- Volume 26, Issue 2, 1976

Microbacterium thermosphactum McLean and Sulzbacher differs to such an extent from the type species of Microbacterium, M. lacticum Orla-Jensen, that it cannot be retained in this genus. Recent studies have shown that M. thermosphactum strains form a distinct taxon worthy of genus status. A new genus, Brochothrix, is established for the species B. thermosphacta (McLean and Sulzbacher) comb. nov. This genus is tentatively placed in the family Lactobacillaceae. B. thermosphacta is the type species of the genus, and ATCC 11509 is designated to be the type strain of B. thermosphacta.

An analysis of the descriptions of the type or neotype strains of 457 named Streptomyces and Streptoverticillium species published in the International Journal of Systematic Bacteriology revealed that the International Streptomyces Project methods for reporting spore mass color, reverse color, and sporechain morphology need improvement. A new system of groups for the separation of strains according to their substrate mycelium color and easily determined morphological sections for preparing dichotomous keys for identification purposes are proposed.

The morphologic, biochemical, and drug susceptibility characteristics of the Keishicho strain, supposedly a strain of Mycobacterium lepraemurium, are compared with these same characteristics of representative strains of other slow-growing mycobacterial species. The Keishicho strain is quite distinct from all other mycobacteria. Special media and very large inocula are needed for in vitro growth; growth is exceedingly slow. The inter-taxon similarity coefficients were low; the highest, only 63%, was to Mycobacterium tuberculosis.

The degree of hybridization between the deoxyribonucleic acids (DNAs) of some different species of heterofermentative lactic acid bacteria was estimated. The DNAs from each of 25 strains comprising 12 species were hybridized with labeled DNAs from the type or reference strains of five species. The results suggest a very close relationship between Leuconostoc mesenteroides, Leuconostoc dextranicum, and Leuconostoc cremoris, whereas Leuconostoc oenos was found to be unrelated to other species of the genus. The results also indicate that Lactobacillus confusus and Lactobacillus viridescens are more allied to the leuconostocs than to other lactobacilli.

Cell wall antigens from each of six Cellulomonas species and two soil isolates were prepared. Cross-reactions were set up with antisera obtained through inoculation of New Zealand white rabbits. The percentage of cross-reaction ranged from 12 to 93. The known cellulomonads clustered in a range of 68 to 93% with one exception: C. uda with C. subalbus at 43%. The soil isolates demonstrated a much lower affinity and thus were hot considered cellulomonads. The cellulomonads, although similar to each other, demonstrated enough diversification to question their reduction to a single species.

A manometric assay system employing ascorbate and N,N,N',N'-tetra-methyl-p-phenylenediamine (TMPD) was used to quantitate terminal oxidase activity in bacterial non-proliferating whole cells. A wide variety of physiologically diverse bacteria, all of which were grown heterotrophically, was tested by this assay. For this survey study, 79 bacterial strains, which represented 34 genera, were used. Turbidimetrically standardized resting (non-proliferating) cell suspensions were prepared from cells harvested at the late logarithmic growth phase; all cells were grown under identical nutritional conditions. The TMPD oxidase activity obtained quantitatively correlated exceptionally well with results of the standard Kovacs oxidase test. In fact, the increased sensitivity of this quantitative assay allowed for further reclassification within the two major divisions of Kovacs oxidase-positive and -negative groups. Groups I and II contained all of the oxidase-positive microorganisms and the bacteria listed in group I had the highest TMPD oxidase rates, the Qo2 values (microliters of O2 consumed per hour per milligram [dry weight] at 30 C) ranging from 393 to 2, 164. The organisms listed in group II still had moderately high TMPD oxidase activity, the Qo2 values ranging from 27 to 280. All oxidase-negative bacteria fell into groups III and IV. Bacteria in group III had low but still measurable TMPD oxidase rates, the Qo2 values ranging from 3 to 33, whereas the bacteria found in group IV were inert and unable to oxidize TMPD. A grouping analysis allowed for the resolution of that point which separates oxidase-positive from oxidase-negative bacteria. This point, for non-proliferating cells, was found to be an absolute TMPD oxidation Qo2 value of 33 (after correcting for the endogenous rate by subtraction) and a Qo2 (TMPD/endogenous) ratio of 5; the latter parameter indicated that the uncorrected TMPD oxidation Qo2 value had to be five times greater than the rate for endogenous respiration. All Kovacs oxidase-positive organisms were found to have TMPD oxidase Qo2 values greater than these two metabolic parameters, whereas all Kovacs oxidase-negative organisms had lower values.

