Monday, December 2, 2013

PHS_3506- Instructor: Dr. Billack

December 2, 2013 :
Lecture Topic(s):

Chapter 14: Mechanisms of Bacterial Pathogenesis; p. 138-146
Chapter 18: Staphylococcus….. pp.174-187


Reading Assignments from:

Medical Microbiology, 7th edition
Patrick R. Murray, Ken S. Rosenthal, Michael A. Pfaller
Elsevier Saunders, Philadelphia, PA


Homework Assignment: (based upon the lectures and the reading assignment)
To assist your understanding of the assigned readings, please answer the following questions in the space below:

(Chapter 14-related)
1. What is the mucociliary escalator of the respiratory tract? How may viruses affect the mucociliary escalator?

2. In what way are alveolar macrophages involved in fighting respiratory infections? What may happen if a brochus becomes obstructed?

3. Why are the muscles of the chest wall and diaphragm important in fighting infections? What impact can trauma or surgery have on these muscles?

4. What bacterial products can exert tissue destruction? What is the difference between cytotoxins, neurotoxins, enterotoxins? Can you list one example, as mentioned in class, of each of the types?

5. What types of bacteria produce coagulase? What does coagulase do? What types of bacteria produce collagenase? What does collagenase do? What types of bacteria produce hemolysins? What does this enzyme do? What types of bacteria produce leukocidins? What do leukocidins do?

6. Describe what a, “superantigen” is. What is, “TSST-1?” and what is its relationship to S. aureus?

7. Explain the role of a capsule in bacterial virulence. Is it an immunogenic structure? Can you list several examples of bacteria with capsules, as mentioned in class?

(Chapter 18-related)

8. Describe the morphology and physiology of Staphylococcus spp.

9. Describe the different types of clinical syndromes caused by (a) S. aureus, (s) S. epidermidis and (c) S. saprophyticus.

10. Describe the pathogenesis of infection by S. aureus.

11. What is MRSA? MVRSA? What are natural penicillins? What are semi-synthetic penicillins? Examples? What is penicillinase and why is it a problem?


12. (from the slides) (a) What is Staphylococcus aureus? (b) What is MRSA (methicillin-resistant Staphylococcus aureus)? (c) Who gets staph or MRSA infections? (d) What is community-associated MRSA (CA-MRSA)? (e) Are certain people at increased risk for community-associated staph or MRSA infections? (f) What are the clinical features of CA-MRSA? (g) What are the criteria for distinguishing community-associated MRSA (CA-MRSA) from healthcare-associated MRSA (HA-MRSA)? (h) What is the main way that staph or MRSA is transmitted in the community? (i) How is a MRSA infection diagnosed? (j) How are CA-MRSA infections treated?

13. Common oral treatments for MRSA? Iv treatment? Why not penicillins, cephalosporins or carbapenems?

14. What is vancomycin resistance? What is vanA?