Antimicrobial activity of cefditoren tested against contemporary (2004-2006) isolates of Haemophilus influenzae and Moraxella catarrhalis responsible for community-acquired respiratory tract infections in the United States

Among orally administered cephalosporins, aminopenicillins (+/- clavulanate), and macrolides, cefditoren was the most potent agent against Haemophilus influenzae (MIC50/90, <= 0.008/0.03 mu g/mL; 316 isolates including 100 beta-lactamase-positive and 10 beta-lactamase-negative ampicillin-resistant [BLNAR]) and was 32-, 64-, and 512-fold more potent than cefdinir, cefuroxime, and cefprozil, respectively. Cefditoren (MIC50 0.03 mu g/mL) was also >= 32-fold more active against BLNAR phenotypes, although newer macrolides provided complete coverage against these strains. All Moraxella catarrhalis isolates were inhibited by cefditoren (0.5 mu g/mL), including beta-lactamase producers (MIC50, 0.12 vs <= 0.008 mu g/mL). Cefditoren retains potent activity against respiratory tract isolates in the United States, including those with resistance phenotypes. (C) 2008 Published by Elsevier Inc.