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Streptococcus pyogenes

Published on October 31, 2024   29 min

A selection of talks on Microbiology

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0:00
Hello, everybody. My name is Dr. Sarah Fouch. Welcome to this short talk where we will be considering group A streptococci or Streptococcus pyogenes. We will be considering the conditions that this organism is associated with and the virulence factors that this organism can produce to make it such a successful pathogen.
0:27
When we consider group A streptococci, we carry this organism in low numbers in our oropharynx. Carriage tends to be seen normally in children and young adults. However, some older adults can also carry this organism as well. Sometimes we can have transient carriage and sometimes permanent carriage. But the carriage will depend on the antibodies that are being produced to the particular M proteins that are being expressed by the organism. Basically, an individual's immune system is reducing the number of organisms that are being carried to a low number. When we think about how strains are transferred between person to person, this is through droplet infection. While I'm talking to you, I have small droplets coming out of my mouth. I'm not spitting all over the camera because that would be particularly unpleasant. But small droplets are actually coming out of my mouth all the time, particularly, when I say B or P. If somebody is in close proximity to me, and they're able to breathe in those droplets, and they don't have antibodies to that particular M protein that's being expressed, they will have an increased risk of obtaining an infection. Group A streptococci can also be part of our normal skin flora so we can have skin colonisation as well. Direct contact can also be an issue with susceptible individuals.

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