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Multiple Choice
Which feature of S. pneumoniae is required for the increased virulence of certain strains?
A
Presence of cord factor.
B
Polysaccharide capsule.
C
Presence of hemagglutinin spikes.
D
Lancefield group A carbohydrate.
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Verified step by step guidance
1
Step 1: Understand the concept of virulence factors in bacteria, which are specific traits that enable a microorganism to cause disease more effectively.
Step 2: Recognize that Streptococcus pneumoniae has several features, but the one most directly linked to increased virulence is its ability to evade the host immune system.
Step 3: Identify that the polysaccharide capsule of S. pneumoniae is a key virulence factor because it prevents phagocytosis by host immune cells, allowing the bacteria to survive and multiply.
Step 4: Differentiate the polysaccharide capsule from other features such as cord factor (associated with Mycobacterium tuberculosis), hemagglutinin spikes (found in viruses like influenza), and Lancefield group carbohydrates (used for classification of streptococci but not directly linked to virulence in S. pneumoniae).
Step 5: Conclude that the presence of the polysaccharide capsule is required for the increased virulence of certain strains of S. pneumoniae.