A review of the antimicrobial activity of clavulanate

Clavulanate is a broad-spectrum beta-lactamase inhibitor, with activity against many of the chromosomally and plasmid-mediated beta-lactamases of both Gram-positive and Gram-negative bacteria. Although clavulanate has minimal antibacterial activity in vitro, accumulating evidence suggests that it may have an effect on pathogenic bacteria regardless of beta-lactamase production. Like other beta-lactams, clavulanate has been shown to bind to penicillin-binding proteins (PBPs) in Gram-positive and Gram-negative bacteria. It was found to bind selectively to PBP3 in Streptococcus pneumoniae. It has been suggested that complementary binding to different PBPs and subsequent effects on autolysis contribute to the enhancement of the activity of other beta-lactams by clavulanate. In addition, co-amoxiclav has been shown to enhance the intracellular killing functions of human polymorphonuclear cells (PMNs) in studies undertaken with beta-lactamase-producing and non-beta-lactamase-producing strains of bacteria. These data from in vitro and cell culture systems have been reflected in vivo, where clavulanate enhanced the activity of amoxicillin against non-beta-lactamase-producing organisms. Further studies are required to determine whether the effects seen within in vitro and in vivo animal studies have clinical significance.