Week 2 - Antimicrobial Therapy

Question 1

Define selective toxicity

Answer 1

The ability to kill the microbe but not harm the patient which is achieved by targeting a structure of the pathogen which is different to humans

Question 2

Define the term bactericidal

Answer 2

Directly kill the bacteria

Question 3

Define the term bacteriostatic

Answer 3

Inhibit growth of the bacteria that then enables the body’s defence mechanisms to remove the bacteria

Question 4

Describe the difference between broad spectrum and narrow spectrum antibiotics

Answer 4

• Broad Spectrum kill a wide range of gram-positive & Gram-negative bacteria but also destroy normal flora
• Narrow Spectrum effective against a select group of pathogens

Question 5

Advantages of Broad spectrum antibiotics

Answer 5

Immediate treatment

Question 6

Disadvantages of Broad spectrum antibiotics

Answer 6

• Antibiotic resistance
• Second degree infection
• Broad-spectrum antibiotics can lead to a dangerous form of diarrhoea, called “C. diff” which can require removal of the bowel

Question 7

Advantages of narrow spectrum antibiotics

Answer 7

• Decreased killing of normal flora
• Decreased Antibiotic resistance
• Effective against a select group of pathogens. For example Penicillin which is effective against Gram-positive bacteria

Question 8

Disadvantages of Narrow spectrum antibiotics

Answer 8

• Takes time to know there is bacteria
• Organisms not killed of if wrong antibiotic
• Often, the exact species of bacteria causing the illness is unknown, in which case narrow-spectrum antibiotics can’t be used

Question 9

List four ways that antimicrobials work

Answer 9

• Interfere with cell wall synthesis (eg. penicillin)
• Inhibit protein synthesis (eg. Erythromycin)
• Interference with DNA replication (eg. Ciprofloxacin)
• Interrupt metabolic reactions inside the cell (eg. Trimethoprim)

Question 10

Explain the term antibiotic resistance

Answer 10

When bacteria and fungi develop the ability to defeat the drugs designed to kill them. That means the bacteria and fungi are not killed and continue to grow

Question 11

Describe three ways to reduce antibiotic resistance

Answer 11

• Avoid Excessive prescribing of antimicrobials
• Finish the full course of antibiotics to discourage the survival & proliferation of resistant strains
• Never use left-over antibiotics or antibiotics that are prescribed for someone else