MEN 10700, a new penem antibiotic: in vitro antibacterial activity on clinical isolates

MEN 10700 is a new broad-spectrum penem, currently in preclinical development. In the present study, the activity of MEN 10700 was compared to that of imipenem, meropenem, cefotaxime, ampicillin/sulbactam, amikacin and ciprofloxacin against 619 gram-positive and gram-negative bacterial strains, and to that of imipenem, meropenem, cefotaxime, ceftriaxone, ceftazidime, cefepime and ampicillin/sulbactam against 38 strains of ciprofloxacin-resistant Escherichia coli, and against 19 extended-spectrum-beta-lactamase (ESBL)-producing strains of the KES group. MEN 10700 was highly active against most gram-positive and gram-negative strains, and overall demonstrated comparable activity to imipenem and meropenem. Methicillin-susceptible Staphylococcus aureus and methicillin-susceptible Staphylococcus epidermidis were highly susceptible to MEN 10700, which was the most potent among the antibiotics tested. MEN 10700 was less potent than the carbapenem antibiotics on Morganella morganii, Serratia marcescens and Acinetobacter spp. Ciprofloxacin-resistant E. coli were uniformly susceptible to MEN 10700, imipenem and meropenem, with MIC90 values in the range of < or = 0.12-0.25 mg/l, while showing much lower susceptibility to the other antibiotics tested, including the fourth-generation cephalosporin cefepime. This feature was even more evident in ESBL-producing strains of the KES group, with an MIC90 of 1- 2 mg/l for MEN 10700, imipenem and meropenem, and a MIC90 of 16-64 mg/l for the other antibiotics tested, including cefepime.