SELENOO and Alzheimer disease: The enterotoxin gene cluster (EGC) consisting of seg, sei, selm, seln, selo, and selu was present in 13 (24.7%) S. aureus isolates from lesional skin, 4 (14.8%) isolates from non-lesional skin, 0 nasal isolates from AD patients, and 31 (30.7%) isolates from controls.