PubMed Health⌕ Search

Biomedical subjects

E Falsen

Publications and source records attributed to E Falsen.

At least 19 recordsLinked to original sources
PubMed1996

Polyphasic approach to the classification and identification of Gardnerella vaginalis and unidentified Gardnerella vaginalis-like coryneforms present in bacterial vaginosis.

A taxonomic study of Gardnerella vaginalis and G. vaginalis-like coryneforms was performed in order to clarify the phylogenetic affiliation of these organisms and to improve future identification. We examined 50 strains by performing whole-cell protein and fatty acid analyses, a 16S rRNA sequence analysis, and an extensive phenotypic characterization analysis. The results of both chemotaxonomic techniques which we used divided the organisms into two main clusters, and the 16S rRNA sequence analysis revealed that the clusters represent different genera, which were easily distinguished by the results of classical phenotypic tests. The cluster I strains were identified as G. vaginalis, which was shown to be a close relative of the genus Bifidobacterium. An improved description of G. vaginalis is presented. The cluster II strains belong to or are closely related to Actinomyces turicensis.

Bacterial Proteins↗
PubMed1996

Taxonomic study of lancefield streptococcal groups C, G, and L (Streptococcus dysgalactiae) and proposal of S. dysgalactiae subsp. equisimilis subsp. nov.

Streptococcus dysgalactiae consists of at least five distinct subgroups on the basis of serogroups, biotypes, and hosts. A chemotaxonomic and phenotypic examination of 80 S. dysgalactiae strains representing the known diversity within this species and 49 reference strains representing all members of the streptococcal pyogenic species group revealed two subpopulations of strains within S. dysgalactiae. The name S. dysgalactiae subsp. dysgalactiae is proposed for strains of animal origin. These strains belong to Lancefield serogroups C and L, are alpha-, beta-, or nonhemolytic, and do not exhibit streptokinase activity on human plasminogen or proteolytic activity on human fibrin. The name S. dysgalactiae subsp. equisimilis is proposed for human isolates. These strains belong to Lancefield serogroups C and G, are beta-hemolytic, and exhibit streptokinase activity on human plasminogen and proteolytic activity on human fibrin.

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↗
PubMed1995

Cytotoxin production in 100 strains of Haemophilus ducreyi from different geographic locations.

One-hundred strains of Haemophilus ducreyi, representing isolates from different parts of the world, including the reference strains, were obtained from different collections and characterized with special reference to cytotoxin production in vitro. The cytotoxic activity on cultured epithelial cells (HEp-2) was examined with two methods. The activity in bacterial sonicates was tested on freshly trypsinated cells and strains manifesting little or no cytotoxic activity in sonicates were investigated using attached living bacteria on HEp-2 cell-monolayers. Sonicates from the majority of the H. ducreyi strains (89%) produced significant cytotoxic effects on HEp-2 cells. The reciprocal cytotoxic titers of the sonicates ranged from 2.4 x 10(2) to 5.3 x 10(5). Sonicates of 11 strains had low cytotoxic titers (< or = 1:3 to 1:81), eight of those originating from Asia and three from Africa. These 11 strains caused no damage to the cell monolayer, indicating that the 11 strains produce little or no cytotoxic activity in vitro. In summary, the majority of H. ducreyi isolates produce cytotoxic activity, which support the hypothesis that the cytotoxin may be an important virulence factor of this species.

Africa↗
PubMed1995

Development of a species-specific polymerase chain reaction assay for Gardnerella vaginalis.

The nucleotide sequence of the region between the 16S and 23S rRNA genes of the facultative anaerobic bacterium Gardnerella vaginalis has been determined, together with the 5' proximal 500 nucleotides of the 23S rRNA gene. Regions suited for the development of specific, probe-confirmable polymerase chain reaction (PCR) assays were selected. PCR assays were evaluated with respect to sensitivity and specificity, the latter in comparison with a number of G. vaginalis reference strains and closely related species like Bifidobacterium spp. In an initial diagnostic study it appeared that the PCR test detected G. vaginalis in 40% of women irrespective of their clinical status. Ten out of 11 patients suffering from bacterial vaginosis as defined on the basis of clinical parameters were carrying G. vaginalis.

Base Sequence↗
PubMed1995

Primary identification of Microbacterium spp. encountered in clinical specimens as CDC coryneform group A-4 and A-5 bacteria.

