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Production and Testing of Antimicrobial Peptides and Their Mimics
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Production and Testing of Antimicrobial Peptides and Their Mimics

Published on: April 10, 2026

In vitro susceptibility of the Streptococcus milleri group to antimicrobial peptides

K L Bartie1, D A Devine, M J Wilson

  • 1Department of Oral Microbiology, Leeds Dental Institute, Clarendon Way, University of Leeds, Leeds, UK.

International Endodontic Journal
|May 16, 2008
PubMed
Abstract

Insights

The Streptococcus milleri group (SMG) showed sensitivity to amidated antimicrobial peptides like mastoparan and magainin 2 amide. Resistance to human-derived peptides may aid oral cavity colonization and infection survival.

Area of Science:

  • Microbiology
  • Biochemistry
  • Infectious Diseases

Background:

  • The Streptococcus milleri group (SMG) comprises bacteria frequently associated with various infections.
  • Understanding their susceptibility to antimicrobial agents is crucial for effective treatment strategies.

Purpose of the Study:

  • To evaluate the susceptibility of Streptococcus milleri group strains to a panel of commercially available antimicrobial peptides.
  • To identify specific antimicrobial peptides with activity against SMG.

Main Methods:

  • Thirty strains of the Streptococcus milleri group were tested.
  • Susceptibility was assessed using a double-layer diffusion assay against ten antimicrobial peptides of human, animal, or insect origin.

Main Results:

  • Most SMG strains were sensitive to amidated peptides: mastoparan (100%), magainin 2 amide (95%), and indolicin (91%).
  • Cecropin B and histatin showed lower activity, while defensins (HNP-1, HNP-2), histatin 8, cecropin P1, and magainin 2 were inactive.
  • A majority of strains were resistant to human-derived peptides.

Conclusions:

  • Amidated and alpha-helical antimicrobial peptides demonstrate activity against the Streptococcus milleri group.
  • Resistance to human peptides might contribute to SMG's colonization and survival in oral and endodontic infections.
  • Structural modifications of active peptides could lead to novel preventative or therapeutic agents.

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