Bacteriology: Bartonella henselae: 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: Bartonella henselae

Sample item

A man with HIV and a CD4 count of 40 cells per cubic mm has multiple red-purple, friable, bleeding papules on the skin. He keeps kittens at home. Biopsy shows lobular proliferation of capillaries with neutrophils and granular purple material. Which organism and demonstration method fit best?

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

The answer and the reasoning

A. Bartonella henselae, shown by Warthin-Starry silver stain

Bacillary angiomatosis is caused by Bartonella henselae (cat scratch, cat flea) or Bartonella quintana in immunosuppressed patients. The lesions resemble Kaposi sarcoma, but biopsy shows neutrophils and clumps of bacilli that are visible with Warthin-Starry silver stain. Treatment is with erythromycin or doxycycline.

Option by option

  • A. Bartonella henselae, shown by Warthin-Starry silver stain (correct)

    Neutrophilic capillary proliferation with silver-stained bacilli in a patient with cats is bacillary angiomatosis.

  • B. Human herpesvirus 8, shown by LANA immunostaining

    HHV-8 causes Kaposi sarcoma, which shows spindle cells and has no neutrophilic infiltrate or bacilli.

  • C. Staphylococcus aureus, shown by Gram stain

    Staphylococcal infection produces pyogenic lesions that stain on Gram stain but are not vascular proliferations with silver-staining bacilli.

  • D. Mycobacterium avium complex, shown by Ziehl-Neelsen stain

    Mycobacterium avium complex causes disseminated disease with foamy macrophages and does not produce vascular papules.

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 A, Bartonella henselae, shown by Warthin-Starry silver stain. Bacillary angiomatosis is caused by Bartonella henselae (cat scratch, cat flea) or Bartonella quintana in immunosuppressed patients.

Why is "Human herpesvirus 8, shown by LANA immunostaining" not the answer?

HHV-8 causes Kaposi sarcoma, which shows spindle cells and has no neutrophilic infiltrate or bacilli.

Why is "Staphylococcus aureus, shown by Gram stain" not the answer?

Staphylococcal infection produces pyogenic lesions that stain on Gram stain but are not vascular proliferations with silver-staining bacilli.

Why is "Mycobacterium avium complex, shown by Ziehl-Neelsen stain" not the answer?

Mycobacterium avium complex causes disseminated disease with foamy macrophages and does not produce vascular papules.

What concept does this question test?

It tests Bacteriology: Bartonella henselae in Microbiology. The lesions resemble Kaposi sarcoma, but biopsy shows neutrophils and clumps of bacilli that are visible with Warthin-Starry silver stain. Treatment is with erythromycin or doxycycline.

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: Bartonella henselae?

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.