Antibacterial activity of moxifloxacin against periodontal anaerobic pathogens involved in systemic infections I. Milazzo, G. Blandino , R. Musumeci, G. Nicoletti, A.M. Lo Bue, A. Speciale Department of Microbiological and Gynaecological Sciences  / Section of Microbiology, University of Catania, Via Androne, 81, 95124 Catania, Italy Abstract The in vitro activity of moxifloxacin was compared with that of penicillin G, amoxycillin/clavulanate, cefoxitin, erythromycin, clindamycin and metronidazole against 158 isolates associated with periodontal infections. MIC 50 /MIC 90 values of moxifloxacin were respectively 0.06/0.5 mg/l for Porphyromonas gingivalis (35), for Prevotella spp. (28) and Actinomyces spp. (35), 0.12/0.25 mg/l for Fusobacterium nucleatum (20) and 0.06/0.12 mg/l for Peptostreptococcus spp. (30). The minimum inhibitory concentration (MIC) range of moxifloxacin for Bacteroides forsythus (6) and Campylobacter rectus (4) was 0.06  /0.12 mg/l. The minimum bactericidal concentrations were equal to or 2  /4 times the MIC values. Moxifloxacin produced a bactericidal effect at 8 h. Our results show that moxifloxacin has good antibacterial activity against periodontal pathogens comparable with that of cefoxitin and amoxycillin/clavulanate, and better than that of clindamycin, metronidazole and penicillin. # 2002 Elsevier Science B.V. and International Society of Chemotherapy. All rights reserved. Keywords: Moxifloxacin; Antibacterial activity; Periodontal anaerobes 1. Introduction Periodontal anaerobic pathogens are frequently asso- ciated with various infections, mainly systemic illnesses (bacteraemia, endocarditis, brain abscesses, urogenital infections and skin and soft tissue infections) [1,2]. In particular, the spectrum of infections with Prevotella spp. and Porphyromonas spp., other than the period- ontal ones, includes bacteraemia (mostly of orophar- yngeal origin), head and neck infections (such as chronic otitis media, sinusitis and mastoiditis, peritonsillar and retro pharyngeal abscesses), pulmonary infections (as a result of aspiration), gastrointestinal and urogenital infections, and skin and soft tissue infections (especially around the oropharyngeal area) [3  /9]. The different susceptibilities of these pathogens to antimicrobial agents makes therapy very difficult [10  /13]. Older fluoroquinolones have relatively poor activity against anaerobic pathogens but newer fluoroquinolones have more activity against these organisms. Moxifloxacin is a new oral 8-methoxy-quinolone with a wide spectrum of activity; it is active against Gram- negative and multi-resistant Gram-positive bacteria, aerobic and anaerobic bacteria, and atypical micro- organisms [14,15]. The aim of this study was to evaluate the antibacterial activity of moxifloxacin in comparison with other antibiotics against anaerobic pathogens involved in periodontal infections. 2. Material and methods 2.1. Bacterial strains The strains tested were 158 recent clinical isolates collected from periodontal infections. The isolates comprised: Bacteroides forsythus (6), Porphyromonas gingivalis (35), Prevotella melaninogenica (11), Pre- votella intermedia (9), Prevotella spp. (8), Fusobacterium nucleatum (20), Campylobacter rectus (4), Actinomyces spp. (35) and Peptostreptococcus spp. (30). The isolates were identified by conventional tests [16,17].  Corresponding author. Tel.:  /39-95-312386; fax:  /39-95-325032 E-mail address: blandino@mbox.unict.it (G. Blandino). International Journal of Antimicrobial Agents 20 (2002) 451  /456 www.isochem.org 0924-8579/02/$ - see front matter # 2002 Elsevier Science B.V. and International Society of Chemotherapy. All rights reserved. PII:S0924-8579(02)00190-5