Tor Hofstad

Dysgonomonas gen. nov. to accommodate Dysgonomonas gadei sp. nov., an organism isolated from a human gall bladder, and Dysgonomonas capnocytophagoides (formerly CDC group DF-3)

Results of a polyphasic taxonomic study on an unknown Gram-negative, facultatively anaerobic, coccobacillus-shaped organism isolated from an infected human gall bladder are presented. Phenotypic and molecular taxonomic studies revealed the organism to be close to, but distinct from, organisms designated CDC (Centers for Disease Control and Prevention) group DF-3. The unknown bacterium was readily distinguished from reference strains of Bacteroides, Prevotella, Porphyromonas and related taxa by 16S rRNA gene sequencing, biochemical tests, analysis of cellular long-chain fatty acids and electrophoretic analysis of whole-cell proteins. Based on the results of the present study, it is proposed that the unknown bacterium be classified in a new genus, Dysgonomonas, as Dysgonomonas gadei sp. nov. (type strain CCUG 42882T = CIP 106420T). In addition, a new species, Dysgonomonas capnocytophagoides sp. nov., is proposed to accommodate strains previously belonging to CDC group DF-3. The type species of the genus Dysgonomonas is Dysgonomonas gadei.

The Distribution of Heptose and 2-Keto-3-deoxy-octonate in Bacteroidaceae

Summary: A survey of phenol-water extracts of 17 different Fusobacterium and Bacteroides species, including subspecies, and of Leptotrichia buccalis has been carried out using colorimetric and chromatographic techniques to demonstrate the presence of heptose and 2-keto-3-deoxy-octonate. Both sugars were found in the water phase of the extracts from Fusobacterium strains and Leptotrichia buccalis. Neither heptose nor 2-keto-3-deoxy-octonate were detected in the water or the phenol phase of extracts from strains classified as Bacteroides.

Fatty Acids of Fusobacterium Species: Taxonomic Implications

Fatty acids of Fusobacterium species were examined by gas-liquid chromatography. Fusobacterium nucleatum, F. necrophorum, F. mortiferum, F. gonidiaformans and F. varium showed similar patterns, characterized by the presence of 3-hydroxytetradecanoate, n-tetradecanoate, hexadecenoate, n-hexadeconoate, ocadecenoate, n-octadecanoate and a component having the properties of octadecadienoate. Fusobacterium nucleatum contained 3-hydroxyhexadecanoate as a distinctive character. Simpler fatty acid patterns characterized by the absence of 3-hydroxytetradecanoate and other hydroxy fatty acids were observed in F. plauti, the single strain of F. prausnitzii and in the majority of strains classified as F. russii and F. naviforme. Neither methyl-branched nor cyclopropane fatty acids could be detected in any of the strains examined. In addition to fatty acid methyl esters, the chromatographic profiles of all species except F. mortiferum, F. gonidiaformans and F. naviforme contained substantial amounts of fatty aldehyde dimethyl acetals of chain lengths C14 to C18.

Evaluation of the API ZYM system for identification ofBacteroides andFusobacterium species

The API ZYM patterns of 97Bacteroides and 25Fusobacterium strains were examined. The system discriminated betweenB. asaccharolyticus, B. melaninogenicus ss.melaninogenicus, andB. melaninogenicus ss.melaninogenicus, but not between otherBacteroides species or between species ofFusobacterium. The results provided new information on the enzymatic activity of theses gorups of bacteria.

Structure of the polysaccharide antigen of Eubacterium saburreum, strain L44.

Abstract Structural studies of the polysaccharide antigen produced by the anaerobic, oral filamentous micro-organism Eubacterium saburreum, strain L44, are reported. It is concluded that the polysaccharide is linear and composed of β-(1→6)-linked D -glycero- D -galacto-heptopyranose residues. About 65% of these residues carry an O-acetyl group in the 7-position.

Adherence of Campylobacter jejuni and Campylobacter coli to porcine intestinal brush border membranes

The adhesion of Campylobacter jejuni and C. coli to isolated porcine intestinal brush border membranes was studied by phase‐contrast and electron microscopy. Approximately 45% of the cell population adhered to the brush borders, possibly in a specific manner. Pretreatment of the brush borders with trypsin or pronase, and competitive inhibition with L‐rhamnose caused a slight reduction of the adhesion. Different forms of pretreatment of the bacterial cells reduced their ability to adhere, but also their motility.

Chemical studies of partially hydrolysed lipopolysaccharides from four strains of Campylobacter jejuni and two strains of Campylobacter coli.

Lipopolysaccharides (LPS) from four strains of Campylobacter jejuni and two strains of C. coli were partially hydrolysed with 1% acetic acid. Subsequent chloroform extraction led to the formation of a polysaccharide-containing aqueous layer, an interfacial material and a lipid A-containing chloroform layer. The polysaccharides contained the neutral sugars, amino sugars, 2-keto-3-deoxy-octonic acid, and part of the phosphorus present in the undegraded LPS. The lipid As were made up of glucosamine, phosphorus, ester- and amide-linked 3-hydroxytetradecanoic acid, and ester-linked n-tetradecanoic and n-hexadecanoic acid. The interfacial material was made up of lipid A and undegraded LPS. When chromatographed on Bio-GEl P-60, the degraded polysaccharides were eluted as two incompletely separated peaks (strains NCTC 11168, NCTC 11351, 11041 and 11101) or as one peak (strains NCTC 11392 and E 8035). All peaks appeared close to the total volume of the column. When the different fractions were re-chromatographed on Bio-GEl P-10, the peaks still appeared close to the total volume of the column. These findings indicate that LPS from C. jejuni and C. coli are devoid of long O-antigenic side-chains.

The cell-wall antigen from Eubacterium saburreum strain L 13, a new type of biopolymer

Abstract In the cell-wall antigen of Eubacterium saburreum strain L13, the main chain consists of alternating residues of 3-amino-3,6-dideoxy-α- d -galactopyranose and l -glyceric acid, joined via glycosidic and amidic linkages as depicted below. Every third 3-amino-3,6-dideoxy-α- d -galactopyranosyl residue has a β- d -fructofuranosyl group linked to its 2-position. The antigen also contains O -acetyl groups. According to the IUPAC-IUB recommendations, this new type of biopolymer is not a proper polysaccharide but it seems, nevertheless, eligible to be designated as a polysaccharide.

Eubacterium plautii (Séguin 1928) comb. nov.

The type strain (ATCC 29863 = VPI 0310) of Fusobacterium plautii has a multilayered cell envelope structure consisting of a barely visible cell membrane, a dense intermediate layer, and a single-layered outer membrane. The cells do not have flagella and are not motile in hanging drop preparations. The results of this and earlier investigations indicate that despite having a negative Gram reaction, this strain is a gram-positive bacterium with a gram-variable cell wall structure. Since the type strain of F. plautii fits the generic description of Eubacterium, the species is transferred to this genus as Eubacterium plautii (Seguin) comb. nov.

Septicaemia with Neisseria elongata ssp. Nitroreducens in a Patient with Hypertrophic Obstructive Cardiomyopathia

Neisseria elongata ssp. nitroreducens, a commensal of the human upper respiratory tract, is a newly recognized cause of endocarditis. We report the isolation of the organism from blood cultures of a 30-y-old man with hypertrophic obstructive cardiomyopathy. The patient was successfully treated with benzylpenicillin and netilmicin in combination, followed by ceftriaxone and amoxicillin.