Define the terms ‘bactericidal’ and ‘bacteriostatic’ used to classify antibiotics with examples. (8 marks)

Speculated mark distribution:

• Definitions for 'bactericidal' and 'bacteriostatic': 2 marks
• At least 3 antibiotics for each category, 1 mark for each correctly named/allocated antibiotic.

Comment: Initially the question looks daunting, but the definition of bactericidal and bacteriostatic is well known, and most pharmacists should be able to at least guess 1-2 antibiotics for each category.

Definition of bactericidal: Antibiotics which are able to irreversibly kill bacteria.

Bactericidal antibiotics: penicillin, metronidazole, vancomycin, cephalexin, aminoglycosides (eg. gentamycin), fluoroquinolones (eg. ciprofloxacin)

Definition of bacteriostatic: Antibiotics which slow down or prevent the growth of bacteria but don't kill them. This action is reversible.

Bacteriostatic antibiotics: trimethoprim, co-trimoxazole, clindamycin, tetracycline, chloramphenicol, macrolides

Reference:

Clinical Relevance of Bacteriostatic versus Bactericidal Mechanisms of Action in the Treatment of Gram-Positive Bacterial Infections