Strep Throat: Cause, Symptoms & Treatments

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  • 0:06 Strep Throat
  • 0:38 Streptococcal Pharyngitis
  • 1:19 Streptococcus Pyogenes
  • 2:53 Symptoms and Treatment
  • 4:42 Lesson Summary
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Lesson Transcript
Instructor: Artem Cheprasov

Artem has a doctor of veterinary medicine degree.

This lesson will discuss something we've almost all had: strep throat. We'll discuss beta-hemolysis, Streptococcus pyogenes, pharyngitis, halitosis, pus, and all sorts of other things pertaining to strep throat.

Strep Throat

If you've ever had a bad sore throat and had the pleasure of standing in front of the bathroom mirror only to notice some nasty white stuff at the back of your mouth, then you probably had something colloquially known as 'strep throat.' In addition, you almost certainly didn't have very nice breath to go along with that painful sore throat.

I'm not sure which is worse, the terrible pain in your throat or the embarrassment of the bad breath associated with it. In any case, this lesson will cover the cause of both of these issues and more associated with strep throat.

Streptococcal Pharyngitis

The more technical term for strep throat is actually streptococcal pharyngitis. The 'pharyngitis' in 'streptococcal pharyngitis' refers to the inflammation, 'itis', of the 'pharynx'. Basically, part of the pharynx is the back of the throat you see when you say 'AAAAH' in front of the mirror.

In any case, the pharynx becomes inflamed because certain bacteria, called streptococcal bacteria, are spread about in airborne droplets during a cough or sneeze. When a person breathes these bacteria in, especially if their immune system is already compromised as it is fighting off a viral infection such as the flu, they may develop strep throat.

Streptococcus pyogenes

The main bacterium that causes strep throat is known as Streptococcus pyogenes. This bacterium is known as a Gram-positive, group A beta-hemolytic streptococcus. The fact that this is a Gram-positive bacterium means it has a very thick cell wall compared to a Gram-negative bacterium. Since this bacterium is known as a 'coccus', that automatically means it has a round shape, as opposed to a rod-shaped bacteria.

Furthermore, streptococcal bacteria form chains of bacteria, as opposed to staphylococcal bacteria, which are also round-shaped bacteria but do not form the characteristic chains of streptococci. The way I recall that streptococci are formed into chains, especially in the context of this lesson, is by realizing that many people wear chains around their neck. Well, the neck includes the throat, which is where strep throat occurs!

Finally, Streptococcus pyogenes is known as beta-hemolytic because it causes complete hemolysis, or the complete destruction of red blood cells, when grown on a special plate containing red blood cells. This hemolysis occurs because these bacteria release a toxin that causes the red blood cells to burst open, like a balloon would burst open when pricked by a needle. Beta-hemolysis is in contrast to alpha hemolysis, which results in incomplete destruction of red blood cells, or incomplete hemolysis by other types of streptococcal bacteria.

Symptoms and Treatments

Okay, with that massive amount of science mumbo-jumbo out of the way, we can focus on the more relatable aspects of what almost everyone has experienced when they had strep throat. Besides getting a fever, chills, and a throat that really hurts, people can develop some pretty nasty-looking white stuff at the very back of the throat where the bacteria have settled in.

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