Bacteriostatic and Bactericidal In Vitro Activities of Clarithromycin and Erythromycin against Periodontopathic Actinobacillus actinomycetemcomitans

The susceptibilities of 87 periodontitis-associated strains of Actinobacillus actinomycetemcomitans to clarithromycin and erythromycin were determined by standard methodology recommended for Haemophilus influenzae. For clarithromycin the MIC at which 90% of the isolates were inhibited was ≤2.0 μg/ml and the minimal bactericidal concentration at which 90% of the strains were killed was ≤4.0 μg/ml, suggesting that it would be a candidate for therapeutic trials in patients with periodontitis.