Molecular epidemiology and phylogenetic analyses of environmental and clinical isolates of Cryptococcus gattii sensu lato in Taiwan

Abstract

Background The rare occurrence of cryptococcosis caused by Cryptococcus gattii sensu lato (C. gattii s.l.) leads to the difficulties in studying the molecular epidemiology of this globally emerging disease. Objectives To establish the molecular epidemiological profile of C. gattii s.l. in Taiwan, and understand the genetic relationship between locally endemic and global isolates. Methods A nationwide survey on environmental C. gattii s.l. in Taiwan was conducted from 2017 to 2019. The geographic distribution and molecular epidemiology based on multilocus sequence typing (MLST) data of the environmental isolates were compared with 18 previously collected clinical isolates. Phylogenetic analysis was performed to elucidate the genetic relationship between the global isolates and the isolates endemic to Taiwan. Results From a total of 622 environmental samples, 104 (16.7%) were positive for C. gattii s.l.. Seven sequence types were identified among the environmental isolates. The genetic population structure showed that the environmental and clinical isolates were closely linked by sequence types and geographical locations. Phylogenetic analysis revealed the association between the C. gattii s.l. isolates in Taiwan and those from South America and South Asia. The recombination test suggested that, in Taiwan, the C. gattii sensu stricto (C. gattii s.s). isolates undergo clonal reproduction and sexual recombination, whereas C. deuterogattii isolates were clonal. Conclusions The molecular epidemiology of environmental C. gattii s.l. isolates is closely linked to the clinical isolates. Phylogenetic analysis of the environmental isolates provides an insight into the mechanisms underlying reproduction and dispersal of C. gattii s.l. in Taiwan.

Multilocus sequence typing of strains from the Cryptococcus gattii species complex from different continents

“…Among the other VGI strains, we identified one strain of ST106, one of the most virulent strains in the invertebrate model, Galleria mellonella 28 , and the dominant ST in Taiwan. It was also isolated in Singapore, Malaysia and the USA 30 . Another ST, ST56, the most represented in this study among the VGIs, was previously described in Brazil and Italy 31 .…”

Epidemiological and Clinical Characteristics, Antifungal Susceptibility, and MLST-Based Genetic Analysis of Cryptococcus Isolates in Southern Taiwan in 2013–2020

“…In this study, around 10% of CM cases were caused by C. gattii during 2000–2010 and 2013–2020 at KCGMH. Lin et al reported that, although no environmental C. gattii isolates were found in Pingtung, ST630 was commonly identified in Kaohsiung [ 19 ]. However, no ST630 clinical isolates were found in Taiwan, according to Lin et al and the current study.…”

“…In the last few decades, several widely used molecular methods have been used worldwide to determine the genotypes of clinical, environmental, and veterinary isolates of the members of the C. neoformans and C. gattii species complexes to investigate their geographical distribution, molecular epidemiology, and population genetics [ 19 , 20 , 21 , 22 , 23 ]. Understanding the epidemiological and microbiological characteristics of local Cryptococcus strains and clinical features of CM is essential for the development of efficient diagnosis and treatment strategies.…”

Yeasts from temperate forests

“…Members of the currently delineated genus Cryptococcus inhabit temperate forests worldwide (Chowdhary et al, 2012; Cogliati et al, 2016; Kidd et al, 2007; Lin et al, 2021). Non‐pathogenic Cryptococcus species are rare and only known from a very few isolates of plant‐insect origin, including C. amylolentus , C. wingfieldii , and C. floricola (Passer et al, 2019).…”