Whole-Genome Sequencing of a Potentially Novel Aeromonas Species Isolated from Diseased Siberian Sturgeon (Acipenser baerii) Using Oxford Nanopore Sequencing
Akzhigit Mashzhan, Izat Smekenov, Serik Bakiyev, Kalamkas Utegenova, Diana Samatkyzy, Asset Daniyarov, Ulykbek Kairov, Dos D. Sarbassov, Amangeldy Bissenbaev
Abstract
Aeromonas spp. are opportunistic pathogens that are widely distributed in water sources, with several species being associated with fish and human diseases. We have previously identified an Aeromonas AB005 isolate from diseased Acipencer baerii. This isolate was identified as A. hydrophila based on the 16S rRNA and gyrB gene sequences. However, this novel strain does not produce indole and tested negative for ornithine decarboxylase and d-xylose fermentation—differences that set it apart from typical A. hydrophila strains. In the present study, this strain was subjected to whole-genome sequencing and compared with the genomes of the type strain (Aeromonas hydrophila ATCC 7966T) and other Aeromonas spp. Comprehensive genome analysis suggests that AB005 represents a distinct species within the genus. The draft genome of the AB005 strain comprises 4,780,815 base pairs with a GC content of 61.2% and contains 6104 predicted protein-coding sequences along with numerous genes implicated in antibiotic resistance. The core/pan-genome analysis reveals extensive genetic diversity, indicative of a dynamic genomic structure. These findings collectively underscore the taxonomic distinction of the AB005 strain as a novel species and highlight its potential pathogenic implications in aquaculture and public health settings.