Pneumococcal 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 May 2023 View Patient Education Diseases Caused by Pneumococci Diagnosis Treatment Prevention Key Points More Information Streptococcus pneumoniae (pneumococci) are gram-positive, alpha-hemolytic, aerobic, encapsulated diplococci.