Overview of Clostridial Infections By Larry M Bush, MD, FACP, Charles E Schmidt College of Medicine, Florida Atlantic University; Maria T Vazquez-Pertejo, MD, FACP, Wellington Regional Medical Center Reviewed / Revised Jun 2023 View Patient Education Pathophysiology Diseases Caused by Clostridia Topic Resources Selected Conditions Associated.. Clostridia are spore-forming, gram-positive, anaerobic bacilli present widely in dust, soil, and vegetation and as normal flora in mammalian gastrointestinal tracts.