Abstract and Introduction
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.
Coccidioidomycosis is an endemic fungal infection of the desert southwestern United States, and its incidence in Arizona has markedly increased over the past 2 decades. Solid organ transplant recipients are exquisitely susceptible to severe coccidioidal infection because of the iatrogenic suppression of the cell-mediated immunity required to control this infection. Indeed, coccidioidal infection in transplant patients is frequently disseminated, with high mortality rates. Recently, the Transplant-Associated Infection Surveillance Network reinforced the notion that endemic fungi, including Coccidioides, are important pathogens causing invasive fungal infections in organ transplant recipients.
Tests currently used to diagnose coccidioidomycosis include serology, culture, cytology, histology, molecular analysis with tools such as polymerase chain reaction (PCR), and detection of antigenuria. Small case series of transplant recipients with coccidioidomycosis have indicated that such patients often display lower seroreactivity compared with that of immunocompetent patients; nonetheless, little is known about the sensitivity of these and other diagnostic tests in patients who have undergone solid organ transplantation. Therefore, we conducted a retrospective review to better characterize the utility of various diagnostic tests in the evaluation of newly acquired, active coccidioidomycosis in solid organ transplant recipients.