Development of an ELISA specific for Listeria monocytogenes using a polyclonal antibody raised against a cell extract containing internalin B |
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| Authors: | L Karamonová M Blažková L Fukal P Rauch M Greifová K Horáková |
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| Institution: | 1. Department of Biochemistry and Microbiology , Institute of Chemical Technology , Technická 5, Prague , 166 28 , Czech Republic;2. Department of Food Science and Technology , Slovak Technical University , Radlinského 9, 812 37 , Bratislava , Slovakia;3. Department of Biochemistry and Microbiology , Slovak Technical University , Radlinského 9, 812 37 , Bratislava , Slovakia |
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| Abstract: | We have developed a new enzyme-linked immunosorbent assay (ELISA) that is specific to the foodborne pathogenic micro-organism Listeria monocytogenes. It is based on an antibody raised against an L. monocytogenes cell preparation optimized for extraction of internalin B. Only in a sandwich ELISA format was the protein A-purified antibody specific to L. monocytogenes. In a competitive ELISA format, the antibody recognizes other Listeria species. The sandwich ELISA shows no recognition of L. innocua, L. ivanovii, L. welshimeri, L. seeligeri, or L. grayii. It has a minimum detectable level for L. monocytogenes of log10?6.37 cfu ml?1 in pure culture, is reproducible, and is unaffected by the presence of high numbers (approximately log10?8.0 cfu ml?1) of the other Listeria species. Possible reasons for the format-dependent specificity are discussed. When the ELISA was applied to milk samples inoculated with L. monocytogenes reference material (5 cfu ml?1), there was a strong response to the enrichment cultures. The new assay may prove useful in detection of L. monocytogenes in enrichment cultures of food samples. |
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| Keywords: | ELISA Listeria monocytogenes internalin B |
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