RESUMEN
Five Gram-negative bacterial isolates, recovered from an outbreak that occurred in March 2006 in Huelva, Spain, affecting adult diseased cultured wedge sole [Dicologlossa cuneata (Moreau)], were characterized phenotypically and genotypically in order to clarify their taxonomic position. On the basis of 16S rRNA gene sequence analysis, the isolates were included in the genus Pseudomonas, within the Pseudomonas fluorescens-related species group, their closest relatives being the Pseudomonas jessenii and Pseudomonas koreensis subgroups. The highest sequence similarities were recorded with the type strains of Pseudomonas reinekei, P. moorei, P. umsongensis, P. jessenii and P. mohnii (99.4-99.3â% similarity). Sequence analysis of the housekeeping genes gyrB and rpoD clearly differentiated the isolates from currently described Pseudomonas species, the highest sequence similarities recorded to type strains being below 95â% for both genes. Phylogenetic analysis using concatenated sequences of the three genes showed Pseudomonas moraviensis DSM 16007T and P. koreensis DSM 16610T as the closest reference strains. DNA-DNA hybridization assays with related strains confirmed that these isolates belong to a novel species of the genus Pseudomonas, for which the name Pseudomonas baetica sp. nov. is proposed. The type strain is strain a390T (=CECT 7720T=LMG 25716T). The novel species could be easily distinguished from phylogenetically related species by several phenotypic characteristics, including gelatin hydrolysis, acid production from glucose and growth at 6â% NaCl. Virulence assays revealed that the novel species is pathogenic for wedge sole.
Asunto(s)
Peces Planos/microbiología , Filogenia , Pseudomonas/aislamiento & purificación , Animales , Técnicas de Tipificación Bacteriana , ADN Bacteriano/genética , Ácidos Grasos/química , Enfermedades de los Peces/microbiología , Genes Bacterianos , Hígado/microbiología , Datos de Secuencia Molecular , Hibridación de Ácido Nucleico , Pseudomonas/clasificación , Pseudomonas/genética , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , EspañaRESUMEN
We report the first isolation of Vibrio harveyi from wedge sole Dicologoglossa cuneata. The pathogen was recovered from ulcers and internal organs of ailing cultured fish, from 7 different outbreaks between 2004 and 2006. The 15 isolates found were phenotypically characterized using biochemical tests and BIOLOG GN plates, which revealed high phenotypic diversity. Diagnosis was confirmed with PCR using V harveyi specific primers and partial 16S and 23S rRNA gene sequencing. A virulence evaluation of the isolates was also performed using fry and juvenile wedge sole. Significant mortalities were recorded by intraperitoneal injection; however, no mortalities were recorded by bath immersion.