Sixty Years from Segretain’s Description: What Have We Learned and Should Learn About the Basic Mycology of Talaromyces marneffei?

Abstract

The fungus Talaromyces marneffei was described by Professor Gabriel Segretain in 1959, originally as a member of the genus Penicillium. As early as 60 years ago, its peculiarity in exhibiting temperature-dependent morphological dimorphism, its characteristic ability to secrete diffusing red pigment during the mycelial phase and its pathogenicity have already been recognised. Six decades have passed, and our understanding on this intriguing fungus has improved. Apart from the clinical aspect, we have gained a glimpse on its taxonomy, animal or environmental source(s), mechanism of thermal dimorphism, molecular genetics, virulence as well as pathogenesis. However, we are still on our way to get out of the talaromycosis mist. A lot more collective endeavour on T. marneffei research is needed to solve the jigsaw puzzle. Keywords Talaromyces marneffei Á Segretain Á Sixty years Á Anniversary This year marks the 60th anniversary of the official description of the thermally dimorphic fungus, Talaromyces marneffei (previously called Penicillium marneffei), which is an important fungal pathogen endemic in Southeast Asia especially to HIV-positive patients, by Professor Gabriel Segretain [1]. This fungus was first isolated in 1955 by Capponi and Sureau from laboratory Chinese bamboo rats (Rhizomys sinensis), which are native in the Central Highlands of Vietnam, at Institut Pasteur de Dalat [2], where it caused fatal spontaneous disseminated infection involving the reticuloendothelial system in three of the rats. The pathogenicity of T. marneffei was further demonstrated by Segretain, Capponi and Sureau in various animal models, including mice, rats, hamsters and guinea pigs [2, 3]. Six decades have passed since the discovery of T. marneffei; however, our understanding on this peculiar fungus is still poor despite its clinical significance. Such a lack of knowledge could be reflected by the fact that up to the end of August 2019, there are only *730 published articles about T. marneffei indexed in PubMed. This figure significantly lags behind those

Clinical characteristics and risk factors for poor prognosis among HIV patients with Talaromyces marneffei bloodstream infection

“…It is estimated that there will be 4951 TM cases per year in patients with AIDS in southern China by 2050, and the endemic areas are increasing [ 12 ]. The disease is mostly localized to the lungs and skin and is related to exposure by inhalation or direct contact TM [ 14 , 15 ]. However, in clinical settings, because the onset of the disease is relatively insidious and mild, the clinical symptoms are non-specific, and patients often experience delayed diagnosis or misdiagnosis by doctors who are not familiar with the symptoms of TM disease.…”

Characterization of a novel yeast phase-specific antigen expressed during in vitro thermal phase transition of Talaromyces marneffei

“…It is possible that the antigenic glycoprotein recognized by MAb 4D1 is only expressed in the T. marneffei yeast phase. Due to the difficulties and inconsistencies of the tool for investigating the basic biology of phase transition in T. marneffei, in vitro phase transition models (especially in host macrophages) remain essential for studying the virulence factors and pathogenicity of this dimorphic fungus 11 . Therefore, the goal of this study is to characterize the expression profiles between mold and yeast phase transition and the biochemical nature of T. marneffei antigenic glycoproteins recognized by MAb 4D1.…”

A global view on fungal infections in humans and animals: infections caused by dimorphic fungi and dermatophytoses

“…The fungus Talaromyces marneffei was described by Gabriel Segretain in 1959, originally as a member of the anamorphic genus Penicillium which caused fatal spontaneous disseminated infection involving the reticuloendothelial system in rats (Tsang et al 2019). This species exhibits temperature-dependent morphological dimorphism and has an ability to secrete a diffusing red pigment during the mycelial phase (Guo et al 2019).…”