IA. General microbiology | 10. Antibiotics used in combination.

Question 1

I. Antibiotics
1. What is the role of Antibiotics?

Answer 1

• Antibiotics kill/inhibit growth of bacteria, treat & prevent infections
• Increase the antibacterial effect
• Reduce the toxicity
• Prevent selection of resistant cell

Question 2

I. Antibiotics
2. What are the targets of antibiotics?

Answer 2

○ -folic acid synthesis
○ -dna gyrase(no supercoiling)
○ -rna synthesis(no ribosomes, no trna, no mrna)
○ -cell wall synthesis
○ -protein synthesis (will block the epa site of ribosome)

Question 3

II. Aim of Combination
1. What is the aim of antibiotics combinations?

Answer 3

1. Synergy (2 substances that together have a greater effect than just 1)
2. Avoiding Resistance
3. Targets polymicrobial Infection (presence of at least 2+ micro-organisms)

Question 4

II. Aim of Combination
2A. One of the aim of combination is SYNERGY
=> Explain why

Answer 4

Synergy (2 substances that together have a greater effect than just 1)

Question 5

II. Aim of Combination
2B. What are examples of SYNERGY?

Answer 5

1. Sumetrolim: TMP + SMX
   - Trimethoprim is an antibiotic used mainly in the treatment of bladder infections.
   - Sulfamethoxazole is an antibiotic. Also used to treat bladder infections (uti’s) bronchitis, and prostatitis, effective against both gram negative and positive bacteria such as listeria monocytogenes and E. coli
2. Synercid: quinupristin + dalfopristin
3. Penicillin + gentamicin

Question 6

II. Aim of Combination
3. One of the aim of combination is Avoiding Resistance
=> Give an example

Answer 6

β-lactam + enzyme inhibitors

Question 7

II. Aim of Combination
4. One of the aim of combination is Targeting polymicrobial Infection
=> Explain why

Answer 7

Targets polymicrobial Infection (presence of at least 2+ micro-organisms)

Question 8

III. What is the contradiction of antibiotics used in combination?

Answer 8

β-lactam (Acts only on multiplying bacteria) + bacteriostatic (inhibits multiplication of bacteria)