Open Access Research article

Comparison of the major virulence-related genes of Listeria monocytogenes in Internalin A truncated strain 36-25-1 and a clinical wild-type strain

Daisuke Kyoui, Hajime Takahashi*, Satoko Miya, Takashi Kuda and Bon Kimura

Author Affiliations

Department of Food Science and Technology, Faculty of Marine Science, Tokyo University of Marine Science and Technology, 4-5-7 Konan, Minato, Tokyo 108-8477, Japan

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BMC Microbiology 2014, 14:15  doi:10.1186/1471-2180-14-15

Published: 28 January 2014

Abstract

Background

Internalin A (InlA) facilitates the invasion of Listeria monocytogenes into a host cell. Some strains of Listeria monocytogenes express truncated forms of InlA, which reduces invasiveness. However, few virulence-related genes other than inlA have been analyzed in InlA-truncated strains. In the present study, we sequenced the draft genome of strain 36-25-1, an InlA-truncated strain, with pyrosequencing and compared 36 major virulence-related genes in this strain and a clinical wild-type strain.

Results

Strain 36-25-1 possessed all of the virulence-related genes analyzed. Of the analyzed genes, only 4 genes (dltA, gtcA, iap, and inlA) differed when the nucleotide sequences of strain 36-25-1 and the clinical wild-type strain were compared. Analysis of the deduced amino acid sequences found no mutations that significantly influenced virulence in genes other than inlA.

Conclusions

The virulence-associated genes in strain 36-25-1 differ little from those of the clinical wild-type strain, indicating that a slight mutation in the nucleotide sequence determines the virulence of the InlA-truncated strain. In addition, the results suggest that, aside from InlA-mediated cell invasiveness, there is almost no difference between the virulence of strain 36-25-1 and that of the clinical wild-type strain.

Keywords:
Listeria monocytogenes; Internalin A; Next-generation-sequencing