Final answer:
The bacteria responsible for causing strep throat are Streptococcus pyogenes, also known as group A strep (GAS). They are gram-positive, chain-forming cocci that produce infections often identifiable by rapid enzyme immunoassay or more accurately by culture identification, and are treated with ß-lactam antibiotics.
Step-by-step explanation:
The chain-forming bacteria that cause the severe pharyngitis known as a strep throat are A. Streptococcus pyogenes. This bacterium belongs to the Lancefield group A and is characterized as being ß-hemolytic. They are called group A strep, or GAS, and are notable for being a pyogenic pathogen, which refers to their association with pus production during infections. S. pyogenes is the most common cause of bacterial pharyngitis and also contributes to skin infections that can range from mild to life-threatening, such as necrotizing fasciitis.
Streptococcus bacteria are known for looking like strings of beads, which is indicative of their chain-forming nature. Proper diagnosis of strep throat often involves a rapid enzyme immunoassay for the group A antigen, but due to the possibility of false-negative results, culture identification remains the gold standard for confirming infections caused by S. pyogenes. Treatment typically involves ß-lactam antibiotics like oral amoxicillin or intramuscular penicillin G.