Draft Genome Sequence of Fish Pathogen Aeromonas bestiarum GA97-22.

Aeromonas bestiarum is a Gram-negative mesophilic motile bacterium causing acute hemorrhagic septicemia or chronic skin ulcers in fish. Here, we report the draft genome sequence of A. bestiarum strain GA97-22, which was isolated from rainbow trout in 1997. This genome sequence will improve our understanding of the complex taxonomy of motile aeromonads.

GENOME ANNOUNCEMENT

Aeromonas species are autochthonous to aquatic environments and cause disease in fish and mammals. Aeromonas hydrophila, A. veronii, A. sobria, A. caviae, and A. bestiarum species are causative agents of motile aeromonad septicemia (MAS) (1–3). A. bestiarum is a mesophilic motile aeromonad first described in 1996 (2), and it causes hemorrhagic septicemia and skin ulcers in fish (2, 4–6).

The genome sequencing of A. bestiarum strain GA97-22 was conducted with an Illumina Genome Analyzer IIx, and the draft genome sequence was obtained by adaptor trimming, quality control, and de novo assembly by using CLC Workbench 6.5.1 (CLC Bio) and Sequencher 5.4.5 (Gene Codes Corporation). Genome assembly included 6,380,282 reads (143× coverage of the genome), and the draft genome was annotated by using Prokaryotic Genomes Automatic Annotation Pipeline (PGAAP) (7) and Rapid Annotations using Subsystems Technology (RAST) (8). The draft genome of A. bestiarum strain GA97-22 is 4,714,837 bp (26 contigs) and has a G+C content of 60.5%. It contains 4,349 predicted genes encoding 4,247 proteins, and no plasmid sequences were identified.

Average nucleotide identity (ANI) calculation (9) was used to differentiate A. bestiarum from other Aeromonas species using 95% ANI as the species cutoff (10). The calculated ANI between A. bestiarum strain GA97-22 and the reference A. bestiarum strain CECT 4227 (GenBank accession number NZ_CDDA00000000) was 97.1%. A lower ANI value (88.3%) was obtained between A. bestiarum strain GA97-22 and the catfish isolate A. hydrophila strain ML09-119 (11). Similarly, the ANI value between A. bestiarum strain GA97-22 and A. salmonicida subsp. salmonicida A449 (12) was below the species cutoff (89.7%).

A type 3 secretion system (T3SS), the chitobiose-specific regulators ChbF and ChbR, O polysaccharide, cold shock protein CspG, and cytoplasmic copper homeostasis protein CutC are unique to A. bestiarum strain GA97-22 compared to the reference A. bestiarum genome CECT 4227. Also, a type 6 secretion system and mannose-sensitive hemagglutinin type 4 pilus system are unique to A. bestiarum strain GA97-22 compared to A. hydrophila strain ML09-119 and A. salmonicida subsp. salmonicida A449, respectively.

Accession number(s).

The draft genome sequence of A. bestiarum strain GA97-22 was submitted to GenBank under the accession number PPUX01000000.