- Volume 44, Issue 3, 1994

Five strains of the genus Leptospira belonging to serogroup Pyrogenes were isolated from cattle slaughtered in Zimbabwe and subjected to cross-agglutinin absorption and restriction fragment length polymorphism analysis. One strain, SBF 2, represents a new genetic strain of serovar kwale, while another strain, SBF 49, is a new genetic strain closely related to serovar nigeria. Three strains belong to a new serovar for which the name mombe with reference strain SBF 20 is proposed. Restriction fragment length polymorphism analysis indicated that each of these three strains represents a different restriction polymorphism pattern group.

Pulsed-field electrophoresis (PFGE) of the Ssp I genomic digests of 14 Thermus isolates showed that each one had a unique restriction enzyme digestion pattern. A group of New Zealand strains showed some shared bands, but each isolate gave essentially a unique fingerprint. In addition, evolutionary distances between Thermus strains estimated by using PFGE restriction fragment length polymorphisms (PFGE-RFLPs) correlate well with those based on small-subunit rRNA sequence data. As a consequence, the phylogenetic trees constructed on the basis of PFGE-RFLPs and those constructed by using small-subunit rRNA sequences generally agree. On the basis of the evolutionary distances estimated by using PFGE-RFLPs, the estimated average genomic rate of divergence for Thermus spp. is approximately 0.27% per million years.

Previously, nine fecal isolates from wild birds and a domestic swine were identified as helicobacters by phenotypic characterization and reaction with a helicobacter genus-specific DNA probe. These isolates fell into three biotypes by analysis of phenotypic traits. To further characterize these isolates, full 16S rRNA sequences were determined for strains representing each biotype, and sequence comparison indicated that the strains represented three novel, phylogenetically defined Helicobacter species. Three 16S rRNA-based DNA probes were designed and used to identify the remaining strains. Probe reactivity divided the strains into the same three groups identified phenotypically. Six of the isolates represented a new species of the genus Helicobacter for which we propose the name Helicobacter pametensis sp. nov. The following phenotypic features distinguished H. pametensis from other Helicobacter and Campylobacter species: positive tests for oxidase, catalase, alkaline phosphatase, nitrate reduction, growth at 42°C, and growth in the presence of 1% glycine; negative tests for urease, gamma glutamyl transpeptidase, indoxyl acetate hydrolysis, and hippurate hydrolysis; and susceptibility to nalidixic acid and cephalothin. H. pametensis cells were motile and possessed one subterminal sheathed flagellum at each end. The two additional Helicobacter species were similar to H. pametensis except that they were urease positive, hydrolyzed indoxyl acetate, and were resistant to cephalothin. Because these two additional species are phenotypically similar and are represented by only two isolates for one species and one isolate for the other, they are not formally named but are referred to as Helicobacter sp. “Bird-B” and Helicobacter sp. “Bird-C.” These three new Helicobacter species can easily be confused with Campylobacter coli, Campylobacter lari, and Campylobacter jejuni if only a limited number of phenotypic traits are used for identification. Since it is now known that birds can harbor Helicobacter as well as Campylobacter species, methods which clearly distinguish these genera should be used to identify bird campylobacter-like isolates or bacterial strains traceable to bird fecal contamination. The zoonotic potential of these new Helicobacter species should be examined.

Fatty acid composition was assessed for 31 pathogenic and nonpathogenic strains phenotypically related to Streptomyces scabies and isolated in eastern Canada. The profiles of these strains consisted of 12 to 17 fatty acids, most of which were saturated iso and anteiso acids. The 31 strains were clustered into two groups within a Euclidian distance of 25. Members in the first group were characterized by the predominance in their profile of the 16:0 acid palmitate. The second group was split into two subgroups at a Euclidian distance of 12. The 15:0 anteiso acid was the predominant fatty acid in strains of the first subgroup. Three acids (15:0 iso, 15:0 anteiso, and 16:0), each representing about 20% of the total fatty acid profile, characterized strains of the second subgroup. The protein profiles of some of those strains were also compared, and the genetic relatedness among the strains was estimated by DNA-DNA hybridization. Hybridization values suggested that two genetically diverse groups of strains are included in S. scabies. No correlation was established between fatty acid profiles and genetic clusters. No distinctive characteristics were associated with pathogenic strains.

