Samples from Antarctica continent can be source of potential human opportunistic fungi?
Fungi are an important component of the microbial communities resident in different environments and substrates of Antarctica and have shown different ecological roles as symbionts, saprobes, and potentially pathogens. Some studies have shown that there is a group of some filamentous fungi that are phylogenetically close to opportunistic pathogenic and mycotoxigenic taxa and showed potential physiologic virulence characteristics in vitro. Fungal species display different morpho-physiological and biochemical strategies to adapt and survive in environments with extreme temperatures, low nutrient availability, prolonged desiccation, and solar irradiation. The resilience and adaptation arising from the high genetic plasticity of some fungi present in the extreme environments may result in their ability to infect plants and animals with deficiencies in their defence barriers. Characteristics like capability of grow at 37 °C and/or different pH, display macro- and micro morphological polymorphism, display haemolytic and phospholipase activities, produce tiny spores and show resistance to amphotericin B are some of virulence factors in vitro that we can find when the diversity of cultivable fungi from samples of Antarctica is accessed. The most commonly taxa with physiologic virulence characteristics in vitro isolated from Antarctica were Penicillium chrysogenum, P. tardochrysogenum (rocks) and Aspergillus fumigatus (ornithogenic soil). Aspergillus species are capable of causing infection in immunocompromised patients which A. fumigatus has great importance because is often reported as the main cause of aspergillosis. Considering the results obtained with isolates of A. fumigatus from Antarctic ornithogenic soil and the fact of the number of cases of systemic fungal infections has increased in immunocompromised patients, we decided to performed in vivo assays. The recent results allowed a better understanding of the real risk of potential pathogens spreading to other regions of the planet and the consequences for people, mainly to those with disturbed immune systems.