In vitro activity of cefodizime (HR-221) in combination with beta-lactamase inhibitors.

Cefodizime (formerly HR221) was tested either for in vitro microbiological activity or for its stability to beta-lactamases in the presence of two beta-lactamase inhibitors (clavulanic acid, tazobactam). Cefodizime was a poor substrate of class C enzymes but hyperproducer strains were generally resistant with or without a beta-lactamase inhibitor used in combination. On the contrary, class A enzymes were able to hydrolyze cefodizime. However, strains expressing class A beta-lactamase were susceptible to cefodizime in combination with clavulanic acid.