In this patient with a subacute decline, pulmonary infiltrates, allograft abscesses, and recent residence in the Southwest, the most likely diagnosis is disseminated coccidioidomycosis. Coccidioidomycosis is acquired by inhalation of arthroconidia and in the normal host is typically associated with a relatively mild, self-limited respiratory infection. However, disseminated disease occurs in the majority of immunocompromised patients. Coccidioides species may disseminate to almost any tissue, although the skin, bone, and meninges are common sites. 9 A renal biopsy would be the next step in this case, with the purpose of looking for the prototypic spherules. The staff of the microbiology laboratory should be informed of the concern about coccidioidomycosis, to minimize the risk of exposure during handling of the culture plates. The use of molecular genetic techniques has shown that coccidioidomycosis is caused by at least two species: Coccidioides immitis and C. posadasii. These two species appear similar morphologically but seem to have different geographic distributions, with C. immitis predominantly in the San Joaquin Valley area of southern California. Since this patient had lived in a desert region of the Southwest, C. posadasii would be the more likely species. The pathologic or therapeutic implications of the genetic distinction remain unclear.
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