NOVEL SEQUENCING OF ARGENTINEAN GENOMES OF Leptospira: SNPs ANALYSIS FOR EPIDEMIOLOGICAL PURPOSES

VANINA VARNI; KARINA CAIMI; ARIEL NAGEL; PAULA RUYBAL; ARIEL AMADIO

Córdoba

Congreso; XI Congreso Argentino de Microbiología General (SAMIGE); 2015

SAMIGE

Leptospirosis, caused by more than 250 different serotypes of the genus Leptospira, is one of the most common and widespread zoonotic disease worldwide. Infection is primarily spread through contact with water contaminated by urine of infected carrier animals. Leptospirosis is clearly an emerging and reemerging infectious disease. In the last years the whole-genome sequencing has become a technology increasingly used for diagnosis and molecular epidemiology of various pathogens due to the fast data generation and the decrease of the costs involved. Our group has focused on the development of molecular markers based on the sequencing of gene regions (MLST). These studies led to the identification of the major genotypes circulating in isolates from Argentina, both in cattle and humans. However, these markers have a low resolution when investigating outbreaks with one predominant serogroup or genotype. The analysis of local genomic sequences can help in the development of genotyping methods that provide a more precise discrimination. The objective of this work was to generate the genomic sequence from a strain of serogroup Pomona, predominant in Argentina. From this starting point, we aim to perform comparisons with Leptospira genomes previously sequenced in order to identify SNPs that enable the discrimination, with the perspective of developing a high resolution typing tool.Among the strains previously studied by MLST, we selected an Argentinean strain belonging to Leptospira interrogans serogroup Pomona for whole genome sequencing. It was performed using the Illumina "MySeq" technology. We also selected 8 Leptospira Pomona genomes from different countries, available in databases. The alignment of the the 9 Pomona genomes to a reference genome (Leptospira interrogans Cophenageni, strain Fiocruz L1-130) allowed the identification of polymorphic positions. A phylogenetic analysis was performed using the of SNPs obtained for each genome, in order to explore the differences among the strains. A panel of 47,182 SNPs between the reference genome and the 9 Pomona were identified, where the 67 % were located in coding regions. The phylogenetic analyzes enabled the differentiation of strains that were previously indistinguishable by their genotype or serogroup. The clusters of isolates appeared to relate to their geographic origins.ConclusionsThe comparison of a local Leptospira genome with worldwide genomes of the same serogroup allowed the identification of SNPs. The analysis of those presents a promising perspective for local epidemiology of Leptospira, leading to the phylogenetic discrimination of isolates that could not be achieved by traditional molecular markers. The information thus generated, when validated in a larger set of strains, may lead to the development of a tool for high-resolution typing of this pathogen.