A strictly anaerobic, moderately halophilic, gram-negative bacterium was isolated from a highly saline oil field brine. The bacterium was a non-spore-forming, nonmotile rod, appearing singly, in pairs, or occasionally as long chains, and measured 0.3 to 0.4 by 2.6 to 4 μm. The bacterium had a specific requirement for NaCl and grew at NaCl concentrations of between 6 and 24%, with optimal growth at 9% NaCl. The isolate grew at temperatures of between 22 and 51°C and pH values of between 5.6 and 8.0. The doubling time in a complex medium containing 10% NaCl was 9 h. Growth was inhibited by chloramphenicol, tetracycline, and penicillin but not by cycloheximide or azide. Fermentable substrates were predominantly carbohydrates. The end products of glucose fermentation were acetate, ethanol, CO2, and H2. The major components of the cellular fatty acids were C14:0, C16:0, C16:1, and C17:0 cyc acids. The DNA base composition of the isolate was 34 mol% G+C. Oligonucleotide catalog and sequence analyses of the 16S rRNA showed that strain VS-752T was most closely related to Haloanaerobium praevalens GSLT (ATCC 33744), the sole member of the genus Haloanaerobium. We propose that strain VS-752 (ATCC 51327) be established as the type strain of a new species, Haloanaerobium salsugo, in the genus Haloanaerobium.

Previously published phylogenetic studies of 16S rRNA showed that methylotrophic, slightly halophilic, methanogenic strain GS-16T (T = type strain) represents a new species of bacterium. We propose the name Methanolobus taylorii for this species; strain GS-16 is the type strain.

Ruminai fluid which was enriched with trans-aconitate yielded a gram-negative diplococcus (strain AO) which was identified by 16S ribosomal DNA sequence analysis as Acidaminococcus fermentans. In contrast to the original description, the A. fermentans type strain and strain AO were found to utilize citrate as an energy source and to produce hydrogen and hydrogen sulfide. The descriptions of the genus and species are emended accordingly.

16S ribosomal DNA analysis indicates that Propionibacterium innocuum is a phylogenetic neighbor of Luteococcus japonicus and that this pair of organisms branches intermediately between the genus Propionibacterium on the one side and the genera Aeromicrobium and Nocardioides on the other side. Phenotypically, strains of P. innocuum differ from species of Propionibacterium by exhibiting aerobic growth and possessing arabinose in the cell wall, they differ from species of Aeromicrobium and Nocardioides by the formation of propionic acid, and they differ from species of Luteococcus in morphology. Consequently, P. innocuum should not be classified with authentic Propionibacterium species, and the transfer of P. innocuum Pitcher and Collins 1991 to a new genus, Propioniferax, as Propioniferax innocua gen. nov., comb. nov. is proposed.

16S rRNA gene sequencing studies were performed on Dermabacter hominis and four meso-diaminopimelic acid-containing species of the genus Brevibacterium. Phylogenetic analysis revealed a close association between Dermabacter hominis and representatives of the lysine-containing genera Arthrobacter, Micrococcus, and Renibacterium. By contrast, the genus Brevibacterium formed a distinct line of descent within the high-guanine- plus-cytosine-containing actinomycetes, displaying no specific affinity with any other organism examined.

The 16S rRNA gene sequences of Sarcina ventriculi DSM 286T (T = type strain) and Sarcina maxima DSM 316T were determined. Phylogenetic analysis revealed that these two species are closely related to each other and belong to group I Clostridium (sensu Johnson and Francis). The implications of these phylogenetic findings for future revision of the genus Clostridium are discussed.