Trichosporon mycotoxinivorans , a Novel Respiratory Pathogen in Patients with Cystic Fibrosis

Abstract

This report describes the molecular epidemiology, in vitro susceptibility, colonial and microscopic morphologies, and biochemical features of Trichosporon mycotoxinivorans, a newly recognized pathogen that appears to have a propensity for patients with cystic fibrosis. The index patient died with histologically documented Trichosporon pneumonia complicating cystic fibrosis. This is also the first report of disease caused by a Trichosporon species in a nontransplant patient with cystic fibrosis. As T. mycotoxinivorans has not previously been recognized as a respiratory pathogen, the significance of its recovery from sputum samples was not initially appreciated. Genetic analysis of archived clinical samples found three additional cases of T. mycotoxinivorans infection which had previously been identified as other members of the genus. An additional isolate of T. mycotoxinivorans was identified from a clinical sample on initial testing. Three of these four cases were also patients with cystic fibrosis. All isolates had MICs at 48 h of amphotericin B of >1 g/ml and of echinocandins of >16 g/ml, but they displayed various susceptibilities to the triazoles. In summary, Trichosporon mycotoxinivorans is a newly recognized human pathogen that is associated with cystic fibrosis.Trichosporon species are uncommon but potentially lifethreatening causes of localized and disseminated infections in immunocompromised patients. The most common species causing deep-seeded disseminated infection that has been recognized is Trichosporon asahii (11). Other species of Trichosporon are seldom reported as causes of deep-seeded infections. Herein, we describe the first case of human disease caused by Trichosporon mycotoxinivorans. Previously recognized as an industrial source for detoxification of mycotoxins, T. mycotoxinivorans has not been reported to cause disease in humans (20,28). Additional testing of archived isolates of the genus Trichosporon at the University of Texas San Antonio Fungus Testing Laboratory (FTL) revealed three additional cases, including two in patients with cystic fibrosis. These isolates had previously been classified under other species of Trichosporon on the basis of their biochemical profiles alone. A newly acquired sample in the FTL collection, from a cystic fibrosis patient, was also analyzed and identified as T. mycotoxinivorans. This report describes the molecular epidemiology, in vitro susceptibility, colonial and microscopic morphologies, and biochemical features of T. mycotoxinivorans, a newly recognized pathogen that appears to have a propensity for patients with cystic fibrosis. Index case.A 20-year-old male with a history of cystic fibrosis presented to the emergency department complaining of acute onset of dyspnea. He was found to have a right-sided pneumothorax. He was treated with supplemental oxygen, a chest tube was placed, and he was then admitted to the ward for supportive care. His recent medical history was notable for receiving home therapy with piperacillin-tazobactam and trimethoprim-su...

Disseminated Trichosporon mycotoxinivorans, Aspergillus fumigatus, and Scedosporium apiospermum Coinfection after Lung and Liver Transplantation in a Cystic Fibrosis Patient

“…It appeared to be phylogenetically closely related to Trichosporon loubieri, a nonpathogenic species. T. mycotoxinivorans was initially considered nonpathogenic, until the first case of invasive and fatal pneumonia in a nontransplanted CF patient was reported in 2009, followed by the retrospective identification of three additional cases in CF patients from archived clinical samples, suggesting a propensity of T. mycotoxinivorans for colonizing airways in CF patients (9).…”

Isolation and characterization of yeasts capable of efficient utilization of hemicellulosic hydrolyzate as the carbon source

“…The proximity of the yeast strains isolated in this study to T. mycotoxinivorans varied between 99% (CBA-506, CBA-531) and 100% (CBA-507) identity. These Trichosporon species have been previously described as pathogenic yeasts (Girmenia et al, 2005;Hickey et al, 2009;Sharman et al, 2010;Gabriel et al, 2011). These species share a close similarity in the phylogenetic tree based on the D1/D2 regions of the 26S ribosomal DNA, and the (approximately) 600-bp 18S ribosomal DNA.…”

Cultivation of Trichosporon mycotoxinivorans in sugarcane bagasse hemicellulosic hydrolyzate

“…It occurrence was also described in grape marc in southern Peloponnese, Greece, by Ntougias et al (2010), which reports it as closely related to an unidentified member of Trichosporon clade, isolated from the xylophagous beetle Phrenapetes bennetti (Tenebrionidae), collected in Panama by Suh et al (2005). Hickey et al (2009) have found T. mycotoxinivorans to be a novel respiratory pathogen in patients with cystic fibrosis. Together, these findings suggest a cosmopolitan habitat and opportunist pathogenicity, which has also been described by Chagas-Neto et al (2008) as common features of this genus.…”