1081 - Characteristics and Outcomes of Nocardiosis in a Solid Organ Transplant Cohort

Background: Solid organ transplant (SOT) recipients are at increased risk for nocardiosis, an infection associated with high risk of relapse and/or mortality. Novel antimicrobial regimens may be associated with improved outcomes. Here we describe a cohort of SOT recipients with Nocardia infection, to address knowledge gaps regarding the epidemiology of, risk factors for, and outcomes of nocardiosis in SOT.

Methods: This is a single center retrospective study performed at a 700 bed academic transplant center. Cases of nocardiosis were identified via review of microbiology laboratory records; transplant status was ascertained via the electronic medical record. All SOT recipients with a culture growing Nocardia species between 1/1/2007 and 12/31/2019 were included.Figure 1. Epidemiologic curve


Results: We identified 27 SOT recipients with nocardiosis. The incidence of nocardiosis increased over the study period (Figure 1). Demographic data are shown in Table 1. Induction immunosuppression varied; 37% received an interleukin-2 receptor antagonist, 30% received anti-thymocyte globulin, and 18% received steroids alone. The majority of positive cultures were from respiratory specimens (63%) and the most common species identified were N. nova complex and N. farcinica (Table 2). The majority of patients were lymphocytopenic and received treatment for rejection. 92% of subjects received a sulfonamide agent as part of their treatment regimen and 73% received an oxazolidinone (Table 3). 73% of subjects had resolution of infection without relapse; 15% expired.Table 1. Cohort demographics
Table 2. Infection characteristics
Table 3. Treatment and outcomes


Conclusion: The epidemiology and risk factors for nocardiosis in this SOT cohort are consistent with established literature. Less than a third of cases occurred in subjects who had received lymphocyte-depleting induction immunosuppression; however, most subjects were lymphocytopenic at diagnosis. While nearly all subjects received a sulfonamide as part of their treatment, the majority also received an agent from the newer drug class of oxazolidinones. Overall outcomes were positive, but treatment varied, thus limiting the ability to determine if a particular combination regimen is beneficial. Multicenter randomized studies are needed to better address knowledge gaps particularly pertaining to treatment.