Sulbactam is a β-lactamase inhibitor given in combination with β-lactam antibiotics to inhibit β-lactamase, an enzyme produced by bacteria that destroys the antibiotics. Sulbactam in combination with semisynthetic antibiotic ampicillin sodium is indicated for the treatment of infections due to susceptible strains of the designated microorganisms: Skin and Skin Structure Infections caused by beta-lactamase producing strains of Staphylococcus aureus, Escherichia coli etc; Intra-Abdominal Infections caused by beta-lactamase producing strains of Escherichia coli, Klebsiella spp. (including K. Pneumoniae) tec; Gynecological Infections caused by beta-lactamase producing strains of Escherichia coli, and Bacteroides spp. (including B. fragilis).

Brobactam is a synthetic inhibitor of beta-lactamases produced by both gram-positive and gram-negative bacteria. Brobactam potentiates the antibacterial activity of ampicillin against a wide range of clinically important bacterial strains which produce beta-lactamase. No resistant sub-population was observed amongst the strain s of staphylococci studied, and the development of resistance in vitro was not recorded in individual strains of Staphylococcus aureus and Escherichia coli exposed to subinhibitory concentrations of ampicillin/brobactam. Reduced sensitivity was observed in the case of one strain of M. morganii, which was known to produce an inducible chromosomal cephalosporinase.