CEFETAMET PIVOXIL - COMPARABLE EVALUATION WITH OTHER ORALLY AVAILABLEANTIBIOTICS AGAINST SELECTED SPECIES OF RESPIRATORY PATHOGENS

Cefetamet pivoxil, the prodrug ester of cefetamet, is a new third-gene ration cephalosporin with a broad spectrum of activity. The in vitro a ctivity of cefetamet was superior to that of cefaclor, ceftibuten, amo xicillin plus clavulanic acid, and amoxicillin alone when tested again st 403 strains of freshly isolated upper and lower respiratory tract p athogens. Cefetamet killed 100% Haemophilus influenzae and H. parainfl uenzae, including beta-lactamase-producing strains, at less than or eq ual to 0.25 mg/l, Streptococcus pyogenes and S. pneumoniae at less tha n or equal to 0.5 mg/l, S. agalactiae at less than or equal to 0.1 mg/ l, and streptococci at less than or equal to 2.0 mg/l. Moreover, at le ss than or equal to 4 mg/l (breaking point), cefetamet was also highly effective against Escherichia coli (94%), Klebsiella pneumoniae (92%) , K. oxytoca (91%) and, at 1 mg/l, against Moraxella catarrhalis (90%) , including Rho-lactamase-producing strains. Furthermore, time-killing analyses at 4 x MIC demonstrated that cefetamet was bactericidal agai nst P-lactamase-producing H. influenzae, M. catarrhalis, and K pneumon iae within 6 h and S, pneumoniae within 4 h. Hydrolysis studies confir med cefetamet's stability to TEM1 and SHV1, the most common enterobact erial beta-lactamases.