Over nearly two decades, 13 yellow- or orange-pigmented, fermentative gram-positive rods belonging to the genus Microbacterium were encountered in clinical specimens. All 13 strains, 10 of which came from blood cultures, were initially identified as CDC coryneform group A-4 and A-5 bacteria according to the scheme of Hollis and Weaver for the identification of gram-positive rods. The clinical isolates were compared with the type strains of the six species constituting the genus Microbacterium as well as with three Microbacterium strains isolated from hospital environments. By biochemical methods only 5 of 13 clinical isolates could be identified to species level. Peptidoglycan analysis proved to be a valuable tool for differentiation between Microbacterium spp. and related genera, whereas cellular fatty acid analysis did not allow species identification within the genus Microbacterium. The 22 Microbacterium strains studied were, in general, susceptible to antimicrobial agents used in the treatment of infections caused by gram-positive rods. This report is the first one concerning the isolation of Microbacterium strains from clinical specimens. The sources as well as the mode of transmission remain to be established.

Actinomycetales↗
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

Classification of Pseudomonas diminuta Leifson and Hugh 1954 and Pseudomonas vesicularis Büsing, Döll, and Freytag 1953 in Brevundimonas gen. nov. as Brevundimonas diminuta comb. nov. and Brevundimonas vesicularis comb. nov., respectively.

The taxonomic positions of strains previously assigned to Pseudomonas diminuta and Pseudomonas vesicularis were investigated by a polyphasic approach. The results of DNA-rRNA hybridization studies indicated that these two species belong to a separate genus in the alpha subclass (rRNA superfamily IV) of the Proteobacteria, for which the name Brevundimonas is proposed. Genus delineation and species delineation were determined by comparing the results of numerical analyses of whole-cell protein patterns, fatty acid compositions, and phenotypic characteristics and by measuring DNA base ratios and degrees of DNA relatedness. Taxonomic characteristics of Brevundimonas diminuta and Brevundimonas vesicularis strains were compared with characteristics of reference strains belonging to the following phylogenetically related taxa: a group of organisms gathered in Enevold Falsen group 21, the genera Sphingomonas and Rhizomonas, and the generically misclassified organisms [Pseudomonas] echinoides and "[Pseudomonas] riboflavina."

Animals↗
PubMed1993

Moraxella lincolnii sp. nov., isolated from the human respiratory tract, and reevaluation of the taxonomic position of Moraxella osloensis.

A polyphasic taxonomic study was performed to determine the relationships of 10 Moraxella-like strains isolated mainly from the human respiratory tract in Sweden. Two of the strains formed a separate subgroup on the basis of both their protein contents and their fatty acid contents. However, the overall protein and fatty acid profiles revealed that all 10 strains were highly related. Representative strains of the two subgroups exhibited high DNA binding values (98%) with each other and had an identical DNA base ratio (44 mol% G+C). DNA-rRNA hybridizations revealed that this taxon can be included in the genus Moraxella, which is only distantly related to phenotypically similar genera, such as the genera Neisseria and Kingella. The results of an extensive phenotypic analysis indicated that the general biochemical profile of the 10 strains conforms with the description of the genus Moraxella given in Bergey's Manual of Systematic Bacteriology. We therefore consider these organisms members of a new Moraxella species, for which the name Moraxella lincolnii is proposed. Furthermore, we also conclude that Moraxella osloensis belongs, genotypically as well as phenotypically, to the genus Moraxella.

Adult↗
PubMed1993

Neisseria weaveri sp. nov. (formerly CDC group M-5), from dog bite wounds of humans.

The taxonomic relationships of strains belonging to Centers for Disease Control group M-5 were examined. Previous studies of rRNA cistron similarities placed this organism on the Neisseriaceae rRNA branch of rRNA superfamily III; the closest neighbors included the genus Neisseria and groups EF-4a and EF-4b. The group M-5 strains were characterized by a range of phenotypic tests, and their G + C contents and DNA-DNA relatedness levels were determined. In addition, a numerical taxonomic analysis of the whole-cell protein patterns (obtained by sodium dodecyl sulfate-polyacrylamide gel electrophoresis) of group M-5 and related taxa was performed. The strains studied included 45 group M-5 strains, the type strains of six Neisseria species or subspecies, three group EF-4a reference strains, and three group EF-4b reference strains plus the type strain of the phenotypically similar organism Oligella urethralis. Our results showed that the group M-5 strains were members of a homogeneous taxon distinct from phylogenetically closely related taxa. The genomic divergence as revealed by levels of rRNA cistron similarity and phenotypic characteristics indicate that group M-5 can be considered a new species of the genus Neisseria. We therefore propose the new species Neisseria weaveri, with NCTC 12742 (= CCUG 4007 = ISL775/91 = LMG 5135) as the type strain. N. weaveri strains are strictly aerobic, gram-negative, nonmotile, rod-shaped organisms which are catalase and oxidase positive, nonsaccharolytic, and able to grow on MacConkey agar and do not reduce nitrate but generally reduce nitrite.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Specific binding of lactoferrin to Aeromonas hydrophila.

