Cystic fibrosis pathogens: Burkholderia cepacia complex: 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 · Cystic fibrosis pathogens: Burkholderia cepacia complex

Sample item

An adolescent with cystic fibrosis who had stable lung function develops fever, rapid decline and necrotising pneumonia with bacteraemia. Sputum grows an oxidase-positive Gram-negative bacillus on selective BCSA medium that is intrinsically resistant to polymyxins and aminoglycosides. Which organism is most likely?

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

The answer and the reasoning

D. Burkholderia cepacia complex

Burkholderia cepacia complex infects cystic fibrosis lungs and can cause cepacia syndrome, a rapid decline with necrotising pneumonia and septicaemia. It is intrinsically resistant to polymyxins and aminoglycosides, and it is selected on BCSA medium. It also infects patients with chronic granulomatous disease.

Option by option

  • A. Haemophilus influenzae

    Haemophilus influenzae is a fastidious organism that is polymyxin-susceptible and does not grow on BCSA.

  • B. Staphylococcus aureus

    Staphylococcus aureus is a Gram-positive coccus and is oxidase negative.

  • C. Pseudomonas aeruginosa

    Pseudomonas aeruginosa is common in cystic fibrosis but is usually susceptible to polymyxins and aminoglycosides.

  • D. Burkholderia cepacia complex (correct)

    Correct. Intrinsic polymyxin resistance and the clinical syndrome point to B. cepacia complex.

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 D, Burkholderia cepacia complex. Burkholderia cepacia complex infects cystic fibrosis lungs and can cause cepacia syndrome, a rapid decline with necrotising pneumonia and septicaemia.

Why is "Haemophilus influenzae" not the answer?

Haemophilus influenzae is a fastidious organism that is polymyxin-susceptible and does not grow on BCSA.

Why is "Staphylococcus aureus" not the answer?

Staphylococcus aureus is a Gram-positive coccus and is oxidase negative.

Why is "Pseudomonas aeruginosa" not the answer?

Pseudomonas aeruginosa is common in cystic fibrosis but is usually susceptible to polymyxins and aminoglycosides.

What concept does this question test?

It tests Cystic fibrosis pathogens: Burkholderia cepacia complex in Microbiology. It is intrinsically resistant to polymyxins and aminoglycosides, and it is selected on BCSA medium. It also infects patients with chronic granulomatous disease.

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 Cystic fibrosis pathogens: Burkholderia cepacia complex?

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.