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A Murine Model of Group B Streptococcus Vaginal Colonization
10:19

A Murine Model of Group B Streptococcus Vaginal Colonization

Published on: November 16, 2016

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Differing mechanisms of surviving phagosomal stress among group B Streptococcus strains of varying genotypes

Michelle L Korir1, Clare Laut1, Lisa M Rogers2

  • 1a Department of Microbiology and Molecular Genetics , Michigan State University , East Lansing , MI , USA.

Virulence
|October 30, 2016
PubMed

Insights

Group B Streptococcus (GBS) strains exhibit varied survival mechanisms within macrophages. Serotype III GBS demonstrates enhanced resilience to phagosomal stressors, suggesting diverse GBS persistence strategies.

Area of Science:

  • Microbiology
  • Immunology
  • Infectious Diseases

Background:

  • Group B Streptococcus (GBS) is a primary cause of neonatal sepsis and meningitis.
  • GBS asymptomatically colonizes women and can persist despite antibiotic treatment.
  • GBS survival within macrophages is a key factor in persistent colonization, but the mechanisms are poorly understood.

Purpose of the Study:

  • To investigate the intracellular survival mechanisms of different GBS strains within macrophages.
  • To compare the persistence of GBS strains ST-17 and ST-12 under antibiotic pressure.
  • To assess GBS tolerance to phagosomal stressors and identify strain-specific survival strategies.

Main Methods:

  • Macrophage assays were performed to evaluate GBS intracellular survival and phagocytosis.
  • GBS strains were exposed to antibiotics (ampicillin, erythromycin) and phagosome acidification inhibitors.
  • A multiple stress medium simulating phagosomal conditions was used to test the resilience of 30 GBS strains.

Main Results:

  • The ST-17 GBS strain showed higher phagocytosis and longer intracellular survival compared to the ST-12 strain.
  • The ST-12 strain exhibited ampicillin tolerance, while sub-inhibitory antibiotics affected ST-17 phagocytosis.
  • Phagosome acidification inhibition reduced ST-17 survival, indicating a pH-dependent mechanism. Serotype III GBS demonstrated superior survival in the stress medium.

Conclusions:

  • Diverse GBS strains employ distinct mechanisms for persistence within host cells.
  • Serotype III GBS strains possess enhanced capabilities to withstand specific phagosomal stressors.
  • Understanding these varied survival strategies is crucial for developing effective GBS treatment and prevention methods.
Keywords:
Group B StreptococcusStreptococcus agalactiaeintracellular survivalmacrophagesphagocytosis

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