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K Kersters

Publications and source records attributed to K Kersters.

At least 55 records · Page 3Linked to original sources
PubMed1996

Polyphasic analysis of strains of the genus Capnocytophaga and Centers for Disease Control group DF-3.

A polyphasic approach was used to determine the relationships between well-characterized reference strains representing all seven Capnocytophaga species. One Centers for Disease Control (CDC) group DF-3 strain, a presumed relative of the genus Capnocytophaga, and 15 field isolates were included as well. Fourteen isolates were assigned to named Capnocytophaga species, all of which could be differentiated by means of whole-organism protein electrophoresis. A separate position was occupied by the CDC group DF-3 strain and by one field isolate representing a novel Capnocytophaga species. The phylogenetic position of each taxon was determined by means of 16S rRNA sequence analysis. A considerable genotypic heterogeneity within the genus Capnocytophaga was detected in spite of the minimal phenotypic differences. Comparative 16S rRNA sequence analysis revealed that CDC group DF-3 is not a close relative of the capnocytophagas but constitutes a separate genus that clusters together with Bacteroides forsythus and Bacteroides distasonis, two generically misclassified Bacteroides species. The degree of protein similarity correlated with our and published DNA-DNA binding values. Percentage 16S rRNA similarity values of greater than 97% did not guarantee conspecificity. All Capnocytophaga strains had very similar fatty acid contents characterized by significant amounts of 14:0, 15:0 iso (greater than 55%), 16:0, 16:0 3OH, and 17:0 iso 3OH. PCR-mediated DNA fingerprinting allowed discrimination of most species, although some strains could not be classified efficiently because of DNA polymorphisms.

Animals↗
PubMed1996

Emended description of Herbaspirillum; inclusion of [Pseudomonas] rubrisubalbicans, a milk plant pathogen, as Herbaspirillum rubrisubalbicans comb. nov.; and classification of a group of clinical isolates (EF group 1) as Herbaspirillum species 3.

[Pseudomonas] rubrisubalbicans, a mild plant pathogen. Herbaspirillum seropedicae, and EF group 1 strains (clustered by an immunological method) were investigated by a polyphasic approach with DNA-rRNA and DNA-DNA hybridizations and auxanography on 147 substrates. Our results show that they all belong to the genus Herbaspirillum. In addition to H. seropedicae, two other species are described: Herbaspirillum rubrisubalbicans and a new unnamed species, Herbaspirillum species 3, containing mainly strains of clinical origin. The three species can be differentiated on the basis of their auxanographic features and DNA-DNA similarities. The type strain of H. rubrisubalbicans is NCPPB 1027 (=LMG 2286); representative strains of the third Herbaspirillum species are strains CCUG 189 (=LMG 5523), CCUG 10263 (=LMG 5934), and CCUG 11060 (=LMG 5321). It has been confirmed that H. rubrisubalbicans is an endophytic diazotroph. It colonizes the roots, the stems, and predominantly the leaves of sugarcane (Saccharum spp.), while Herbaspirillum seropedicae colonizes in large numbers many different species of the Gramineae. Both diazotrophic Herbaspirillum species could be differentiated with meso-erythritol and N-acetylglucosamine. Oligonucleotide probes based on partial sequences of the 23S rRNA of H. seropedicae and H. rubrisubalbicans (HS and HR probes, respectively), were constructed and used as diagnostic probes.

Base Sequence↗
PubMed1996

Bordetella trematum sp. nov., isolated from wounds and ear infections in humans, and reassessment of Alcaligenes denitrificans Rüger and Tan 1983.

