A mixed mushroom poisoning in humans associated with the ingestion of Collybiopsis orientisubnuda.

Mushroom poisoning is the leading foodborne illness in China. However, accurate identification of the causative species remains challenging, particularly in cases involving several species. In July 2022, a mushroom poisoning incident involving six individuals occurred in Yunnan Province, China, after consuming a meal of mixed wild mushrooms. Five of them developed poisoning symptoms, including nausea, vomiting, dizziness, and fever. Laboratory examination revealed abnormalities in one female patient's blood biochemistry parameters and coagulation profiles, although these specific tests were not performed on the other patients. Morphological and phylogenetic analyses identified the implicated mushrooms as three species: Collybiopsis orientisubnuda (Omphalotaceae), Russula compacta and Russula rosea (Russulaceae). While both Russula species are widely documented as edible, C. orientisubnuda has been implicated in a prior mixed-sample poisoning case. Based on the identification results, clinical investigations, and literature review, we conclude that C. orientisubnuda was the most likely causative agent of this poisoning event. This study provides the first detailed report of the poisoning syndrome and clinical manifestations associated with C. orientisubnuda.