Exophiala asiatica, a new species from a fatal case in China

Abstract

We describe a new species, Exophiala asiatica, isolated from an infection of the pharynx in a 20-year-old, immunocompetent woman in Nanjing, China. The infection was initiated by a fishbone prick in the pharynx, soon developed with facial nodules but subsequently seemed to have disappeared. Tonsil ulceration with progressive soreness of the pharynx was observed 3 years later. Dysphagia, headache and paralysis occurred four years after first signs of infection. Hyphae and yeast-like cells were detected in tissue and a black fungus was recovered repeatedly from pharynx tissue. Despite antifungal therapy for more than one year, the patient died of apparent cerebral dissemination of the etiologic agent. On the basis of morphology, nutritional physiology, ribosomal small subunit DNA and ITS sequence data the strain could not be matched with any existing species. A new species, Exophiala asiatica, is therefore proposed.

Waterborne Exophiala species causing disease in cold-blooded animals

“…Roughly speaking, clades with species able to grow at temperatures well over 36–37 °C ( bantiana , dermatitidis and jeanselmei clades) may cause systemic or disseminated infections in humans, while those with a maximum around 36–37 °C ( carrionii and europaea clades) cause (sub)cutaneous and superficial infections. Species of the salmonis clade have maxima at 27–33 °C, exceptionally 36 °C, and cause superficial, barely invasive infections at most (Li et al 2009, Saunte et al 2011). …”

“…The most serious pathogens, eventually leading to disseminated, fatal infections are the neurotrope Exophiala dermatitidis (Sudhadham et al 2008), the osteotrope E. spinifera (Li et al 2008), and a species tending to cause disseminated infection, E. asiatica (Li et al 2009). These species are able to grow at 37–40 °C, which is taken to be one of the main virulence factors in Chaetothyriales , also being expressed in several pathogenic Cladophialophora species (Badali et al 2008).…”

Melanized Fungi in Human Disease

“…E. xenobiotica, which is capable of growing in the presence of high concentrations of xenobiotics such as xylene, toluene, or creosote-treated utility poles, was the agent of subcutaneous phaeohyphomycosis in a nonHodgkin lymphoma patient (36). E. asiatica is a newly described species causing a fatal, disseminated cerebral phaeohyphomycosis in China (452). Cladophialophora.…”

In Vitro Activities of Eight Antifungal Drugs against 106 Waterborne and Cutaneous Exophiala Species

“…Infections range from asymptomatic cutaneous colonization to fatal disseminated and cerebral disease. Among the more serious opportunistic fungi are the neurotrope Exophiala dermatitidis (1), the osteotrope E. spinifera (2), and E. asiatica (3), all of which have the potential to cause fatal infections in individuals without apparent immune or metabolic disorders. The presence of melanin and the ability to assimilate alkylbenzenes have been suggested to play roles in pathogenicity and evasion of the host defense (4).…”