Chemical and Phenotypic Characteristics of Flavobacterium thalpophilum Compared with Those of Other Flavobacterium and Sphingobacterium Species

195

121

The phylogenetic position of the causative agent of septicemia anserum exsudativa, now most often referred to as [Moraxella] anatipestifer (brackets indicate a generically misnamed taxon) or "[Pasteurella] anatipestifer," was established by performing rRNA cistron similarity studies.[Moraxella] anatipestifer belongs to rRNA superfamily V, together with the genera Flavobacterium, Cytophuga, Fkxibacter, Weeksella, Capnocytophaga, and Sphingobacterium. The detailed structure of rRNA superfamily V, which now contains five major rRNA homology groups, is described. An analysis of various phenotypic parameters, including new data (cellular proteins and fatty acids) and previously published data (respiratory quinones, enzyme activities, and classical phenotypic features), revealed that [Moraxella] anatipestifer differs in many aspects from its closest relatives, Flavobacterium indologenes, Flavobacterium gleum, Flavobacterium indoltheticum, Flavobacterium balustinum , Flavobacterium meningosepticum, and Weekseh zoohelcum. The combined genotypic and phenotypic data indicate that this organism should be placed in a separate genus; the name Riemerella anatipestifer gen. nov., comb. nov. is proposed for this bacterium. The specific epithet anatipestifer is kept in order to avoid nomenclatural confusion. However, it should be emphasized that the illness caused by this organism is a septicemic disease which is not restricted to ducks.The epizootic infectious disease of domestic birds known as septicemia anserum exsudativa was first described ,by Riemer in 1904 (30). The taxonomic status of few other bacteria has been changed as often as the taxonomic status of the organism causing this disease. The phylogenetic position of this organism remained unsettled (it was classified in various genera with several specific epithets) from 1904 until 1986, when Piechulla and coworkers described for the first time its correct affiliation with the FlavobacteriumCytophaga group (29). An overview of this nomenclatural odyssey was given by Floren et al. (14). At present, the organism is most often referred to as [Moraxella] anatipestifer (brackets indicate a generically misnamed taxon) or " [Pasteurella] anatipestifer," and it is considered a species incertae sedis in Be%ey s Manual of Systematic Bacteriology (5,24). The numerous similarities between this organism and members of the Flavobacterium-Cytophaga group (lack of flagellation, low DNA base ratio, presence of menaquinones as the sole respiratory quinones, presence of branchedchain fatty acids in high percentages, absence of carbohydrate fermentation, and similar hydrolytic enzyme patterns) were significant parameters used to determine genomic relatedness, as shown by Rossau and coworkers (31). Rossau et al. also showed by performing a DNA-rRNA hybridization analysis that [Moraxella] anatipestifer indeed is not a close relative of the Muraxella or Pasteurella rRNA homology clusters but belongs to the Flavobacten'urn-Cytophaga rRNA homology cluster (31).The phylogenetic relationships...

Section: Fig 2 Protein Profiles Of Strains Listed Insupporting

confidence: 79%

Riemerella anatipestifer gen. nov., comb. nov., the Causative Agent of Septicemia Anserum Exsudativa, and Its Phylogenetic Affiliation within the Flavobacterium-Cytophaga rRNA Homology Group

Segers

Mannheim²,

Vancanneyt³

et al. 1993

195

121

“…As is common in other members of the FlavobacteriumCytophaga rRNA cluster, menaquinones were the only respiratory quinones detected (5, 8,18,47). 0. rhinotracheale LMG 11553 and LMG 11556 reportedly contain menaquinone 7 as their only respiratory quinones, which is similar to the quinone composition of R. anatipestifer (18).…”

Section: Discussionmentioning

confidence: 99%

Ornithobacterium rhinotracheale gen. nov., sp. nov., Isolated from the Avian Respiratory Tract

