Oxalobacter formigenes

Oxalobacter formigenes is an oxalate-degrading anaerobic bacterium that colonizes the large intestines of numerous vertebrates, including humans. O. formigenes and humans share a beneficial symbiosis. The broad-spectrum quinolone antibiotics kill O. formigenes. If a person's gastrointestinal (GI) tract lacks this bacterium, and therefore lacks the primary source for the oxalyl-CoA decarboxylase enzyme, then the GI tract cannot degrade dietary oxalates which on digestion get absorbed easily and after some vitamin B6-modulated partial metabolical degradation in the body, is excreted in the kidney, where it precipitates with calcium to form calcium oxalate kidney stones. The role and presence of O. formigenes in the human gut is an area of active research.