Carbenicillin is a broad-spectrum carboxypenicillin antibiotic.
1 It is active against Gram-negative and certain Gram-positive bacteria, including
S. pyogenes,
S. epidermidis,
P. mirabilis,
P. vulgaris,
E. coli, and
P. aeruginosa (MICs = 0.19, 1.56, 1.56, 3.12, 3.12, and 50 μg/ml, respectively). It is also active against penicillinase-producing and non-producing strains of
S. aureus (MICs = 1.56 and 12.5 μg/ml, respectively). Carbenicillin is protective against systemic
S. pyogenes,
P. vulgaris,
E. coli, and
S. aureus infection in a mouse model of systemic lethal infection with 50% protective dose (PD
50) values of 7.8, 224, 19.3, and 34 mg/kg, respectively. It also decreases viable colony counts in the kidney in a rat model of
P. vulgaris or
E. coli urinary tract infection when administered at a dose of 100 mg/kg. Formulations containing carbenicillin have previously been used in the treatment of upper and lower urinary tract infections and prostatitis.
