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Andreas Roggenkamp - One of the best experts on this subject based on the ideXlab platform.

  • Description of Enterobacter ludwigii sp. nov., a novel Enterobacter species of clinical relevance
    Systematic and Applied Microbiology, 2005
    Co-Authors: Harald Hoffmann, Sibylle Stindl, Anita Stumpf, André Mehlen, Daniel Monget, Jürgen Heesemann, Karl H. Schleifer, Andreas Roggenkamp
    Abstract:

    Abstract A new species, Enterobacter ludwigii, is presented on the basis of the characteristics of 16 strains, which were isolated from clinical specimens. These bacteria form a distinct genetic cluster in phylogenetic analyses of the population structure of the Enterobacter cloacae complex. As determined by DNA–DNA cross-hybridization experiments in microplates, this genetic cluster can be delineated from the other species of the E. cloacae complex with Δ T m values equal to or above 5 °C with Enterobacter hormaechei being the closest relative. The bacteria are gram-negative, fermentative, motile rods with the general characteristics of the genus Enterobacter and the E. cloacae complex in particular. E. ludwigii can be differentiated from the other Enterobacter species by its growth on myo-inositol and 3-0-methyl- d -glucopyranose. The type strain is EN-119 (=DSM 16688T=CIP 108491T).

  • Reassignment of Enterobacter dissolvens to Enterobacter cloacae as E. cloacae subspecies dissolvens comb. nov. and emended description of Enterobacter asburiae and Enterobacter kobei.
    Systematic and Applied Microbiology, 2005
    Co-Authors: Harald Hoffmann, Sibylle Stindl, Anita Stumpf, André Mehlen, Daniel Monget, Jürgen Heesemann, Karl H. Schleifer, Wolfgang Ludwig, Andreas Roggenkamp
    Abstract:

    Abstract The taxonomic position of Enterobacter dissolvens was re-evaluated based on the analysis of the type strain ATCC 23373 T and three clinical isolates. The strains were assigned to the genetic cluster of the species by phylogenetic sequence analysis in the frame of a recent population genetic study. The relatedness of E. dissolves to the other species of the E. cloacae complex was analyzed by DNA–DNA hybridization studies based on melting profiles in microplates. The genetic cluster of E. dissolvens fell into the same DNA-relatedness group like E. cloacae with mean Δ T m -values of 3.9 °C confirming the hybridization results of three former studies. Phenotypic analysis of the E. cloacae and E. dissolvens strains, respectively, based on 115 biochemical reactions yielded the esculin test as the only one differentiating between them by being positive for E. dissolvens and negative for E. cloacae strains. The name E. cloacae subsp. dissolvens comb. nov. is proposed for the group of organisms formerly referred to as E. dissolvens , and the name E. cloacae subsp. cloacae comb. nov. for the group of organisms formerly referred to as E. cloacae . The species descriptions of Enterobacter kobei and Enterobacter asburiae were emended based on the data collected on 17 and 15 strains, respectively. The strains were assigned to the respective species by a combination of phylogenetic sequence analyzes and DNA–DNA hybridizations. Phenotypic analyzes of 115 reactions gave detailed species profiles with new differentiating phenotypic properties.

  • population genetics of the nomenspecies Enterobacter cloacae
    Applied and Environmental Microbiology, 2003
    Co-Authors: Harald Hoffmann, Andreas Roggenkamp
    Abstract:

    The genetic heterogeneity of the nomenspecies Enterobacter cloacae is well known. Enterobacter asburiae, Enterobacter cancerogenus, Enterobacter dissolvens, Enterobacter hormaechei, Enterobacter kobei, and Enterobacter nimipressuralis are closely related to it and are subsumed in the so-called E. cloacae complex. DNA-DNA hybridization studies performed previously identified at least five DNA-relatedness groups of this complex. In order to analyze the genetic structure and the phylogenetic relationships between the clusters of the nomenspecies E. cloacae, 206 strains collected from 22 hospitals, a veterinarian, and an agricultural center in 11 countries plus all 13 type strains of the genus and reference strain CDC 1347-71R were examined with a combination of sequence and PCR-restriction fragment length polymorphism (PCR-RFLP) analyses of the three housekeeping genes hsp60, rpoB, and hemB as well as ampC, the gene of a class C β-lactamase. Based on the neighbor-joining tree of the hsp60 sequences, 12 genetic clusters (I to XII) and an unstable sequence crowd (xiii) were identified. The robustness of the genetic clusters was confirmed by analyses of rpoB and hemB sequences and ampC PCR-RFLPs. Sequence crowd xiii split into two groups after rpoB analysis. Only three strains formed a cluster with the type strain of E. cloacae, indicating that the minority of isolates identified as E. cloacae truly belong to the species; 13% of strains grouped with other type strains of the genus, suggesting that the phenotypes of these species seem to be more heterogeneous than so far believed. Three clusters represented 70% of strains, but none of them included a type or reference strain. The genetic clustering presented in this study might serve as a framework for future studies dealing with taxonomic, evolutionary, epidemiological, or pathogenetic characteristics of bacteria belonging to the E. cloacae complex.

