Antibiotics

Ampicillin is a semi-synthetic derivative of penicillin, a β-lactam antibiotic with an amino group attached to the penicillin structure. Inhibits bacterial cell-wall synthesis by inactivating transpeptidases in peptidoglycan cross linking mecanism. So, in E.coli it inhibits cell wall synthesis. Against gram-positive bacteria, ampicillin has a similar mode of action as benzylpenicillin and against gram-negative bacteria, it has a similar mode of action as chloramphenicol and tetracyclines.