In Vitro Activity of Tebipenem (SPR859) against Penicillin-Binding Proteins of Gram-Negative and Gram-Positive Bacteria

Tebipenem (SPR859) is the microbiologically active form of SPR994, tebipenem-pivoxil, an orally available carbapenem with activity against extended spectrum β-lactamase (ESBL) producing Enterobacteriaceae . Measurement of the relative binding of SPR859 to the bacterial cell targets revealed that it is a potent inhibitor of multiple penicillin-binding proteins (PBPs), but primarily a Gram-negative PBP2 inhibitor, similar to other compounds in this class. These data support further clinical development of SPR994.