In addition to strict anaerobic bacteria, microaerophilic streptococci and "Streptococcus salivarius" can also be present. It was renamed Streptococcus pneumoniae in 1974 because it was very similar to streptococci. The bacteria most commonly involved are streptococci and "Staphylococcus aureus". Oral streptococci have both harmless and harmful bacteria. Streptokinase was discovered in 1933 from beta-hemolytic streptococci. Beta-hemolytic streptococci, pneumococci, staphylococci, and enterococci are usually susceptible to macrolides. Typically, this includes alpha-hemolytic streptococci, staphylococci, and bacteroides groups. These include "Ureaplasma urealyticum", "Mycoplasma hominis", group B streptococci, HIV-1, and syphilis. The bacterial most commonly involved are streptococci or staphylococci. The bacteria most commonly involved are streptococci or staphylococci. Bacteria that enter through the skin, such as streptococci and staphylococci, tend to predominate. SpeB was identified in 1919 as an ectoenzyme secreted by certain strains of streptococci. Existence of streptococci strains was additionally found in World War II. Dried streptococci in the air are not infectious to intact skin. Microaerophilic and other streptococci are also often isolated.