How does the capsule of Streptococcus contribute to the bacterium’s ability to cause disease
College sophomore Nadia is a star point guard for her school’s basketball team. She is excited about the divisional finals Friday night – she’s even heard rumors that a professional scout will be in the stands. On Thursday morning, she wakes up with a sore throat. Her forehead doesn’t feel warm, so she forces herself to attend Thursday classes; but when she wakes up on Friday morning, her throat is noticeably worse. Still, she forces herself to attend Friday morning class but feels tired and much worse by noon. It is downright painful to swallow, and she skips lunch.
Nearly crying, she heads back to the form and checks her temperature – 101°F. Desperate, she walks to the student health center, where a nurse practitioner notices white spots on the back of Nadia’s throat and on her tonsils. The divisional basketball game starts in six hours, but it only takes a few minutes for the nurse to perform a rapid streptococcal antigen test and determine that Nadia has streptococcal pharyngitis – strep throat. She will miss the big game.
Strep throat is caused by an encapsulated, Gram-positive bacterium, Streptococcus pyogenes.
The only good news is that by taking the prescribed penicillin, Nadia should be ready for her next big game – hopefully, the quarterfinals.
Here are some questions to consider.
1) How does the capsule of Streptococcus contribute to the bacterium’s ability to cause disease?
2) What bacterial structures, besides the capsule, may be allowing Streptococcus to infect Nadia’s throat?
3) Penicillin works by interrupting the formation of peptidoglycan. What bacterial structure contains
peptidoglycan? In a Gram-positive organism like Streptococcus, is this structure typically thicker or
thinner than it would be in a Gram-negative bacterium?
For full credit, you must share your thoughts (at least one paragraph) and comment on at least two classmates’ postings.
Answer preview to how does the capsule of Streptococcus contribute to the bacterium’s ability to cause disease
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