The interaction of lactoferrin (Lf) with Aeromonas hydrophila (n = 28) was tested in a 125I-labeled protein-binding assay. The mean per cent binding values for human Lf (HLf) and bovine Lf (BLf) were 13.4 +/- 2.0 (SEM), and 17.5 +/- 2.7 (SEM), respectively. The Lf binding was characterized in type strain A. hydrophila subsp. hydrophila CCUG 14551. The HLf and BLf binding reached a complete saturation within 2 h. Unlabeled HLf and BLf displaced 125I-HLf binding in a dose-dependent manner, and more effectively by the heterologous (1 microgram for 50% inhibition) than the homologous (10 micrograms for 50% inhibition) ligand. Apo- and holo-forms of HLf and BLf both inhibited more than 80%, while mucin caused approx. 50% inhibition of the HLf binding. Various other proteins (including transferrin) or carbohydrates did not block the binding. Two HLf-binding proteins with an estimated molecular masses of 40 kDa and 30 kDa were identified in a boiled-cell-envelope preparation, while the unboiled cell envelope demonstrated a short-ladder pattern at the top of the separating gel and a second band at approx. 60 kDa position. These data establish a specific interaction of Lf and the Lf-binding proteins seem to be porins in A. hydrophila.

Aeromonas hydrophila↗
PubMed1991

Revision of Campylobacter, Helicobacter, and Wolinella taxonomy: emendation of generic descriptions and proposal of Arcobacter gen. nov.

Hybridization experiments were carried out between DNAs from more than 70 strains of Campylobacter spp. and related taxa and either 3H-labeled 23S rRNAs from reference strains belonging to Campylobacter fetus, Campylobacter concisus, Campylobacter sputorum, Campylobacter coli, and Campylobacter nitrofigilis, an unnamed Campylobacter sp. strain, and a Wolinella succinogenes strain or 3H- or 14C-labeled 23S rRNAs from 13 gram-negative reference strains. An immunotyping analysis of 130 antigens versus 34 antisera of campylobacters and related taxa was also performed. We found that all of the named campylobacters and related taxa belong to the same phylogenetic group, which we name rRNA superfamily VI and which is far removed from the gram-negative bacteria allocated to the five rRNA superfamilies sensu De Ley. There is a high degree of heterogeneity within this rRNA superfamily. Organisms belonging to rRNA superfamily VI should be reclassified in several genera. We propose that the emended genus Campylobacter should be limited to Campylobacter fetus, Campylobacter hyointestinalis, Campylobacter concisus, Campylobacter mucosalis, Campylobacter sputorum, Campylobacter jejuni, Campylobacter coli, Campylobacter lari, and "Campylobacter upsaliensis." Wolinella curva and Wolinella recta are transferred to the genus Campylobacter as Campylobacter curvus comb. nov. and Campylobacter rectus comb. nov., respectively. Bacteroides gracilis and Bacteroides ureolyticus are generically misnamed and are closely related to the genus Campylobacter. Campylobacter nitrofigilis, Campylobacter cryaerophila, and an unnamed Campylobacter sp. strain constitute a new genus, for which the name Arcobacter is proposed; this genus contains two species, Arcobacter nitrofigilis comb. nov. (type species) and Arcobacter cryaerophilus comb. nov. Wolinella succinogenes so far is the only species of the genus Wolinella. The genus Helicobacter is also emended; Campylobacter cinaedi and Campylobacter fennelliae are included in this genus as Helicobacter cinaedi comb. nov. and Helicobacter fennelliae comb. nov., respectively. The genus "Flexispira," with "Flexispira rappini" as the only species, is closely related to the genus Helicobacter. The free-living, sulfur-reducing campylobacters do not belong to any of these genera; they probably constitute a distinct genus within rRNA superfamily VI.

