Étudiante-chercheure étoile November 2012

Katherine Tanaka

Master's student in Microbiology
Université Laval

Award-winning publication: An Insertion Sequence-Dependent Plasmid Rearrangement in Aeromonas salmonicida Causes the Loss of the Type Three Secretion System

Published in: PLoS One, March 2012


"Aeromonas salmonicida, a bacterial pathogen found in salmonids (salmon, trout, char), possesses a type III secretion system that is responsible for its virulence. The system's genes are located in a specific region of a plasmid (DNA molecule). My article describes a first case in which a plasmid was rearranged when one of its regions was deleted by recombining its insertion sequences (mobile elements of DNA). This rearrangement is all the more significant since the region targeted by the deletion contains the coding genes for a major virulence factor in A. salmonicida."

This infectious agent causes furunculosis, a skin disease in fish that chiefly affects farmed species, whose stress levels are higher than those of species in the wild. The rearrangement mechanism presented by Katherine Tanaka could become the target of an eventual treatment to decrease the virulence of the bacteria, diverging from the traditional method of eliminating the virulence through antibiotics and vaccines. This new type of intervention could lead to less bacterial resistance and benefit Québec fish farmers, who mainly farm species affected by A. salmonicida.