Antibiotics

Question 1

What are bacteriostatic and bactericidal antibiotics?

Answer 1

Bacteriostatic antibiotics stop the reproduction and growth of bacteria
Bactericidal antibiotics kill the bacteria directly

Question 2

Why is it important to follow local antibiotic resistance guidelines?

Answer 2

Bacteria in different populations may develop resistance to different antibiotics. Therefore, it is crucial to follow local policies for antibiotic use, as resistance patterns can vary by region.

Question 3

Name examples of antibiotics that inhibit cell wall synthesis.

Answer 3

Beta-lactam antibiotics:
* Penicillin
* Carbapenems (e.g., meropenem)
* Cephalosporins
Non-beta-lactam antibiotics:
* Vancomycin
* Teicoplanin

Question 4

How do antibiotics target folic acid metabolism in bacteria?

Answer 4

Folic acid is necessary for bacterial DNA synthesis.
Sulfamethoxazole blocks the conversion of PABA to DHFA.
Trimethoprim blocks the conversion of DHFA to THFA.
Co-trimoxazole is a combination of sulfamethoxazole and trimethoprim and is bactericidal.

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Question 5

What is the mechanism of action of Metronidazole?

Answer 5

Metronidazole is reduced in anaerobic bacteria to its active form, which inhibits DNA synthesis. It is bactericidal and effective against anaerobes but not aerobes.

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Question 6

Name some antibiotics that target bacterial ribosomes and inhibit protein synthesis.

Answer 6

Macrolides (e.g., erythromycin, clarithromycin, azithromycin)
* Clindamycin
* Tetracyclines (e.g., doxycycline)
* Aminoglycosides (e.g., gentamicin)
* Chloramphenicol

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Question 7

What is the role of Nitrofurantoin and how does it work?

Answer 7

Nitrofurantoin is used for lower urinary tract infections. It is bactericidal, concentrated in the urine, and attacks bacterial DNA, ribosomes, and other components. It is not used for upper urinary tract infections.

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Question 8

What should be considered when a patient reports a penicillin allergy?

Answer 8

True penicillin allergy can lead to anaphylaxis and should not be taken lightly.
Cross-reactivity with cephalosporins and carbapenems is low (around 1%).
Always ask for details about the allergic reaction—diarrhoea is a side effect, not an allergy.

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Question 9

How does the antibiotic escalation process work in hospitals?

Answer 9

The stepwise escalation of antibiotics includes:
* Amoxicillin (covers Streptococci, Listeria, Enterococci)
* Co-amoxiclav (adds coverage for Staphylococci, Haemophilus, E. coli)
* Piperacillin + tazobactam (adds coverage for Pseudomonas)
* Meropenem (adds coverage for ESBLs)
* Teicoplanin or Vancomycin (for MRSA)
* Clarithromycin or Doxycycline (for atypical bacteria)

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