Bacterial Typing Techniques↗
PubMed1990

Acidovorax, a new genus for Pseudomonas facilis, Pseudomonas delafieldii, E. Falsen (EF) group 13, EF group 16, and several clinical isolates, with the species Acidovorax facilis comb. nov., Acidovorax delafieldii comb. nov., and Acidovorax temperans sp. nov.

Pseudomonas facilis and Pseudomonas delafieldii are inappropriately assigned to the genus Pseudomonas. They belong to the acidovorans rRNA complex in rRNA superfamily III (i.e., the beta subclass of the Proteobacteria). The taxonomic relationships of both of these species, two groups of clinical isolates (E. Falsen [EF] group 13 and EF group 16), and several unidentified or presently misnamed strains were examined by using DNA:rRNA hybridization, numerical analyses of biochemical and auxanographic features and of fatty acid patterns, polyacrylamide gel electrophoresis of cellular proteins, and DNA:DNA hybridization. These organisms form a separate group within the acidovorans rRNA complex, and we propose to transfer them to a new genus, Acidovorax. We describe the following three species in this genus: the type species, Acidovorax facilis (formerly Pseudomonas facilis), with type strain LMG 2193 (= CCUG 2113 = ATCC 11228); Acidovorax delafieldii (for the former Pseudomonas delafieldii and most of the EF group 13 strains), with type strain LMG 5943 (= CCUG 1779 = ATCC 17505); and Acidovorax temperans (for several former Pseudomonas and Alcaligenes strains and most of the EF group 16 strains), with type strain CCUG 11779 (= LMG 7169).

Base Composition↗
PubMed1990

Identification of Campylobacter cinaedi isolated from blood and feces of children and adult females.

Five Campylobacter-like organisms isolated from blood and feces were identified by numerical analysis of gel electrophoretic protein profiles and immunotyping as Campylobacter cinaedi. Two of these strains were isolated from adult females; the remaining three strains were isolated from children, two of whom were girls. C. cinaedi has hitherto been isolated only from rectal swabs and blood of homosexual and bisexual males with gastrointestinal symptoms. The results presented extend our knowledge of the features and the habitat of C. cinaedi.

Adult↗
PubMed1989

Isolation of Francisella tularensis biovar palaearctica from human blood.

Francisella tularensis septicemia has previously been reported in the USA, where Francisella tularensis biovar tularensis (type A) occurs endemically. The present report describes two cases of septicemia caused by the Euro-Asian Francisella tularensis biovar palaearctica (type B). The patients lived in an endemic region of Sweden and presented with high fever and pneumonia. Both patients recovered. The ability of Francisella tularensis biovar palaearctica to cause bacteremia has consequences for laboratory safety.

Aged↗
PubMed1989

Microbial growth and accumulation in industrial metal-working fluids.

The dynamics of microbial growth in metal-working fluids (MWF) and the effect of the addition of biocides were studied in large fluid systems, in this case, one central tank which holds 150 m3. In this system, populations of Pseudomonas pseudoalcaligenes (greater than 10(8) CFU/ml) were sustained for a year, although large quantities of biocides were added. Quantitation of 3-OH lauric acid, a marker for many Pseudomonas spp., by gas chromatography indicated that the bacterial biomass exceeded the viable counts by approximately 15 times. Fungi were grown on several occasions, the dominating genera being Fusarium and Candida. Soon after the old MWF was removed and the tank was provided with fresh MWF, which consisted of an emulsion of mineral oil in water, there was a massive growth of P. pseudoalcaligenes that reached levels of greater than 10(8) bacteria per ml. Initially, only low concentrations of other species were found for some weeks. After this period, different enterobacteria and other gram-negative rods often appeared at high concentrations (10(7) and 10(8) bacteria per ml, respectively). Bacteria identified as P. pseudoalcaligenes showed great variation with respect to colony morphology and a certain heterogeneity with respect to biochemical characteristics. Certain bacterial species grew as microcolonies on metal strips immersed in the circulating MWF, but P. pseudoalcaligenes was not recovered from this habitat. The total bacterial count in the air surrounding the machines in the metal-working shop showed an inverse relation to increasing distance from the machine. The concentration of bacteria in the air varied because of the number of machines in use, temperature, and humidity.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Microbiology↗