Draft Whole-Genome Sequences of 14 Vibrio parahaemolyticus Clinical Isolates with an Ambiguous K Serogroup

Vibrio parahaemolyticus is a bacterial pathogen responsible for mild to severe gastroenteritis, wound infections, and septicemia resulting from the ingestion or handling of raw or undercooked contaminated seafood. Here, we report the draft whole-genome sequences and annotations of 14 Canadian V. parahaemolyticus clinical isolates that were serologically identified as K group II using polyvalent antisera but were not specifically K serogrouped using monovalent antisera.

widely distributed in temperate estuaries and is one of several etiological agents of human vibriosis. Since 2000, there has been an increasing prevalence of V. parahaemolyticus infections in Canada (1). However, the true incidence of infection is likely underestimated, due to a lack of awareness of the disease and its self-limiting nature. For effective V. parahaemolyticus epidemiological surveillance, including source attribution, strain delineation is necessary. Serology, the classic method of V. parahaemolyticus surveillance, has been unreliable in tracking the spread of outbreak-associated clonal complexes (CC), since several serovariants can simultaneously be associated with illness (2). In particular, two serotypes (O4:K12 and O12:K12) of CC36 are responsible for outbreaks associated with the consumption of raw oysters harvested on the North American Pacific coast; the two serotypes are descended from a common sequence type 36 (ST36) ancestor (3). So far, the genomic sequence of only one strain belonging to the V. parahaemolyticus CC36 (serotype O4:K12) has been published (3).
Between 2000 and 2009, several V. parahaemolyticus clinical isolates originating from provincial public health laboratories along the Pacific coast were submitted to the National Microbiology Laboratory (Public Health Agency of Canada), British Columbia Centre for Disease Control (BCCDC), and the Bureau of Microbial Hazards (BMH) (Health Canada). Twenty-six of these isolates were identified as ST36 and O4, indicating inclusion in CC36, but only weakly agglutinated with the polyvalent antiserum K group II and failed to agglutinate with any of the seven associated monovalent antisera (K agglutinins 9, 10, 11, 12, 13, 15, and 17) (4). Each of these 26 isolates was positive for both the tdh and crossmark trh virulence markers (4). Since K group II isolates are a prevalent cause of Canadian illness, genome sequencing was undertaken as an approach to further investigate the genetics underlying ambiguous serological classification. Briefly, sequencing was performed as described by Petronella et al. (5) and Pightling and Pagotto (6). Sequencing libraries were prepared from DNA extracted using the Maxwell 16 SEV cell DNA purification kit (Promega, Madison, WI). The short-read sequence data were generated by preparing a paired-end library with the Nextera XT DNA sample preparation kit (Illumina, San Diego, CA) and sequencing the library on a MiSeq benchtop sequencer (Illumina) for 500 cycles. The reads were assembled de novo into high-quality draft genomes with SPAdes version 3.1.1 (7), utilizing the MismatchCorrector tool, and error correction was performed with BayesHammer (8). This resulted in nonoverlapping contiguous sequences for each genome ( Table 1), each of which had a total GϩC content of 45%. The gene predictions and annotations were performed by the National Center for Biotechnology Information (NCBI) Prokaryotic Genome Annotation Pipeline (PGAP) (9).
Nucleotide sequence accession numbers. These nucleotide sequences have been deposited at DDBJ/EMBL/GenBank as Bio-Project PRJNA272927 under the accession numbers provided in Table 1.

ACKNOWLEDGMENTS
This work was funded (A-base) by Health Canada to support Canada's Food Safety Programs. J.R. is supported by the Visiting Fellow in a Government Laboratory Program.
We thank Franco Pagotto and Arthur Pightling of the BMH research division of Health Canada for peer reviewing the manuscript and offering useful comments.