- Volume 37, Issue 2, 1987

Two strains of sporeforming, xylan-digesting, rod-shaped bacteria were isolated from a 10−8dilution of rumen ingesta taken from two sheep fed a corn stover ration. To determine the source of these strains, we examined the corn stover and isolated two strains of similar bacteria from it. The four strains were remarkably tolerant to oxygen although they did not grow in liquid medium that was shaken while exposed to air. They fermented a wide variety of carbon sources and produced formic, acetic, and lactic acids, ethanol, carbon dioxide, and hydrogen from xylan. The deoxyribonucleic acid base composition was 40 mol% guanine plus cytosine. The name proposed for these strains is Clostridium aerotolerans; the type strain is strain X8A62 (ATCC 43524).

Sixteen spiroplasma isolates, recovered over a 2-year period from symptomatic periwinkle plants (Catharanthus roseus) collected in eight different locations in Syria, were compared with other established Spiroplasma species or serogroups. Serological analysis of selected representatives of the new isolates revealed sharing of some antigenic components with several spiroplasmas currently classified within subgroups of group I of the genus. Strain P40Twas selected as the type strain and examined, meeting the criteria proposed by the International Committee on Systematic Bacteriology Subcommittee on the Taxonomy of Mollicutes. The organism was shown to belong to the class Mollicutes by its morphology, ultrastructure of its limiting membrane, colony characteristics, and filtration patterns. The helicity and motility of the cells indicated its placement within the family Spiroplasmataceae. Although some serological cross-reactions could be observed with representatives of group I subgroups, strain P40Tcould be readily distinguished from other plant or insect pathogenic spiroplasmas in subgroup I-1 (Spiroplasma citri), subgroup I-2 (S. melliferum), or subgroup I-3 (S. kunkelii) and from spiroplasmas assigned to subgroups I-4 through I-7 and groups II through XI. Cholesterol was required for growth. Glucose was fermented, and arginine was hydrolyzed. The base composition (guanine plus cytosine) of the deoxyribonucleic acid of strain P40Twas found to be 26 mol%. Deoxyribonucleic acid-deoxyribonucleic acid hybridization comparisons between strain P40Tand other subgroup I representatives revealed approximately 60% relatedness to S. citri and S. kunkelii and 50% relatedness to S. melliferum. Experimental transmission of two of the new isolates (P40Tand P354) occurred through inoculation of spiroplasma broth cultures into leafhoppers (Macrosteles fascifrons), multiplication of the organism in the insects, and subsequent transmission of the organism by insect feeding on aster or periwinkle plants. The organism was also successfully recovered from broth cultures of symptomatic tissues of experimentally infected periwinkle plants, thus fulfilling Koch’s postulates. We propose that such strains be named Spiroplasma phoeniceum. Strain P40Thas been deposited in the American Type Culture Collection (= ATCC 43115T)

Comparisons of 5S ribosomal ribonucleic acid (rRNA) nucleotide sequences were used for the phylogenetic characterization of a number of “morphologically conspicuous” sulfide-oxidizing eubacteria and certain of their non-sulfide oxidizing counterparts. Nucleotide sequences were determined for 5S rRNAs isolated from Thiovulum sp., Beggiatoa alba B18LD, Thiothrix nivea JP2, strain 30 (a Thiothrix-like organism), Vitreoscilla beggiatoides B23SS, Vitreoscilla filiformis L1401-7, V.filiformis ATCC 15551, Vitreoscilla stercoraria VT1, and Leptothrix discophora (Stokes). All 5S rRNAs characterized in this study, except that of Thiovulum sp., belong to either the gamma or beta subdivisions of the “purple bacteria,” which form 1 of the 10 major eubacterial divisions so far defined by 16S rRNA oligonucleotide catalog analysis. Although its 5S rRNA is clearly eubacterial in character, Thiovulum sp. appears to have no specific relatives among the eubacteria presently represented in the 5S rRNA data collection.

Clostridium fervidus sp. nov. was isolated from a hot spring in New Zealand. The cells were strictly anaerobic, gram negative, sporeforming, and sluggishly motile rods (0.65 to 0.75 μ wide and 2 to 3 μm long). The spherical spores were subterminal to terminal and did not distend the sporangium. Lysis of the culture occurred at the onset of stationary phase. The deoxyribonucleic acid guanine-plus-cytosine content was 39 mol%. The temperature optimum was 68°C (range, > 37 and < 80°C), and the pH optimum was 7.0 to 7.5 (range, > 5.5 and < 9.0). Growth occurred on Trypticase peptone (BBL Microbiology Systems) or yeast extract. However, with the exception of serine, which could be catabolized as the sole carbon source, either peptone or yeast extract was essential for the fermentation of carbohydrates including glucose, maltose, mannose, xylan, starch, and pyruvate. Acetate was always the major fermentation end product. CO2, H2, and minor quantitites of valerate, butyrate, ethanol, and lactate were also produced. C. fervidus (type strain Rt4-B1T) has been deposited with the American Type Culture Collection (ATCC 43204).

