin and host. ST52 and ST47, represented mostly by Argentinian isolates, grouped the higher number of isolates. These isolates were serotyped as serogroups Pomona and Icterohaemorrhagiae, showing a unidirectional correlation in which the isolates with the same ST belong to the same serogroup. In summary, this scheme combines the best loci from the most widely used MLST schemes for Leptospira spp. and supports worldwide strains classification. The Argentinian isolates exhibited congruence between allelic profile and serogroup, providing an alternative to serological methods.Fil: Varni, Vanina Delia. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Ruybal, Paula. Instituto Nacional de Tecnología Agropecuaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Lauthier, Juan José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Patología Experimental; Argentina. Universidad Nacional de Salta; ArgentinaFil: Tomasini, Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Patología Experimental; Argentina. Universidad Nacional de Salta; ArgentinaFil: Brihuega, Bibiana. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Koval, Ariel. Biogenesis Bago S.a; ArgentinaFil: Caimi, Karina Cynthia. Instituto Nacional de Tecnología Agropecuaria; Argentin