- Volume 38, Issue 1, 1988

Phenotypic and chemotaxonomic characteristics of four isolates of yeast-lysing bacteria isolated from wastewater treatment systems were examined. The isolates were nonsporeforming, gram-positive, facultative anaerobic, irregular rods that were motile by multitrichous flagella. The isolates had an absolute requirement for hemin or hemoproteins for aerobic growth. Under anaerobic conditions, the isolates did not need heme compounds, but needed carbon dioxide. The deoxyribonucleic acid (DNA) base composition was 65.7 to 66.1 mol% guanine plus cytosine. The amino acid composition of the cell wall peptidoglycan was d-alanine, l-alanine, d-glutamic acid, l-ornithine, and d-serine (1:1:2:1:1). The major fatty acid of whole cells was 12-methyltetradecanoic acid. The major isoprenoid quinone was menaquinone with nine isoprene units. DNA-DNA hybridizations revealed clear separation of the isolates from known genera of the coryneform group. Therefore, Rarobacter faecitabidus gen. nov., sp. nov., is proposed for the isolates. The type strain is YLM-1 (JCM 6097).

Lactobacillus kefiranofaciens sp. nov. is described. Four strains of this species isolated from kefir grains are slime-forming, homofermentative, rod-shaped lactic acid bacteria. They differ from all the validly described homofermentative species of the genus Lactobacillus in their carbohydrate fermentation pattern. Their guanine-plus-cytosine content of deoxyribonucleic acid is 34 to 35 mol%. Deoxyribonucleic acids obtained from six other Lactobacillus species do not show significant relatedness to a representative strain of the new species. The type strain of L. kefiranofaciens sp. nov. is WT-2B (ATCC 43761).

Streptococcus hansenii, Streptococcus morbillorum, and Streptococcus pleomorphus were characterized by performing a comparative analysis of their 16S ribosomal ribonucleic acids and by determining their deoxyribonucleic acid base compositions and peptidoglycan types. None of these anaerobic streptococci is closely related to streptococci, enterococci, or lactococci. S. hansenii and S. pleomorphus are more closely related to certain clostridia, whereas Gemella haemolysans is the closest known relative of S. morbillorum.

Fifteen strains of Streptococcus intermedius and three mannitol-fermenting S. intermedius-like isolates from urine were studied by the S1 nuclease DNA homology assay and two physiological characterization methods. Three distinct homology groups (I, II, and III) were found. The three mannitol-fermenting S. intermedius-like strains and 2 of the 15 strains of S. intermedius did not fall within these groups. Each of the distinct homology groups could be distinguished by physiological testing. Homology group I strains were bile esculin positive (BE+), starch negative (Sta−), non-CO2 dependent, and melibiose negative (mel−); homology group II strains were BE−, Sta−, CO2 dependent, and mel−; homology group III strains were BE−, Sta+, non-CO2 dependent, and mel+. The two nonhomologous S. intermedius strains and three S. intermedius-like isolates from were phenotypically distinct from those in homology groups I through III. Characterization by the Rapid Strep system (Analytab Products, Plainview, N.Y.) identified homology groups I and II as either “S. milleri” I or II and homology group III strains as S. sanguis I or II. One nonhomologous S. intermedius strain was identified as S. sanguis I, and the other “S. milleri” I and the S. intermedius-like mannitol-fermenting strains were identified as S. milleri III by this method. We conclude that homology groups I, II, and III and the S. intermedius-like isolates from urine may represent separate taxa, but we do not make such a proposal on the basis of our limited data.

Strains of streptococci originally isolated from the dental plaque of monkeys (Macaca fascicularis) and designated as Streptococcus mutans serotype h were compared with the other species of the mutans streptococcus group. Despite the close resemblance noted previously between these strains and Streptococcus sobrinus, closer examination revealed several important differences. Strains of serotype h ferment mannitol but not sorbitol, melibiose, inulin, or raffinose, do not produce hydrogen peroxide, and are unable to grow in the presence of bacitracin at 2 units per ml. They exhibit a distinct polypeptide pattern by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and possess several antigens absent from S. sobrinus as revealed by Western blotting (immunoblotting). Virtually identical polar lipid patterns were observed by two-dimensional thin-layer chromatography for both serotype h strains and S. sobrinus, although on the basis of long-chain fatty acid analysis by capillary gas-liquid chromatography, the former could be distinguished by the presence of a peak tentatively identified as cyclopropane acid (cis-9, 10-methyleneoctadecanoate (ΔC 19:0). Deoxyribonucleic acid (DNA)-DNA hybridization studies by both the S1 nuclease and renaturation rate methods showed that serotype h strains differ from S. mutans, S. sobrinus, Streptococcus cricetus, Streptococcus rattus, Streptococcus ferus, and Streptococcus macacae. On the basis of these data, we believe that S. mutans serotype h strains represent a distinct species for which the name Streptococcus downei is proposed. The DNA base composition is 41 to 42 moles percent guanine plus cytosine. The type strain is strain MFe28 (NCTC 11391T), which is cariogenic in monoassociated germfree rats.

