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Gewählte Publikation:

Publikationstyp: Zeitschriftenaufsatz
Dokumenttyp: Originalarbeit

Jahr: 2001

AutorInnen: Hein, I; Klein, D; Lehner, A; Bubert, A; Brandl, E; Wagner, M

Titel: Detection and quantification of the iap gene of Listeria monocytogenes and Listeria innocua by a new real-time quantitative PCR assay.

Quelle: Res Microbiol. 2001; 152(1):37-46



Autor/innen der Vetmeduni Vienna:

Hein Ingeborg
Klein Dieter
Wagner Martin

Beteiligte Vetmed-Organisationseinheiten
Institut für Lebensmittelsicherheit, Lebensmitteltechnologie und öffentliches Gesundheitswesen in der Veterinärmedizin, Abteilung für Lebensmittelmikrobiologie
Institut für Virologie


Zugehörige(s) Projekt(e): Der quantitative Nachweis von Listerien in Milch und Milchprodukten mittels der Real-Time Quantitative PCR


Abstract:
A real-time quantitative polymerase chain reaction (PCR) assay for direct detection and enumeration of Listeria monocytogenes and Listeria innocua was developed and applied to artificially contaminated milk samples. The iap gene present in both species was used as a target for amplification of a 175-bp (L. monocytogenes) and a 309-bp (L. innocua) fragment. To ensure that L. monocytogenes and L. innocua are specifically detectable, tests were carried out using 42 L. monocytogenes strains and 33 L. innocua strains belonging to different serovars. Specificity was also confirmed using 22 bacterial strains not belonging to the genus Listeria, including closely related bacteria. In addition to specificity, the reported assay is characterized by a wide dynamic range of quantification and a high sensitivity, as we could detect as few as six copies of the iap gene per PCR using purified DNA as template. When applied to direct detection and quantification of L. monocytogenes in milk, the more rapid real-time quantitative PCR assay was as sensitive as the traditional plate count method, but real-time quantitative PCR-derived iap gene copy numbers were one to two logs higher than colony-forming units obtained by the plate count method.

Keywords Pubmed: Animals
Bacterial Proteins/genetics*
Colony Count, Microbial
Culture Media
DNA Primers
DNA, Bacterial/analysis
DNA, Bacterial/isolation & purification
Genes, Bacterial
Listeria/genetics*
Listeria/isolation & purification*
Listeria monocytogenes/genetics
Listeria monocytogenes/growth & development
Listeria monocytogenes/isolation & purification*
Milk/microbiology*
Polymerase Chain Reaction/methods*
Sensitivity and Specificity


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