In vitro antimicrobial activity of MK-0787 and therapeutic efficacy of MK-0787/MK-0791 in respiratory tract infections

In vitro antimicrobial activity of MK-0787, a new β-lactam antibiotic, was examined by the broth dilution method with the MIC 2000 system. The minimum inhibitory concentrations(MICs) of MK-0787 against 120 clinical isolates were compared with those of ceftazidime (CAZ), cefoperazone (CPZ), latamoxef (LMOX) and gentamicin (GM) against 20 isolated each of S. aureus, E. coli, K. pneumoniae, S. marcescens, Enterobacter spp. and P. aeruginosa. Against S. aureus, MK-0787 was shown to be most active among the five drugs and significantly more active than CPZ against all other isolates tested. The therapeutic efficacy of MK-0787/MK-0791 was evaluated in patients with respiratory tract infections. Eighteen patients were treated with intravenous drip infusions of this drug at the dose of 0.5 gram of MK-0787 twice to four times a day. The response to treatment was excellent in one patient, good in eleven, fair in two and poor in four. Slight epigastralgia was observed in one patient during administration of this drug, and laboratory test revealed eosinophilia in two patients, elevation of serum transaminase in four and elevation of blood urea nitrogen in one. All of these abnormalities in laboratory tests were of slight, transient and returned to normal after cessation of the administration of the drug.