A new mesophilic strain of Methanothrix, strain FE, was highly purified from the sludge of an anaerobic digester after enrichment on sodium acetate and is described. Strain FE was compared with other strains of Methanothrix, Methanothrix soehngenii strain OpfikonT (= DSM 2139T) (T = type strain) and Methanothrix concilii strain GP6T (= DSM 3671T). The differences within the strains were mainly related to their requirement for yeast extract. The three strains were found to be similar in their deoxyribonucleic acid guanine-plus-cytosine contents (50.2 to 52.6 mol%) and showed 100% deoxyribonucleic acid-deoxyribonucleic acid homology. For these reasons we propose to recognize synonymy, reject the name Methanothrix concilii Patel 1985, 35:223, and assign this organism to the species Methanothrix soehngenii Huser, Wuhrmann and Zehnder 1983, 33:439.

Characteristics of a Mycobacterium intracellulare reference precipitation system for immunodiffusion and immunoelectrophoresis analyses are presented. The system was produced by the initiative of the International Working Group on Mycobacterial Taxonomy, and the purpose is to permit comparisons of precipitinogenic patterns of mycobacteria obtained in different laboratories. The reference material, consisting of an antigen preparation and a corresponding antiserum, is available for students of mycobacterial antigens in accordance with guidelines adopted by the Working Group.

Fourteen strains of indole-positive bacteroides (eight from cats and six from humans), phenotypically similar to Bacteroides zoogleoformans, previously were shown to have only 45 to 49% deoxyribonucleic acid (DNA) homology with the type strain of B. zoogleoformans, ATCC 33285, which is indole negative. These 14 strains and 7 strains isolated from horses have an average of 71% DNA homology with Bacteroides heparinolyticus ATCC 35895T, which also is indole positive. The seven strains from horses have an average of 71% DNA homology with the indole-positive strains from humans, an average of 86% DNA homology with the strains from cats, and an average of 42% DNA homology with B. zoogleoformans ATCC 33285T. These indole-positive strains from humans, cats, and horses were identified as B. heparinolyticus and could be distinguished from B. zoogleoformans by their production of indole.

Chemotaxonomic studies were performed on some gram-positive coryneform bacteria of uncertain taxonomic position isolated from poultry deep litter. On the basis of the present chemical and previous phenetic studies, we suggest that these bacteria be classified in a new genus, Brachybacterium, as Brachybacterium faecium gen. nov., sp. nov. The type strain of Brachybacterium faecium is strain NCIB 9860.

The name Yersinia ruckeri was initially applied to a group of serologically and biochemically homogeneous bacteria from diseased salmonid fish. Subsequently, isolates that differed in serology and in their ability to ferment d-sorbitol were also called Y. ruckeri. Strains of serovars II, III, V, and VI showed a high degree of relatedness in dot-blot deoxyribonucleic acid hybridization assays on nitrocellulose filters. In reciprocal tests, serovar I and II isolates had relative binding ratios (RBRs) of greater than 70%. Serovar V isolates appeared more closely related to serovar II (85% RBR) than to serovar I (70% RBR) strains. Serovar III strains appeared closely related to both serovar I and II strains, with the exception of a single sorbitol-fermenting strain. The single serovar IV isolate was excluded from Y. ruckeri (8% RBR), as were other isolates that ferment l-arabinose, d-xylose, and l-rhamnose. Y. ruckeri had low levels of hybridization with Hafnia alvei, Salmonella cholerae-suis subsp. arizonae, and Yersinia enterocolitica in dot blots and colony hybridization. Overall, the description of Y. ruckeri can be broadened to include isolates that differ from previously studied strains in their serological reactions and ability to ferment d-sorbitol.