Ten strains recognized on the basis of a computer-assisted numerical comparison of whole-cell protein patterns as members of a novel species belonging to the family Alcaligenaceae were examined by using an integrated phenotypic and genotypic approach. This species, for which we propose the name Bordetella trematum sp. nov., was more closely related to the type species of the genus Bordetella (Bordetella pertussis) than to the type species of the genus Alcaligenes (Alcaligenes faecalis) and had the general characteristics of members of this family (i.e., a DNA base ratio in the range from 57 to 70 mol%, a fatty acid profile characterized by high percentages of 16:0, 17:0 cyclo, and 14:0 3OH, nonsaccharolytic metabolism, and several classical biochemical characteristics, including aerobic and microaerobic growth, catalase activity, assimilation of citrate, an absence of anaerobic growth, and an absence of acetylmethylcarbinol and indole production, gelatin liquefaction, and esculin hydrolysis). A reevaluation of the criteria used to classify Alcaligenes denitrificans Rüger and Tan 1983 and Achromobacter xylosoxidans Yabuuchi and Ohyama 1971 as subspecies of Alcaligenes xylosoxidans and additional evidence provided in recent studies revealed that, consistent with present standards, it is appropriate to consider these two taxa distinct species of the genus Alcaligenes.

Alcaligenes↗
PubMed1996

A polyphasic reassessment of the genus Paenibacillus, reclassification of Bacillus lautus (Nakamura 1984) as Paenibacillus lautus comb. nov. and of Bacillus peoriae (Montefusco et al. 1993) as Paenibacillus peoriae comb. nov., and emended descriptions of P. lautus and of P. peoriae.

Seventy-seven strains representing 10 species in the Paenibacillus polymyxa 16S rRNA group and 3 other species that exhibit phenetic relatedness to members of this group, Bacillus lautus, "Bacillus longisporus," and Bacillus peoriae, were characterized genotypically and phenotypically by performing an amplified ribosomal DNA restriction analysis, a randomly amplified polymorphic DNA analysis, a fatty acid methyl ester analysis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell proteins, pyrolysis mass spectrometry, and API and other routine phenotypic tests. These analyses revealed distinct clusters representing Paenibacillus alvei, Paenibacillus amylolyticus, Paenibacillus azotofixans, Paenibacillus durum, Paenibacillus larvae subsp. larvae, Paenibacillus larvae subsp. pulvifaciens, B. lautus, Paenibacillus macerans, Paenibacillus macquariensis, B. peoriae, P. polymyxa, and Paenibacillus validus, which confirmed the distinctness of these species, but appreciable within-species heterogeneity was observed in P. alvei, B. lautus, P. macerans, P. polymyxa, and P. validus. The type strain of Paenibacillus pabuli did not cluster with other strains of this species, and in several analyses a relationship between strains of P. pabuli and "B. longisporus" was observed. As the analyses showed that B. lautus and B. peoriae are closely related to the genus Paenibacillus, these species are reclassified as members of this genus.

Bacillus↗
PubMed1996

The presence of two S-layer-protein-encoding genes is conserved among species related to Lactobacillus acidophilus.

Previously we have shown that the type strain of Lactobacillus acidophilus possesses two S-protein-encoding genes, one of which is silent, on a chromosomal segment of 6 kb. The S-protein-encoding gene in the expression site can be exchanged for the silent S-protein-encoding gene by inversion of this slp segment. In this study the presence of S-protein and corresponding S-protein-encoding genes of strains belonging to species that are closely related to L. acidophilus was determined. All strains investigated were identified by numerical comparison of highly standardized one-dimensional SDS-PAGE whole-cellular-protein patterns. Western blot and Southern blot methods were used to identify the presence of, and homology between, S-proteins and S-protein-encoding genes. From these analyses we conclude that strains of L. acidophilus, L. crispatus, L. amylovorus and L. gallinarum possess an S-layer and contain two slp genes. Strains of L. helveticus possess an S-layer but have only one intact slp gene. Strains of L. gasseri, L. johnsonii and L. delbrueckii subsp. bulgaricus have neither an S-layer nor S-protein-encoding genes hybridizing with probes derived from the L. acidophilus slpA or slpB region. The presence of a highly conserved 5' region in the slp genes of strains of L. acidophilus, L. crispatus, L. amylovorus and L. gallinarum suggests that S-layer variation is a common feature for strains of these species.

