A Five-Year Survey of Dematiaceous Fungi in a Tropical Hospital Reveals Potential Opportunistic Species

Abstract

Dematiaceous fungi (black fungi) are a heterogeneous group of fungi present in diverse environments worldwide. Many species in this group are known to cause allergic reactions and potentially fatal diseases in humans and animals, especially in tropical and subtropical climates. This study represents the first survey of dematiaceous fungi in Malaysia and provides observations on their diversity as well as in vitro response to antifungal drugs. Seventy-five strains isolated from various clinical specimens were identified by morphology as well as an internal transcribed spacer (ITS)-based phylogenetic analysis. The combined molecular and conventional approach enabled the identification of three classes of the Ascomycota phylum and 16 genera, the most common being Cladosporium, Cochliobolus and Neoscytalidium. Several of the species identified have not been associated before with human infections. Among 8 antifungal agents tested, the azoles posaconazole (96%), voriconazole (90.7%), ketoconazole (86.7%) and itraconazole (85.3%) showed in vitro activity (MIC ≤1 µg/mL) to the largest number of strains, followed by anidulafungin (89.3%), caspofungin (74.7%) and amphotericin B (70.7%). Fluconazole appeared to be the least effective with only 10.7% of isolates showing in vitro susceptibility. Overall, almost half (45.3%) of the isolates showed reduced susceptibility (MIC >1 µg/mL) to at least one antifungal agent, and three strains (one Pyrenochaeta unguis-hominis and two Nigrospora oryzae) showed potential multidrug resistance.

Cladosporium spp: Morfologia, infecções e espécies patogênicas

“…O espectro de doenças com as quais estão associados incluem desde infecções superficiais de pele e tecidos moles até sepse disseminada, com elevada mortalidade (Yew et al, 2014). As infecções mais comuns incluem feo-hifomicoses, doença alérgica, infecções superficiais e profundas locais, pneumonia, abscesso cerebral, e infecção disseminada.…”

Identification and characterization ofDaldinia eschscholtziiisolated from skin scrapings, nails, and blood

“…To the best of our knowledge, all previous isolations of D. eschscholtzii from humans were by our group (Chan et al, 2015; Ng et al, 2012; Yew et al, 2014). Nevertheless, the clinical evidence of infection caused by this fungus remains unclear.…”

“…D. eschscholtzii had not been reported as a human pathogen until we isolated this species from skin scrapings and the blood of patients with suspected fungal infections (Chan et al, 2015; Ng et al, 2012; Yew et al, 2014). To the best of our knowledge, all previous isolations of D. eschscholtzii from humans were by our group (Chan et al, 2015; Ng et al, 2012; Yew et al, 2014).…”

Insight into different environmental niches adaptation and allergenicity from the Cladosporium sphaerospermum genome, a common human allergy-eliciting Dothideomycetes

“…The isolate was subjected to DNA extraction, amplification, DNA sequencing and ITS-based phylogenetic analysis was performed as previously described with slight modification7. The selection of species to be included in the phylogenetic analysis was limited to species closely related to C. sphaerospermum .…”