Partial 16S ribosomal ribonucleic acid sequences were determined for Campylobacter concisus, Campylobacter fetus subsp. intestinalis, Campylobacter sputorum subsp. bubulus, Wolinella curva, Wolinella recta, Wolinella succinogenes, Bacteroides gracilis, and Bacteroides ureolyticus. These sequences were compared with previously published sequences of Campylobacter laridis, Campylobacter jejuni, Campylobacter coli, Campylobacter pylori, Thiovulum sp., Escherichia coli, and Bacteroides fragilis, and percentages of homology were calculated. With the exception of C. pylori, all of the campylobacters formed a tight phylogenetic cluster. Within this cluster were the following organisms that have been classified as species of Wolinella and Bacteroides: W. curva, W. recta, B. gracilis, and B. ureolyticus. The average level of interspecies homology within this group was 94.4%. W. succinogenes and C. pylori formed a second cluster with a level of interspecies homology of 90.4%. The average level of homology of the W. succinogenes-C. pylori cluster with species of the campylobacter cluster was 85.1%. Thiovulum sp. was only 83% homologous with either of the two clusters. Based upon the sequence data, we suggest that all members of the campylobacter cluster should be placed in the genus Campylobacter. However, formal resolution of the taxonomic status of the campylobacter cluster may require additional information provided by other experimental methods.

Guanine-plus-cytosine (G+C) content determinations, deoxyribonucleic acid (DNA) relatedness estimations, and phenotypic similarity analyses of 90 strains identified previously as Bacillus coagulans Hammer 1915 revealed that 52 (group 1) strains were Bacillus coagulans sensu stricto; 30 of the remaining organisms segregated into two distinct DNA relatedness groups, one consisting of 26 (group 2) strains and the other of 4 (group 4) organisms. Five (group 3) strains were Bacillus licheniformis, and three (group 5) strains were B. stearothermophilus. Because group 2 was a major cluster of strains which did not correspond in their characteristics to any previously known group, efforts were made to determine its taxonomic position. Group 2, with G+C contents ranging from 37 to 40 mol%, was compared with other species generally characterized as having G+C contents ranging from 37 to 44 mol% or capable of growing at 50°C or both (namely, Bacillus alcalophilus, Bacillus azotoformans, Bacillus badius, Bacillus firmus, Bacillus globiformis, Bacillus laterosporus, Bacillus macquariensis, Bacillus marinus, Bacillus megaterium, Bacillus pumilus, and Bacillus subtilis). Low DNA relatedness values and poor matching of phenotypic characteristics strongly indicated that group 2 organisms are strains of a new species, for which the name Bacillus smithii is proposed. The type strain of the new species is strain NRRL NRS-173.

A mycoplasma designated strain 1219T (T, type strain) was isolated from the phallus of a gander in Hungary. It was assigned to the class Mollicutes, order Mycoplasmatales, on the basis of morphological, cultural, and physical studies. The base composition of its deoxyribonucleic acid was 25 mol% guanine plus cytosine. It was dependent on sterol for growth, and its growth was inhibited by digitonin. The organism was assigned to the genus Mycoplasma since it did not hydrolyze urea and there was no evidence of helical forms. It hydrolyzed arginine, but other biochemical tests were negative. Strain 1219T could not be identified as any of 77 accepted Mycoplasma species by growth inhibition, immunofluorescence, or metabolism inhibition tests and thus appeared to be a new species. We propose the name Mycoplasma anseris for this organism, for which the type strain is strain 1219.

The type strain Enterobacter agglomerans ATCC 27155 was examined for deoxyribonucleic acid (DNA) relatedness to 54 strains of the “Erwinia herbicola-Enterobacter agglomerans complex,” to 23 strains of other Erwinia and Enterobacter species, and to 50 reference strains of 49 different species in other genera of the family Enterobacteriaceae. The DNA-DNA hybridization values (at the optimal renaturation temperature; nitrocellulose filter method) showed that 24 strains were highly related to Enterobacter agglomerans ATCC 27155T (62 to 97% DNA relatedness) and formed a genotypic group provisionally called DNA hybridization group 27155. These strains were received as Enterobacter agglomerans (including strains of DNA hybridization groups V and XIII [D. J. Brenner, G. R. Fanning, J. K. Leete Knutson, A. G. Steigerwalt, and M. I. Krichevsky, Int. J. Syst. Bacteriol. 34:45-55, 1984]); as Erwinia herbicola, including the type strain NCPPB 2971; as Erwinia milletiae, including the type strain NCPPB 2519; and as yellow-pigmented Enterobacter strains. Numerical analysis of the protein electropherograms of these strains revealed the existence of seven protein electrophoretic groups, each showing a characteristic protein pattern. These seven groups separated at an infraspecific level and allowed assignment of 37 additional strains, received as Enterobacter agglomerans, Erwinia herbicola, and Erwinia milletiae, to DNA hybridization group 27155. The resulting group hybridized below 55% DNA relatedness with all remaining phenotypic or genotypic groups of the “Erwinia herbicola-Enterobacter agglomerans complex” and below 57% DNA relatedness with other Erwinia and Enterobacter species. DNA binding with 49 other species of the family Enterobacteriaceae was less than 38%. Since DNA hybridization group 27155 contains the type strains of Erwinia herbicola, Erwinia milletiae, and Enterobacter agglomerans, these species names are subjective synonyms, and the specific epithet agglomerans has priority. Further genotypic studies with several closely related genera are required for final placement of this species in a genus. The description of Enterobacter agglomerans, Erwinia herbicola, and Erwinia milletiae is emended.

