INTRODUCTION:Dactylaria (Ochroconis) species is a dematiaceous fungus that rarely causes infection in immunocompromised patients. There are 16 published reports of human Dactylaria infection, five of which presented as isolated primary pulmonary infection. Overall, ∼50% of patients with Dactylaria infection died despite treatment. As more patients are on immunosuppressive therapies, the likelihood of encountering such atypical infections increases. Our goal is to provide further insight into the presentation and diagnostic findings in pulmonary Dactylaria, as well the efficacy of treatment.
CASE PRESENTATION:We present a case of a 58 year-old male at ten months post heart transplant who had a three week history of diarrhea, a draining perirectal skin lesion, and low grade fevers. He reported a 15 pound weight loss over the preceding few weeks. No other symptoms were present. He also had a history of diabetes mellitus, hypertension, hyperlipidemia, and chronic renal insufficiency. His immunosuppressive regimen consisted of mycophenolate 1500 mg t.i.d. and tacrolimus 10 mg t.i.d. Vital signs were normal, with no fever or hypoxia. The remainder of the physical exam was unremarkable except for perirectal and gluteal fold lesions draining white fluid that were found to be due to Herpes simplex virus. The white blood cell count was 5,800, hemoglobin was 7.7 g/dL and creatinine was 3.1 mg/dL. Tacrolimus trough was 14 ng/mL. A routine chest x-ray done after myocardial biopsy revealed new left sided parenchymal lung opacities concerning for infection. Further evaluation with computed tomography (CT) scan of the chest demonstrated a 1.8 × 1.9 cm left lower lobe opacity abutting the posterior pleura (Figure 1) as well as smaller opacities in the right lower lobe and the right upper lobe. Percutaneous CT-guided needle aspiration of the largest lesion revealed fungal forms consistent with Dactylaria (Figure 2) and subsequent growth of Dactylaria species. The patient was started on oral voriconazole 200 mg twice daily. Formal antifungal susceptibility testing revealed voriconazole was effective (with an MIC of 0.125 mcg/mL). Immunosuppressant therapy was reduced. He was discharged home in stable condition after receiving intravenous fluids for volume depletion associated with diarrhea. Amoxicillin/clavulanate and valacyclovir were also prescribed to treat the aforementioned superinfected perirectal HSV lesions. Follow-up CT scans of the chest done at 1, 5, and 8 months after therapy initiation (Figure 1) demonstrated that the initial lesion had lessened in size. The patient is clinically well 11 months after therapy was begun. He continues on treatment dose voriconazole.
DISCUSSIONS:Dactylaria is a ubiquitous fungus in soil and decaying vegetative materials. It was initially reported to cause fungal encephalitis in poultry and first reported as a human pathogen two decades ago. The pathogenesis is unknown but it probably gains entry via inhalation of spores. Its dark appearance (Figure 2) in culture makes it virtually unique among human pathogens. Amphotericin, flucytosine, itraconazole, and voriconazole all have activity against Dactylaria in vitro, but there is no consensus on the drug of choice since there are so few reports. This represents the sixth reported primary pulmonary infection, and the first case treated with voriconazole monotherapy.
CONCLUSION:This report offers further data regarding radiographic characteristics of the infection (five of the cases involved the upper lobes) and appearance, as only two of the prior reports provides radiographs. Further we demonstrate that Dactylaria infection may be indolent in nature, despite its apparently high mortality rate, and that it responds to voriconazole monotherapy.
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