Nocardia seriolae sp. nov. Causing Nocardiosis of Cultured Fish

Abstract

were studied to establish their taxonomic status. Well-developed fragmenting vegetative mycelium was observed. The chemotype was type IVA containing rneso-diaminopimelic acid, arabinose, and galactose. The predominant isoprenoid quinone was MK-8(H4), and mycolic acids were present. These morphological and chemical properties are characteristic of the genus Nocurdiu. The physiological and biochemical characteristics were most similar to those of Nocurdiu usteroides; however, these organisms were different in their decomposition of urea, growth temperature, utilization of nitrogen sources, survival at 50°C for 8 h, mycolic and fatty acid profiles, and deoxyribonucleic acid-deoxyribonucleic acid hybridization characteristics. Therefore, we propose a new species for these strains, Nocurdiu seriolae. The type strain is strain JCM 3360.A disease caused by actinomycetes in cultured fishes occurred first in rudderfishes (Seriola quinqueradiata and Seriola purpurascens) in Mie Prefecture, Japan, in 1967 (2, 13) and then spread to fish farms in the western district of Japan. This disease is characterized by the formation of abscesses in the epidermis and of tubercles in gills, kidneys, and spleens (13,15,17, 18). In 1968, the causative organisms were initially isolated, and their morphological, physiological, and biochemical characteristics were examined by Kariya et al. (13). Although these authors suggested that the strains were related to Nocardia asteroides, they proposed a new species, "Nocardia kampachi," for these organisms because of differences in some physiological and biochemical characteristics. However, morphology was the sole characteristic used for assignment of these strains to the genus Nocardia, and the description of " N . kampachi" lacked designation of a type strain. This name has never been validated, and original strains are not available anymore. Later, in 1973 and1974, Kusuda and Taki (17) and Kusuda et al. (18) isolated bacteria from infected yellowtails and identified them as " N . kampachi."We studied one of the strains of Kusuda (17) and four strains newly isolated from infected fishes (yellowtails [S. quinqueradiata] and a Japanese flounder [Paralichthys olivaceus]) to establish the taxonomic status of these strains. Based on morphological and chemical properties, we assigned the isolates to the genus Nocardia, and we propose a new species, Nocardia seriolae, for them on the basis of deoxyribonucleic acid (DNA)-DNA hybridization results and mycolic and fatty acid profiles in addition to physiological and biochemical characteristics. MATERIALS AND METHODSBacterial strains. In this study we used five strains isolated from cultured fishes from various fish farms in Japan and, for comparison, some strains of N . asteroides and related strains (Table 1).Morphology. The morphology of the isolates was studied by growing the strains on dilute yeast extract-malt extract agar (ISP medium no. 2 diluted to a 1/10 concentration) at 28°C for 5 days. A sample for electron microscopy was * Corresponding au...

Nocardia veterana sp. nov., isolated from human bronchial lavage.

“…Nocardia brasiliensis and Nocardia transvalensis are the main causal agents of actinomycete mycetoma (McNeil & Brown, 1994 ;McNeil et al, 1992), and the predominant agents of nocardiosis are Nocardia asteroides, Nocardia farcinica and Nocardia nova (Schaal & Lee, 1992 ;Wallace et al, 1991). Nocardia seriolae (Kudo et al, 1988) and Nocardia salmonicida (Isik et al, 1999) . are fish pathogens, whereas Nocardia crassostreae is the causal agent of nocardiosis in Pacific oysters (Friedman et al, 1998).…”

Nocardia salmonicida nom. rev., a fish pathogen

“…Chemotaxonomy. Freeze-dried biomass of strain JCM 4826' (50mg) was degraded by acid methanolysis and hexane extracts examined for mycolic acids by TLC as described by Minnikin et al (1975Minnikin et al ( , 1980. Menaquinone was analysed using HPLC as described previously (Chun & Goodfellow, 1995).…”

“…Strain JCM 4826T, a fish pathogen isolated from blueblack salmon (Oncorhynchus nerka), was assigned to the genus Streptomyces as Streptomyces salmonicida (Rucker, 1949) but was transferred to the genus Nocardia as Nocardia salmonicida when wholeorganism hydrolysates of the strain were found to contain meso-diaminopimelic acid, arabinose and galactose (Pridham & Lyons, 1969 ;Pridham, 1970). This reclassification was subsequently underpinned by additional chemotaxonomic and morphological data (Goodfellow, 1971 ;Alderson et al, 1985;Kudo et 1988) and the organism was shown to be most closely related to Nocardia asteroides on the basis of the results from DNA : DNA relatedness (Mordarski et al, 1977;Kudo et al, 1988) and numerical phenetic (Orchard & Goodfellow, 1980) studies. ' Nocardia salmonicida' JCM 4826T also fell outwith the Streptomyces clusters in the numerical phenetic survey of Williams et al (1983).…”

Nocardia araoensis sp. nov. and Nocardia pneumoniae sp. nov., isolated from patients in Japan

“…Nitrogen sources are not utilized. Kinoshita et al (2001), Kudo et al (1988), Maldonado et al (2000), Yassin et al (2001), Wang et al (2001) …”