Clostridium barkeri sp. n

Clostridium barkeri sp. n. has been described, and its relationship to other clostridia is discussed.     

艰难梭菌的研究进展

艰难梭菌为革兰阳性厌氧芽胞杆菌,可引起艰难梭菌相关性腹泻,导致一系列肠道感染症状和相关临床表现。近年来由于高致病株的出现、菌株耐药性的增加,艰难梭菌感染在全球呈蔓延趋势。本文就艰难梭菌的耐药机制、检测技术、防治及国内感染现状等作一简要综述。     

Presence of Cytochrome and Menaquinone in Clostridium formicoaceticum and Clostridium thermoaceticum

Cytochrome b and menaquinone have been demonstrated in the homoacetate-fermenting Clostridium formicoaceticum and Clostridium thermoaceticum.     

Phylogenetic basis for a taxonomic dissection of the genus Clostridium

The 16S rDNA-based phylogenetic analysis of the genus Clostridium has been completed by determination of the phylogenetic position of the type strains of 15 species and two non-validated species. These strains are members of phylogenetic clusters I, III, IV, V, IX, XIVa and XVIII as defined previously by Collins et al. [Int. J. Syst. Bacteriol. 44 (1994) 812-826]. Members of the genus Clostridium span a large evolutionary distance and the genus is not a phylogenetically coherent taxon but is intermixed with members of different genera, exhibiting a combination of Clostridium- and non-Clostridium-type properties. Anaerobacter polyendosporus, Syntrophococcus sucromutans and Acetivibrio multivorans also cluster within the radiation of Clostridium species. Although several taxa have been described for former Clostridium species with distinct phenotypic properties, the majority of Clostridium species, which are not members of the core cluster I, can at present not be reclassified as long as taxon-specific, phenotypic properties are not available.     

Multiplex PCR for rapid differentiation of three species in the "Clostridium clostridioforme group"

Clostridium clostridioforme is a relatively antimicrobial resistant, phenotypically heterogeneous anaerobe that has been involved in a variety of infections. 16S rDNA sequencing analysis revealed three principal species in what has been called Clostridium clostridioforme - Clostridium bolteae, C. clostridioforme, and Clostridium hathewayi. Based on the 16S rDNA sequence information we obtained, we developed a cost-effective, timesaving one-step multiplex PCR assay for rapid and accurate differentiation of these three species. The established multiplex PCR identification scheme was applied to the identification of 88 clinical isolates that had previously been identified phenotypically as C. clostridioforme. The identification obtained from multiplex PCR assays showed 100% agreement with 16S rDNA sequencing identification. This scheme will permit more accurate assessment of the role of these three Clostridium species in infection and of the degree of antimicrobial resistance in each of the species.     

Regeneration of protoplasts of Clostridium pasteurianum ATCC 6013

A procedure has been developed for the regeneration of Clostridium pasteurianum protoplasts with frequencies of up to 10% reversion being obtained.     

Genome sequence of the anaerobic bacterium Clostridium arbusti SL206(T)

A new Clostridium species has been isolated from pear orchard soil in Daejeon, Republic of Korea. The isolate, Clostridium arbusti SL206(T) (KCTC 5449(T)), showed a nitrogenase activity as well as an organic acid production. Here we first report the draft genome sequence of a novel species in the genus Clostridium within the largest Gram-positive group.     

Draft genome sequence of the nontoxigenic Clostridium difficile strain CD37

Here we report the draft genome sequence of Clostridium difficile strain CD37, the first nontoxigenic strain sequenced. Every sequenced strain of Clostridium difficile has been shown to contain multiple different mobile genetic elements. The draft genome sequence of strain CD37 reveals the presence of two putative conjugative transposons.     

A new nitrogen-fixing Clostridium species from a high Arctic ecosystem.

A hitherto undescribed species of yellow-pigmented, Gram-negative Clostridium sp., possessing nitrogenase activity, has been isolated from a number of sampling sites on the Truelove Lowland of Devon Island in the Canadian high Arctic. This bacterium, tentatively designated Clostridium arcticum sp. nov., accounted for 19% of all isolates recovered which were capable of anaerobic nitrogen fixation.     

Differentiation of the main species of Clostridium by gas chromatography

For the first time in the USSR the properties of microorganisms of the genus Clostridium have been studied with the use of the gas-chromatographic techniques. The analysis of the quantitative and qualitative composition of extracellular alcohols and carboxylic acids in 99 museum and newly isolated strains of 18 Clostridium species has made it possible to classify these microorganisms with 7 sharply differing groups. The above techniques permit the classification of clostridia with one of the groups within 2 hours if the microbial cultures have been grown in glucose-containing peptone yeast medium.     

