Final answer:
Streptococcal pharyngitis, or strep throat, is caused by the bacterium Streptococcus pyogenes, which is a ß-hemolytic bacterium. It's treated with antibiotics such as amoxicillin or penicillin G, and proper treatment is crucial to prevent bacterial resistance.
Step-by-step explanation:
The infection streptococcal pharyngitis, often known as strep throat, is caused by the bacterium Streptococcus pyogenes. This organism is a gram-positive bacterium that is classified in the Lancefield group A, and it is notable for being ß-hemolytic. It can cause not only pharyngitis but also skin infections, with severity ranging from relatively mild to life-threatening conditions such as necrotizing fasciitis.
Streptococcus pyogenes produces a range of harmful substances that contribute to the symptoms of strep throat, which include a fever, sore throat, and often redness with dark spots - known as petechiae - on the tonsils and roof of the mouth. A rapid enzyme immunoassay can often diagnose the presence of this bacterium, but due to a high rate of false negatives, culture identification remains the gold standard. Treatment usually involves antibiotics such as amoxicillin or penicillin G.
In some cases, complications like scarlet fever or streptococcal toxic shock syndrome can occur due to other toxins produced by certain strains of this bacteria. Maintaining the full course of antibiotic treatment is important to prevent the development of resistant strains of the bacteria.