PTGS2 and infection: Based on these findings, Ebrahimzadeh and colleagues (72) assessed urinary prostaglandin E2 (PGE2), which is a product of arachidonic acid conversion by the COX-2 enzyme, as a biomarker for rUTI in a cohort of 92 postmenopausal women (31 women with acute UTI and a rUTI history, 35 women with rUTI but without an active infection and 26 healthy controls).