Sequenciamento genômico, análises comparativas e predição de alvos vacinais em Streptococcus agalactiae isolados de peixes, seres humanos e bovinos

Abstract

Streptococcus agalactiae (Lancefield group B; GBS) is an important pathogen for humans, cattle and fish causing neonatal septicemia, mastitis and meningo-encephalitis, respectively. This pathogen is responsible for significant mortality rate in human neonates and great economic losses in fish and milkproduction in Brazil and worldwide. Although there are already available genomes of strains of this bacterial species isolated from humans, cattle and fish, fewis known about the genomic features of strains of fish. This study was conducted with the following objectives: to sequence the genome of a strain of S. agalactiae (SA20-06) isolated from an outbreak of disease in fish in Brazil and do comparative analyzes with other 14 available genomes of strains of this species isolated from humans, cattle and fish. From the data of these genomes were analyzed for pan-genome, metabolic pathways, pathogenicity islands and prediction of potential vaccine targets. The complete genome of Brazilian strain sequenced showed smaller size when compared to the genome of strains of other hosts. Great diversity in the genome strains of S. agalactiae was observed, but the fish genome strains showed to be less variable. Possible vaccine targets predicted by bioinformatics tools are discussed in the overall picture of all the strains and in the subgroup of isolates from different hosts. Comparative analyzes of the genomes of the species contributed to the understanding of host pathogen interactions and suggest new genes to be characterized functionally.