The Gram-Positive and Gram-Negative Cocci of Medical Importance

A set of flashcards covering key concepts on Gram-positive and Gram-negative cocci, focusing on their structure, pathogenicity, diseases, and prevention measures.

What color do Gram-positive cocci stain when Gram stained?

Purple

What color do Gram-negative cocci stain when Gram stained?

Red

How do Staphylococcus cells arrange themselves?

In grapelike clusters

What type of bacteria are Staphylococcus classified as?

Facultative anaerobes

What is a virulent strain of Staphylococcus commonly associated with human diseases?

Staphylococcus aureus

What is Staphylococcus epidermidis known for?

Being normal microbiota of human skin and causing opportunistic infections

What is the effect of Handwashing in relation to Staphylococcus infections?

Helps prevent infections

What structures contribute to Staphylococcus's pathogenicity?

Structures that evade phagocytosis, production of enzymes, and production of toxins

What is the role of Protein A in Staphylococcus?

Coats the cell surface and inhibits opsonization and complement cascade

What is the function of hyaluronidase in Staphylococcus?

Breaks down hyaluronic acid allowing bacteria to spread between cells

Name a toxin produced by S. aureus that affects skin cells.

Exfoliative toxins

What are the symptoms of toxic-shock syndrome (TSS) caused by Staphylococcus?

Fever, vomiting, rash, and low blood pressure

What is a common disease caused by S. pneumoniae?

Pneumococcal pneumonia

What distinguishes Group A Streptococcus?

Streptococcus pyogenes

Which component of Group A Streptococcus helps it evade phagocytosis?

M protein

What is the most common disease caused by Group A streptococcus?

Pharyngitis or strep throat

What complication can arise from untreated streptococcal pharyngitis?

Rheumatic fever

What is the principal serotype of Group B Streptococcus?

Streptococcus agalactiae

What type of infections is Group B Streptococcus most associated with?

Neonatal bacteremia, meningitis, and pneumonia

What opportunistic infections can viridans group streptococci lead to?

Meningitis and endocarditis

What is the primary role of the polysaccharide capsule in S. pneumoniae?

Inhibiting phagocytosis

How can one prevent gonorrhea?

Through sexual abstinence, monogamy, and proper condom use

What makes Neisseria gonorrhoeae particularly concerning in terms of treatment?

The emergence of resistant strains

What is a clinical sign of gonorrhea in men?

Painful urination and pus-filled discharge

How is Neisseria meningitidis commonly transmitted?

By respiratory droplets among close contacts

What is a critical aspect of diagnosing meningitis caused by Neisseria meningitidis?

Rapid diagnosis is critical