Review 3: S.aureus

Question 1

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

Answer 1

Genus and species name: Staphylococcus aureus
Gram reaction: Gram +
Cell shape: coccus
Disease name: 
Transmission:
Virulence factors:
Clinical symptoms of disease:
Treatment:

Question 2

2. Be able to translate the organism’s genus and species name into the English language.

Answer 2

As you know, “staphylococcus” means “cluster of round, ball-shaped bacteria.”
“Aureus” is derived from “aurum,” which is Latin for “gold.” (That’s why Gold is “Au” on the Periodic Table)

Question 3

3. Define pyogenic.

Answer 3

Pyogenic (pus generating) cocci

Question 4

4. Define Beta-hemolytic

Answer 4

Beta-hemolytic: complete destruction of red blood cells

Question 5

5. What is the preferred site of colonization in the human body by S.aureus?

Answer 5

Nose is preferred site for S.aureus or moist skin

Question 6

6. Outline the 6 virulence factors for S.aureus and explain them.

Answer 6

1. Hemolysins
2. Protein A:
3. Hyaluronidase
4. Leukocidin
5. Coagulase
6. Capsule:

Question 7

7. Which virulence factors are structural parts of S.aureus bacteria cell? (Hint: there are 2)

Answer 7

Protein A

Capsule

Question 8

8. Which virulence factors are secretions by S.aureus bacteria cell? (Hint: there are 5)

Answer 8

1. Hemolysins
2. Protein A:
3. Hyaluronidase
4. Leukocidin
5. Coagulase

Question 9

9. What are the differences between an exogenous, endogenous, nosocomial and opportunistic infection with S.aureus?

**not fully answered***

Answer 9

exogenous
endogenous: Endogenous Source
     due to patients own Staph strain
     Impaired host resistance (poor health, chemotherapy)
     Skin wound(animal bite, burn)

nosocomial: hospital acquired (extensive surgery, aseptic procedures not enforced)

opportunistic infection: Endogenous Source
due to patients own Staph strain
Impaired host resistance (poor health, chemotherapy)
Skin wound(animal bite, burn)

Question 10

10. What is the single most important thing that nurses and doctors can do in a clinical setting to deter transmission of nosocomial infections between patients?

Answer 10

Wash their hands.

Question 11

11. What is the CDC?

Answer 11

Center for Disease Control

Question 12

12. What are the specific differences between Folliculitis, Furuncle and Carbuncles as they relate to a Staph infection? Which one of these is most serious?

Answer 12

Folliculitis:
Inflammation of a hair follicle
Small red bump, pimple
Pus in the hair follicle
Causes: shaving, blockage of follicle (dirt), friction from clothing (jeans)
Damaged follicle can then be infected by Staph

Furuncle:
Round, red painful, pus-filled sore on the skin
Exterior abscess
Infected hair follicle that extends to adjacent subcutaneous tissue
Pus may drain from boil

Carbuncles:(cluster of boils)
Massive lesion, further spread of abscess
Large area of redness, swelling, pain, and several sites of draining pus
Fever present

Most serious is Carbuncles

Question 13

13. Define Abscess.

Answer 13

Pus filled: living and dead WBC, dead tissue, infectious agent
No blood vessels: destroyed or pushed aside
Helps to localize infection most oral antibiotics noneffective (absence of blood flow)

Question 14

14. Is an abscess treatable with only oral antibiotics? Why or why not?

Answer 14

No. Because a walling off abscess by inflammation may prevent antibiotics from reaching abscess in effective quantities which is one reason drainage of abscess is so important.

1. Adequate drainage of abscess (lance)
2. Debridement: surgical removal of necrotic tissue (dead)
3. Antibiotic Therapy

Question 15

15. What is septicimea?

Answer 15

Abscesses can expand (or rupture) into the bloodstream and cause septicemia
Septic = diseased, -emia = blood
Remember, pus is poisonous garbage! You don’t want your abscess draining into your bloodstream, any more than your septic tank!
Septicemia can cause:
A massive, life-threatening, systemic infection!
Abscesses to form in the heart, bone, and joints!
Septicemia is pretty much the Worst Case Scenario of the average Staph infection

Question 16

16. What are the different levels of a wound infection?

Answer 16

Superficial: skin and subcutaneous (easiest to treat)
Deep: muscle or bone
Organ Space: involves an organ infection usually from surgical wounds (most serious)

Question 17

17. Is drug resistance a problem in treating S.aureus infections?

Answer 17

Yes!!!

Question 18

18. Define MRSA.

Answer 18

MRSA (methicillin resistant Staphylococcus aureus)

Question 19

19. Is MRSA treatable?

Answer 19

Yes but it is becoming harded to do so due to its ability to mutate.

Question 20

20. What is a phage (as discussed on the MRSA film)?

Answer 20

Virus that infects Staph infection

Question 21

21. Why is phage typing a useful laboratory tool in identifying different strains of Staph bacteria in a clinical setting?

Answer 21

Allows infection control team to compare MRSA bacteria strains and determine how many patients are infected with those strain

Question 22

22. Does the human body mount an effective immune response against S.aureus?

Answer 22

No

Question 23

23. What category of patient is at most risk of Staph infections?

Answer 23

ill patients / wound/surgery

Question 24

6. Outline the 6 virulence factors for S.aureus and explain them.
7. Hemolysins

Answer 24

Hemolysins:

 a) hemo: hemoglobin
 b) lysin: lyse 
 c) destroy red blood cells 
 d) β(beta) – hemolytic

Question 25

6. Outline the 6 virulence factors for S.aureus and explain them. 2. Protein A:

Answer 25

Protein A: a) found in cell wall and as a secretion by bacteria b) resists phagocytosis c) binds to IgG so Ab cannot bind to MØ

Question 26

6. Outline the 6 virulence factors for S.aureus and explain them. 3. Hyaluronidase

Answer 26

Hyaluronidase – a) breaks down hyaluronic acid, b) promotes tissue penetration, c) produced by 90% of S.aureus strains

Question 27

6. Outline the 6 virulence factors for S.aureus and explain them. 4. Leukocidin

Answer 27

``` Leukocidin Leuko – leukocytes cidin – means to kill or destroy kills neutrophils interferes with non-specific resistant mechanisms ```

Question 28

6. Outline the 6 virulence factors for S.aureus and explain them. 5. Coagulase

Answer 28

Coagulase – a) causes plasma to clot b) promotes attachment to host tissue c) actually helps wall off infection in an abscess d) hinders movement of WBC to infection by producing clots in capillaries

Question 29

6. Outline the 6 virulence factors for S.aureus and explain them. 6. Capsule

Answer 29

Capsule: a) polysaccharide b) inhibits phagocytosis