Clavulanic acid was found as a metabolic product of Streptomyces clavuligerus
This small molecule has a lactam ring like all antibiotics of the beta-lactam group (penicillins (penams), cephalosporins (cephems), monobactams, carbapenems), but it does not have any antibiotic power itself.
It is useful in that it is a competitive inhibitor of bacterial β-lactamase; it joins onto the active site of this enzyme, used by resistant bacteria to break down and deactivate many antibiotics of that group, and deactivates the bacterial enzyme. As a result, it can be used in conjunction with antibiotics that would otherwise be ineffective.
Examples of this include Co-amoxiclav (Augmentin), in which clavulanic acid is combined with amoxicillin.
This so-called broad-spectrum or combination antibiotic may be used against a variety of bacteria, possibly including Klebsiella