Agglutination serotypes were investigated by testing mycobacterial cultures from various sources with a large battery of antisera raised in rabbits. Absorption of agglutinins was performed when necessary to clarify serological relationships. Types in addition to those already described were recognized as follows: Mycobacterium scrofulaceum, serotype Cole; Mycobacterium gordonae, seven serotypes (34 strains isolated from various water sources were serotype Marshall); Mycobacterium marinum types 1 and 2; and Mycobacterium xenopi. It is proposed that these types be numbered, respectively, as follows: Mycobacterium avium complex, serotype 44; M. gordonae, serotypes 1 to 7 (Kowal, Marshall, Szent, Puntal, Moore, Lanton, and Brown, respectively); M. marinum, serotypes 1 and 2; and M. xenopi. The strains of M. xenopi included in this study could not be separated into different types by the techniques utilized.

The digestion of polypectate by each of the 11 indole-positive strains of Klebsiella pneumoniae studied is reported. The possible significance of pectinolytic activity for the identification of indole-positive strains of K. pneumoniae, the so-called “Oxytocum” group, is discussed.

One hundred thirty-eight phenotypic features were determined in 38 Zymomonas strains from diverse origin (Zairese fermenting palm saps, Mexican pulque, British spoiled beer, and sick cider). The similarity between all the strains was very high: 27 features were present, and 74 features were absent in all of them; 37 features were variable. By numerical analysis all strains formed one cluster above the simple matching coefficient of 0.88. There were no significant differences between motile and nonmotile strains or between sucrose-fermenting and non-sucrose-fermenting strains. A strain from sick cider in Bristol, United Kingdom, was a border case in its phenotypic features, deoxyribonucleic acid relatedness, and protein electropherograms. We propose: (i) to discontinue the use of the species name of Zymomonas anaerobia and its subspecies Z. anaerobia subsp. anaerobia and Z. anaerobia subsp. immobilis, and to include all of the strains in this species in Zymomonas mobilis; (ii) to consider Zymomonas congolensis as a nomen nudum and as a synonym of Z. mobilis. We concluded the following from our data: That Z. mobilis is the only species in the genus Zymomonas so far; that all the strains of our Zymomonas collection except one belong in Z. mobilis subsp. mobilis, the type strain of which is ATCC 10988; and that the cider sickness organisms belong in Z. mobilis subsp. pomaceae (Millis) comb. nov., with type strain T. H. Delft (= strain I [Barker] = ATCC 29192).

The taxonomic positions of several recently described species, Levinea malonatica, Levinea amalonatica, Citrobacter diversus, and Enterobacter agglomerans, were investigated by numerical analysis. A set of 141 strains, for which a total of 240 characters was recorded, was analyzed and also compared with representatives of a set of 384 strains of bacteria, examined in an earlier study, representing genera within the family Enterobacteriaceae. Three clusters of Citrobacter spp. were observed, Citrobacter freundii, Citrobacter spp., and Levinea amalonatica, with strains received as Citrobacter diversus and Levinea malonatica clustering with the Citrobacter spp. Citrobacter intermedius was concluded to be synonymous with C. freundii. L. malonatica, from the results of this study, was included in the species C. diversus. Hydrogen sulfide-positive strains of Escherichia coli were not judged to warrant separate species status. Klebsiella aerogenes, Klebsiella pneumoniae, Klebsiella oxytoca, and Klebsiella edwardsii were found to be highly related (similarity values > 90%). It is proposed that these species be merged into a single species, Klebsiella pneumoniae.

