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Differential phenotyping of Brucella species using a newly developed semi-automated metabolic system.

Al Dahouk S, Scholz HC, Tomaso H, Bahn P, Göllner C, Karges W, Appel B, Hensel A, Neubauer H, Nöckler K - BMC Microbiol. (2010)

Bottom Line: The comprehensive testing of metabolic activity allows cluster analysis within the genus Brucella.The biotyping system developed for the identification of Brucella and differentiation of its species and biovars may replace or at least complement time-consuming tube testing especially in case of atypical strains.An easy to handle identification software facilitates the applicability of the Micronaut™ system for microbiology laboratories.

View Article: PubMed Central - HTML - PubMed

Affiliation: Federal Institute for Risk Assessment, Diedersdorfer Weg 1, D-12277 Berlin, Germany. Sascha.Al-Dahouk@gmx.de

ABSTRACT

Background: A commercial biotyping system (Taxa Profile™, Merlin Diagnostika) testing the metabolization of various substrates by bacteria was used to determine if a set of phenotypic features will allow the identification of members of the genus Brucella and their differentiation into species and biovars.

Results: A total of 191 different amines, amides, amino acids, other organic acids and heterocyclic and aromatic substrates (Taxa Profile™ A), 191 different mono-, di-, tri- and polysaccharides and sugar derivates (Taxa Profile™ C) and 95 amino peptidase- and protease-reactions, 76 glycosidase-, phosphatase- and other esterase-reactions, and 17 classic reactions (Taxa Profile™ E) were tested with the 23 reference strains representing the currently known species and biovars of Brucella and a collection of 60 field isolates. Based on specific and stable reactions a 96-well "Brucella identification and typing" plate (Micronaut™) was designed and re-tested in 113 Brucella isolates and a couple of closely related bacteria.Brucella species and biovars revealed characteristic metabolic profiles and each strain showed an individual pattern. Due to their typical metabolic profiles a differentiation of Brucella isolates to the species level could be achieved. The separation of B. canis from B. suis bv 3, however, failed. At the biovar level, B. abortus bv 4, 5, 7 and B. suis bv 1-5 could be discriminated with a specificity of 100%. B. melitensis isolates clustered in a very homogenous group and could not be resolved according to their assigned biovars.

Conclusions: The comprehensive testing of metabolic activity allows cluster analysis within the genus Brucella. The biotyping system developed for the identification of Brucella and differentiation of its species and biovars may replace or at least complement time-consuming tube testing especially in case of atypical strains. An easy to handle identification software facilitates the applicability of the Micronaut™ system for microbiology laboratories.

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Cluster analysis of Brucella field isolates based on biochemical reactions. Cluster analysis of 113 Brucella strains including the reference strains and two isolates of a potentially new species that originated from Austrian foxes based on 93 biochemical reactions tested with the newly developed Brucella specific Micronaut™ microtiter plate. Hierarchical cluster analysis was performed by the Ward's linkage algorithm using the binary coded data based on the empirically set cut-off.
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Figure 3: Cluster analysis of Brucella field isolates based on biochemical reactions. Cluster analysis of 113 Brucella strains including the reference strains and two isolates of a potentially new species that originated from Austrian foxes based on 93 biochemical reactions tested with the newly developed Brucella specific Micronaut™ microtiter plate. Hierarchical cluster analysis was performed by the Ward's linkage algorithm using the binary coded data based on the empirically set cut-off.

Mentions: The panel of 93 discriminating reactions was re-evaluated for its usefulness in the identification of Brucella and the differentiation of its species and biovars using a broad spectrum of well characterized field strains. Both inter- and intra-assay variability were ascertained to be negligible. Results of the cluster analysis of the 113 strains investigated regarding their ability to metabolize the 93 selected substances supported our findings in the smaller collection of Brucella reference strains (Figure 3). Based on the metabolic profiles determined by the Brucella specific 96-well Micronaut™ plate, B. melitensis and B. abortus isolates fell into two distinct groups (Figure 3). B. suis (except for biovar 5) could be found in another group but the biovars 1, and 3 and 4 gathered together with B. inopinata and B. canis isolates, respectively. B. suis bv 2 could be separated by its substrate assimilation pattern. B. suis bv 5 showed metabolic traits similar to B. ovis, B. neotomae and the marine mammal strains. Each Brucella strain investigated revealed an individual metabolic profile.