The name Yokenella regensburgei was validly published in June 1984 by Kosako, Sakazaki, and Yoshizaki (Jpn. J. Med. Sci. Biol. 37:117–124). Working independently, Hickman-Brenner, Huntley-Carter, Fanning, Brenner, and Farmer described Koserella trabulsii, which was validly published in January 1985 (J. Clin. Microbiol. 21:39–42). Both names gained standing in the nomenclature in April 1985 when they appeared in Validation List 17 (Int. J. Syst. Bacteriol. 35:223–225). Nine strains of Y. regensburgei and five of K. trabulsii were compared by deoxyribonucleic acid (DNA)-DNA hybridization and phenotype. By DNA-DNA hybridization (3H-labeled DNA, 65°C, nitrocellulose filter method), the type strain of Y. regensburgei was highly related (99%) to the type strain of K. trabulsii and highly related (78 to 100%) to the other strains of both species. The type strain of K. trabulsii was highly related (80%) to the type strain of Y. regensburgei and highly related (80 to 98%) to the other strains of both species. Y. regensburgei and K. trabulsii were almost identical phenotypically based on 68 phenotypic characteristics studied in Japan and 47 biochemical tests done in the United States. Based on their extremely close relationships by both molecular and phenotypic methods, we concluded that all 14 strains should be classified in a single species. The present Bacteriological Code does not indicate whether Y. regensburgei or K. trabulsii is the correct name for this species. Similarly, the recent proposal (April 1986) to emend the Bacteriological Code does not consider some of the unique features of this case. For these reasons, a Request for an Opinion will be made to the Judicial Commission to resolve this nomenclatural question. In the meantime, we recommend that both species names be written together with one name in parentheses.

A gram-negative bacterium with peritrichous flagella isolated from internally discolored rhizomes of Japanese horseradish, Eutrema wasabi Maxim. (Japanese common name, wasabi), was compared with other soft rot Erwinia spp. The wasabi bacterium induced soft rot on slices of various vegetables, such as wasabi rhizomes, potato tubers, and carrot and radish roots, on midribs of chinese cabbage and intact wasabi, and on tomato and tobacco plants, but not on rice, corn, or chrysanthemum. Although this bacterium was more similar to Erwinia carotovora than to Erwinia chrysanthemi in physiological and biochemical properties, it differed from E. carotovora subsp. carotovora, E. carotovora subsp. atroseptica, and E. carotovora subsp. betavasculorum in being negative in the o-nitrophenyl-β-d-galactopyranoside test, curd formation and peptonization of litmus milk, growth in yeast extract-peptone broth containing 0.075% KCN or 5% NaCI, growth at 36°C, and fermentation of lactose, raffinose, and melibiose. This bacterium also differed in having a 24-h lag in galactose fermentation, rapid fermentation of trehalose, and different serological properties. The guanine-plus-cytosine content of deoxyribonucleic acid was 51.4 to 51.7 mol%. Such significant differences warranted the designation of the wasabi bacterium as a new subspecies of E. carotovora, and the name Erwinia carotovora subsp. wasabiae subsp. nov. is proposed. Strain SR91 (=ATCC 43316, and PDDCC 9121) is designated the type strain.

Twenty-five phenotypically and genotypically similar strains of a fastidious, xylem-limited bacterium were isolated from 10 plant disease sources including Pierce’s disease of grapevines, phony disease of peach, periwinkle wilt, and leaf scorches of almond, plum, elm, sycamore, oak, and mulberry. The cells were single (occasionally filamentous), nonmotile, aflagellate straight rods (0.25 to 0.35 by 0.9 to 3.5 μm). They were gram negative, catalase positive, and oxidase negative, utilized hippurate, and produced gelatinase and often beta-lactamase but not beta-galactosidase, coagulase, lipase, amylase, phosphatase, indole, or H2S. The bacteria were strict aerobes with optimum growth at 26 to 28°C and pH 6.5 to 6.9 and had doubling times of 0.45 to 1.98 days in periwinkle wilt broth. Monoclonal antibodies prepared against the Pierce’s disease bacterium reacted with all strains. DNA composition was 51 to 53 mol% guanine plus cytosine, and strains were at least 85% related in DNA hybridization. Sequencing of 16S ribosomal ribonucleic acid related them to the xanthomonads. These bacteria form a distinct group, and the name Xylella fastidiosa is proposed, establishing a new genus with one species in the gamma subgroup of the eubacteria. Strain PCE-RR (ATCC 35879) is designated as the type strain.

