🦠microbiology review

Extrapolymeric substance (EPS)

Written by the Fiveable Content Team • Last updated August 2025
Written by the Fiveable Content Team • Last updated August 2025

Definition

Extrapolymeric substances (EPS) are high-molecular-weight compounds secreted by microorganisms into their environment. These substances form a protective and structural matrix around microbial communities, particularly biofilms.

5 Must Know Facts For Your Next Test

  1. EPS are crucial for the formation and stability of biofilms, which protect bacteria from environmental stress.
  2. They primarily consist of polysaccharides, proteins, lipids, and nucleic acids.
  3. Instruments like electron microscopes can visualize the complex structures formed by EPS in biofilms.
  4. Pathogenic bacteria use EPS to evade host immune responses and enhance their virulence.
  5. EPS contribute to antibiotic resistance by limiting the penetration of antimicrobial agents into biofilms.
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