1. Vibrio parahaemolyticus lineages in the Northeast US
Invasive and endemic
Vibrio parahaemolyticus lineages in the Northeast US
Feng Xu, Ashley Marcinkiewicz,
Narjol Gonzalez-Escalona, Vaughn Cooper, Steve Jones, & Cheryl A. Whistler
Vp infection rate is rising in the US; #13 on the USDA list of most costly foodborne pathogens; Estimated $41M annual medical costs; 27% revenue loss to shellfish industry over 10-year period/closure; Current methods unable to accurately discriminate between harmless and pathogenic bacteria; need to provide methodologies to prevent contaminated product from reaching consumers; Illnesses lead to costly recalls, harvest closures, potential lawsuits and consumer avoidance; Protocols for management must be ISSC/NSSP approved

2. Starting at the end (Our conclusions)
Most infections in the Northeast are caused by two resident lineages: Pacific-originating ST36 (O4:K12) and Atlantic endemic ST631 (O11:KUT).
The Atlantic US Coast has at least 3 distinct and recognizable (by their genetic fingerprint) ST36 populations, each founded by a single bacterium.
ST631 is the first reported major endemic pathogen to have evolved from the North Atlantic Vp population, and it acquired its “pathogenicity island” from a Pacific strain (potentially from ST36).
Other lineages derived from the Pacific, the Gulf of Mexico, Asia, and even the Baltic Sea have been implicated in local infections.

3. Disease is dominated by relatively few unrelated strains
Proportion of Infection by Sequence Type
Xu et al., 2015 and unpublished

4. Disease is dominated by relatively few unrelated strains
Proportion of Infection by Sequence Type
Asia: ST3, ST8, ST120
Xu et al., 2015 and unpublished

5. Disease is dominated by relatively few unrelated strains
Proportion of Infection by Sequence Type
Asia: ST3, ST8, ST120
PNW: ST43, ST636
GOM: ST110, ST34, ST308
Xu et al., 2015 and unpublished

6. Regional ST36 sub-populations are distinctive

7. Rapid identification of isolates by subpopulation
PI.family
PI.26
NEA
tlh control

8. Clade II ST631 is a mixed population

9. Virulence genes are contained in one of three types of pathogenicity islands

10. Most emergent pathogens harbor a similar hybrid-type VPaIγ

11. Pacific invasive and Atlantic native ST631 have the same tdh3 allele (Gulf of Mexico derived lineages typically have tdh5)

12. VPaIγ of ST631 clade II shares a common origin with VPaIγ of invasive Pacific lineages

13. Strain- and island-specific MPN-qPCR
Cullen, J.J. and H.L. MacIntyre (2015). J. Appl. Phycol.
DOI /s x. 

14. Re-Conclusions
Relatively few strains cause the majority of infections in the Northeast US
Several originated in the Pacific Ocean
Most Northeast US emergent pathogenic lineages share a similar pathogenicity island
The most prevalent Atlantic endemic lineage acquired virulence through lateral exchange with non-Atlantic natives
Surveillance of pathogens could be improved by targeted enumeration of prevalent strains or their associated island

15. Acknowledgements MA Department of Public Health
MA Division of Marine Fisheries
C. Schillaci, Tracy Stiles, M. Hickey (ohters)
NH Department of Public Health
ME CDC & Department of Marine Resources
CT Department of Agriculture
Bureau of Aquaculture
K. DeRosia-Banick, Joe DeCrescenzo
FDA
J. Jones (PCR Queen)

16. Origin and evolution of major resident
northwest Atlantic pathogenic lineages