Topic Completed: 1 September 2011

Minor changes: 11 June 2021

Copyright: 2003-2021,, Inc.

PubMed search: nocardia [title] pulmonary

Elliot Weisenberg, M.D.
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Cite this page: Weisenberg E. Nocardia. website. Accessed October 25th, 2021.
Clinical features
  • Ubiquitous saphrophyte; disease caused by inhalation or direct implantation into skin
  • More than 30 species with clinical significance (Clin Microbiol Rev 2006;19:259)
  • Opportunistic lung infection associated with transplantation, chemotherapy, immunosuppression, steroids
  • Disease is relatively uncommon in HIV likely due to sulfonamide prophylaxis directed against P. jeroveci; HAART treatment may be effective (Can J Infect Dis Med Microbiol 2009;20:e103)
  • Complication of alveolar proteinosis
Gross images

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Microscopic (histologic) description
  • Focal bronchopneumonia with microabscesses, variable histiocytic response and ill defined granulomas
  • If identified by anatomic pathologist, clinical microbiology laboratory should be notified as routine culture may not isolate the organism
Microscopic (histologic) images

Contributed by Yale Rosen, M.D.
Small abscess

Small abscess

Gram stain Gram stain

Gram stain

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Modified acid fast stain shows weakly acid fast branching, filamentous bacilli

Modified acid fast stain
shows weakly acid fast
branching, filamentous bacilli

Positive stains
  • Modified acid fast, Fite, Gram stain and GMS
  • Gram stain: slender, slightly beaded, branching filamentous bacilli
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