Streptococcal infections- Gram-positive bacteria arranged in chains or pairs
- Not part of normal cutaneous flora (but resident of aerodigestive tract and vagina)
- Classification via two methods:
- Ability to induce hemolysis (α, β, γ ) and/or
- Lancefield groups (A–D, G) based on characteristic polysaccharide cell wall
- Of note, group A β-hemolytic streptococci (S.pyogenes, GAS) most pathogenic
- The following antibodies become positive after infection with GAS: antistreptolysin O (ASO), antihyaluronidase, and anti-DNase-B
- Certain strains with erythrogenic toxins: S.pyogenes exotoxins (SPE-A, SPE-B, SPE-C)
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