Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2002 Dec;68(12):6273-82.
doi: 10.1128/AEM.68.12.6273-6282.2002.

Direct identification in food samples of Listeria spp. and Listeria monocytogenes by molecular methods

Luca Cocolin  1 , Kalliopi Rantsiou, Lucilla Iacumin, Carlo Cantoni, Giuseppe Comi
Affiliations

Direct identification in food samples of Listeria spp. and Listeria monocytogenes by molecular methods

Luca Cocolin et al. Appl Environ Microbiol. 2002 Dec.

Abstract

A new molecular approach for the detection and identification of Listeria spp. and Listeria monocytogenes in food is presented here. The method is based on the PCR amplification of a fragment of the iap gene from the five species belonging to the genus and on the analysis of the PCR products obtained by denaturing gradient gel electrophoresis (DGGE). The protocol was first optimized by using strains from international collections. Based on the differences present in the sequences amplified, it was possible to obtain species-specific DGGE migration that allowed fast and easy identification of L. monocytogenes, L. innocua, L. welshimeri, L. seeligeri, and L. ivanovii. Moreover, for L. monocytogenes serotypes, partial differentiation was possible. The optimized protocol was used for identification of Listeria strains traditionally isolated from food and for direct detection and identification of Listeria members in food after an overnight enrichment. Identification of 48 food isolates and direct detection of Listeria spp. in 73 food samples show the potential of the method that can be used as a fast screening test to investigate the presence of Listeria spp. and L. monocytogenes in food.

PubMed Disclaimer

Figures

FIG. 1.
FIG. 1.
Agarose gel electrophoresis of the products obtained after amplification of the iap gene from different Listeria species. Lane 1, 100-bp ladder (Sigma); lane 2, negative control; lane 3, L. ivanovii DSMZ 20750; lane 4, L. seeligeri DSMZ 20751; lane 5, L. welshimeri DSMZ 20650; lane 6, L. innocua DSMZ 20649; lane 7, L. monocytogenes 1/2a NCTC 7979; lane 8, L. monocytogenes 1/2b NCTC 10887; lane 9, L. monocytogenes 1/2c NCTC 9862; lane 10, L. monocytogenes 3a NCTC 5105; lane 11, L. monocytogenes 3b CIP 78.35; lane 12, L. monocytogenes 4b NCTC 10527. The numbers on the left indicate the molecular size of the DNA bands in base pairs.
FIG. 2.
FIG. 2.
DGGE profiles of Listeria species obtained from international collections. Lane 1, L. monocytogenes 1/2a NCTC 7979; lane 2, L. monocytogenes 1/2b NCTC 10887; lane 3, L. monocytogenes 1/2c NCTC 9862; lane 4, L. monocytogenes 3a NCTC 5105; lane 5, L. monocytogenes 3b CIP 78.35; lane 6, L. monocytogenes 4b NCTC 10527; lane 7, L. innocua DSMZ 20649; lane 8, L. welshimeri DSMZ 20650; lane 9, L. seeligeri DSMZ 20751; lane 10, L. ivanovii DSMZ 20750.
FIG. 3.
FIG. 3.
DGGE patterns of Listeria strains isolated from food. Lanes 1 to 3, L. monocytogenes serotypes 1/2a NCTC 7979, 1/2b NCTC 10887, and 1/2c NCTC 9862, respectively; lane 4, L. innocua DSMZ 20649; lanes 5 to 12, strains isolated from food.
FIG. 4.
FIG. 4.
Results obtained from the direct amplification and characterization of Listeria spp. in food. Lane labels indicate the number of the food sample shown in the gel and also reported in Table 4. (A) List-univ. 1 and List-univ. 2 PCR amplification. (B) DGGE profiles of food samples. (C) Specific L. monocytogenes PCR using primers Mar 1 and Mar 2 (38). The DGGE bands indicated by an asterisk were excised, reamplified, sequenced, and identified by sequence analysis. Abbreviations: Lm 1/2c, L. monocytogenes serotype 1/2c; Lm b, L. monocytogenes serogroup b; Linn, L. innocua; Liv, L. ivanovii; Ls, L. seeligeri; Lw, L. welshimeri.
See this image and copyright information in PMC

References

    1. Asperger, H., H. Heistinger, M. Wagner, A. Lehner, and E. Brandl. 1999. A contribution of Listeria enrichment methodology-growth of Listeria monocytogenes under varying conditions concerning enrichment broth composition, cheese matrices and competing microbial flora. Food Microbiol. 16:419-431.
    1. Bansal, N. S., F. H. Y. McDonell, A. Smith, G. Arnold, and G. F. Ibrahim. 1996. Multiplex PCR assay for the routine detection of Listeria in food. Int. J. Food Microbiol. 33:293-300. - PubMed
    1. Beumer, R. R., M. C. T. Giffel, M. T. C. Kok, and F. M. Rombouts. 1996. Confirmation and identification of Listeria spp. Lett. Appl. Microbiol. 22:448-452. - PubMed
    1. Bibb, W. F., B. G. Schwartz, B. G. Gellin, B. D. Plikaytis, and R. E. Weaver. 1989. Analysis of Listeria monocytogenes by multilocus enzyme electrophoresis and application of the method to epidemiologic investigations. Int. J. Food Microbiol. 8:233-239. - PubMed
    1. Brosch, R., C. Buchrieser, and J. Rocourt. 1991. Subtyping of Listeria monocytogenes serovar 4b by use of low-frequency-cleavage restriction endonucleases and pulsed-field gel electrophoresis. Res. Microbiol. 142:667-675. - PubMed

MeSH terms

Substances

LinkOut - more resources