Bacteriology: Streptococcus anginosus group: practice question

A Microbiology 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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Microbiology · Bacteriology: Streptococcus anginosus group

Sample item

A man with chronic sinusitis develops a frontal lobe abscess. Aspirated pus grows catalase-negative Gram-positive cocci in chains with a butterscotch odour, and they are normal oropharyngeal flora. Which organisms are most likely?

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

The answer and the reasoning

B. Streptococcus anginosus group

The Streptococcus anginosus (milleri) group is part of oral and gut flora and is characteristically linked to deep abscesses in the brain, liver and lung. Colonies often smell of caramel or butterscotch.

Option by option

  • A. Streptococcus mutans

    S. mutans is the main cause of dental caries and a cause of viridans endocarditis, not typical brain abscess.

  • B. Streptococcus anginosus group (correct)

    Correct. The anginosus group typically forms deep abscesses and smells of caramel.

  • C. Enterococcus faecalis

    E. faecalis is a salt-tolerant bile-esculin positive organism of urinary and biliary infection.

  • D. Streptococcus agalactiae

    S. agalactiae causes neonatal sepsis and meningitis, with no butterscotch odour.

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.

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Questions about this Microbiology question

What is the answer to this Microbiology question?

The best answer is B, Streptococcus anginosus group. The Streptococcus anginosus (milleri) group is part of oral and gut flora and is characteristically linked to deep abscesses in the brain, liver and lung.

Why is "Streptococcus mutans" not the answer?

S. mutans is the main cause of dental caries and a cause of viridans endocarditis, not typical brain abscess.

Why is "Enterococcus faecalis" not the answer?

E. faecalis is a salt-tolerant bile-esculin positive organism of urinary and biliary infection.

Why is "Streptococcus agalactiae" not the answer?

S. agalactiae causes neonatal sepsis and meningitis, with no butterscotch odour.

What concept does this question test?

It tests Bacteriology: Streptococcus anginosus group in Microbiology. Colonies often smell of caramel or butterscotch.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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 Bacteriology: Streptococcus anginosus group?

Make a one-line identity card for each organism: shape and stain, defining test, toxin, disease and drug. Then use the flashcards and the other Microbiology 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.