Moraxellaceae representatives Acinetobacter sp A bacterium resembling

Moraxellaceae representatives acinetobacter sp a

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Moraxellaceae representatives Acinetobacter sp. A bacterium, resembling Acinetobacter, was recovered from sexually mature Atlantic salmon, comprising wild stock from the River Surma, Norway (Roald and Hastein, 1980). Acinetobacter sp. Cultures comprise round, raised, translucent, mucoid colonies of 1.5 mm in diameter within 48 h incubation at 22°C. Colonies contain fairly unreactive, short, plump, facultatively anaerobic, non-motile. Gram-negative rods of 1.6-1.8 x 0.8- 1.2 |im in size. Catalase and oxidase are produced, but not arginine dihydrolase, P-galactosidase, H2S, indole, lysine or ornithine decarboxylase or tryptophan deaminase. Blood (haemolysis) is degraded, but not gelatin or urea. Nitrates are not reduced. The methyl red test and Voges Proskauer reaction are negative. Sodium citrate is not utilised. Acid is produced from galactose, maltose and mannose, but not from adonitol, amygdalin, arabinose, cellobiose, glucose, ino- sitol, lactose, mannitol, melibiose, raffinose, rhamnose, saccharose, salicin, sorbi- tol or xylose. Unfortunately, the G + C ratio of the DNA has not been determined.
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124 Bacterial Fish Pathogens From the available information, Roald and Hastein (1980) considered that the pathogen corresponded to an as yet unnamed species of Acinetobacter. Although this appears to be a sound decision, bona fide Acinetobacter spp. should not produce oxidase (Juni, 2005). In fact, this ability belongs to the morphologically similar Moraxella (Juni and B0vre, 2005) and Neisseria (Vedros, 1984). There is some degree of resemblance between the fish pathogen and Mor. atlantae and Mor. osloensis, although one of the general traits of moraxellae is an inability to produce acid from carbohydrates. Thus, as a compromise solution it would appear that the fish patho- gen should be classified in the area loosely bounded by Acinetobacter, Moraxella and Neisseria. Moraxella sp. A bacterium was recovered as pure culture growth from internal organs of juvenile striped bass, and equated with Moraxella (Baya et ai, 1990b). Moraxella sp. Cultures comprise non-motile, short (0.8-1.0 x 1.3 |im in size), non-fermentative, paired rods with pronounced bipolar staining. Catalase and oxidase are produced, but not so arginine dihydrolase, P-galactosidase, H2S, indole or lysine or ornithine decarboxylase. Sheep's blood is degraded, but not gelatin or urea. Citrate utilisa- tion, nitrate reduction and the Voges Proskauer reaction are negative. Acid is produced weakly from galactose and mannose, but not from amygdalin, arabin- ose, glucose, inositol, lactose, maltose, mannitol, rhamnose, saHcin, sorbitol or sucrose. Whereas similarities to Moraxella were noted (Juni and B0vre, 2005), the organism strongly resembled the Acinetobacter described by Roald and Hastein (1980). Indeed, the major differences concerned acid production from maltose. Clearly, the precise taxonomic position of both organisms must await further study.
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  • Spring '20
  • Bacteria, representative, gram-negative bacteria

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