Differential phenotyping of Brucella species using a newly developed semi-automated metabolic system.

Al Dahouk S, Scholz HC, Tomaso H, Bahn P, Göllner C, Karges W, Appel B, Hensel A, Neubauer H, Nöckler K - BMC Microbiol. (2010)

Cluster analysis of Brucella field isolates based on biochemical reactions. Cluster analysis of 113 Brucella strains including the reference strains and two isolates of a potentially new species that originated from Austrian foxes based on 93 biochemical reactions tested with the newly developed Brucella specific Micronaut™ microtiter plate. Hierarchical cluster analysis was performed by the Ward's linkage algorithm using the binary coded data based on the empirically set cut-off.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2984481&req=5

Figure 3: Cluster analysis of Brucella field isolates based on biochemical reactions. Cluster analysis of 113 Brucella strains including the reference strains and two isolates of a potentially new species that originated from Austrian foxes based on 93 biochemical reactions tested with the newly developed Brucella specific Micronaut™ microtiter plate. Hierarchical cluster analysis was performed by the Ward's linkage algorithm using the binary coded data based on the empirically set cut-off.
Mentions: The panel of 93 discriminating reactions was re-evaluated for its usefulness in the identification of Brucella and the differentiation of its species and biovars using a broad spectrum of well characterized field strains. Both inter- and intra-assay variability were ascertained to be negligible. Results of the cluster analysis of the 113 strains investigated regarding their ability to metabolize the 93 selected substances supported our findings in the smaller collection of Brucella reference strains (Figure 3). Based on the metabolic profiles determined by the Brucella specific 96-well Micronaut™ plate, B. melitensis and B. abortus isolates fell into two distinct groups (Figure 3). B. suis (except for biovar 5) could be found in another group but the biovars 1, and 3 and 4 gathered together with B. inopinata and B. canis isolates, respectively. B. suis bv 2 could be separated by its substrate assimilation pattern. B. suis bv 5 showed metabolic traits similar to B. ovis, B. neotomae and the marine mammal strains. Each Brucella strain investigated revealed an individual metabolic profile.

Bottom Line: The comprehensive testing of metabolic activity allows cluster analysis within the genus Brucella.The biotyping system developed for the identification of Brucella and differentiation of its species and biovars may replace or at least complement time-consuming tube testing especially in case of atypical strains.An easy to handle identification software facilitates the applicability of the Micronaut™ system for microbiology laboratories.

View Article: PubMed Central - HTML - PubMed

Affiliation: Federal Institute for Risk Assessment, Diedersdorfer Weg 1, D-12277 Berlin, Germany. Sascha.Al-Dahouk@gmx.de

ABSTRACT

Background: A commercial biotyping system (Taxa Profile™, Merlin Diagnostika) testing the metabolization of various substrates by bacteria was used to determine if a set of phenotypic features will allow the identification of members of the genus Brucella and their differentiation into species and biovars.

Results: A total of 191 different amines, amides, amino acids, other organic acids and heterocyclic and aromatic substrates (Taxa Profile™ A), 191 different mono-, di-, tri- and polysaccharides and sugar derivates (Taxa Profile™ C) and 95 amino peptidase- and protease-reactions, 76 glycosidase-, phosphatase- and other esterase-reactions, and 17 classic reactions (Taxa Profile™ E) were tested with the 23 reference strains representing the currently known species and biovars of Brucella and a collection of 60 field isolates. Based on specific and stable reactions a 96-well "Brucella identification and typing" plate (Micronaut™) was designed and re-tested in 113 Brucella isolates and a couple of closely related bacteria.Brucella species and biovars revealed characteristic metabolic profiles and each strain showed an individual pattern. Due to their typical metabolic profiles a differentiation of Brucella isolates to the species level could be achieved. The separation of B. canis from B. suis bv 3, however, failed. At the biovar level, B. abortus bv 4, 5, 7 and B. suis bv 1-5 could be discriminated with a specificity of 100%. B. melitensis isolates clustered in a very homogenous group and could not be resolved according to their assigned biovars.

Conclusions: The comprehensive testing of metabolic activity allows cluster analysis within the genus Brucella. The biotyping system developed for the identification of Brucella and differentiation of its species and biovars may replace or at least complement time-consuming tube testing especially in case of atypical strains. An easy to handle identification software facilitates the applicability of the Micronaut™ system for microbiology laboratories.

Show MeSH
Related in: MedlinePlus