ABSTRACT
In 1976, R. B. Woodward announced the first penem that combined the essential structure elements of penicillins and cephalosporins. Penem antibiotics are susceptible to hydrolysis by renal dehydropeptidase-I in animals and man, and they tend to have a rather short plasma half-life. The in vivo antimicrobial activity of penem 2 against Staphylococcusaureus and Escherichia coli was compared with those of SUN 5555, cefpodoxime proxetil, and cephalexin. However, imipenem is subjected to hydrolysis by dehydropeptidase I, and it was nephrotoxic when administered alone. T. Miyadera et al. synthesized a new carbapenem antibiotic. RS-533 was more active against methicillin-susceptible Staphylococci than cefotaxime, and it was comparable to imipenem. RS-533 overall had activity similar to that of imipenem, with minor differences in minimal inhibitory concentrations noted for individual isolates. Penem antibiotics possess potent in vitro activity against Grampositive and Gram-negative bacteria including β-lactamase-producing strains.
