Questions and Answers
Match the Lancefield group to the correct species:
S.equismimilis = C S.bovis group = D, non-Enterococcus S.agalactiae = B E.faecalis = D, Enterococcus S.mutans = None S.pyogenes = A E.faecium = Enterococcus, D S.anginosus = F
Lancefield's classification of Streptococcus is based on?
Cell wall polysaccharide
Streptolysin O is?
Antigenic
What would be an incorrect reaction for Enterococcus?
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Sequelae of group ___________________________ infection may lead to acute rheumatic fever or acute glomerulonephritis.
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Colonies of Streptococcus pneumoniae at 24 hours are typically?
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What are the best tests to identify B-hemolytic streptococci isolated from a throat culture of a 15-year-old male?
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What is the expected reaction of the B-hemolytic streptococci for Species: Streptococcus pyogenes?
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What is the expected reaction of the B-hemolytic streptococci for Species: Streptococcus agalactiae?
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What is the expected reaction of the B-hemolytic streptococci for Species: Groups C, F, and G?
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What is the expected reaction for the a-hemolytic and non-hemolytic streptococci for Species: Group D Enterococcus?
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What is the expected reaction for the a-hemolytic and non-hemolytic streptococci for Species: Group D-S.bovis group?
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What is the expected reaction for the a-hemolytic and non-hemolytic streptococci for Species: Streptococcus pneumoniae?
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What is the expected reaction for the a-hemolytic and non-hemolytic streptococci for Species: Viridans streptococci?
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Identify B-hemolytic streptococci that are PYR negative, CAMP negative, resistant to bacitracin, and susceptible to sulfamethoxazole.
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The nutritionally variant streptococci require?
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What has intrinsic resistance to penicillin and the aminoglycosides, shows acquired resistance to many antibiotics including vancomycin, and are nosocomial pathogens?
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Study Notes
Lancefield Classification
- Lancefield groups categorize Streptococcus species based on specific polysaccharide antigens found in cell walls.
- Group A Streptococcus matches with S.pyogenes, which is associated with harmful infections.
- Group B Streptococcus corresponds to S.agalactiae, significant in neonatal infections.
- S.equismimilis falls under Group C.
- Non-Enterococcus categories include S.bovis group (D) and additional groups such as C, F, or G.
- Enterococcus species like E.faecalis and E.faecium correspond to Group D.
Streptococcus Characteristics
- Streptolysin O is an antigenic component important for serological testing.
- Streptococcus pneumoniae colonies at 24 hours present as mucoid and alpha-hemolytic.
- Group-specific reactions are essential for identifying beta-hemolytic streptococci:
- S.pyogenes typically shows PYR positive and bacitracin susceptible.
- S.agalactiae is usually CAMP positive and PYR negative.
Clinical Implications
- Infections caused by Group A Streptococcus can lead to complications such as acute rheumatic fever or acute glomerulonephritis.
- Enterococci have intrinsic resistance to penicillin and aminoglycosides, posing a challenge in treating infections and may show acquired resistance to other antibiotics like vancomycin.
- Nutritionally variant streptococci require Vitamin B6 for growth, highlighting their specific nutritional needs.
Test Identification
- For identifying beta-hemolytic streptococci, tests like bacitracin sensitivity and PYRase are crucial.
- Distinctions between groups can guide appropriate antibiotic therapy and clinical management decisions.
- PYR negative tests are uncommon for Enterococcus, serving as an identification marker for bacterial differentiation.
Additional Information
- Viridans group streptococci, known for their alpha-hemolytic properties, play a role in endocarditis and are generally opportunistic pathogens.
- The expected reactions of non-hemolytic streptococci, like the S.bovis group and Streptococcus pneumoniae, highlight their biochemical profiles for laboratory diagnosis.
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Description
This quiz focuses on Chapter 8 of Clinical Microbiology, specifically matching Lancefield groups to their corresponding species. Each card presents a different species, allowing for interactive learning and memorization of key classifications.