An aerobic, gram-negative bacterium that causes seedling blight of rice was isolated from diseased rice seedlings and bed soil in nursery boxes in Chiba and Niigata Prefectures, Japan. The cells are nonsporeforming and nonencapsulated straight rods (0.7 to 1.0 by 1.4 to 1.9 μm) that occur singly, in pairs, or in short chains and are motile with one to three polar flagella. The bacterium displays the characteristics of the genus Pseudomonas and can be clearly differentiated from Pseudomonas glumae and Pseudomonas avenae, which are known to cause seedling diseases in rice grown in nursery boxes, and from other bacteria. The deoxyribonucleic acid base composition is 64.8 mol% guanine plus cytosine. A new species, Pseudomonas plantarii sp. nov., is proposed. The type strain is NIAES 1723 (JCM 5492, AZ 8201). All strains of the new species produce the disease-causing substance tropolone (a nonbenzenoid aromatic compound with a seven-membered ring) and a reddish brown pigment which was considered to be a derivative of the substance.

Immunodiffusion and an enzyme-linked immunosorbent assay (ELISA) were used to reveal serological relationships between coryneform bacteria responsible for annual ryegrass toxicity (ARGT) and other plant-pathogenic corynebacteria, particularly those associated with similar diseases of grasses, Clavibacter iranicum, Clavibacter rathayi, and Clavibacter tritici. Antisera were raised in rabbits against one strain each of C. iranicum, C. rathayi, C. tritici, and the ARGT bacterium. The antisera were tested against 26 strains belonging to that group of species and one strain each of eight other species of plant-pathogenic corynebacteria. Immunodiffusion with antiserum against the ARGT bacterium did not show cross-reactions with any of the other species tested, whereas, antisera against C. iranicum, C. rathayi, and C. tritici all showed some heterologous cross-reactions. The ELISA revealed cross-reactions undetected by immunodiffusion and allowed the organisms to be grouped by hierarchical cluster analysis. The results indicate that coryneform bacteria pathogenic to Lolium rigidum and responsible for its toxicity to livestock are serologically distinct from the other plant-pathogenic corynebacteria causing similar diseases of grasses. Amino acid analysis of the ARGT bacterium cell wall revealed the presence of 2,4-diaminobutyric acid, indicating that this bacterium should be classified in the genus Clavibacter.

Chemotaxonomic and deoxyribonucleic acid homology studies were carried out on various “Streptococcus suis” strains to clarify their taxonomic position. The results of the present study indicate that these strains belong to one species, namely, S. suis (ex Elliott) nom. rev. Strain NCTC 10234 is proposed as the type strain.

Neisseria polysaccharea is a new species which can be differentiated from the other species of the genus Neisseria by γ-glutamyltransferase activity, nutritional requirements in chemically defined medium, and production of extracellular polysaccharide. These phenotypic characteristics allow N. polysaccharea to be distinguished among a group of genotypically related species (N. gonorrhoeae, N. meningitidis, and N. lactamica) with which it shares 69 to 71% deoxyribonucleic acid (DNA) relatedness, (S1 nuclease; DE-81 filter method), with ΔT m (melting point) values between 3.6 to 5°C. The guanine-plus-cytosine contents of the DNAs of the latter three species are, respectively, 53.2, 53.2, and 52.0 mol%; for N. polysaccharea the content is 53.0 mol%. The DNA homologies with other Neisseria species are between 0 and 46 mol%.

A new species, Erysipelothrix tonsillae, is proposed for avirulent Erysipelothrix strains of serotype 7, which is frequently isolated from tonsils of apparently healthy pigs. This species is morphologically and biochemically indistinguishable from the Erysipelothrix rhusiopathiae strains characterized to date. Seven strains of E. tonsillae that belonged to serotype 7 were avirulent for swine, except for strain T-334, which induced a local urticarial lesion at the site of inoculation. The 50% lethal dose values in mice ranged from 1.0 CFU to 6.9 × 105CFU. The E. rhusiopathiae strains belonging to serotypes 2 (six strains), 6 (one strain), 11 (one strain), 12 (one strain), and 16 (one strain) induced generalized or local urticarial lesions after intradermal inoculation, except for strain T-312 of serotype 12, which showed 50% lethal dose values of ≤2.5 × 10 CFU in mice. The deoxyribonucleic acid base composition of E. tonsillae is 36 to 40 mol% guanine plus cytosine. Strains of this species have little deoxyribonucleic acid homology (15 to 43%) with the type strain of E. rhusiopathiae (ATCC 19414). The type strain of E. tonsillae is T-305T(ATCC 43339).

The isolation and characteristics of Methanosarcina barkeri MST(DSM 800T), accomplished in 1966 by Marvin P. Bryant, are described.

The isolation and characteristics of Methanobacterium formicicum MF (DSM 863), accomplished in 1966 by M. P. Bryant, are described.