Antibacterial activity and post-antibiotic effect of flurithromycin compared with other macrolides and penicillins against periodontal pathogens

In this study the authors examined the activity of flurithromycin compared to that of erythromycin, spiramycin and penicillin against 107 strains of v arious species supposed to cause periodontitis, The range of MICs of flurit hromycin was: less than or equal to0.06-2 mg/l for P, gingivalis (28 isolat es), 0.06-2 mg/l for P, melaninogenica (7), 0.5-4 mg/l for P, intermedia (5 ), 0.25-8 mg/l for Prevotella sp, (8), 1-16 mg/l for F, nucleatum (14), 0.1 2-0.5 mg/l for W. recta (2), 0.5-32 mg/l for E, corrodens, 0.5-2 mg/l for B , forsythus (2); less than or equal to0.06-64 mg/l for Peptostreptococcus s p. (11), less than or equal to0.06-1 mg/l for A. odontolyticus (11) and for A. naeslundii (7) and less than or equal to0.06-16 mg/l for A. viscosus (7 ). Macrolide activity was ranked in decreasing order from flurithromycin to er ythromycin to spiramycin, Beta-lactamase production was demonstrated in Prevotella sp. (20%) and in F , nucleatum (7%), Isolates which were beta -lactamase negative but resistan t to penicillin were found among Peptostreptococcus sp. and Actinomyces sp. A post-antibiotic effect of 2 hours was seen for flurithromycin on P, gingi valis and E, corrodens, The good in vitro activity of flurithromycin against bacteria supposed to c ause periodontitis suggests clinical potential in the treatment of these di seases.