Topic 7A Antimicrobial Resistence

Question 1

What are antibiotics limitations

Answer 1

• Not effective against exotoxin-mediated diseases
• Delivery of drug to infection site (blood-brain barrier, UTI)
• Physiology of infection site (pH of stomach)
• Bacteriostatic agents are not effective in abscesses (no active cell division)
• Bacteriostatic agents require functional host immune system to kill
• Bacteria may develop antibiotic resistance

Question 2

What is innate resistance

Answer 2

Resistance:
Lack of drug target. Example: mycoplasma genitalium is innately resistant to penicillin as it has no cell wall.
Physiological incompatibility with drug. Example: aerobic bacteria are innately resistant to metronidazole because it
targets a specific electron carrier protein only found in anaerobic bacteria.

Question 3

What is acquired resistance

Answer 3

Resistance:
Inappropriate usage by patients: patient doesn’t finish medication artificial selection for more resistant bacteria. Inappropriate drug prescription: using an ineffective drug may cause resistance in the patient’s other bacteria.
Large scale prophylaxis use in commercial farming