A fatal case of Emergomyces pasteurianus pulmonary infection in an immunocompromised patient with concomitant listeriosis and invasive aspergillosis

A van der Hoeven, S Akerboom, I Norbart, MT van der Beek, MGJ de Boer, EJ Kuijper

Objectives (Introduction)
Immunocompromised patients can become accidental hosts of dimorphic fungi by inhaling dust-borne conidia of fungal species belonging to the genus Emergomyces. Emergomyces is a recently proposed new genus of saprophytic dimorphic fungi related to the genus Emmonsia that are distributed worldwide of which the exact environmental or animal source is still unknown. The genus Emergomyces contains two species:  E. pasteurianus and E. africanus. These species have been found in human cases of disseminated infection in immunocompromised hosts, mainly in South Africa. Both new species lack adiaspores, classically associated with the genus Emmonsia. We report an E. pasteurianus pulmonary infection in an immunocompromised patient. 

Methods (Clinical presentation)
The patient, in the 8th decade of life, with a medical history of B-CLL and chronic kidney failure, was admitted with a decreased level of consciousness and fever. Due to his haematological condition and therapy (cyclophosphamide and prednisone since 11 months) chronic neutropenia had developed. The patient had returned two months earlier from visiting relatives in Iraq. Cerebrospinal fluid (CSF) analysis showed pleocytosis (WBC 613*106/l), normal glucose (2.4 mmol/l) and an elevated protein concentration (3.6 g/l). Cultures of CSF and blood showed Listeria monocytogenes and treatment with high dose amoxicillin was started. After one week, there was moderate neurological improvement, but fever and tachypnea developed, no skin abnormalities were seen. Broad spectrum antibiotics (cefuroxime/gentamicin) were added to amoxicillin treatment. A CT-thorax showed bilateral extensive infiltrative abnormalities, suggestive for fungal infection. A bronchoalveolar lavage (BAL) was performed and liposomal amphotericin B 3 mg/kg was started as empirical therapy. The patient was transferred to the Intensive Care Unit, but died within 36h after onset of tachypnea, because of respiratory insufficiency, cardiac failure and sepsis caused by Pseudomonas aeruginosa. 

Results (Fungal diagnostics)
BAL fluid and serum tested strongly positive in the galactomannan assay (Platelia Aspergillus, Bio-Rad). No Aspergillus could be cultured, but PCR on BAL fluid was positive for Aspergillus fumigatus (ErasmusMC, Rotterdam, the Netherlands). Culture of BAL fluid showed after three days some small colonies suspected for a fungus. After three weeks of incubation, a dimorphic fungus was diagnosed without production of adiaspores at 25°C. Molecular identification by in-house ITS sequencing and additional analysis (ITS and LSU sequencing) at CBS-KNAW Fungal Biodiversity Centre, Utrecht, The Netherlands revealed Emergomyces pasteurianus.

Conclusion
This is the first report - to the best of our knowledge - of a pulmonary infection due to Emergomyces pasteurianus in an immunocompromised Iraqi patient in The Netherlands. Skin lesions were not present. We cannot exclude a more prolonged course of an imported infection. The patient had concomitant Listeria meningitis and invasive pulmonary Aspergillus infection. This case illustrates that clinicians should be aware of the potential presence of mixed fungal infections with fungi other than Aspergillus and Zygomycetes in immunocompromised patients.