The utility of diagnostic testing for active coccidioidomycosis in solid organ transplant recipients

Solid organ transplant recipients who acquire coccidioidomycosis have high rates of disseminated infection and mortality, and diagnosis of infection in these immunosuppressed patients is challenging because of suboptimal sensitivity of diagnostic tests. To characterize the utility of diagnostic tests for coccidioidomycosis in this population, we conducted a retrospective chart review of all solid organ transplant recipients with newly acquired coccidioidomycosis who were seen at our institution from 1999 to 2011. We identified 27 solid organ transplant recipients with newly acquired, active coccidioidomycosis. The positivity of any single serologic test ranged from 21% (5/24; immunoglobulin M by immunodiffusion) to 56% (14/25; immunoglobulin G by enzyme immunoassay), compared with 77% (20/26) seropositivity for a battery of serologic tests (enzyme immunoassay, immunodiffusion and complement fixation). Serology performed approximately 1 month later increased positive test findings to 92%. Culture of respiratory or tissue specimens yielded Coccidioides sp in 54% (14/26) of the cultures submitted, and 10/16 (63%) of patients tested. Chest-computed tomography was abnormal in 86% (19/22). Multiple test modalities may be needed to diagnose coccidioidomycosis in solid organ transplant recipients, and repeat studies over time may increase sensitivity of the diagnostic assays.