title: Subtractive hybridization reveals a high genetic diversity in the fish pathogen Photobacterium damselae subsp. piscicida: evidence of a SXT-like element.
abstract: Photobacterium damselae subsp. piscicida is the causative agent of fish pasteurellosis, a severe disease affecting cultured marine fish worldwide. In this study, suppression subtractive hybridization was used to identify DNA fragments present in the virulent strain PC554.2, but absent in the avirulent strain EPOY 8803-II. Twenty-one genomic regions of this type (that included twenty-six distinct putative ORFs) were analysed by DNA sequencing. Twenty ORFs encoded proteins with homology to proteins in other bacteria, including four homologues involved in siderophore biosynthesis, and four homologues related to mobile elements; three of these were putative transposases and one was a putative conjugative transposon related to the Vibrio cholerae SXT element. This sequence was shown to be integrated into a prfC gene homologue. Six ORFs showed no significant homology to known bacterial proteins. Among the 21 DNA fragments specific to strain PC554.2, 5 DNA fragments (representing 7 ORFs) were also absent in the avirulent strain ATCC 29690. The analysis of these differential regions, as well as the screening of their presence in a collection of strains, demonstrated the high genetic heterogeneity of this pathogen.
authors.affiliation: Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Campus de Cantoblanco, 28049 Madrid, Spain.|Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
authors.forename: Sandra
authors.initials: S
authors.lastname: Juíz-Río
authors.affiliation: Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
authors.forename: Carlos R
authors.initials: CR
authors.lastname: Osorio
authors.affiliation: Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Campus de Cantoblanco, 28049 Madrid, Spain.
authors.forename: Víctor
authors.initials: V
authors.lastname: de Lorenzo
authors.affiliation: Departamento de Microbiología y Parasitología, Instituto de Acuicultura, Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
authors.forename: Manuel L
authors.initials: ML
authors.lastname: Lemos
mesh_terms: D000818:Animals; D001482:Base Composition; D004251:DNA Transposable Elements / Q000235:genetics*; D005393:Fish Diseases / Q000382:microbiology*; D005399:Fishes / Q000382:microbiology; D014644:Genetic Variation; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010776:Photobacterium / Q000235:genetics* / Q000254:growth & development / Q000302:isolation & purification*
chemical_list: D004251:DNA Transposable Elements