Faropenem, a new oral penem: antibacterial activity against selected anaerobic and fastidious periodontal isolates

The in vitro activity of faropenem, an oral penem, was compared with those of penicillin, coamoxiclav, cefoxitin, clindamycin, erythromycin and metronidazole against 106 isolates of anaerobic pathogens involved in systemic infections. The organisms tested comprised Porphyromonas gingivalis (29), Prevotella spp. (eight), Prevotella melaninogenica (seven), Prevotella intermedia (five), Actinomyces spp. (25), Fusobacterium nucleatum (14), Peptostreptococcus spp. (11), Bacteroides ureolyticus (five) and Bacteroides forsythus (two). The antimicrobial properties of faropenem were investigated by studying MICs, MBCs, time–kill kinetics and postantibiotic effect (PAE). Faropenem was highly active against all the anaerobes tested (MIC90 ≤ 0.5 mg/L) and was bactericidal against both β-lactamase-positive and -negative anaerobes, with a maximum bactericidal effect at 10 × MIC at between 12 and 24 h. In addition, faropenem had an in vitro PAE on all the tested isolates and this was not influenced by β-lactamase production. Faropenem may be useful for treating infections caused by periodontal bacteria or oral flora.