Respiratory medicine: Mycoplasma pneumonia: practice question

A General Medicine question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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General Medicine · Respiratory medicine: Mycoplasma pneumonia

Sample item

A 20-year-old student has had 10 days of dry cough, headache and low-grade fever. The chest radiograph shows patchy reticular shadowing that looks worse than he feels. A sputum Gram stain shows no organisms, and a blood film shows red cell clumping that disperses on warming. Which antibiotic is most appropriate?

AAmoxicillinBAzithromycinCCeftriaxoneDCefuroxime

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Azithromycin

Mycoplasma pneumoniae causes atypical pneumonia with cold agglutinins. It has no cell wall, so beta-lactam antibiotics are ineffective. A macrolide such as azithromycin, doxycycline or a fluoroquinolone is used.

Option by option

A. Amoxicillin
Amoxicillin acts on the cell wall, which this organism lacks.
B. Azithromycin (correct)
Correct. Macrolides inhibit protein synthesis and are effective against cell wall-deficient organisms.
C. Ceftriaxone
Ceftriaxone is a beta-lactam and is ineffective against Mycoplasma.
D. Cefuroxime
Cefuroxime is a beta-lactam and has no activity against cell wall-deficient organisms.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this General Medicine question

What is the answer to this General Medicine question?

The best answer is B, Azithromycin. Mycoplasma pneumoniae causes atypical pneumonia with cold agglutinins.

Why is "Amoxicillin" not the answer?

Amoxicillin acts on the cell wall, which this organism lacks.

Why is "Ceftriaxone" not the answer?

Ceftriaxone is a beta-lactam and is ineffective against Mycoplasma.

Why is "Cefuroxime" not the answer?

Cefuroxime is a beta-lactam and has no activity against cell wall-deficient organisms.

What concept does this question test?

It tests Respiratory medicine: Mycoplasma pneumonia in General Medicine. It has no cell wall, so beta-lactam antibiotics are ineffective. A macrolide such as azithromycin, doxycycline or a fluoroquinolone is used.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Respiratory medicine: Mycoplasma pneumonia?

For each disease know the classic presentation, the best test, and the first-line treatment. Then use the flashcards and the other General Medicine questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.