Spine: pyogenic spondylodiscitis organism: practice question

A Orthopaedics 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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Orthopaedics · Spine: pyogenic spondylodiscitis organism

Sample item

A 62-year-old diabetic man has two weeks of severe back pain and fever. ESR is 95 mm in the first hour, and MRI shows endplate erosion and a T2 bright disc at L3-L4. Which organism is the most common cause of this infection?

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

The answer and the reasoning

C. Staphylococcus aureus

Staphylococcus aureus accounts for more than half of pyogenic vertebral infections, typically seeded through the haematogenous route via the arterial supply and the paravertebral venous plexus. Gram-negative organisms are seen mainly after urinary tract instrumentation or with intravenous drug use. Blood cultures or image-guided biopsy confirm the organism.

Option by option

  • A. Escherichia coli

    E. coli is the next most frequent group in elderly patients with urinary sources but is not the commonest.

  • B. Pseudomonas aeruginosa

    Pseudomonas is particularly linked to intravenous drug use and is less frequent overall.

  • C. Staphylococcus aureus (correct)

    Correct. Staphylococcus aureus is the commonest pathogen in pyogenic spondylodiscitis.

  • D. Salmonella typhi

    Salmonella spinal infection is uncommon and mostly seen in sickle cell disease.

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 Orthopaedics question

What is the answer to this Orthopaedics question?

The best answer is C, Staphylococcus aureus. Staphylococcus aureus accounts for more than half of pyogenic vertebral infections, typically seeded through the haematogenous route via the arterial supply and the paravertebral venous plexus.

Why is "Escherichia coli" not the answer?

E. coli is the next most frequent group in elderly patients with urinary sources but is not the commonest.

Why is "Pseudomonas aeruginosa" not the answer?

Pseudomonas is particularly linked to intravenous drug use and is less frequent overall.

Why is "Salmonella typhi" not the answer?

Salmonella spinal infection is uncommon and mostly seen in sickle cell disease.

What concept does this question test?

It tests Spine: pyogenic spondylodiscitis organism in Orthopaedics. Gram-negative organisms are seen mainly after urinary tract instrumentation or with intravenous drug use. Blood cultures or image-guided biopsy confirm the organism.

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 Spine: pyogenic spondylodiscitis organism?

Pair each fracture with its classic complication and nerve injured. Then use the flashcards and the other Orthopaedics 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.