Staphylococcus epidermidis Pathogenic Mechanisms

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the primary role of extracellular polysaccharides in the context of S. epidermidis adhesion?

  • Facilitating adherence to plastics and metals (correct)
  • Promoting resistance to antibiotics
  • Facilitating adherence to human tissues
  • Strengthening the biofilm structure

How does the polysaccharide capsule of S. epidermidis contribute to its pathogenicity?

  • By producing anti-inflammatory factors
  • By facilitating the evasion of the immune system
  • By enhancing the bacteria's ability to colonize heart valves
  • By hindering phagocytosis by neutrophils (correct)

What is the implication of S. epidermidis producing anti-inflammatory factors?

  • Increased susceptibility to antimicrobial peptides
  • Direct damage to host tissues through inflammation
  • Reduction of the host's immune response, aiding persistent colonization (correct)
  • Enhancement of the immune response, leading to rapid bacterial clearance

Why are infections associated with S. epidermidis biofilms difficult to treat?

<p>The bacteria within a biofilm exhibit increased resistance to antibiotics and immune evasion. (B)</p> Signup and view all the answers

How does S. epidermidis benefit from producing proteases and lipases?

<p>By facilitating the breakdown of proteins and lipids, aiding in dissemination (D)</p> Signup and view all the answers

What is the role of PIA (polysaccharide intercellular adhesin) in S. epidermidis?

<p>Protecting bacteria and facilitating their co-growth (C)</p> Signup and view all the answers

What is the implication of S. epidermidis being coagulase-negative in laboratory tests?

<p>It helps differentiate it from other Staphylococci species, such as <em>S. aureus</em>. (B)</p> Signup and view all the answers

How does S. epidermidis colonize prosthetic heart valves?

<p>By forming biofilms on the artificial surface, leading to inflammation (D)</p> Signup and view all the answers

What is a key characteristic of S. epidermidis infections associated with orthopedic prostheses?

<p>They often require the removal of the infected implant for effective treatment. (B)</p> Signup and view all the answers

What is the significance of S. epidermidis resistance to antimicrobial peptides?

<p>It compromises the effectiveness of the body's natural defenses on the skin. (C)</p> Signup and view all the answers

Flashcards

S. epidermidis

An opportunistic pathogen that is normally part of the microbiota of the skin and mucous membranes.

Adherence to Surfaces

The ability to adhere to surfaces, especially medical devices and host tissues, using adhesion proteins.

Extracellular Polysaccharides

Extracellular polysaccharides that facilitate adherence to plastics and metals.

Biofilm Formation

A structure composed of intercellular adhesive polysaccharide (PIA) and extracellular proteins and DNA, providing antibiotic resistance and immune evasion.

Signup and view all the flashcards

S. epidermidis Toxins

Proteases and lipases that degrade proteins and lipids, aiding in dissemination; delta-toxin causes mild cellular damage.

Signup and view all the flashcards

Bacteremia and Sepsis

Occurs when S. epidermidis enters the bloodstream via an infected venous catheter, potentially causing fever, edema, and septic shock.

Signup and view all the flashcards

Prosthetic Valve Endocarditis

Infection of prosthetic heart valves, leading to inflammation of the endocardium.

Signup and view all the flashcards

S. epidermidis Lab Tests

Appear Gram-positive (+) under a gram stain, produce catalase (+), and are coagulase-negative (-).

Signup and view all the flashcards

Antimicrobial Peptide Resistance

Ability to survive on the skin despite natural defenses.

Signup and view all the flashcards

System Modulation

The ability to produce anti-inflammatory factors that reduce the immune response.

Signup and view all the flashcards

Study Notes

  • S. epidermidis is an opportunistic pathogen and normally part of the microbiota of the skin and mucous membranes.
  • It is a main cause of infections linked to medical devices, due to its ability to form biofilms.

Pathogenic Mechanisms

  • Adherence to surfaces involves adhesion proteins that bind to medical devices and host tissues.
  • Extracellular polysaccharides facilitate adherence to plastics and metals.
  • Fibrinogen binding proteins mediate adhesion to human tissues.

Biofilm Formation

  • Biofilms are composed of:
    • Polysaccharide intercellular adhesin (PIA), which protects bacteria and allows them to grow together.
    • Extracellular proteins and DNA, which strengthen the biofilm.

Biofilm Advantages

  • Provide resistance to antibiotics.
  • Allow evasion of the immune system.
  • Results in persistent colonization.
  • Polysaccharide capsules hinder phagocytosis by neutrophils.
  • System modulation involves anti-inflammatory factors that reduce the immune response.
  • Resistance to antimicrobial peptides allows survival on the skin despite natural defenses.

Toxins

  • Can release proteases and lipases, which degrade proteins and lipids, promoting dissemination.
  • Delta-toxin is similar to that of S. aureus and causes mild cellular damage.

Associated Diseases

  • Bacteremia and sepsis occur when the pathogen enters the bloodstream from an infected venous catheter, leading to fever, edema, and septic shock.
  • Endocarditis in prosthetic valves occurs when the pathogen colonizes artificial heart valves, causing inflammation of the endocardium, fever, fatigue, and heart failure.
  • Causes chronic orthopedic prosthesis infections, which are difficult to treat and often require implant removal.

Lab Tests

  • Gram stain (+).
  • Blood agar (non-hemolytic).
  • Salt mannitol agar (no mannitol fermentation).
  • Catalase +.
  • Coagulase -.
  • PCR.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser