Strep Pneumo Flashcards & Quiz

Questions and Answers

Strep pneumoniae and viridans are what type of hemolytic?

Beta

Alpha (correct)

Gamma

None of the above

What does alpha hemolytic mean?

Partial hemolysis

Strep pneumoniae has a capsule.

True

Strep pneumoniae is sensitive to what?

Optochin Signup and view all the answers

What shape is Strep pneumoniae?

Dual lancet (diplococci) Signup and view all the answers

Is Strep pneumoniae bile soluble?

False Signup and view all the answers

Strep pneumoniae is the #1 cause of what?

CAP (community acquired pneumonia) Signup and view all the answers

CAP caused by Strep pneumoniae shows what symptoms?

Rust colored sputum, Lobar pneumonia Signup and view all the answers

What diseases does Strep pneumoniae cause?

Meningitis, OM, Pneumonia, Sinusitis Signup and view all the answers

What are some virulence factors of Strep pneumoniae?

Polysaccharide capsule, IgA protease Signup and view all the answers

Patients with sickle cell disease are particularly susceptible to what?

Strep pneumoniae Signup and view all the answers

Strep pneumoniae is sensitive to what antibiotics?

Macrolides (erythromycin), 3rd generation cephalosporins (ceftriaxone) Signup and view all the answers

How can you prevent Strep pneumoniae?

Vaccine Signup and view all the answers

Adult vaccine to Strep pneumoniae causes what?

T cell response (increase level of IgM only) Signup and view all the answers

Child vaccine to Strep pneumoniae causes what?

Increased IgG due to higher, better T cell response Signup and view all the answers

Strep viridans differs from Strep pneumoniae how?

No capsule, Optochin resistant, Bile insoluble Signup and view all the answers

Strep viridans (especially mutans) can cause what?

Dental caries Signup and view all the answers

Strep viridans group can also affect the heart. What does it do?

Affects the mitral valve - subacute endocarditis Signup and view all the answers

Why does Strep viridans affect damaged valves?

Viridans adheres to platelets (dextrans allow them to do this) Signup and view all the answers

Study Notes

Streptococcus Pneumoniae and Viridans Overview

Both Strep pneumoniae and Strep viridans are classified as alpha-hemolytic streptococci.
Alpha hemolysis indicates partial hemolysis with a green hue around colonies due to hemoglobin oxidation.

Strep Pneumoniae Characteristics

Possesses a polysaccharide capsule, a critical virulence factor.
Sensitive to optochin, distinguishing it from other streptococci.
Exhibits a dual lancet shape, appearing as diplococci.
Soluble in bile, which aids in its identification in laboratory settings.

Clinical Significance of Strep Pneumoniae

Major cause of community-acquired pneumonia (CAP) and associated with the acronym MOPS:
- Meningitis
- Otitis Media (OM)
- Pneumonia
- Sinusitis
Symptoms of CAP include rust-colored sputum and lobar pneumonia.

Virulence Factors of Strep Pneumoniae

Key virulence components include a polysaccharide capsule and IgA protease.
Patients with sickle cell disease have an increased susceptibility to infections caused by Strep pneumoniae.

Antibiotic Sensitivity and Prevention

Strep pneumoniae is sensitive to macrolides (e.g., erythromycin) and third-generation cephalosporins (e.g., ceftriaxone).
Prevention is achievable via vaccination:
- Adult vaccine is a 23-valent polysaccharide vaccine generating T cell responses with specificity to IgM.
- Child vaccine is a 7-valent conjugated vaccine that aims for a robust T cell response and improved IgG levels.

Strep Viridans Characteristics

Lacks a capsule, making it structurally distinct from Strep pneumoniae.
Exhibits resistance to optochin and is bile insoluble, distinguishing it from other groups.

Clinical Importance of Strep Viridans

Particularly notable is Strep mutans, which is a primary contributor to dental caries.
Can lead to subacute endocarditis, primarily affecting the mitral valve in those with prior valve damage.

Mechanism of Damage in Endocarditis

Strep viridans adheres to platelets via dextrans, allowing attachment to fibrin located in damaged tissues.

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Description

Test your knowledge on Strep pneumoniae and Strep viridans with these flashcards. Explore key concepts such as hemolytic characteristics and virulence factors. Perfect for microbiology students looking to reinforce their learning.