Tazobactam is an inhibitor of β-lactamases with greater activity against Ambler class A serine penicillinases and class C cephalosporinases, including TEM-1, SHV-1, and P99 (IC50s = 97, 150, and 8.5 nM). It also inhibits the class D oxacillinase OXA-2 (IC50 = 10 nM). Tazobactam is commonly paired with piperacillin, although it also supports other cephalosporin antibiotics.
