Nokea
A patient with a severe sore throat had a throat culture revealing Gram-positive cocci in chains. The bacteria were beta-hemolytic. What is the most likely causative agent?
Correct Answer: A
Rationale: The correct answer is A: Streptococcus pyogenes. This bacterium is the most likely causative agent due to its characteristic features. Streptococcus pyogenes is Gram-positive cocci in chains, which matches the description provided in the question. It is also known to be beta-hemolytic, causing complete lysis of red blood cells on blood agar. Streptococcus pyogenes is a common pathogen causing sore throat, often associated with pharyngitis.
Explanation for incorrect choices:
B: Streptococcus pneumoniae - This bacterium is Gram-positive but usually occurs in pairs (diplococci) and is alpha-hemolytic.
C: Enterococcus faecalis - This bacterium is Gram-positive cocci but is not typically beta-hemolytic and is not commonly associated with sore throat infections.
D: Staphylococcus aureus - This bacterium is Gram-positive cocci but usually occurs in clusters and