Harald Hoffmann - One of the best experts on this subject based on the ideXlab platform.

  • Description of Enterobacter ludwigii sp. nov., a novel Enterobacter species of clinical relevance
    Systematic and Applied Microbiology, 2005
    Co-Authors: Harald Hoffmann, Sibylle Stindl, Anita Stumpf, André Mehlen, Daniel Monget, Jürgen Heesemann, Karl H. Schleifer, Andreas Roggenkamp
    Abstract:

    Abstract A new species, Enterobacter ludwigii, is presented on the basis of the characteristics of 16 strains, which were isolated from clinical specimens. These bacteria form a distinct genetic cluster in phylogenetic analyses of the population structure of the Enterobacter cloacae complex. As determined by DNA–DNA cross-hybridization experiments in microplates, this genetic cluster can be delineated from the other species of the E. cloacae complex with Δ T m values equal to or above 5 °C with Enterobacter hormaechei being the closest relative. The bacteria are gram-negative, fermentative, motile rods with the general characteristics of the genus Enterobacter and the E. cloacae complex in particular. E. ludwigii can be differentiated from the other Enterobacter species by its growth on myo-inositol and 3-0-methyl- d -glucopyranose. The type strain is EN-119 (=DSM 16688T=CIP 108491T).

  • Reassignment of Enterobacter dissolvens to Enterobacter cloacae as E. cloacae subspecies dissolvens comb. nov. and emended description of Enterobacter asburiae and Enterobacter kobei.
    Systematic and Applied Microbiology, 2005
    Co-Authors: Harald Hoffmann, Sibylle Stindl, Anita Stumpf, André Mehlen, Daniel Monget, Jürgen Heesemann, Karl H. Schleifer, Wolfgang Ludwig, Andreas Roggenkamp
    Abstract:

    Abstract The taxonomic position of Enterobacter dissolvens was re-evaluated based on the analysis of the type strain ATCC 23373 T and three clinical isolates. The strains were assigned to the genetic cluster of the species by phylogenetic sequence analysis in the frame of a recent population genetic study. The relatedness of E. dissolves to the other species of the E. cloacae complex was analyzed by DNA–DNA hybridization studies based on melting profiles in microplates. The genetic cluster of E. dissolvens fell into the same DNA-relatedness group like E. cloacae with mean Δ T m -values of 3.9 °C confirming the hybridization results of three former studies. Phenotypic analysis of the E. cloacae and E. dissolvens strains, respectively, based on 115 biochemical reactions yielded the esculin test as the only one differentiating between them by being positive for E. dissolvens and negative for E. cloacae strains. The name E. cloacae subsp. dissolvens comb. nov. is proposed for the group of organisms formerly referred to as E. dissolvens , and the name E. cloacae subsp. cloacae comb. nov. for the group of organisms formerly referred to as E. cloacae . The species descriptions of Enterobacter kobei and Enterobacter asburiae were emended based on the data collected on 17 and 15 strains, respectively. The strains were assigned to the respective species by a combination of phylogenetic sequence analyzes and DNA–DNA hybridizations. Phenotypic analyzes of 115 reactions gave detailed species profiles with new differentiating phenotypic properties.

  • population genetics of the nomenspecies Enterobacter cloacae
    Applied and Environmental Microbiology, 2003
    Co-Authors: Harald Hoffmann, Andreas Roggenkamp
    Abstract:

    The genetic heterogeneity of the nomenspecies Enterobacter cloacae is well known. Enterobacter asburiae, Enterobacter cancerogenus, Enterobacter dissolvens, Enterobacter hormaechei, Enterobacter kobei, and Enterobacter nimipressuralis are closely related to it and are subsumed in the so-called E. cloacae complex. DNA-DNA hybridization studies performed previously identified at least five DNA-relatedness groups of this complex. In order to analyze the genetic structure and the phylogenetic relationships between the clusters of the nomenspecies E. cloacae, 206 strains collected from 22 hospitals, a veterinarian, and an agricultural center in 11 countries plus all 13 type strains of the genus and reference strain CDC 1347-71R were examined with a combination of sequence and PCR-restriction fragment length polymorphism (PCR-RFLP) analyses of the three housekeeping genes hsp60, rpoB, and hemB as well as ampC, the gene of a class C β-lactamase. Based on the neighbor-joining tree of the hsp60 sequences, 12 genetic clusters (I to XII) and an unstable sequence crowd (xiii) were identified. The robustness of the genetic clusters was confirmed by analyses of rpoB and hemB sequences and ampC PCR-RFLPs. Sequence crowd xiii split into two groups after rpoB analysis. Only three strains formed a cluster with the type strain of E. cloacae, indicating that the minority of isolates identified as E. cloacae truly belong to the species; 13% of strains grouped with other type strains of the genus, suggesting that the phenotypes of these species seem to be more heterogeneous than so far believed. Three clusters represented 70% of strains, but none of them included a type or reference strain. The genetic clustering presented in this study might serve as a framework for future studies dealing with taxonomic, evolutionary, epidemiological, or pathogenetic characteristics of bacteria belonging to the E. cloacae complex.

