What does streptolysin mean?
Streptolysin is a toxin made by certain streptococcal bacteria, particularly Streptococcus pyogenes. It belongs to a group of bacterial hemolysins: substances that damage the membranes of red blood cells and cause them to rupture, a process called hemolysis. The two best-known forms are streptolysin O, which is sensitive to oxygen, and streptolysin S, which resists serum and is oxidized by hydrogen peroxide. In scientific and medical writing, streptolysin may refer either to a particular toxin or more broadly to this class of streptococcal toxins. These proteins have been studied as virulence factors and as laboratory reagents for testing blood-cell integrity. The term is uncommon in general conversation but useful in microbiology, immunology, toxicology, and clinical diagnostics, where distinctions among individual streptolysins can be significant.
nounA toxin produced by certain streptococci that destroys red blood cells by damaging their membranes. The best-known forms are streptolysin O and streptolysin S, both associated especially with Streptococcus pyogenes.
- A streptococcal toxin, especially one that causes red blood cells to rupture by damaging their membranes.
"The researchers measured streptolysin production to assess the virulence of the bacterial isolate."
"Laboratory analysis detected high levels of streptolysin in the culture."
"Streptolysin can damage host cells beyond those of the bacterial infection itself."
The plural is used when referring to multiple distinct streptolysin toxins; the singular may name the toxin class or act as a collective term.
"The bacteria produced several streptolysins that damaged red blood cells."
Its name combines strepto-, meaning “twisted chain,” with lysis, meaning “dissolving”—a fitting label for a toxin that tears open cells.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of streptolysin
Streptolysin combines the combining form strepto-, ultimately from Greek streptos, meaning “twisted,” with lysis, from Greek lysis, meaning “a loosening” or “dissolving.” The formation reflects the toxin’s association with streptococci, whose cells are characteristically arranged in chains, and with its ability to rupture cells.
Related word forms
How streptolysin is actually used
This is primarily a technical term in microbiology, immunology, and clinical research. Names such as streptolysin O and streptolysin S refer to distinct molecular forms and are normally written with the identifying letter as part of the name.
Easily confused with streptolysin
Streptolysin is a bacterial toxin that damages cells, whereas streptomycin is an antibiotic used to treat susceptible bacterial infections.