Meningococcal Diseases 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 Sep 2022 View Patient Education Diseases Caused by Meningococci Pathophysiology Symptoms and Signs Diagnosis Treatment Prevention Key Points More Information Topic Resources Meningococcemia Petechiae and Purpura Secondary... Petechiae Secondary to Meningococ... Petechiae Secondary to Meningococ... Widespread Rash Secondary... Cutaneous Necrosis Secondary... Meningococci (Neisseria meningitidis) are gram-negative diplococci that cause meningitis and meningococcemia.