Eva M Kulik Kunz1, Krystyna Lenkeit2, Tuomas Waltimo3, Roland Weiger2, Clemens Walter2. 1. Department of Preventive Dentistry and Oral Microbiology, School of Dental Medicine, University of Basel, Switzerland. Electronic address: eva.kulik@unibas.ch. 2. Department of Periodontology, Endodontology and Cariology, School of Dentistry, University of Basel, Switzerland. 3. Department of Preventive Dentistry and Oral Microbiology, School of Dental Medicine, University of Basel, Switzerland.
Abstract
OBJECTIVE: The aim of the present study was to analyze in vitro the combinatorial effects of the antibiotic combination of amoxicillin plus metronidazole on subgingival bacterial isolates. DESIGN: Aggregatibacter (Actinobacillus) actinomycetemcomitans, Prevotella intermedia/nigrescens, Fusobacterium nucleatum and Eikenella corrodens from our strain collection and subgingival bacteria isolated from patients with periodontitis were tested for their susceptibility to amoxicillin and metronidazole using the Etest. The fractional inhibitory concentration index (FICI), which is commonly used to describe drug interactions, was calculated. RESULTS: Synergy, i.e. FICI values ≤ 0.5, between amoxicillin and metronidazole was shown for two A. actinomycetemcomitans (FICI: 0.3), two F. nucleatum (FICI: 0.3 and 0.5, respectively) and one E. corrodens (FICI: 0.4) isolates. Indifference, i.e. FIC indices of >0.5 but ≤4, occurred for other isolates and the 14 P. intermedia/nigrescens strains tested. Microorganisms resistant to either amoxicillin or metronidazole were detected in all samples by Etest. CONCLUSION: Combinatorial effects occur between amoxicillin and metronidazole on some strains of A. actinomycetemcomitans, F. nucleatum and E. corrodens. Synergy was shown for a few strains only.
OBJECTIVE: The aim of the present study was to analyze in vitro the combinatorial effects of the antibiotic combination of amoxicillin plus metronidazole on subgingival bacterial isolates. DESIGN:Aggregatibacter (Actinobacillus) actinomycetemcomitans, Prevotella intermedia/nigrescens, Fusobacterium nucleatum and Eikenella corrodens from our strain collection and subgingival bacteria isolated from patients with periodontitis were tested for their susceptibility to amoxicillin and metronidazole using the Etest. The fractional inhibitory concentration index (FICI), which is commonly used to describe drug interactions, was calculated. RESULTS: Synergy, i.e. FICI values ≤ 0.5, between amoxicillin and metronidazole was shown for two A. actinomycetemcomitans (FICI: 0.3), two F. nucleatum (FICI: 0.3 and 0.5, respectively) and one E. corrodens (FICI: 0.4) isolates. Indifference, i.e. FIC indices of >0.5 but ≤4, occurred for other isolates and the 14 P. intermedia/nigrescens strains tested. Microorganisms resistant to either amoxicillin or metronidazole were detected in all samples by Etest. CONCLUSION: Combinatorial effects occur between amoxicillin and metronidazole on some strains of A. actinomycetemcomitans, F. nucleatum and E. corrodens. Synergy was shown for a few strains only.
Authors: Eva M Kulik; Tuomas Waltimo; Roland Weiger; Irene Schweizer; Krystyna Lenkeit; Elisabeth Filipuzzi-Jenny; Clemens Walter Journal: Clin Oral Investig Date: 2014-12-09 Impact factor: 3.573