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MarA and ramA regulate virulence in Salmonella enterica serovar Choleraesuis

Jen-Jie Lee1, Shih-Ling Hsuan1, Chih-Jung Kuo2

  • 1Graduate Institute of Veterinary Pathobiology, National Chung Hsing University, Taiwan, ROC.

Veterinary Microbiology
|November 27, 2015
PubMed

Insights

The multiple antibiotic resistance factor A (marA) and regulator of acetate metabolism A (ramA) in Salmonella Choleraesuis are crucial for survival in acidic and bile salt environments. These regulators also significantly impact the pathogen

Area of Science:

  • Microbiology
  • Bacterial Pathogenesis
  • Molecular Biology

Background:

  • Salmonella enterica serovar Choleraesuis is a significant porcine pathogen causing systemic infections.
  • Multidrug resistance (MDR) in S. Choleraesuis leads to poor treatment outcomes.
  • Multiple antibiotic resistance factor A (MarA) and Regulator of Acetate Metabolism A (RamA) are key regulators of antibiotic tolerance via efflux pumps.

Purpose of the Study:

  • To investigate the role of MarA and RamA in regulating the virulence of Salmonella Choleraesuis.
  • To determine the impact of MarA and RamA on S. Choleraesuis survival in host-relevant conditions.
  • To assess the contribution of MarA and RamA to S. Choleraesuis pathogenesis in a murine model.

Main Methods:

  • Quantitative reverse transcription PCR (qRT-PCR) to assess protective responses.
  • In vitro assays to evaluate bacterial invasion and survival in host cells.
  • In vivo studies using a BALB/c mouse model to determine LD50 and clearance efficiency.

Main Results:

  • MarA and RamA are essential for S. Choleraesuis survival in acid and bile salt environments.
  • marA- or ramA-deficient strains exhibited reduced invasion and intracellular survival.
  • Mutant strains showed attenuated virulence in mice, with higher LD50 and reduced clearance.

Conclusions:

  • MarA and RamA are critical regulators of both antibiotic resistance and virulence in Salmonella Choleraesuis.
  • Targeting MarA and RamA may offer novel strategies to combat S. Choleraesuis infections.
  • These findings highlight the dual role of MarA and RamA in bacterial pathogenesis.
Keywords:
MarARamASalmonellaCholeraesuisVirulence

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