Cronobacter Support
06-03-2009, 05:29 PM
1st International Conference on Cronobacter Poster Abstract 59
Development of a new test panel for identification of both Gram-negative and Gram-positive bacteria
The objective of this project was to simplify biochemical/phenotypic testing of bacteria by developing a single test panel that could be used to identify both Gram-negative and Gram-positive bacteria. This has been impossible in the past because bacterial genera are quite diverse and no one has found universal culture and chromogenic testing chemistries that would work with a broad range of genera. We employed phenotype MicroArrays to study, in detail, the metabolic and chemical sensitivity properties of diverse bacteria. From this effort we succeeded in developing assay conditions and a tetrazolium-based colorimetric chemistry that can be used to fingerprint and identify more than 1,000 species, including Gram-negative enteric, non-fermenter and fastidious species as well as important Gram-positive species such as Bacillus, Corynebacterium, Staphylococcus, Streptococcus, Lactobacillus, and Nocardia. Using computer-assisted analysis we selected from the Phenotype MicroArray assays a final set of 94 tests that are taxonomically informative. The 71 carbon source utilization assays include sugars, carbohydrates, sugar alcohols, hexose-phosphates, hexuronic acids, D- and L-amino acids, carboxylic acids, and other types of naturally occurring biochemicals. The 23 chemical sensitivity assays test the sensitivity to potentially inhibitory conditions. The conditions include high salt (8% NaCl), high lactic acid (1%), low pH (5.0), and sensitivity to other taxonomically useful agents such as antibiotics, cations, anions, oxidizers, and detergents. Because the panel identifies both Gram-negative and Gram-positives, a bacterial isolate can be identified without a Gram-stain or any other pre-tests. The one-minute set up procedure consists of preparing a cell suspension from agar-grown cells, and inoculating 100 hl into each well of the panel. The system recommends 33° C for incubation, which permits identification of many more species. In addition to simplicity, a major advantage over identification based on 16s-rDNA gene sequence is that you simultaneously gain detailed information about the properties and growth phenotypes of the bacterium that you have identified.
Amalia Franco-Buff, Vanessa Gomez, Eric Olender, Peter Gadzinski and Barry Bochner.
Biolog Inc., 21124 Cabot Blvd., Hayward, CA, 94545, USA.
Development of a new test panel for identification of both Gram-negative and Gram-positive bacteria
The objective of this project was to simplify biochemical/phenotypic testing of bacteria by developing a single test panel that could be used to identify both Gram-negative and Gram-positive bacteria. This has been impossible in the past because bacterial genera are quite diverse and no one has found universal culture and chromogenic testing chemistries that would work with a broad range of genera. We employed phenotype MicroArrays to study, in detail, the metabolic and chemical sensitivity properties of diverse bacteria. From this effort we succeeded in developing assay conditions and a tetrazolium-based colorimetric chemistry that can be used to fingerprint and identify more than 1,000 species, including Gram-negative enteric, non-fermenter and fastidious species as well as important Gram-positive species such as Bacillus, Corynebacterium, Staphylococcus, Streptococcus, Lactobacillus, and Nocardia. Using computer-assisted analysis we selected from the Phenotype MicroArray assays a final set of 94 tests that are taxonomically informative. The 71 carbon source utilization assays include sugars, carbohydrates, sugar alcohols, hexose-phosphates, hexuronic acids, D- and L-amino acids, carboxylic acids, and other types of naturally occurring biochemicals. The 23 chemical sensitivity assays test the sensitivity to potentially inhibitory conditions. The conditions include high salt (8% NaCl), high lactic acid (1%), low pH (5.0), and sensitivity to other taxonomically useful agents such as antibiotics, cations, anions, oxidizers, and detergents. Because the panel identifies both Gram-negative and Gram-positives, a bacterial isolate can be identified without a Gram-stain or any other pre-tests. The one-minute set up procedure consists of preparing a cell suspension from agar-grown cells, and inoculating 100 hl into each well of the panel. The system recommends 33° C for incubation, which permits identification of many more species. In addition to simplicity, a major advantage over identification based on 16s-rDNA gene sequence is that you simultaneously gain detailed information about the properties and growth phenotypes of the bacterium that you have identified.
Amalia Franco-Buff, Vanessa Gomez, Eric Olender, Peter Gadzinski and Barry Bochner.
Biolog Inc., 21124 Cabot Blvd., Hayward, CA, 94545, USA.