Principles of anti microbial therapy

Question 1

When must antimicrobial therapy be administered for it to be considered as empirical therapy?

Answer 1

After the onset of symptoms and before the definite pathogen is isolated

Question 1

What is the goal of prophylaxis?

Answer 1

The goal of prophylaxis is to prevent the onset of an infection.

Question 2

What are bactericidal and bacteriostatic antimicrobials?

Answer 2

They are antimicrobials that kill bacteria (bactericidal) or arrest the growth of bacteria (bacteriostatic) respectively at therapeutic drug concentrations .

Question 3

Name AT LEAST 6 host factors that need to be considered before administering an antibiotic to a patient?

Answer 3

1. Age,
2. Weight,
3. Renal function,
4. Hepatic function,
5. Drug allergies,
6. Recent antimicrobial use,
7. immune system status,
8. Diet, (Taking with dairy products or supplements)
9. Pregnancy status,
10. Genetic factors (e.g. G6PD status)
11. Medications that are being taken for other concurrent illnesses
12. Other co-morbdities

Question 4

What does it mean when an antibiotic is said to demonstrate time-dependent killing? What is the best doising strategy?

Answer 4

The rate and extent of microbe killing remains UNCHANGED regardless of how high antimicrobial concentrartion, as long as antimicrobial concentration is above the MIC (T>MIC)

Should be administered redularly to ensure antibiotic concentration is above MIC

Question 5

What does it mean when an antibiotic is said to demonstrate concentration-dependent killing? What is the best doising strategy?

Answer 5

The rate and extent of microbe killing are dependant on how high antimicrobial concentration.

The pharmacodynamic parameter predictive of outcome for concentration dependent drugs is the peak concentration (Cmax/MIC).

Drugs are gievn at high doses at less frequency intervals

Question 6

What is a post antibiotic effect?

Answer 6

PAE is the suppression of microbial growth that persists even after the levels of antibiotic have fallen below the MIC.

Question 7

Name 3 local routes of antibiotic drug administration

Answer 7

1. Aural (ear drops)
2. Ocular (eye drops)
3. Vaginal (pessary)
4. Topical (skin surface)

Question 8

Name 2 paraenteral and 2 enternal routes of antibiotic drug administration

Answer 8

Paraenternal:Intramuscular and intravenous

Enteral: Oral and rectal

Question 9

What are super-infections?

Answer 9

Superinfections are secondary infections following a previous infection especially when caused by microorganisms that are resistant or have become resistant to the antibiotics used earlier

Question 10

Name 4 mechanisms of antimicrobial resistance.

Answer 10

1. Enhanced export of antibiotic by efflux pumps
2. Release of microbial enzymes that destroy the antibiotic
3. Alteration of microbial proteins that transform pro-drugs to the effective moieties
4. Alteration of target proteins
5. Development of alternative pathways to those inhibited by the antibiotic.