Twenty stem- and root-nodulating bacterial strains isolated from stem nodules of Sesbania rostrata were compared by numerical analysis of 221 phenotypic features with nine strains which effectively nodulate only the roots of this plant and with representative strains from the genera Rhizobium and Bradyrhizobium. Representative organisms from the different clusters were investigated further, together with possibly related organisms, by performing comparative gel electrophoresis of whole-cell proteins and by performing deoxyribonucleic acid (DNA)-DNA and DNA-ribosomal ribonucleic acid (rRNA) hybridizations. 3H-labeled rRNA was prepared from Sesbania stem- and root-nodulating bacterial strain ORS 571T (T = type strain); [14C]rRNA from Bradyrhizobium japonicum NZP 5549T was also used. The following conclusions were drawn: (i) the Sesbania root-nodulating bacterial strains are genuine rhizobia; (ii) the Sesbania stem- and root-nodulating strains are quite different from Rhizobium and Bradyrhizobium, and thus they constitute a separate rRNA subbranch on the Rhodopseudomonas palustris rRNA branch in rRNA superfamily IV; and (iii) the closest relative of these organisms is Xanthobacter, but they are phenotypically and genotypically sufficiently different from the latter genus to deserve a separate generic rank. Because the feature of free-living nitrogen fixation is quite discriminative, a new genus, Azorhizobium, is proposed, with one species, Azorhizobium caulinodans. The type strain is strain ORS 571 (= LMG 6465).

Two deoxyribonucleic acid hybridization groups were found among Brochothrix strains isolated from various sources. One genospecies contained 165 strains and included the type strain of Brochothrix thermosphacta. The other genospecies (five strains) represented a new species, for which the name Brochothrix campestris sp. nov. is proposed. The type strain is strain S3 (= CIP 102920 = ATCC 43754). B. campestris differs from B. thermosphacta by growth in the presence of 8 and 10% NaCI and 0.05% (wt/vol) potassium tellurite, by hippurate hydrolysis, and by acid production from rhamnose.

Spiroplasma isolates recovered from female mosquitoes (Culex tritaeniorhynchus) collected in Taiwan were found to be similar in their serological properties. Strain CT-1T (T = type strain) proved to be serologically unrelated to all currently recognized spiroplasma groups and subgroups. Strain CT-1T was studied by using criteria proposed by the International Committee on Systematic Bacteriology Subcommittee on Taxonomy of Mollicutes for the description of new mollicute species. The organisms were shown to belong to the class Mollicutes by the ultrastructure of their limiting membrane, their colonial morphology, and their filtration patterns and to the family Spiroplasmataceae by their helical morphology and motility. Growth in SP-4, M1A, and M1D media occurred at 22 to 30°C. Cholesterol was required for growth. Glucose was fermented, but arginine was not hydrolyzed. The base composition (guanine-plus-cytosine content) of the deoxyribonucleic acid of strain CT-1T was found to be 25 ± 1 mol%. On the basis of these findings, we propose that spiroplasma strains with these characteristics should be recognized as a new species, Spiroplasma taiwanense. Strain CT-1T has been deposited in the American Type Culture Collection as strain ATCC 43302T.

To determine deoxyribonucleic acid sequence variability within ribosomal ribonucleic acid (rRNA) genes and flanking regions of Mycoplasma hominis, plasmids containing parts of rRNA genes from Mycoplasma sp. strain PG50 or M. hominis type strain PG21 were used as probes to detect restriction fragment length polymorphisms (RFLPs). A total of 26 M. hominis strains selected to show either maximum diversity (14 strains) or possible cluster formation (12 strains) with respect to antigenic and genetic composition were included in the study. Although most of the RFLPs observed could be explained by variation in restriction enzyme cleavage sites outside the rRNA cistrons, variation in restriction enzyme cleavage sites within rRNA cistrons was also observed. RFLPs within the rRNA genes were demonstrated in three strains from the group selected to show heterogeneity. RFLPs outside the rRNA genes were equally pronounced in the two groups of M. hominis strains.

Nucleic acid and biochemical studies were performed on some lactobacilli from the human oral cavity which phenotypically resemble Lactobacillus brevis. The oral strains were distinct from L. brevis and other heterofermentative Lactobacillus species and warrant a new species, for which the name Lactobacillus oris sp. nov. is proposed. The type strain of Lactobacillus oris is NCDO 2160T.