Riemerella Segers et al. 1993
General information
Description and emendation
Cells are gram-negative, nonsporulating rods. Most strains grow aerobically and microaerobically after primary isolation in a CO2-enriched atmosphere. A number of carbohydrates are weakly acidified or fermented. At present it is not possible to give a general biochemical profile for the genus as only a single species is known. The type species is R. anatipestifer. The DNA base composition ranges from 29 to 35 mol% G+C.
1: Riemerella cells are Gram-negative, nonsporulating and nonmotile rods 0.24-5 µm wide and 1-23 µm long. All strains grow microaerobically and most of them aerobically on blood agar. Some strains grow anaerobically at 37°C. Colonies are smooth, non-pigmented or greyish-white to beige pigmented. Growth on litmus lactose agar is strain-dependent, no growth is obtained on MacConkey's agar. Most strains show a positive Voges-Proskauer reaction. Nitrates are not reduced. Reaction for acid production from glucose is frequently negative in peptone-containing media. Activity of the following enzymes is present: oxidase, catalase, gelatinase, α-glucosidase, α-maltosidase, alkaline and acid phosphatase, esterase lipase C8, esterase C4, naphthol-AS-BI-phosphohydrolase, leucine arylamidase, valine arylamidase, cystine arylamidase and L-aspartic acid arylamidase. The following reactions are strain-dependent: urease, chymotrypsin, trypsin and arginine dihydrolase activity, indole production, haemolysis on blood, aesculin hydrolysis. Depending on the micro-test kit used, the following enzyme reactions give variable results: β-glucosidase, α-galactosidase and lipase activity (these three reactions were all positive in the API ID32E and negative in the API ZYM system) and N-acetyl-β-glucosaminidase [negative in API ZYM and API ID32E, positive in LRA-ZYM-OSIDASES; only some representative R. anatipestifer strains were tested using the latter system]. Activity of the following enzymes is absent: chondroitin sulfatase, hyaluronidase, β-galactosidase, β-glucuronidase, α-mannosidase, α-fucosidase, trypsin, ornithine and lysine decarboxylase. None of the strains used malonate as a carbon source, or assimilated in the API 20NE system D-glucose, L-arabinose, D-mannose, Dmannitol, N-acetylglucosamine, maltose, D-gluconate, caprate, adipate, L-malate, citrate or phenyl acetate. No acid production was detected from D-arabitol and L-arabitol, galacturonate, 5-ketogluconate, phenol red, D-mannitol, maltose, adonitol, palatinose, saccharose, L-arabinose, trehalose, rhamnose, inositol, sorbitol or cellobiose in the API ID32E system. Using the BSS test, however, acidification of the following carbohydrates may be detected: D-glucose, maltose, D-mannose and dextrin, and to a lesser extent D-fructose, L-sorbose and trehalose. No acid was produced from lactose, D-galactose, N-acetyl-D-glucosamine, lactulose, trehalose, saccharose, D-mannitol, L-arabinose, myo-inositol, D-sorbitol, D-xylose, dulcitol, salicin or adonitol. The genus is a member of the family Flavobacteriaceae. The closest phylogenetic neighbours are the genera Chryseobacterium and Bergeyellu. Menaquinone-6 is the major respiratory quinone detected in the type species. The dominant fatty acids are the branched-chain fatty acids 13:0 iso, 15:0 iso, 15:0 anteiso, 15:0 iso 3-OH and 17:0 iso 3-OH. Isolated mainly from diseased birds, in a few cases from pigs. The illness caused by the organism is a septicaemic disease in ducks, pigeons and other domestic and wild birds. The DNA G+C composition ranges from 29 to 37 mol%.
2: Cells are Gram-staining-negative, non-sporulating rods, 0.2-0.5 mm in diameter and 1-2.5 μm long. Colonies are smooth, circular droplets, 1-2 mm diameter with regular edges. No growth on MacConkey agar. Positive for catalase and cytochrome oxidase. The major respiratory quinone is MK-6. The dominant fatty acid (.40%) is the branchedchain fatty acid 15:0 iso. The DNA G+C content of the type strains is 35-36 mol%. A member of the family Flavobacteriaceae, class Flavobacteria, phylum Bacteroidetes.
Subdivision(s)
MID | Name | Rank | Taxon ID |
---|---|---|---|
M02050401040N001 | Riemerella anatipestifer | Species | 34085 |
M02050401040N002 | Riemerella columbina | Species | 103810 |
M02050401040N003 | Riemerella columbipharyngis | Species | 1071918 |