Reliability of Listeria monocytogenes Identification by Specific PCR Assessed by Phenotypic and Genotypic Techniques
- PDF / 192,041 Bytes
- 9 Pages / 595.276 x 790.866 pts Page_size
- 23 Downloads / 198 Views
Reliability of Listeria monocytogenes Identification by Specific PCR Assessed by Phenotypic and Genotypic Techniques Rosa Aznar & Patricia Elizaquível
Received: 4 October 2007 / Accepted: 10 January 2008 / Published online: 19 March 2008 # Springer Science + Business Media, LLC 2007
Abstract This study evaluates the possibility of using polymerase chain reaction (PCR) for rapid identification of food-borne Listeria monocytogenes as an alternative to API Listeria system and estimates the incidence of API Listeria misidentifications in food-borne Listeria species. A total of 198 strains, 11 L. monocytogenes, 28 other Listeria species, and 159 food isolates were phenotypically and genotypically characterized by API Listeria profiles and randomly amplified polymorphic DNA (RAPD) profiles, respectively. They were also tested for PCR amplification using genusand species-specific primers. Clustering analysis of phenotypic and genotypic data showed discrepancies in species identification of some isolates by API Listeria profiles. Their identities were confirmed by 16S rDNA sequencing, and thus, it was revealed that 33% of Listeria innocua and 19% of Listeria welshimeri were misidentified as L. monocytogenes by API Listeria profiles. Reliable identification of L. monocytogenes was obtained by LM1–LM2 specific primers which allowed PCR amplification only in R. Aznar : P. Elizaquível Departamento de Microbiología y Ecología, Universitat de València, València, Spain R. Aznar : P. Elizaquível Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Madrid, Spain R. Aznar (*) Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de los Alimentos, Apartado de Correos 73, 46100 Burjassot, Valencia, Spain e-mail: [email protected]
reference strains and isolates previously identified as L. monocytogenes by RAPD and 16S rDNA sequence analysis. These results corroborate the suitability of specific PCR as a rapid and accurate test for the identification of L. monocytogenes, avoiding misidentification with other Listeria species commonly found in food products. Keywords Listeria monocytogenes . Specific PCR . RAPD . Identification Abbreviations RAPD randomly amplified polymorphic DNA CECT Spanish type culture collection, Spain
Introduction The genus Listeria includes six species (Listeria monocytogenes, Listeria innocua, Listeria ivanovii, Listeria welshimeri, Listeria seeligeri and Listeria grayi) currently recognized on the basis of DNA similarity, 16S rRNA sequence identity, chemotaxonomic properties, and multilocus enzyme analysis (Rocourt 1999). L. monocytogenes is considered of grave concern in food safety due to its high fatality rate. Other Listeria species, like L. seeligeri and L. ivanovii, have occasionally been implicated in human listeriosis or L. innocua in animal disease (Cummings et al. 1994; Rocourt et al. 1986; Walker et al. 1994). Official regulations on food safety regarding L. monocytogenes vary among countries and also among food products, ranging from abs
Data Loading...
