Review Lesson 9: Streptococcus pyogenes Flashcards
(42 cards)
1
Q
1. Know the following characteristics about each disease studied: Genus and species name Gram reaction Cell shape Disease name Transmission Virulence factors Clinical symptoms of disease Treatment
A
Genus name: Streptococcus species name: pyogenes Gram reaction: + Cell shape: coccus Disease name: Transmission: Virulence factors: Clinical symptoms of disease: Treatment:
2
Q
- Be able to translate the organism’s genus and species name into the English language as given in class.
A
Chain former, pus generating
3
Q
- What are the three hemolytic reactions for classifying Strep bacteria?
A
Strep Classification by Hemolytic Reaction
Alpha(α) – hemolysis: partial destruction of RBC; greenish color on blood agar
Beta(β) – hemolysis: complete destruction of RBC; clear zone around bacteria
Gamma(γ) – hemolysis: no reaction with RBC
4
Q
- What is the hemolytic reaction for: S.aureus and S.pyogenes?
A
Beta hemolytic
5
Q
- On what characteristic of the bacteria cell is Rebecca Lansfield’s system of classifying Strep bacteria based?
A
Rebecca Lansefield Classification of Strep
Based on distinct cell wall Ags
Each Ag is designated with a letter (A – O)
(Lansefield devoted much of her life research to studying Strep bacteria)
6
Q
- The M protein protects S.pyogenes from what host resistant mechanism?
A
M protein:
located in cell wall
interferes with phagocytosis
7
Q
- What is Hyaluronidase?
A
Hyaluronidase: destroys hyaluronic acid; leads to tissue penetration
8
Q
- What is Otitis Media?
A
Middle ear infection
9
Q
- What is the source of the erythrogenic toxin of Scarlet fever?
A
Source: Prophage(virus) genome integrated into bacterial chromosome
10
Q
- What category of virulence factors does erythrogenic toxin belong?
A
Exotoxins
11
Q
- After recovery of Scarlet fever, does permanent immunity occur (listen to the audio lecture)?
A
Complete immunity for life
12
Q
- What is a prophage?
A
Virus
13
Q
- Why is a prophage involved in the symptoms of Scarlet fever?
A
Refer to handout
14
Q
- If the prophage is removed from S. pyogenes, does the bacteria still cuase disease? If so, what disease?
A
Yes, strep throat
15
Q
- What are the two late sequelae of Streptococcal pharyngitis?
A
Rheumatic Heart Disease, Acute Glomerulonephritis
16
Q
- Is Scarlet fever a late sequelae? Why or why not?
A
No it’s not. It happens at the same time.
17
Q
- Why has there been a dramatic decline in Rheumatic Heart Disease cases in the USA?
A
Early detection, antibiotics available,
18
Q
- Why is Rheumatic Heart Disease described as an Autoimmune disorder?
A
Antibodies will attack heart valves along with S. pyrogens
19
Q
- Is Rheumatic Heart disease caused by a bacteria infection to the heart?
A
Complications of a Strep throat infection
20
Q
- What valve of the heart is damaged the most in rheumatic heart disease by antibody attack?
A
Mitral valve
21
Q
- What percentage of patients have Carditis from Rheumatic Heart Disease?
A
50%
22
Q
- Between what 2 chambers of the heart is the Mitral valve located?
A
Left atrium and left ventricle
23
Q
- Can antibiotics be used to treat the symptoms of Rheumatic Heart disease? Why or why not?
A
Yes
24
Q
- Is Rheumatic Heart disease contagious?
A
No it’s not contagious
25
25. Why do patients recovering from Rheumatic Heart disease need to be on long term antibiotics if the disease is not caused by a bacteria infection?
They are more susceptible to getting and if they get it, it can mutate and be harder to treat.
26
26. Is Acute glomerulonephritis a common or rare disease?
Rare
27
27. What causes damage or even complete destruction to the glomerulus of the nephron kidney unit?
Complete stoppage like drain, due to immune complex disease
28
28. What is edema?
Swelling
29
29. Would you expect the blood pressure to initially increase or decrease because of a failure of the kidney nephron system in acute glomerulonephritis?
Increase due to all the pressure
30
30. Is Acute glomerulonephritis contagious? Why or why not?
No
31
31. Is Acute glomerulonephritis more common in males or females?
Male
32
32. What is hematuria?
Blood in urine
33
33. What is the best prevention to decrease chances of a late sequelae developing from a Strep throat infection?
Early detection, complete antibiotic treatment
34
34. Define necrotizing.
Dead tissue
No blood supply
Anaerobic
35
35. Define fasciitis.
White/ gray, connective tissue, thick or thin
| Inflammation of
36
36. What are the 2 virulence factors involved in the aggressive tissue damage associated with necrotizing fasciitis?
Pyrogenic exotoxin A
| Exotoxin B
37
37. What is a super antigen?
Bacteria exotoxin
Not processed intracellular by MØ for presentation to T-cells
Bind directly to T-cells without specificity
Effects 2 – 20% of T-cell population
Many T-cells die from excessive stimulation
38
38. Why are antibiotics not very effective in treating necrotizing fasciitis?
Drug therapy: Penicillin (early) but no effect on toxins or on bacteria in necrotic tissue
39
39. Is there a blood supply to necrotic tissue?
No
40
40. If a surgeon debrides away necrotic tissue, what is he/she doing?
Remove dead tissue until they get to healthy pink. That way antibiotic can help treat
41
41. What would be the reason behind removal of necrotic tissue to effect a cure?
Relieve pressure of swollen tissue
| Amputation may be necessary
42
42. Which S.pyogenes infection did we study that doesn’t involve strep throat as a primary infection?
Necrotizing Fasciitis
