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29 Cards in this Set
- Front
- Back
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What are the three types of surface components used by pathogens to avoid phagocytosis?
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membrane-bound proteins
slimy polysaccharide capsules LPS |
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How do certain surface components prevent phagocytosis?
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prevent deposition of antibodies and complement on surface
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Give an example of a pathogen that uses an extensive polysaccharide capsule to avoid phagocytosis.
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Streptococcus pneumoniae
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Describe the Streptococcus pneumoniae morphology
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non-motile
non-sporulating Gram-positive cocci usually diplococci, but sometimes occur singly or in small chains |
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Streptococcus pneumoniae is a transient member of the normal flora (T/F)
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T
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Streptococcus pneumoniae colonizes the ___ of ___% of healthy adults.
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Nasopharynx. 40%.
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Streptococcus pneumoniae is very sensitive to what?
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heat, cold, drying
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Describe Streptococcus pneumoniae transmission
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close contact via respiratory droplets
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What are the major virulence factors of Streptococcus pneumoniae?
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anti-phagocytic capsule
several adhesins pneumolysin lipoteichoic acid (LTA) |
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What does pneumolysin do?
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binds to cholesterol in the host cell membrane and disrupts it by forming pores
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The major clinical symptoms associated with Streptococcus pneumoniae are...
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pneumonia, bacteremia, meningitis, otitis media (ear infection)
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Streptococcus pneumoniae is an opportunistic pathogen (T/F)
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T
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Name two groups at increased risk to develop disease from Streptococcus pneumoniae
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smokers and drinkers
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What are the two forms of pneumococcal pneumonia?
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bronchial
lobar |
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Bronchial pneumonia is most prevalent in...
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infancts, young children, and elderly
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Lobar pneumonia more prevelent in...
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young adults
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How does pneumotoxin function during infection?
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- facilitates colonization by damaging host mucosal cells
- induces local inflammatory response |
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What causes meningitis?
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When Streptococcus pneumoniae from bloodstream attach to membranes that cover brain
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What happens when Streptococcus pneumoniae lyse in the lung?
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pneumotoxin is released, damaging the host mucosal cells, which impairs host ability to clear bacteria caught in mucous
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What is the min criteria for Streptococcus pneumoniae identification?
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Gram-positive staining, hemolytic activity, and bile sensitivity in a sample from sputum, blood or cerebrospinal fluid
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On blood agar in aerobic conditions, Streptococcus pneumoniae causes ___ hemolysis
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alpha (partial hemolysis from reduction of hemoglobin)
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On blood agar in anaerobic conditions, Streptococcus pneumoniae causes ___ hemolysis
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beta (complete lysis)
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The Streptococcus pneumoniae capsule by itself is toxic (T/F)
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F
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___ different types of Streptococcus pneumoniae capsule have been identified
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90
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An antibody response to Streptococcus pneumoniae cannot be induced (T/F)
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F
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How is the capsular type of Streptococcus pneumoniae determined? What is the name given to the reaction occuring in a positive result?
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sample of bacterial colony mixed with specific monoclonal antibody. Quellung reaction
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Streptococcus pneumoniae mutants lacking capsule are pathogenic (T/F)
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F
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What part of complement is responsible for opsonization?
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C3b
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What is the current Streptococcus pneumoniae vaccine?
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purified capsular polysaccharide antigens from 23 types of Streptococcus pneumoniae
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