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Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes
14:05

Imaging InlC Secretion to Investigate Cellular Infection by the Bacterial Pathogen Listeria monocytogenes

Published on: September 19, 2013

Involvement of the mpo operon in resistance to class IIa bacteriocins in Listeria monocytogenes

Safia Arous1, Karine Dalet, Yann Héchard

  • 1MFA, Laboratoire de Chimie de l'Ean et de l'Environnement, UMR CNRA 6008, Université de Poitiers, 40 avenue du Recteur Pineau, 86022 Poitiers Cedex, France.

FEMS Microbiology Letters
|September 1, 2004
PubMed

Insights

Listeria monocytogenes intermediate resistance to bacteriocins is linked to the mptACD operon. A new mpoA mutant also shows intermediate resistance, revealing cross-regulation between mpo and mpt operons.

Area of Science:

  • Microbiology
  • Bacteriocin Resistance Mechanisms
  • Bacterial Genetics

Background:

  • High resistance in Listeria monocytogenes to class IIa bacteriocins is associated with the mptACD operon, encoding the EIIt Man mannose PTS permease.
  • Intermediate resistance has been linked to membrane phospholipid modifications in spontaneous mutants.

Purpose of the Study:

  • To investigate the role of the mpoABCD operon in Listeria monocytogenes bacteriocin resistance.
  • To explore the relationship between mpo and mpt operon expression and resistance phenotypes.

Main Methods:

  • Construction and characterization of a Listeria monocytogenes mutant with an interruption in mpoA.
  • Analysis of mptACD operon expression in wild-type and mutant strains.
  • In silico analysis of mpo operon transcription.

Main Results:

  • A novel mpoA-interrupted mutant exhibited an intermediate resistance phenotype to class IIa bacteriocins.
  • Intermediate resistant mutants, including the mpoA mutant, showed decreased mptACD expression.
  • A cross-regulation between the mpo and mpt operons was demonstrated, with the mpo mutant displaying a defect in mpt expression.

Conclusions:

  • The mpoABCD operon plays a role in Listeria monocytogenes bacteriocin resistance.
  • The level of mptACD expression correlates with the degree of bacteriocin sensitivity.
  • The intermediate resistance phenotype of the mpoA mutant is likely due to its impaired mpt expression.

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