Bacterial Proteins↗
PubMed1996

Evaluation of the DNA fingerprinting method AFLP as an new tool in bacterial taxonomy.

We investigated the usefulness of a novel DNA fingerprinting technique, AFLP, which is based on the selective amplification of genomic restriction fragments by PCR, to differentiate bacterial strains at the subgeneric level. In totals, 147 bacterial strains were subjected to AFLP fingerprinting: 36 Xanthomonas strains, including 23 pathovars of Xanthomonas axonopodis and six pathovars of Xanthomonas vasicola, one strain of Stenotrophomonas, 90 genotypically characterized strains comprising all 14 hybridization groups currently described in the genus Aeromonas, and four strains of each of the genera Clostridium, Bacillus, Acinetobacter, Pseudomonas and Vibrio. Depending on the genus, total genomic DNA of each bacterium was digested with a particular combination of two restriction endonucleases and the resulting fragments were ligated to restriction halfsite-specific adaptors. These adaptors served as primer-binding sites allowing the fragments to be amplified by selective PCR primers that extend beyond the adaptor and restriction site sequences. Following electrophoretic separation on 5% (w/v) polyacrylamide/8.3 M urea, amplified products could be visualized by autoradiography because one of the selective primers was radioactively labelled. The resulting banding patterns, containing approximately 30-50 visualized PCR products in the size range 80-550 bp, were captured by a high-resolution densitoscanner and further processed for computer-assisted analysis to determine band-based similarity coefficients. This study reveals extensive evidence for the applicability of AFLP in bacterial taxonomy through comparison of the newly obtained data with results previously obtained by well-established genotypic and chemotaxonomic methods such as DNA-DNA hybridization and cellular fatty acid analysis. In addition, this study clearly demonstrates the superior discriminative power of AFLP towards the differentiation of highly related bacterial strains that belong to the same species or even biovar (i.e. to characterize strains at the infrasubspecific level), highlighting the potential of this novel fingerprinting method in epidemiological and evolutionary studies.

Acinetobacter↗
PubMed1996

Survival potential of Aeromonas hydrophila in freshwaters and nutrient-poor waters in comparison with other bacteria.

The survival of a genetically-marked Aeromonas hydrophila strain was studied in water microcosms using viable counts. Aeromonas hydrophila AWWX1 was shown to survive without decline in viable counts for at least 10 d in three of four filtered-autoclaved freshwaters (surface water and groundwater) and in all examined filtered-autoclaved nutrient-poor waters (bottled spring water, Milli-Q and tap water). However, in the unfiltered waters, a rapid decrease in viable counts of Aer. hydrophila AWWX1 was observed after 1-5 d. The survival of Aer. hydrophila AWWX1 in nutrient-poor waters was compared with that of Pseudomonas fluorescens P17 and Spirillum strain NOX. Survival characteristics were organism- and water-dependent. In the filtered-autoclaved waters, viable counts of Spirillum strain NOX were ca 1 log-unit higher than for Aer. hydrophila AWWX1 and Ps. fluorescens P17. The tested strains Aer. hydrophila AWWX1 and Ps. fluorescens P17 survived 3 to 20, respectively 2 to 4 times better in the filtered-autoclaved waters compared to the unfiltered waters. Apparently, any inherent capability of these micro-organisms to adapt to low-nutrient environments was undone by the presence of the autochthonous microbiota. The present findings that Aer. hydrophila survives very poorly in several drinking waters is of utmost importance towards public health and arises questions about the mechanisms involved.

Aeromonas hydrophila↗
PubMed1996

Acidification of methyl-alpha-D-glucopyranoside: a useful test to differentiate Enterococcus casseliflavus and Enterococcus gallinarum from Enterococcus faecium species group and from Enterococcus faecalis.

