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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 pair

Lancet-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

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