The conference participants agreed with the contributor's diagnosis and comments. Calcific bodies were also noted in many of the sections examined. When apposed, these bodies may look like budding yeast, and their laminated structure creates the illusion of a thick cell wall or capsule. Calcific bodies do not stain with GMS or Gridley's stains. The organism is a saprophyte and occurs commonly in soil and water.
Little information is available concerning the pathogenesis of nocardiosis.
The organisms may gain entry by wound contamination, inhalation, or ingestion. Direct extension or hematogenous dissemination may then occur. Cell mediated immunity is apparently critical to control of infection. In one study, injections of Nocardia rubra cell wall skeleton into enlarged subcutaneous lymph nodes of bovine leukemia virus positive cattle had an antitumor effect. N. asteroides has been reported to both inhibit phagosome-lysosome fusion and resist the microbicidal effects of neutrophils.