Análise comparativa de genomas de Leptospira Interrogans isoladas de cães, humano e roedor em um mesmo cenário epidemiológico.

Abstract

PAZ, LN Comparative genomic analysis of Leptospira interrogans isolated from dogs, human and rodent in the same epidemiological setting, Salvador, 2021. 97p. Thesis (PhD degree in Animal Science in the Tropics) - Escola de Medicina Veterinária e Zootecnia – Universidade Federal da Bahia. Leptospirosis is a zoonotic infectious disease associated with a relevant impact on public health. The knowledge on the circulation and diversity of pathogenic Leptospira and its interaction with hosts, in different epidemiological scenarios, is essential for leptospirosis control and prophylaxis. Comparative genomics assist in understanding of the mechanisms of infection, as well as the antimicrobial profile, and the several aspects of the pathogenesis of leptospirosis that are poorly understood. The present study aimed to compare the genome of Leptospira interrogans, serogroup Icterohaemorrhagiae, isolated from of dogs, rodent, and human, in a same epidemiological scenario. A Whole genome sequencing was performed on four isolates (C20, C29, C51, C82) of L. interrogans obtained from blood and urine samples of naturally infected dogs with clinical symptoms. Additionally, raw sequencing data of a strain isolated from a rodent sample and the FASTA file containing the sequence of the reference strain L1-130 isolated from human sample were retrieved from GenBank, both strains recovered from the same epidemiological scenario as the dog samples. After evaluating the quality of the readings, the sequences (canine and rodent) were submitted to the assembly pipeline in order to obtain high-quality contigs and/or scaffolds. Subsequently, phylogenetic analysis were constructed with the ppk gene sequence, using the MEGA-X software, and the average nucleotide identity was calculated with the aid of the pyani software. Genome annotation was performed using the PGAP and RAST software. Finally, the synteny and comparison between the gene content was carried out with the aid of the BRIG, Artemis and Mauve software. The pipeline used herein allowed to obtain, in each sample, two scaffolds corresponding to chromosomes 1 and 2. The minimum depth observed was 81.9 for the C20 stain and all sequences showed coverage greater than 99%. Phylogenetic and genomic similarity analyses confirmed the isolates as L. interrogans. When compared to the reference strain, the genomes of canine and rodent isolates showed high identity and synteny. However, small different regions could also be observed, especially in the genome obtained from a rodent sample. The presence of 23 genes potentially associated with biofilm xii formation was observed, with identification of missense mutations in seven genes. Obtaining high quality genomes still remains a challenging task and is indispensable in comparative, functional and structural genomics. In view of the need to understand the molecular bases involved in biofilm formation, it is of fundamental importance to understand the effect of mutations on the expression of the phenotype (biofilm) between different serovars. The data obtained herein allow to infer that the dogs, rodents and humans from this epidemiological scenario are infected with highly related strains, emphasizing the relevant role these animals play in public health.