Ben D Tall - One of the best experts on this subject based on the ideXlab platform.

  • re examination of the taxonomic status of Enterobacter helveticus Enterobacter pulveris and Enterobacter turicensis as members of the genus cronobacter and their reclassification in the genera franconibacter gen nov and siccibacter gen nov as francon
    International Journal of Systematic and Evolutionary Microbiology, 2014
    Co-Authors: Roger Stephan, Christopher J Grim, Gopal R Gopinath, Mark K Mammel, Venugopal Sathyamoorthy, Larisa H Trach, Hannah R Chase, Seamus Fanning, Ben D Tall
    Abstract:

    Recently, a taxonomical re-evaluation of the genus Enterobacter , based on multi-locus sequence typing (MLST) analysis, has led to the proposal that the species Enterobacter pulveris , Enterobacter helveticus and Enterobacter turicensis should be reclassified as novel species of the genus Cronobacter . In the present work, new genome-scale analyses, including average nucleotide identity, genome-scale phylogeny and k-mer analysis, coupled with previously reported DNA–DNA hybridization values and biochemical characterization strongly indicate that these three species of the genus Enterobacter are not members of the genus Cronobacter , nor do they belong to the re-evaluated genus Enterobacter . Furthermore, data from this polyphasic study indicated that all three species constitute two new genera. We propose reclassifying Enterobacter pulveris and Enterobacter helveticus in the genus Franconibacter gen. nov. as Franconibacter pulveris comb. nov. (type strain 601/05T = LMG 24057T = DSM 19144T) and Franconibacter helveticus comb. nov. (type strain 513/05T = LMG 23732T = DSM 18396T), respectively, and Enterobacter turicensis in the genus Siccibacter gen. nov. as Siccibacter turicensis comb. nov. (type strain 508/05T = LMG 23730T = DSM 18397T).

Nancy D Hanson - One of the best experts on this subject based on the ideXlab platform.

  • plasmid mediated carbapenem hydrolyzing enzyme kpc 2 in an Enterobacter sp
    Antimicrobial Agents and Chemotherapy, 2004
    Co-Authors: Ashfaque Hossain, Mary Jane Ferraro, Richard M Pino, Ellen Smith Moland, Thomas J Lockhart, Kenneth S Thomson, Richard V Goering, Nancy D Hanson
    Abstract:

    A strain of an Enterobacter sp. with reduced susceptibility to imipenem, which produced a plasmid-mediated class A carbapenem-hydrolyzing enzyme, KPC-2 β-lactamase, was isolated from a patient with sepsis at a Boston hospital. This is the first report of the production of a plasmid-encoded KPC-2 β-lactamase by an Enterobacter sp.

Athanassios Tsakris - One of the best experts on this subject based on the ideXlab platform.

  • detection of extended spectrum β lactamases in clinical isolates of Enterobacter cloacae and Enterobacter aerogenes
    Journal of Clinical Microbiology, 2000
    Co-Authors: E Tzelepi, P Giakkoupi, Danai Sofianou, Veneta Loukova, Anastassia Kemeroglou, Athanassios Tsakris
    Abstract:

    The aim of the present study was to investigate the frequency of extended-spectrum β-lactamases (ESBLs) in a consecutive collection of clinical isolates of Enterobacter spp. The abilities of various screening methods to detect ESBLs in Enterobacters were simultaneously tested. Among the 68 consecutive isolates (56 Enterobacter cloacae and 12 Enterobacter aerogenes isolates) that were analyzed for β-lactamase content, 21 (25 and 58%, respectively) possessed transferable ESBLs with pIs of 8.2 and phenotypic characteristics of SHV-type enzymes, 8 (14.3%) of the E. cloacae isolates produced a previously nondescribed, clavulanate-susceptible ESBL that exhibited a pI of 6.9 and that conferred a ceftazidime resistance phenotype on Escherichia coli transconjugants, and 2 E. cloacae isolates produced both of these enzymes. Among the total of 31 isolates that were considered ESBL producers, the Vitek ESBL detection test was positive for 2 (6.5%) strains, and the conventional double-disk synergy test (DDST) with amoxicillin-clavulanate and with expanded-spectrum cephalosporins and aztreonam was positive for 5 (16%) strains. Modifications of the DDST consisting of closer application of the disks (at 20 instead of 30 mm), the use of cefepime, and the use of both modifications increased the sensitivity of this test to 71, 61, and 90%, respectively. Of the 37 isolates for which isoelectric focusing failed to determine ESBLs, the Vitek test was false positive for 1 isolate and the various forms of DDSTs were false-positive for 3 isolates.