Also Known As: Carbenicillin, Geocillin
Carbenicillin is a bacteriolytic antibiotic belonging to the carboxypenicillin subgroup of the penicillins. It was discovered by scientists at Beecham and marketed as Pyopen. It has Gram-negative coverage which includes Pseudomonas aeruginosa but limited Gram-positive coverage. The carboxypenicillins are susceptible to degradation by beta-lactamase enzymes, although they are more resistant than ampicillin to degradation. Carbenicillin is also more stable at lower pH than ampicillin.
The antibiotic is very soluble in water and is acid-labile. Aqueous solutions are short-lived. Working concentration in the lab: up to 100 Âµg per ml.
It is a semi-synthetic analogue of the naturally occurring benzyl-penicillin. Carbenicillin at high doses can cause bleeding.
In molecular biology, carbenicillin may be preferred as a selecting agent (see Plasmid stabilisation technology) because its breakdown results in byproducts with a lower toxicity than analogous antibiotics like ampicillin. Carbenicillin is more stable than ampicillin and results in less satellite colonies on selection plates. However, in most situations this is not a significant problem so ampicillin is sometimes used due to its lower cost.