In vivo pathogenicity characterization of viable opportunistic fungi Aspergillus thermomutatus and Rhodotorula mucilaginosa recovered from maritime Antarctic permafrost

In this study, we evaluated the pathogenic potential of the fungi Aspergillus thermomutatus and Rhodotorula mucilaginosa obtained from maritime Antarctic permafrost using in vivo experiments on immunocompromised BALB/c mice. Despite the low mortality observed, immunosuppressed animals infected with A. thermomutatus and R. mucilaginosa exhibited fluctuations in body mass and induced changes in the neuropsychiatric state of the mice. Fungi were recovered from the lungs, spleen, blood, and brain of infected mice at densities similar to but slightly lower than the inoculum up to 5 days post-inoculation. A. thermomutatus infection induced an inflammatory process in the lungs of infected BALB/c mice. In the target organs of animals infected with R. mucilaginosa, a notable fungal load was detected in the brains of infected animals. These results suggest that viable isolates of fungi such as A. thermomutatus and R. mucilaginosa originating from Antarctic permafrost, which is exposed to increasing melt caused by rising temperatures in the region, may present significant pathogenic potential. This highlights that climate change in Antarctica may facilitate the release and dispersal of fungi and other pathogenic microorganisms capable of infecting humans and animals.