Antibiotic resiatance

Question 1

What is an antibiotic, and what distinguishes it from general compounds with
antimicrobial activity?

Answer 1

It is an antimicrobial agent (inhibits the growth and replication of bacteria) capable of targeting bacterial infections in the body.

Question 2

Why are antibiotics so important for mordern medicine?

Answer 2

1. fight bacterial infections
2. Enable safe open surgery procedures
3. support cancer therapy
4. support transplant patients
5. improved veterinary medicine

Question 3

What are the main causes that lead to the current antimicrobial resistance crisis?

Answer 3

1. mis-precription of antibiotics
2. over-prescription of antibiotics
3. over-use of antibiotics
   in food production
4. not finishing prescribed antibiotics (compliance)
5. poor infection control in hospital and clinics
6. Lack of hygiene and poor sanitation.
7. lack of new antibiotics

Question 4

Enumerate 3 biological processes targeted by antibiotics

Answer 4

1. cell wall biosynthesis -Beta lactams (penicillins)
2. cell membrane biosynthesis - antimicrobial peptide (colistin)
3. DNA synthesis - Fluoroquinolones (ciprofloxacin)
4. Protein synthesis (ribosomes)- aminoglycosides (gentamycin)

Question 5

Define antibiotic resistance, and describe one method that can be used to measure it.

Answer 5

ability of microbes to grow in the prescence of a high concetration of a given antibiotic.

methods:
1. Broth microdilution
2. calibrated dichotomous sensitivitiy test (kirby bauer test and Etest)

Question 6

What determines resistance to a given antibiotic: its ability to kill bacteria or to inhibit
bacterial growth?

Answer 6

the ability of an antibiotic to kill bacteria does not determine its reisistance or susceptibility but a measure of its minimum inhibitory concetration.
When compared with an established mic value, a strain of bacteria can be said to be resistant if it falls under the standard range.

Question 7

Why are Gram-negative bacteria generally more intrinsically resistant to antibiotics?

Answer 7

Gram negative bacteria have an extra lipopolysaccharide membrane ove the cell wall which adds an additional barrier which prevents permiabiliy of antibiotics.

2. thinner peptidoglycan wall

Question 8

What are the 3 most common antibiotic resistance mechanisms?

Answer 8

1. target mutation
2. antibiotic modification
3. drug efflux pumps

Question 9

Define antibiotic persistence. How does it differ from resistance?

Answer 9

Antibiotic persistence is the ability of a subpopulation of a bacteria exposed to bactericidal concentration of an antibiotics to survive (biphasic killing due to persistor cells).