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Kaplan Qbank USMLE



Author11 Posts
  #1

A 51-year-old man received an orthotopic cardiac transplant a month ago. He has developed a fever with cough over the past 5 days. On physical examination his temperature is 37.7 C. A chest CT scan shows consolidation with abscess formation involving the left lower lobe. A sputum gram stain reveals normal upper respiratory tract flora. He does not respond to antibiotic therapy over the next 6 months. His mental status deteriorates and MR imaging of the brain shows multiple abscesses. He is most likely to have an infection with which of the following organisms?

A Mycoplasma pneumoniae
B Aspergillus fumigatus
C Mycobacterium avium-intracellulare
D Nocardia brasiliensis
E Cytomegalovirus
F Pneumocystis carinii

  #2

Nocardia..d?

  #3

Looks like a tough question, The treatment doesnt respond antibiotics and the patient is under immunosuppressive drugs because he has had a past heart transplant. This make me think that the infection could be aspergillus fumigatus(predilection for the immunocompromised). I'm not a hundred percent sure but thats what I would go with . Whats the answer ME007?


B Aspergillus fumigatus

  #4

I thought of Cardiac transplant-->Immunocompromised--->Nocardia--->Lung infection-consolidation--->dissemination-->multiple brain abscesses

Wats the answer?Meoo7?


  #5

I definately understand your thinking, I was thinking that too, Its just that , sulphonamides should take care of a nocardia infection. But we wont know the answer untill me007 tell us.

  #6

B - Incorrect. Aspergillus does not typically produce abscesses.

D - CORRECT. Nocardia can persist and lead to chronic abscesses. It can appear in immunocompromissed patient

  #7

aspergillus DOES produce abscess, but SOLITAY vr. Nocardia MULTIPLE

  #8

aspergillus refers to fungus ball (visible on x-ray) of matted hyphae and fruiting bodies that develops in preexistin cavity in the lung (e.g. old TB site).
Cause of massive hemoptysis.

  #9

i was referring to brain adscess, but what you are saying is true - no doubtnod

  #10

but is nocardia normal flora ? I thought not, why does it say "A sputum gram stain reveals normal upper respiratory tract flora. "

  #11

Neither Nocardia or Aspergillus are normal respiratory flora. This question doesn't give you a whole lot of information. I have no idea what Nocardia is treated with, so can't help you on that score.

I have seen a slide of a brain with Aspergillus in it way back in the 70's. It was one of the patients at our hospital. I remember distinctly someone showing us the slide. It was prepared in Histology, not in micro. Nocardia can be in the brain also. I also remember another patient back in the 70's who supposedly complained of a headache. He was admitted and multiple sites were cultured. He had Nocardia EVERYWHERE, including, eventually, his brain I believe. He died, as did the Aspergillus patient.

Sputum specimens are notoriously bad specimens. We reject quite a few, as we are mandated to screen them by counting epithelials/low power field by our accrediting agency CAP. We reject if we see >25 epis/LPF. Even if they pass muster, we have gone to reporting out either predominant organism or just a comment "mixed bacterial morphotypes seen" if nothing is predominant. The amount of sputum specimens (actual expectorated sputums) we receive for culture has dropped WAY down from what it used to be. We do receive suctioned specimens from patients on vents, and BAL (bronchial alveolar lavage) and bronchoscopy specimens. BAL's have pretty much replaced bronchoscopy specimens. These have saline added and we plate with calibrated loops in order to get a ballpark quantitation on pathogens (0.01u and 0.001 u loop).

Getting back to the question, I think it is another vague Kaplan question, unfortunately.

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Clinical Microbiology since 1974







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