Cefditoren in vitro activity and spectrum: A review of international studies using reference methods

Cefditoren, a broad-spectrum orally administered cephalosporin ester, has d ocumented in vitro efficacy against many Gram-positive and -negative pathog ens and stability against clinically important beta -lactamases. We have re viewed the microbiology and the pharmacokinetic/pharmacodynamic literature regarding the spectrum and potency of this newer agent against the major et iologic agents of community-acquired respiratory infection, (Streptococcus pneumoniae, Hemophilus influenzae and Moraxella catarrhalis), as well as th e Enterobacteriaceae and non-enteric Grain-negative bacilli, staphylococci, and other anerobic and anaerobic Gram-positive cocci. The level of cefdito ren activity against S. pneumoniae (MIC90, 0.5 mug/mL) was superior to all marketed oral cephalosporins and at least equal to amoxicillin +/- clavulan ate. H. influenzae (MIC90, 0.016-0.03 mug/mL) and M. catarrhalis (MIC90, 0. 06-0.5 mug/mL) were also very susceptible to cefditoren. In contrast to cef ixime and ceftibuten, cefditoren was active against oxacillin-susceptible s taphylococci (MIC90, less than or equal to 1 mug/mL) at a level comparable to cefuroxime axetil, cefaclor or cefprozil. Enterococci, Pseudomonas aerug inosa and most anaerobes (Gram-negative) were not cefditoren-susceptible, b ut most Enterobacteriaceae, beta -haemolytic and viridans group streptococc i were highly susceptible. Furthermore, an overview of key in vitro suscept ibility testing methods and issues including disk diffusion testing and Ete st (AB BIODISK, Solna, Sweden) method accuracy, interpretive criteria, and pharmacodynamic considerations for the selection of a breakpoint concentrat ion are provided. The rapid bactericidal nature of the antibacterial activi ty of cefditoren, its post antibiotic effect, penicillin binding protein ta rgets, and extent of beta -lactamase stability are all favorable qualities. In conclusion, this orally administered (BID))beta -lactam possesses promi se for use against commonly isolated problematic respiratory tract pathogen s such as penicillin-non-susceptible pneumococci and beta -lactamase-positi ve M. catarrhalis or H. influenzae. Success in the clinical trials will fur ther define the role of cefditoren in this era of emerging resistant bacter ial pathogens. (C) 2001 Elsevier Science Inc. All rights reserved.