Enterococcus gallinarum and E. casseliflavus are difficult to differentiate from other enterococci, particularly E.faecium. The former two species were found to produce acid from methyl-alpha-D-glucopyranoside in phenol red broth, while E.faecalis strains and strains of the E.faecium species group, including E.faecium, E.durans, E. hirae, and E.mundtii, failed to produce acid from this substrate.

Bacterial Typing Techniques↗
PubMed1996

Polyphasic taxonomy, a consensus approach to bacterial systematics.

Over the last 25 years, a much broader range of taxonomic studies of bacteria has gradually replaced the former reliance upon morphological, physiological, and biochemical characterization. This polyphasic taxonomy takes into account all available phenotypic and genotypic data and integrates them in a consensus type of classification, framed in a general phylogeny derived from 16S rRNA sequence analysis. In some cases, the consensus classification is a compromise containing a minimum of contradictions. It is thought that the more parameters that will become available in the future, the more polyphasic classification will gain stability. In this review, the practice of polyphasic taxonomy is discussed for four groups of bacteria chosen for their relevance, complexity, or both: the genera Xanthomonas and Campylobacter, the lactic acid bacteria, and the family Comamonadaceae. An evaluation of our present insights, the conclusions derived from it, and the perspectives of polyphasic taxonomy are discussed, emphasizing the keystone role of the species. Taxonomists did not succeed in standardizing species delimitation by using percent DNA hybridization values. Together with the absence of another "gold standard" for species definition, this has an enormous repercussion on bacterial taxonomy. This problem is faced in polyphasic taxonomy, which does not depend on a theory, a hypothesis, or a set of rules, presenting a pragmatic approach to a consensus type of taxonomy, integrating all available data maximally. In the future, polyphasic taxonomy will have to cope with (i) enormous amounts of data, (ii) large numbers of strains, and (iii) data fusion (data aggregation), which will demand efficient and centralized data storage. In the future, taxonomic studies will require collaborative efforts by specialized laboratories even more than now is the case. Whether these future developments will guarantee a more stable consensus classification remains an open question.

Amino Acid Sequence↗
PubMed1995

Identification of Enterococcus species isolated from foods of animal origin.

Enterococci isolated from a large variety of fresh and prepared foods of animal origin during routine microbiologic control tests in a distribution firm, were identified to species level using API 20 STREP galleries supplemented with conventional tests, rapid ID32 STREP galleries and SDS-PAGE analysis. API 20 STREP tests correctly identified 77% of the strains, mainly Enterococcus faecium and E. faecalis. A simple presumptive identification scheme based on pigmentation, tetrazolium reduction and acid production from mannitol and raffinose identified 90% of the strains. More complex procedures were necessary to identify the remaining strains. Nearly all strains isolated from hard cheeses and prepared cheese-meat combinations were identified as E. faecium while E. faecalis was the most frequent species in crustaceans. In meat and in prepared meat products E. faecium, E. faecalis and less frequently E. hirae/E. durans were found. Three of four E. gallinarum strains were isolated from products containing turkey meat.

Animals↗
PubMed1995

Chemotaxonomic analyses of Bacteroides gracilis and Bacteroides ureolyticus and reclassification of B. gracilis as Campylobacter gracilis comb. nov.

The cellular fatty acids, respiratory quinones, and proteins of the generically misnamed taxa Bacteroides gracilis and Bacteroides ureolyticus were analyzed and compared with the corresponding chemotaxonomic features of their closest relatives, the campylobacters. Our results and previously published data for genotypic and phenotypic characteristics were used in a polyphasic approach to reconsider the classification of these organisms. We transfer B. gracilis to the genus Campylobacter as Campylobacter gracilis comb. nov. B. ureolyticus can be considered a campylobacter on genotypic grounds; in contrast, the proteolytic metabolism and fatty acid components of this taxon exclude it from the genus Campylobacter. We prefer to consider this taxon a species incertae sedis pending the isolation and characterization of additional B. ureolyticus-like bacteria.

