IMPAM   23988
INSTITUTO DE INVESTIGACIONES EN MICROBIOLOGIA Y PARASITOLOGIA MEDICA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Reassessment of MLST Schemes for Leptospira spp. Typing: A Need for a Common Language.
Autor/es:
VANINA VARNI; RUYBAL, PAULA; JUAN JOSE LAUTHIER; NICOLAS TOMASINI; BRIHUEGA, BIBIANA; KOVAL, ARIEL; CAIMI, KARINA
Lugar:
Fukuoka
Reunión:
Congreso; 8th Scientific Meeting of International of Leptospirosis Society; 2013
Resumen:
Leptospirosis is a neglected zoonosis of global importance. As several Multilocus Sequence Typing (MLST) schemes have been developed for typing Leptospira spp., there is a need to unify them towards establishing a common scheme that can be applied on a global scale. In this study we reassessed those most commonly used MLST schemes in a set of worldwide isolates, with the aim of selecting the loci that could achieve the maximum power of discrimination for typing Leptospira spp. Global eBURST algorithm was used to detect Clonal Complexes (CCs) among allelic profiles (STs), and phylogenetic relationships among concatenated and individual sequences were inferred through maximum likelihood (ML) analysis. The preliminary evaluation of 12 loci combined to type a subset of strains produced 57 different STs. Seven of those loci were selected after studying the number of alleles and polymorphisms, the typing efficiency, the discriminatory power and the ratio dN/dS for each locus. This reassessed 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 belonged 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.