| Properties | Ampicillin | Carbenicillin | Remarks |
| Semi-synthetic | Yes | Yes | Both antibiotics are Semi-synthetic derivatives of penicillin |
| Antibiotic class | β-lactam | β-lactam | Both antibiotics cantain β-lactam ring |
| broad-spectrum | Yes | Yes | Active against both gram-positive and gram-negative bacteria |
| Mode of resistance in bacteria | beta-lactamases | beta-lactamases | Carbenicillin is less sensitive than penicillin |
| Stability (heat and acid) | Lass stable | More stable | |
| Structure |  |  | |
| Selection of bacterial cells harbouring ampicillin resistance gene (beta-lactamases) | Effective | Effective | Carbenicillin is more effective than ampicillin as it is more stable |
| Satellite colonies | Frequent | Less frequent | Carbenicillin is more stable than ampicillin |
| Cost | Less | more | Carbenicillin is 2 – 4 times costlier than ampicillin |
