Schizophyllum commune as an emerging fungal pathogen: a review and report of two cases

Summary We report Schizophyllum commune as the aetiological agent of one case each of allergic broncho‐pulmonary mycosis (ABPM) and pulmonary fungal ball, and present a literature review. The fungus was characterised by clamp connections, hyphal spicules, and formation of basidiocarps with basidiospores. The phenotypic identification was confirmed by sequencing of the ITS region. To‐date, ABPM and pulmonary fungal ball to S. commune have been reported exclusively from Japan and North America respectively. Of the 71 globally reported cases due to S. commune , 45 (63%) were bronchopulmonary, 22 (31%) sinusitis and 4 extrapulmonary. Taken together, cases of bronchopulmonary disease and sinusitis numbered 67 (94%), indicating the respiratory tract as the primary target of disease. Concerning the country‐wise distribution, Japan topped the list with 33 cases (46%), followed by Iran – 7 cases (10%), U.S.A. – 6 cases (9%), and a lower prevalence of 1.4–6% for the remaining 12 countries. The preponderance of the disease in Japan may be attributed to its greater awareness vis‐à‐vis that in other countries rather than to any geographical/climatic factors. We believe that the burden of S. commune‐ incited disease is currently underestimated, warranting comprehensive prospective studies to determine its prevalence.