Bacteriology: Rickettsia rickettsii: 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: Rickettsia rickettsii

Sample item

A child returns from a camping trip with fever, severe headache and a rash that began at the wrists and ankles, then spread centrally and onto the palms and soles. A tick was removed from the scalp. Which organism is most likely?

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

The answer and the reasoning

D. Rickettsia rickettsii

Rocky Mountain spotted fever is caused by Rickettsia rickettsii and transmitted by ixodid ticks. The rash starts peripherally and moves centripetally, often involving palms and soles, and doxycycline is started on suspicion.

Option by option

  • A. Coxiella burnetii

    Coxiella burnetii causes Q fever, usually by inhalation and without a rash.

  • B. Borrelia burgdorferi

    Borrelia burgdorferi causes an expanding annular erythema migrans rather than a spotted peripheral rash.

  • C. Orientia tsutsugamushi

    O. tsutsugamushi causes scrub typhus after a mite bite, usually with an eschar.

  • D. Rickettsia rickettsii (correct)

    Correct. A centripetal rash including palms and soles after a tick bite fits R. rickettsii.

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.

More Microbiology questions

Questions about this Microbiology question

What is the answer to this Microbiology question?

The best answer is D, Rickettsia rickettsii. Rocky Mountain spotted fever is caused by Rickettsia rickettsii and transmitted by ixodid ticks.

Why is "Coxiella burnetii" not the answer?

Coxiella burnetii causes Q fever, usually by inhalation and without a rash.

Why is "Borrelia burgdorferi" not the answer?

Borrelia burgdorferi causes an expanding annular erythema migrans rather than a spotted peripheral rash.

Why is "Orientia tsutsugamushi" not the answer?

O. tsutsugamushi causes scrub typhus after a mite bite, usually with an eschar.

What concept does this question test?

It tests Bacteriology: Rickettsia rickettsii in Microbiology. The rash starts peripherally and moves centripetally, often involving palms and soles, and doxycycline is started on suspicion.

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 Bacteriology: Rickettsia rickettsii?

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.