Fosfomycin (Monurol®) -- mechanism

Cell Wall Synthesis Inhibitor

structural analog of phosphoenol pyruvate (PEP),

blocks  step-1 PDG synthesis

In Step 1: Synthesis of muramic acid (which ends up becoming the glycocele backbone of peptidoglyan)

broad spectrum antibiotic

Resistance emerges quickly from multiple doses

Mild adverse effects = diarrhea, vaginitis

Uses = single dose oral treatment of uncomplicated UTIs

D-cycloserine- mechanism

Cell wall synthesis inhibitor

structural analog of D-alanine--blocks 2 steps in PDG synthesis (1&2)

inhibits conversion of D-alanine dipeptide which ends up becoming the end of the peptide for strength and stability of cell wall. 

D-cycloserine - general info

Broad spectrum

Serious CNS effects (headache, convulsions)- reversible & dose related

Used for second-line TB drug

Cell wall synthesis inhibitor

Inhibits step 3

Depletes lipid carrier for PDG synthesis

topical application only

narrow spectrum

Severe nephrotoxicity

used for skin & opthalmologic infections

Good in combo w/ polymyxin B

Cell Wall Synthesis Inhibitor

Inhibits step 4 & 5

– Binds D-Ala – D-Ala terminus of pentapeptide

– Blocks PDG synthesis (step 4: transglycosylase) and X-linking (step 5: transpeptidase) by binding the substrate