Sulbactam irreversibly inhibits the hydrolytic activity of beta-lactamases. This compound is commercially available in combination with either ampicillin or cefoperazone. In each instance, the activity of the partner antibiotic against P-lactamase-producing bacteria is restored. One of the particular advantages of using sulbactam-containing combinations is that sulbactam itself has inherent activity against some Acinetobacter baumannii. Sulbactam combinations have not demonstrated strong selective pressures for extended-spectrum beta-lactamase-producing Enterobacteriaceae and vancomycin-resistant enterococci. In contrast to clavulanate, sulbactam does not induce class I (Ampc) chromosomal beta-lactamases in Enterobacteriaceae.