Which organism is associated with young adults with cold agglutinins and no cell wall?

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Multiple Choice

Which organism is associated with young adults with cold agglutinins and no cell wall?

The key idea is that cold agglutinin hemolysis in young adults is classically linked to an infection with a cell-wall–less organism. Mycoplasma pneumoniae fits this best because it lacks a peptidoglycan cell wall, which explains its Gram stain invisibility and why it’s resistant to beta-lactam antibiotics that target cell walls. It’s also the classic cause of atypical, milder pneumonia in young adults, and the cold agglutinin antibodies (often IgM) can agglutinate red blood cells at low temperatures. The other organisms all have cell walls and are not characteristically associated with cold agglutinin–mediated phenomena.

The key idea is that cold agglutinin hemolysis in young adults is classically linked to an infection with a cell-wall–less organism. Mycoplasma pneumoniae fits this best because it lacks a peptidoglycan cell wall, which explains its Gram stain invisibility and why it’s resistant to beta-lactam antibiotics that target cell walls. It’s also the classic cause of atypical, milder pneumonia in young adults, and the cold agglutinin antibodies (often IgM) can agglutinate red blood cells at low temperatures. The other organisms all have cell walls and are not characteristically associated with cold agglutinin–mediated phenomena.

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