What type of bacteria is Streptococcus pyogenes classified as?

• A. Gram-negative coccus
• B. Gram-positive bacillus
• C. Gram-positive coccus
• D. Gram-negative bacillus

Answer: (C)

Streptococcus pyogenes is classified as a Gram-positive coccus, which reflects its shape and staining characteristics. The term "coccus" refers to the spherical shape of the bacteria, and "Gram-positive" indicates that it retains the crystal violet stain used in the Gram staining procedure. This retention happens due to the thick peptidoglycan layer in the bacterial cell wall, which is a characteristic feature of Gram-positive bacteria. In clinical settings, Streptococcus pyogenes is known for causing a variety of infections, including strep throat, skin infections, and more serious diseases such as rheumatic fever. Understanding its classification helps in determining appropriate treatment options and understanding its pathogenicity.