is a category B priority pathogenic bacterium causing zoonotic disease in domestic animals (4
). The genus is further classified into several species based on host preference and phenotypic characteristics. Brucella suis
causes swine brucellosis, resulting in reproductive losses, but it is also known to be able to infect several other hosts, including cattle, dogs, and horses, without causing significant disease symptoms in these secondary host animals (1
). Currently, the complete genome sequences of two strains of Brucella suis
) and Brucella suis
ATCC 23445 (http://www.ncbi.nlm.nih.gov/bioproject/59015
), are publically available. Here, we report the complete genome sequence of the Brucella suis
VBI22 strain isolated from raw milk from an infected cow in Texas.
Genomic DNA was sequenced via the Illumina GAIIx sequencer following the standard Illumina 76-cycle paired-end protocols generating 24,600,000 sequence read pairs (49,200,000 reads) per sample. All low-quality bases (<0.99 of quality score) were trimmed from the sequence reads, and contig sequences were assembled using two de novo
assemblers, AByss (6
) and CLCbio genomics workbench. The contig sequences were aligned to a consensus sequence generated from the reads mapped by BWA (5
) to the Brucella suis
1330 reference sequence (7
). The aligned sequences were revised iteratively by a novel iterative mapping-assembly method (H. Tae, R. Settlage, S. Shallom, I. Sethi, G. N. Hawkins, L. G. Adams, and H. R. Garner, submitted for publication). The final output of this assembly is composed of two chromosomes containing 2,108,637 and 1,207,451 bases each.
After assembly, we annotated the genome of this assembly by comparing the nucleotide sequences of annotated genes encoding proteins, tRNAs, and rRNAs found within all published Brucella
references using BLAST. If the length of a BLAST hit was consistent with the length of the corresponding gene, the gene was used as a reference for the annotation. We gave higher priority to genes of Brucella suis
1330 when choosing among several potential annotations. If the lengths of the BLAST hit and the gene of Brucella suis
1330 were different, genes of other species having the lowest number of mismatches to the assembled genome sequence were used for annotation. When a frameshift was identified at a gene position, the annotation from the RAST annotation server (2
) was used for the position. This process resulted in annotations of 3,270 protein-encoding genes, 55 tRNA genes, and 9 rRNA genes.
genome contains an IS711
transposon element that is often used in fingerprinting Brucella
species samples (3
). While Brucella suis
1330 and Brucella suis
ATCC 23445 contain 7 and 13 IS711
copies, respectively, Brucella suis
VBI22 has 8 copies. All 7 IS711
loci in the Brucella suis
1330 genome are observed in the genomes of the ATCC 23445 and VBI22 strains. Brucella suis
VBI22 has an additional IS711
locus right after the stop codon of the BSVBI22_A1627 gene, which has not yet been previously observed in any sequenced Brucella
Nucleotide sequence accession numbers.
The genome sequence of B. suis VBI22 is available in GenBank under accession numbers CP003128 and CP003129.