Bacterial Proteins↗
PubMed1995

Bordetella hinzii sp. nov., isolated from poultry and humans.

A polyphasic taxonomic study that included DNA-rRNA hybridizations, DNA-DNA hybridizations, DNA base ratio determinations, whole-cell protein and fatty acid analyses, and an examination of classical phenotypic characteristics was performed in order to classify human and veterinary isolates that resemble Bordetella avium. Twelve poultry isolates and two human isolates were assigned to a new species, for which we propose the name Bordetella hinzii. The position of this organism in the family Alcaligenaceae and various genotypic, phenotypic, and chemotaxonomic characteristics are described.

Animals↗
PubMed1995

Paenibacillus (formerly Bacillus) gordonae (Pichinoty et al. 1986) Ash et al. 1994 is a later subjective synonym of Paenibacillus (formerly Bacillus) validus (Nakamura 1984) Ash et al. 1994: emended description of P. validus.

A polyphasic study in which we performed an amplified ribosomal DNA restriction analysis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell proteins, a gas chromatographic analysis of methylated fatty acids, pyrolysis mass spectrometry, a random amplified polymorphic DNA analysis, a phenotypic analysis, and an analysis of the levels of DNA binding of Paenibacillus gordonae and Paenibacillus validus strains (including both type strains) showed that these organisms form a homogeneous group and that the names P. gordonae and P. validus are therefore synonyms. P. validus has nomenclatural priority, and an emended description of this species is given; the type strain is strain LMG 11161 (= ATCC 43897).

Bacillus↗
PubMed1995

Diversity of Aeromonas sp. in Flemish drinking water production plants as determined by gas-liquid chromatographic analysis of cellular fatty acid methyl esters (FAMEs).

Gas-liquid chromatography of cellular fatty acid methyl esters (FAMEs) was used to determine the phenotypic and genotypic diversity among 489 presumptive Aeromonas strains isolated from five Flemish drinking water production plants. FAME profiles were compared with the predetermined library profiles of a representative database, AER48C, which contains the mean FAME data of all 14 currently established hybridization groups (HGs) or genospecies within Aeromonas. Using AER48C, more than 93% (457 strains) of all presumptive aeromonads isolated on ampicillin-dextrin agar were unequivocally identified as belonging to this genus. Moreover, 85.5% and 73.5% of these strains could be assigned to a particular phenospecies or HG, respectively. Raw and treated surface water samples were dominated by members of the Aer. hydrophila complex (38.8%, comprising HGs 1-3), followed by the Aer. caviae complex (22.7%, comprising HGs 4-6) and the Aer. sobria complex (16.7%, comprising HGs 7-9). HGs 3, 5A/B and 8 were the most prominent genospecies in this type of water. On the other hand, it was found that raw and treated phreatic groundwater samples displayed a much more limited species diversity since these were almost entirely dominated (95.8%) by strains belonging to HGs 2 and 3 of the Aer. hydrophila complex. In general, flocculation-decantation and sand filtration were not shown to influence the overall species distribution in any of the plants examined.

Aeromonas↗
PubMed1994

Ornithobacterium rhinotracheale gen. nov., sp. nov., isolated from the avian respiratory tract.