Vandamme

Segers

Vancanneyt

et al. 1994

151

104

The phylogenetic position and various genotypic, chemotaxonomic, and classical phenotypic characteristics of 21 gram-negative avian isolates were studied. These strains constitute a genotypically homogeneous taxon in rRNA superfamily V, as shown by DNA-rRNA hybridization data. Determination of the 16s rRNA sequence of this taxon revealed its detailed position within the "flavobacter" subgroup of the "flavobacter-bacteroides" phylum as described by Gherna and Woese (R. Gherna and C. R. Woese, Syst. Apple Microbiol. 15513-521, 1992). This new taxon is only distantly related to other members of the "flavobacter-bacteroides" phylum and is therefore given separate generic status. The DNA-DNA binding values for members of this taxon, for which we propose the name Ornithobacterium rhinotracheale, confirmed that all of the strains are highly interrelated (DNA-DNA binding values greater than 90% were measured). The G+C contents of members of this taxon are between 37 and 39 mol%, An analysis of the cellular proteins and fatty acids and classical phenotypic characteristics allowed us to distinguish 0. rhinotracheafe from phenotypically similar taxa, such as Riemrelliz anatipestiyer and Capnocytophaga species. The respiratory quinone content (menaquinone 7) and carbohydrate pattern of 0 . rhinotracheale conform with the respiratory quinone contents and carbohydrate patterns of other members of rRNA superfamily V.In the past decade, we determined the protein and fatty acid profiles of a large number of avian isolates which could not be classified after primary identification tests were performed in veterinary laboratories. A total of 21 of these isolates had very similar profiles and differed clearly from all of the other strains investigated, including reference strains of well-known fowl pathogens. These 21 strains were isolated from the respiratory tracts of turkeys (10 strains), chickens (7 strains), rooks, (3 strains), and a partridge (1 strain). Clinical data were not available for all of these strains. However, most of the strains were associated with various respiratory tract infections, including tracheitis, pericarditis, sinusitis, airsacculitis, and pneumonia. Preliminary data on some of the chemotaxonomic characteristics of four strains have been described previously (36).We studied a wide range of taxonomic parameters, including genotypic, chemotaxonomic, and classical phenotypic parameters, in order to establish the phylogenetic affiliation and to comprehensively describe the new taxon, for which we propose the name Omithobacterium rhinotracheale. Special emphasis was given to the differentiation of 0. rhinotracheale, Riemerella anatipestifer, and Capnocytophaga species as these taxa share a number of phenotypic characteristics. * Corresponding author. Mailing address: Laboratorium voorMicrobiologie, Universiteit Gent, K. L. Ledeganckstraat 35, B-9000 Gent, Belgium. Phone: 32-9-2645114. Fax: 32-9-2645346. MATERIALS AND METHODSIsolation of 0. rhinotracheale strains. Samples were inoculated onto media routinel...

“…Fatty acids were liberated from whole cells by base hydrolysis (6) and from crude membranes by acid hydrolysis (19). Gas-liquid chromatography of the fatty acids (as methyl esters) was performed by using a 50-m fused-silica capillary column (6).…”

Section: -Piperazine-ethanesulfonic Acid (Hepes) Buffer (Ph 72)mentioning

confidence: 99%

Cell Wall Characteristics of Mobiluncus Species

Carlone

Thomas

Arko

et al. 1986

Self Cite

The three type strains and a reference strain of Mobiluncus examined in this study had a gram-positive type of cell walls. All four strains were susceptible to vancomycin and resistant to colistin, and the overall susceptibility patterns with other antimicrobial agents were consistent with those of gram-positive microorganisms. Strains of Mobiluncus mulieris were lysed by 3% potassium hydroxide, and strains of Mobiluncus curtisii were not. However, all of the strains examined had intermediate levels of Limulus amebocyte-lysate reactivity that was not lipopolysaccharide associated. Lipopolysaccharide was not detected when whole-cell lysates were digested with proteinase K, separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and silver stained. In addition, 2-keto-3-deoxyoctulosonic acid and heptose were not detected by gas chromatography of 0-methyloxime acetate derivatives of whole-cell carbohydrates. Saponification and gas chromatography of whole-cell fatty acids showed that none of the four strains examined had detectable levels of hydroxylated fatty acids. Hydroxylated fatty acids or aldehyde fatty acids were not detected in acid hydrolysates of crude cell membrane preparations. (1,4,17,27,30,35,37,39,41,45,48), although the taxonomic position of members of this genus is still unresolved (15,43).The genus Mobiluncus has been tentatively assigned to the family Bacteroidaceae (43), which includes obligately anaerobic straight, curved, or helical gram-negative and gram-positive rod-shaped bacteria (18). The Gram reactions of strains of Mobiluncus are typically gram negative or variable (15, 43), although electron micrographs show that structurally these organisms have gram-positive cell walls (41, 43) and lack an outer membrane. Likewise, anaerobic curved rod-shaped organisms belonging to the genera Butyrivibrio, Lachnospira, and Acetivibrio (B), which are also members of the family Bacteruidaceae, stain gram negative but are structurally gram positive. Among anaerobic curved rods consistent with Mobiluncus, fatty acid aldehydes (presumably from plasmologens) have been detected, while hydroxlated fatty acids (found predominately in gram-negative bacteria) have not been found (39). Mobiluncus species are resistant to some antimicrobial agents which traditionally inhibit gram-negative microorganisms and are susceptible to some antimicrobial agents which inhibit gram-positive microorganisms (1,8,15,42,43,44). Limulus amebocyte lysate (LAL) reactivity, an indicator of gram-negative endotoxin, has also been reported (29).In this study, we compared characteristics of the type * Corresponding author.strains and a reference strain of Mobiluncus since previous reports have included organisms of undetermined taxonomic position which resemble members of this genus. We examined four strains of Mobiluncus for the following characteristics which are indicative of cell wall type: cell lysis, lipopolysaccharide (LPS), endotoxin reactivity, fatty acid content, antimicrobial agent susceptibility, and carbohyd...