Streptococcus pneumoniae & viridans
Gram ⊕Lancet-shaped diplococci
Streptococcus pneumoniae
α-hemolytic, optochin-sensitive, bile-soluble, encapsulated — MOPS killer.
🎬 The Rusty Lancet Duo
Two lancets in a slimy capsule, rusting the lungs
Scene illustration coming soon.
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Lancet pairLancet-shaped GRAM-POSITIVE DIPLOCOCCI.
🔗 Two lancets = diplococci.
🔬 Identification
- •Lancet-shaped gram-positive diplococci, catalase –.
- •α-hemolytic, OPTOCHIN-sensitive, BILE-soluble.
- •Polysaccharide capsule; positive Quellung reaction.
- •IgA protease aids mucosal colonization.
🦠 Disease (MOPS)
- •Meningitis (#1 in adults).
- •Otitis media (#1 in children).
- •Pneumonia (#1 CAP; rusty sputum, lobar).
- •Sinusitis.
⚠️ High-risk hosts
- •Asplenia / sickle cell (encapsulated organism, poor opsonization).
- •Elderly, immunocompromised.
🛡️ Prevention
- •PCV (conjugate) — T-cell dependent, used in children & adults.
- •PPSV23 (polysaccharide) — adults ≥65 and high-risk.
🧠 Mnemonics
MOPSS. pneumoniae causes Meningitis, Otitis media, Pneumonia, Sinusitis.
OPTOCHIN = pneumO (sensitive)Pneumococcus is optochin-Sensitive and bile-Soluble; viridans is Resistant/insoluble.
Rusty sputum + lobar = pneumococcusClassic CAP buzzword.
🩺 Classic boards tip-off
Older adult with lobar pneumonia and rust-colored sputum → S. pneumoniae. Asplenic patient with overwhelming sepsis → encapsulated pneumococcus.
Lesson Info
- Duration
- 9 minutes
- Status
- Completed
- Topic
- Microbiology
- Unit
- Bacteria