Biohydrogenation of linoleic acid by Clostridium sporogenes, Clostridium bifermentans, Clostridium sordellii and Bacteroides sp.

Abstract Several strains of Clostridium bifermentans, Clostridium sporogenes and Clostridium sordellit and one strain of Bacteroides sp. hydrogenate linoleic acid into transvaccenic acid in vitro following the same pathway. Linoleic acid (18:2; 9- cis , 12- cis ) was first isomerised into 9- cis , 11- trans -octadecadienoic acid, after which the 9- cis double bond was reduced. These species also hydrogenated linoleic acid into an octadecenoic acid in vivo when mono-associated with gnotobiotic rats. Several other species of Clostridium and Bacteroides did not hydrogenate linoleic acid.     

Clostridium difficile electrophoretic typing

Abstract Two typing schemes for Clostridium difficile based on slide agglutinations and polyacrylamide gel electrophoresis (PAGE) have been described. We compared the reference strains of each typing system with a simplified PAGE method using whole cells and Coomassie blue staining. The method was also applied to clinical isolates and immunoblots were performed with a monospecific serum directed against a major band of low molecular weight. The results indicated the great heterogeneity of Clostridium difficile strains complicated by antigenic subdivision for strains belonging to the same electrophoretic type.     

Photoreactivating capacity in Clostridium butyricum and Clostridium acetobutylicum

No difference in survival was observed when u.v.-irradiated clostridial cells were subsequently incubated in the dark or exposed to photoreactivating light. This suggests that photoreactivation does not occur in Clostridium butyricum and in Clostridium acetohutylicum.     

Growth of Clostridium tertium and Clostridium septicum in chemically defined media.

Defined media for the growth of Clostridium tertium and Clostridium septicum are described. The requirements for growth of these two species are compared with each other and with those of Clostridium perfringens.     

Isolation of uroporphyrin III from Clostridium thermoaceticum

$\text{Clostridium thermoaceticum}$ contains a porphyrin which, based on visible absorption and ¹H nmr spectra as well as on chromatographic behavior, has been identified as uroporphyrin III.     

Rapid protocol for electroporation of Clostridium perfringens

A rapid and simple method has been developed for the electroporation of Clostridium perfringens with plasmid DNA. The new improvements, harvesting cells early in the logarithmic stage of growth, keeping the cells at room temperature and the absence of post-shock incubation on ice increased transformation efficiency by one order of magnitude.     

Antibiotics and Clostridium difficile

Clostridium difficile is now established as a major nosocomial pathogen. C. difficile infection is seen almost exclusively as a complication of antibiotic therapy, and is particularly associated with clindamycin and third-generation cephalosporins. Depletion of the indigenous gut microflora by antibiotic therapy has long been established as a major factor in the disease. However, the direct influence of antimicrobials upon virulence mechanisms such as toxin production and adhesion in the bowel, and the exact mechanisms by which the organism causes disease remain to be elucidated.     

Growth of Clostridium tertium and Clostridium septicum in Chemically Defined Media

Defined media for the growth of Clostridium tertium and Clostridium septicum are described. The requirements for growth of these two species are compared with each other and with those of Clostridium perfringens.     

Molecular genetics and the initiation of solventogenesis in Clostridium beijerinckii (formerly Clostridium acetobutylicum) NCIMB 8052

Abstract: A physical map of the Clostridium beijerinckii (formerly Clostridium acetobutylicum ) NCIMB 8052 chromosome has been constructed, encompassing about 90 rare restriction sites. The 14 rrn operons together with 40 genes have been assigned positions on the map. Genetic analysis and gene transfer have been developed in this organism to enable in vivo analysis of the roles of cloned genes using marker replacement technology. Experiments using the available genetic tools have shown that spo0A plays a cardinal role in controlling several aspects of the transition from exponential growth to stationary phase in C. beijerinckii . These include initiation of sporulation, accumulation of the storage polysaccharide, granulose, and production of acetone and butanol. Several C. beijerinckii and C. acetobutylicum genes concerned with fermentative metabolism, whose expression is modulated at the onset of solventogenesis, contain sequence motifs resembling 0A boxes in their 5' regulatory regions. This invites the speculation that they are under direct control of Spo0A, and additional data are now required to test this prediction.