Mutations involved in the emergence of Yersinia ruckeri biotype 2 in France
| Autor: | Moreau, Emmanuelle, Thomas, Tatiana, Brevet, Marie, Fournel, Catherine, Calvez, Ségolène |
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| Přispěvatelé: | Biologie, Epidémiologie et analyse de risque en Santé Animale (BIOEPAR), Institut National de la Recherche Agronomique (INRA) |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | AQUA18 AQUA18, Aug 2018, Montpellier, France. World Aquaculture Society, 848 p., 2018, AQUA |
| Popis: | Yersinia ruckeri is a fish pathogen causing Enteric RedMouth Disease (ERM or yersiniosis). Y. ruckeri belongs to the Enterobacteriacea family and is divided into two biotypes: biotype 1 (BT1) which is motile and has a phospholipase activity and biotype 2 (BT2) which is negative for these 2 characteristics. The aim of this study was to identify mutation in BT2 strains responsible for Y. ruckeri BT2 emergence in France. Fourteen BT2 strains isolated from rainbow trout mainly in Brittany and Adour Garonne regions in France between 2005 and 2009 have been selected based on their origins, their API20E profiles, their serotypes, their pulsotypes and their sequence types, (Calvez et al, 2014, 2015). Two reference strains were also included: ATCC 29473 and EX 5, respectively belonging to BT1 and BT2. Microscopic studies were conducted in order to observe flagellar structures using the Flagella Stain kit (K-13, Presque Ile Culture). The tests revealed presence of flagella in BT1 strains but not in BT2 strains (figure 1). Genes involved in the motility and/or the phospholipase activity have been selected based on the published genome of Y. ruckeri strain ATCC 29473 (Daligault et al. 2014) and on the Evenhuis et al. (2009) study. Genes have been sequenced using the Sanger technology by GATC Biotech (France) and gene sequences have been compared using BioEdit editor. Among French BT2 strains, mutations previously described within fliR, flhA and flhB genes by Welch et al. (2011) have not been found. However, at least 2 new mutations have been revealed within fliG and flhC genes (figure 2). A 4-bp insertion at nucleotide 853 within fliG gene results in a predicted frameshift. Sequencing analysis of flhC reveals a single-residue deletion at nucleotide 474 within flhC sequence. These mutations concern genes which code for protein involved in flagellar biosynthesis. Discovery of two new mutations within these genes could explain, in part, the loss of flagella and motility in BT2 strains and Y. ruckeri BT2 emergence in France. Several independant mutations seem to lead to. ruckeri BT2 phenotype in the world. |
| Databáze: | OpenAIRE |
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