Comparative Analysis of Capsular and Secreted Polysaccharides Produced by Rhodotorula mucilaginosa and Cryptococcus neoformans

Fungal infections are a global public health challenge, especially among immunocompromised patients. Basidiomycetous yeasts, such as Rhodotorula mucilaginosa, have emerged as opportunistic pathogens, but have received less attention than Cryptococcus neoformans. This study aimed to characterize the polysaccharides of R. mucilaginosa and compare them with those of C. neoformans, analyzing their clinical implications. Comprehensive physicochemical, mechanical, and ultrastructural analyses of polysaccharides from both species were performed, revealing correlations with virulence and pathogenicity. R. mucilaginosa cells are surrounded by a capsule smaller than that produced by C. neoformans, but with similar polysaccharides. Those polysaccharides are also secreted by R. mucilaginosa. Cross-reactivity with R. mucilaginosa was observed in a diagnostic C. neoformans antigen test, using both in vitro and in vivo samples, highlighting the need for more reliable tests. Some R. mucilaginosa strains exhibited virulence comparable to that of C. neoformans in an invertebrate experimental model (Tenebrio molitor). This study contributes to a deeper understanding of yeast pathogenicity and virulence, highlighting the need for more accurate diagnostic tests to improve the differential diagnosis of infections caused by basidiomycetous yeasts.

Automated summary

Fungal infections, especially in immunocompromised patients, pose a global public health challenge. This study focused on Rhodotorula mucilaginosa, a basidiomycetous yeast that has emerged as an opportunistic pathogen. The polysaccharides of R. mucilaginosa were characterized and compared with those of Cryptococcus neoformans, revealing correlations with virulence and pathogenicity. The study also highlighted the need for more reliable diagnostic tests to improve the differential diagnosis of basidiomycetous yeast infections. This research contributes to a better understanding of yeast pathogenicity and emphasizes the importance of accurate diagnostic tests.