FINAL EXAM CHP. 14

Question 1

HSV-1 and HSV-2:

Answer 1

• Both found orally and genitals
• Both cause increase in CD4 cells (where HIV binds)
• Patients are asymptomatic but still shed viral particles
• Higher chance of getting HIV

Question 2

Carbapenems:

Answer 2

Beta lactams that are used as a last resort for treatment because they resist beta-lactamase activity

Question 3

How can beta-lactams become ineffective?

Answer 3

Resistant strains to penicillin as derivatives make beta lactamase that breaks down beta lactams

Question 4

Disk diffusion test:

Answer 4

Known conc. of abx is placed on disk-> disk placed on lawn-> abx diffuses-> the larger the diffusion the more effective the abx is

Question 5

E-test:

Answer 5

• Strips have different conc. of abx-> placed on lawn-> lay strip down-> look for the intersection where growth/diffusion of abx has stopped on the strip= MIC
• More effective at determining conc.

Question 6

MIC:

Answer 6

• Minimum inhibitory concentration
• Gives you range for tube dilution
• Tests on pathogen, NOT on human

Question 7

Tube dilution test:

Answer 7

Take drug-> put into culture of known conc. of pathogen of interest= exact conc. of drug that went into tube

Question 8

Trends in antibiotic research: (2)

Answer 8

• Trending downwards because it’s expensive to develop new drugs and the number of FDA approvals for new antimicrobials fallen
• Developing new drugs is large investment and expensive-> not a priority

Question 9

Mechanism of antibiotic resistance by pathogen:

Answer 9

1. pump out drug
2. block penetration.
3. target modification (via natural selection)
4. inactivate enzyme