Ognen Ivanovski M.D.Ph.D
University Clinic of Urology, Medical Faculty, University “Ss Cyril and Methodius” Skopje, FYR Macedonia
Calcium oxalate (CaOx) is the most prevalent type of kidney stone. The amount of oxalate excreted in the urine is a major risk factor for CaOx stone formation. O. formigenes is an anaerobic Gram-negative bacterium that naturally colonizes the colon of vertebrates, including humans, and utilizes oxalic acid as its sole source of energy. The clinical importance of O. formigenes colonization is primarily suggested for patients with recurrent calcium oxalate nephrolithiasis leading to a new research direction in the field of oxalate stone disease prevention and treatment.
The author presents recent research regarding the role of O. formigenes in oxalate metabolism by evaluating its intestinal absorption, plasma concentration, and urinary excretion as well as the possible association between the number of stone episodes and O. formigenes colonization. Based on available evidence the author has proposed a new mechanism of oxalate handling across the liver, stomach, intestinal tract, and kidney (Ivanovski and Drueke, Kidney Int, 2013) and suggests that in the future, anaerobic colonic bacteria such as O. formigenes may find prophylactic and therapeutic applications in patients with recurrent CaOx nephrolithiasis.