Imipenem acts as an antimicrobial through the inhibition of cell wall synthesis of various gram-positive and gram-negative bacteria. This inhibition of cell wall synthesis in gram-negative bateria is attained by binding to pencillin binding proteins (PBPs). In E. coli and selected strains of P. aeruginosa, imipenem has shown to have the highest affinity to PBP-2, PBP-1a, and PBP-1b. This preferential binding to PBP-2 and PBP-1b results in the direct conversion of the individual cell to a spheroblast, which leads to rapid cell lysis and death without filament formation.
Imipenem is a beta-lactam antibiotic belongings to the subgroup of carbapenems. Imipenem has a broad spectrum of activity against aerobic and anaerobic Gram positive as well as Gram negative bacteria. It is particularly important for its activity against Pseudomonas aeruginosa and the Enterococcus species. Imipenem is rapidly degraded by the renal enzyme dehydropeptidase when administered alone, and is always co-administered with cilastatin to prevent this inactivation.