Various microscopically spherical bacteria are known causes of purulent disease in man. They include both Gram positive—Staphylococcus aureus, Streptococcus pyogenes and Streptococcus pneumoniae—and Gram-negative—Neisseria gonorrhoeae and N. meningitidis—species. The Gram-positive cocci are the leading pathogens of man, causing an estimated one-third of all bacterial infections of humans.¹ My focus here will be on the Streptococci, facultative anaerobic cocci not … Continue reading Pyogenic cocci