Strains of Yersinia enterocolitica and Yersinia pseudotuberculosis were characterized by deoxyribonucleic acid (DNA) hybridization, and the extent of DNA relatedness between the strains was assessed by hydroxyapatite chromatography. DNAs from 24 strains of Y. pseudotuberculosis were highly related, but Y. pseudotuberculosis was only 40 to 60% related to Y. enterocolitica. Y. enterocolitica strains formed three DNA relatedness groups, and the data strongly suggest a fourth relatedness group. Each relatedness group can be defined biochemically. One DNA relatedness group corresponds to typical Y. enterocolitica; the second is rhamnose positive; the third is rhamnose positive, melibiose positive, a-methyl glucoside positive, and raffinose positive. The suggested fourth hybridization group is sucrose negative. Although all of these DNA relatedness groups should remain in the genus Yersinia, only the first group is Y. enterocolitica. All of the yersiniae tested are distantly, but significantly, related to other members of Enterobacteriaceae. Yersiniae were more related to members of Enterobacteriaceae than to Pasteurella multocida.

Ninety-three strains of Bacteroides clostridiiformis subsp. clostridiiformis (Burri and Ankersmit) Holdeman and Moore, B. biacutus (Weinberg and Prévot) Holdeman and Moore, Fusobacterium symbiosum (Stevens) Moore and Holdeman, and related organisms, of which 75 were freshly isolated from the fecal material of humans, were studied systematically. They were differentiated into two genera, Clostridium and Bacteroides. We propose that, of the sporeforming strains, those having a guanine plus cytosine (G+C) content of about 49% to be considered C. clostridiiformis (Burri and Ankersmit) comb. nov., for which ATCC 25537 is designated as the neotype strain; those having a G+C content of about 56% be considered a new species in the genus Clostridium; and those having a G+C content of about 46% and producing butyric acid as a major product be considered C. symbiosum (Stevens) comb. nov., for which ATCC 14940 is designated as the neotype strain. Of the nonsporeforming strains, we propose that those having a G+C content of about 53% be considered a new species in the genus Bacteroides.

Twenty-five strains of bacteria with characteristics that conform to those given in the original and subsequent descriptions of the organism currently known as Bacteroides clostridiiformis (Burri and Ankersmit) Holdeman and Moore have been found to produce heat-resistant spores, which are often difficult to detect. Motility, also difficult to demonstrate in these strains, was found to be a variable characteristic within strains. We propose that B. clostridiiformis subsp. clostridiiformis (Burri and Ankersmit) Holdeman and Moore and B. clostridiiformis subsp. girans (Prévot) Holdeman and Moore be transferred to Clostridium as Clostridium clostridiiforme (Burri and Ankersmit) comb. nov. Prévot's strain 171 I (= ATCC 29084 = VPI 3303), placed by Prévot in Ristella clostridiiformis, is designated as the neotype strain. Previously undescribed characteristics of this species are presented.

Three mycoplasmas isolated from the male bovine genital tract and a mastitic udder exhibited serological properties which distinguished them from any of the known Mycoplasma species. Further, a variety of serological procedures failed to identify these organisms with any of the wide range of members of the order Mycoplasmatales tested. These strains are described as belonging to a new species, for which we propose the name Mycoplasma canadense. Strain 275C, designated as the type strain, has been deposited in the National Collection of Type Cultures, Great Britain, under the number 10152.

A hydrocarbon-utilizing, obligately thermophilic bacterium was isolated from a littoral area of North Carolina, and it is herein described and named as a new species. The microorganism, designated strain PTA-1, is a gram-negative, non-sporeforming, nonmotile, pleomorphic rod that can utilize various long-chain n-alkanes, 1-alkenes, primary alcohols, or ketones as substrates for growth. It will not grow on nutrient broth or Trypticase soy broth. The organism is an obligate aerobe which grows most rapidly at 60 C with a generation time of 4.0 to 4.5 h at an optimum pH of 7.2 to 7.5 in minimal salts medium with 0.1% n-heptadecane as substrate. The temperature range for growth is 42 to 70 C. A deoxyribonucleic acid base composition of 68.8 mol% guanine plus cytosine for this organism was determined by thermal denaturation of isolated deoxyribonucleic acid. The cells contain a pink carotenoid pigment(s) that is most evident after growth at minimal temperatures with acetate as the substrate. It is proposed that this organism be placed in the genus Thermomicrobium as a new species, to which we give the name Thermomicrobium fosteri. The type strain of T. fosteri, PTA-1, has been deposited in the American Type Culture Collection under the number 29033.