The phylogenetic position and various genotypic, chemotaxonomic, and classical phenotypic characteristics of 21 gram-negative avian isolates were studied. These strains constitute a genotypically homogeneous taxon in rRNA superfamily V, as shown by DNA-rRNA hybridization data. Determination of the 16S rRNA sequence of this taxon revealed its detailed position within the "flavobacter" subgroup of the "flavobacter-bacteroides" phylum as described by Gherna and Woese (R. Gherna and C. R. Woese, Syst. Appl. Microbiol. 15:513-521, 1992). This new taxon is only distantly related to other members of the "flavobacter-bacteroides" phylum and is therefore given separate generic status. The DNA-DNA binding values for members of this taxon, for which we propose the name Ornithobacterium rhinotracheale, confirmed that all of the strains are highly interrelated (DNA-DNA binding values greater than 90% were measured). The G+C contents of members of this taxon are between 37 and 39 mol%. An analysis of the cellular proteins and fatty acids and classical phenotypic characteristics allowed us to distinguish O. rhinotracheale from phenotypically similar taxa, such as Riemerella anatipestifer and Capnocytophaga species. The respiratory quinone content (menaquinone 7) and carbohydrate pattern of O. rhinotracheale conform with the respiratory quinone contents and carbohydrate patterns of other members of rRNA superfamily V.

Animals↗
PubMed1994

Identification of lactobacilli from sourdough and description of Lactobacillus pontis sp. nov.

The microflora of sourdough preparations was investigated by examining the physiological characteristics, whole-cell protein patterns, and 16S rRNA sequences of Lactobacillus isolates. Strains isolated from sourdough were placed in the species Lactobacillus brevis, Lactobacillus sanfrancisco, and Lactobacillus reuteri. 16S rRNA sequences were determined for L. brevis, Lactobacillus fructivorans, Lactobacillus fermentum, L. sanfrancisco, and L. reuteri, and oligonucleotide probes for fast specific identification of these sourdough lactobacilli were deduced. The physiological characteristics, protein patterns, and 16S rRNA sequences of these organisms were compared with data for other sourdough lactobacilli and additional reference strains. Strains of a Lactobacillus species were isolated from rye sourdough; these strains may account for most of the flora in sourdough made from wheat or rye. These organisms were differentiated from other sourdough lactobacilli by their protein pattern, 16S rRNA sequence, G + C content, and physiological properties. The 16S rRNA sequence of this species was determined, and we constructed a phylogenetic tree which reflected the relationships of this species to other lactobacilli. This organism is closely related to L. reuteri. A new Lactobacillus species, Lactobacillus pontis, is proposed. The type strain is L. pontis LTH 2587 (= DSM 8475 = LMG 14187). We describe a general strategy in which a polyphasic approach was used to characterize a new species.

Bacterial Proteins↗
PubMed1994

Phenotypic and genotypic characterization of bradyrhizobia nodulating the leguminous tree Acacia albida.

Rhizobial isolates that were obtained from both surface and deep soil samples in the Sahelian and Sudano-Guinean areas of Senegal (West Africa) under Acacia albida trees were compared with representative strains of known rhizobial species and genera. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of proteins was used to determine the taxonomic positions of these organisms and the relationships between isolates obtained from the surface and isolates obtained from deep soil. Most of the isolates belonged to eight electrophoretic clusters containing representative strains of Bradyrhizobium japonicum, Bradyrhizobium elkanii, and Bradyrhizobium sp. Isolates were also characterized by the Biolog system, and the results were compared with the results obtained by SDS-PAGE of total proteins; the level of correlation was very low. DNA-rRNA hybridizations with 16S or 23S rRNA from Bradyrhizobium japonicum LMG 6138T (T = type strain) confirmed that most of the protein electrophoretic clusters belong in the Bradyrhizobium-Rhodopseudomonas rRNA complex. Sequencing of 16S rRNA genes showed that some of the A. albida-nodulating isolates belong to a separate lineage together with representatives of other protein electrophoretic clusters. Other isolates that belong to the same electrophoretic cluster as the type strain of Bradyrhizobium japonicum are considered members of the lineage represented by this type strain. The first lineage is as far removed from Bradyrhizobium japonicum as it is from the genus Afipia, Blastobacter denitrificans, and the genus Rhodopseudomonas. The possible relationship among electrophoretic group, geographic origin, and depth of isolation at a particular site is discussed.

Acacia↗