Gram Negative Antibiotics General

Question 1

Broad spectrum agents that are typically used from gram negatives

Answer 1

gentamicin, tobramicin, amikacin (glycopeptides) and ceftazidime (2nd gen cephalosporin)

Question 2

UTI Agents

Answer 2

Nitrofuran (ribosomal protein binding and DNA damage), cephalexin , trimethoprim (folate synthesis inhibitor) and Fosfomycin (cell wall inhibitor, prevents pyruvyl transferase)

Question 3

Colistin Outline

Answer 3

Polymyxin group. Membrane destabilisation and leakage. Anti-endotoxin properties (binds to LPS). Bactericidal, IV prodrug. Used in CRE (use carbapenems for ESBLs)

Question 4

Ceftazidime Outline

Answer 4

3rd Gen Cephalosporin. Beta lactam ring binds to transpeptidase preventing cell wall synthesis. Bactericidal

Question 5

Aminoglycosides Mode of Action

Answer 5

Inhibits protein synthesis by binding to 30S subunit. Proteins are non-functional due to codon misreading. Used in empiric and collective treatment. Adverse effects are nephrotoxity and ototoxicity. Administered by IV

Question 6

Tetracycline Examples

Answer 6

Doxycycline (PO/IV), tetracycline (PO) and tigecycline (IV)

Question 7

Tetracycline Mode of Action

Answer 7

Reversibly binds to 30S subunit of ribosomes. Prevents tRNA interaction with mRNA

Question 8

Protein Inhibitors Outline

Answer 8

Disrupt translation of mRNA at ribosome by binding to 50S and 30S subunits

Question 9

Ciprofloxacin Mode of Action

Answer 9

Inhibits DNA gyrase and topoisomerase 4 (helps unwind the DNA supercoil). The prevention of DNA unwinding results in no replication

Question 10

Tazocin (Piperacillin-tazobactam) Outline

Answer 10

Pipercillin (inhibits transpeptidase) and tazobactam (inhibits beta lactamase)