Hemolysis (or haemolysis) is the rupturing of erythrocytes (red blood cells) and the release of their contents (cytoplasm) into surrounding fluid (e.g., blood plasma).
Streptococcus is a genus of spherical Gram-positive bacteria belonging to the phylum Firmicutes and the lactic acid bacteria group. Cellular division occurs along a single axis in these bacteria, and thus they grow in chains or pairs.
Species of streptococcus are classified based on their hemolytic properties. Alpha hemolytic species cause oxidization of iron in hemoglobin molecules within red blood cells, giving it a greenish color on blood agar. Beta hemolytic species cause complete rupture of red blood cells. On blood agar, this appears as wide areas clear of blood cells surrounding bacterial colonies. Gamma-hemolytic species cause no hemolysis.
In addition to streptococcal pharyngitis (strep throat), certain streptococcus species are responsible for many cases of pink eye, meningitis, bacterial pneumonia, endocarditis, erysipelas and necrotizing fasciitis (the 'flesh-eating' bacterial infections). However, many streptococcal species are nonpathogenic, and form part of the commensal human microbiome of the mouth, skin, intestine, and upper respiratory tract. Furthermore, streptococci are a necessary ingredient in producing Emmentaler ("Swiss") cheese.
Sepsis is a potentially fatal whole-body inflammation caused by severe infection. Sepsis can continue even after the infection that caused it is gone. Sepsis causes millions of deaths globally each year. Sepsis is caused by the immune system's response to a serious infection, most commonly bacteria, but also fungi, viruses, and parasites in the blood, urinary tract, lungs, skin, or other tissues.