Metabolic and phenotypic plasticity may contribute for the higher virulence of Trichosporon asahii over other Trichosporonaceae members

Abstract

Background:The Trichosporonaceae family comprises a large number of basidiomycetes widely distributed in nature. Some of its members, especially Trichosporon asahii, have the ability to cause human infections. This ability is related to a series of virulence factors, which include lytic enzymes production, biofilm formation, resistance to oxidising agents, melanin and glucuronoxylomannan in the cell wall, metabolic plasticity and phenotypic switching. The last two are poorly addressed within human pathogenic Trichosporonaceae.Objective: These factors were herein studied to contribute with the knowledge of these emerging pathogens and to uncover mechanisms that would explain the higher frequency of T. asahii in human infections. Methods:We included 79 clinical isolates phenotypically identified as Trichosporon spp. and performed their molecular identification. Lactate and N-acetyl glucosamine were the carbon sources of metabolic plasticity studies. Morphologically altered colonies after subcultures and incubation at 37°C indicated phenotypic switching. Results and Conclusion:The predominant species was T. asahii (n = 65), followed byTrichosporon ovoides (n = 1) and Cutaneotrichosporon arboriforme (n = 1). T. asahii isolates had statistically higher growth on lactate and N-acetylglucosamine and on glucose during the first 72 h of culture. T. asahii, T. inkin and T. japonicum isolates were able to perform phenotypic switching. These results expand the virulence knowledge of Trichosporonaceae members and point for a role for metabolic plasticity and phenotypic switching on the trichosporonosis pathogenesis.

Differences of clinical characteristics and outcome in proven invasive Trichosporon infections caused by asahii and non‐asahii species

“…asahii than non‐ T . asahii spp 43 . If the studies can further demonstrate the strong virulence of T .…”

“…japonicum can change phenotypes, similar to T . asahii , 42,43 a recent study observed that T . asahii exhibited much faster growth than the other species in a metabolically difficult and harsh environment, which may contribute to the higher virulence of T .…”

“…40 Moreover, T. asahii can produce biofilms that are likely to cause ITIs associated with CAD, making antifungal treatment difficult. 41 Although T. mucoides also has a GXM-like glycan, and T. inkin or T. japonicum can change phenotypes, similar to T. asahii, 42,43 a recent study observed that T. asahii exhibited much faster growth than the other species in a metabolically difficult and harsh environment, which may contribute to the higher virulence of T. asahii than non-T. asahii spp. 43 Recurrent neotypification in the complex Trichosporon genus can confuse physicians, and the inconsistency of species described in the literature can make accurate clinical applications or studies difficult.…”

“…41 Although T. mucoides also has a GXM-like glycan, and T. inkin or T. japonicum can change phenotypes, similar to T. asahii, 42,43 a recent study observed that T. asahii exhibited much faster growth than the other species in a metabolically difficult and harsh environment, which may contribute to the higher virulence of T. asahii than non-T. asahii spp. 43 Recurrent neotypification in the complex Trichosporon genus can confuse physicians, and the inconsistency of species described in the literature can make accurate clinical applications or studies difficult. 1,2,12,17,18,44 Although several authors have mentioned that T. cutaneum is no longer Trichosporon, and Cutaneotrichosporon cutaneum is appropriate because it is affiliated with Cutaneotrichosporon gen. nov., 2,44 other reports have indicated that T. cutaneum is a…”

A novel report on the emerging and zoonotic neurotropic fungus Trichosporon japonicum in the brain tissue of the endangered Brazilian guitarfish (Pseudobatos horkelii) off the southeastern coast of Brazil

“…The first documented clinical case of T. japonicum contamination occurred in 2008, involving a child diagnosed with acute myeloid leukemia (AML) who experienced fungemia associated with T. japonicum [ 75 ]. In Brazil, only two T. japonicum isolates have been isolated from humans [ 76 ] and one from artisanal cheese [ 77 ], making this only the third report of this fungal pathogen in the country, and the first in wildlife consumed by humans.…”