Question

How can  Streptococcus pyogenes initially be differentiated from other Streptococcus species that form part of the throat normal microbiotia?

		By morphology—the bacteria are spherical and grow in long chains.
		By detection of the "A" carbohydrate in its cell wall using antibodies.
		By culturing the bacteria on nutrient agar and checking for hemolysis.
		By Gram staining—it is a Gram-positive organism.
		By specific disease signs and symptoms, including sore throat and fever.

Answer 1

Answer: By culturing the bacteria on nutrient agar and checking for hemolysis.

Explaination:

Disease-causing bacterial organisms present in throat can be identified by a microbiological procedure called throat culture. A throat culture identifies the specific bacterial organisms that are causing a sore throat or throat infection. Normal flora that grow in healthy throat tissues include non-hemolytic and alpha-hemolytic streptococci, some Neisseria species, staphylococci, diphtheria and hemophilus organisms, pneumococci, yeasts, and Gram-negative rods. Symptoms of sore throat or also known symptoms of strep throat usually appear one to three days after being exposed to the streptococcus species such as S. pyogenes. S. pyogenes is known to grow well in growth media such as rich broths or gels (agars) that are supplemented with blood. Its colony morphology on blood agar represents a clear zone of beta hemolysis. Most streptococcus species part of normal throat microbiota are either Alpha Hemolytic or Non Hemolytic. Hemolytic means that these streptococci are capable of destroying red blood cells.

Thus the answer is Streptococcus pyogenes initially be differentiated from other Streptococcus species that form part of the throat normal microbiotia “by culturing the bacteria on nutrient agar and checking for hemolysis”.