Streptococcus pneumoniae: Difference between revisions
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Streptococcus pneumoniae
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* Invasion through epithelial cells into the bloodstream, using the PAF and pIg receptors |
* Invasion through epithelial cells into the bloodstream, using the PAF and pIg receptors |
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* Capsule and various proteins help it to evade immune system |
* Capsule and various proteins help it to evade immune system |
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+ | == Clinical Presentation == |
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+ | === Asymptomatic carriage === |
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+ | * 4-10% in the general adult population, usually lasting several weeks |
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+ | * Highest in children, up to 30-60% depending on the situation, lasting up to 6 months |
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+ | === Otitis media === |
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+ | |||
+ | === Sinusitis === |
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+ | |||
+ | === Bacteremia === |
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+ | |||
+ | === Pneumonia === |
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+ | |||
+ | * Acute onset of cough (92%), fatigue (63%), shortness of breath (47%), and dyspnea (23%) with documented or subjective fever (92%), chills (77%), sweats, purulent sputum, and pleuritic chest pain (79%) |
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+ | |||
+ | === Meningitis === |
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+ | * Most common cause of meningitis in adults |
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+ | * Acquired by hematogenous spread from nasopharynx, or direct invasion from sinuses |
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+ | * May be secondary to otitis media or sinusitis |
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+ | * CSF leaks and other defects predispose to infection |
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+ | * Diagnostic yield in CSF decrease significantly 4 hours after administration of antibiotics |
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{{DISPLAYTITLE:''Streptococcus pneumoniae''}} |
{{DISPLAYTITLE:''Streptococcus pneumoniae''}} |
Revision as of 20:32, 2 October 2019
Microbiology
- Gram-positive, lancet-shaped diplococci
- 90+ serotypes, based on capsular polysaccharide that is bound to peptidoglycan
- Lab identification is based on α-hemolysis of blood agar (from pneumolysin), optochin susceptibility, and bile salt solubility
Epidemiology
- Present worldwide
- Major cause of morbidity and mortality in children
- Leading cause of under-5 mortality worldwide
Pathophysiology
- Acquired by coughing and sneezing
- Asymptomatic carriage or colonization in the nasopharynx
- Invasion through epithelial cells into the bloodstream, using the PAF and pIg receptors
- Capsule and various proteins help it to evade immune system
Clinical Presentation
Asymptomatic carriage
- 4-10% in the general adult population, usually lasting several weeks
- Highest in children, up to 30-60% depending on the situation, lasting up to 6 months
Otitis media
Sinusitis
Bacteremia
Pneumonia
- Acute onset of cough (92%), fatigue (63%), shortness of breath (47%), and dyspnea (23%) with documented or subjective fever (92%), chills (77%), sweats, purulent sputum, and pleuritic chest pain (79%)
Meningitis
- Most common cause of meningitis in adults
- Acquired by hematogenous spread from nasopharynx, or direct invasion from sinuses
- May be secondary to otitis media or sinusitis
- CSF leaks and other defects predispose to infection
- Diagnostic yield in CSF decrease significantly 4 hours after administration of antibiotics