title: Antibiotic susceptibility of periodontal Enterococcus faecalis.
abstract: BACKGROUND
  Enterococcus faecalis may contribute to periodontal breakdown in heavily infected subgingival sites, particularly in patients responding poorly to mechanical forms of periodontal therapy. Because only limited data are available on the antimicrobial sensitivity of enterococci of subgingival origin, this study evaluates the in vitro antibiotic susceptibility of E. faecalis isolated from periodontitis patients in the United States.
  
  
  METHODS
  Pure cultures of 47 subgingival E. faecalis clinical isolates were each inoculated onto specially prepared broth microdilution susceptibility panels containing vancomycin, teicoplanin, and six oral antibiotics of potential use in periodontal therapy. After incubation in ambient air for 18 to 20 hours, minimal inhibitory drug concentrations were determined using applicable Clinical and Laboratory Standards Institute criteria and interpretative guidelines. The organisms were additionally evaluated for in vitro resistance to metronidazole at 4 μg/mL.
  
  
  RESULTS
  Periodontal E. faecalis exhibited substantial in vitro resistance to tetracycline (53.2% resistant), erythromycin (80.8% resistant or intermediate resistant), clindamycin (100% resistant to 2 μg/mL), and metronidazole (100% resistant to 4 μg/mL). In comparison, the clinical isolates were generally sensitive to ciprofloxacin (89.4% susceptible; 10.6% intermediate resistant) and 100% susceptible in vitro to ampicillin, amoxicillin/clavulanate, vancomycin, and teicoplanin.
  
  
  CONCLUSIONS
  Tetracycline, erythromycin, clindamycin, and metronidazole revealed poor in vitro activity against human subgingival E. faecalis clinical isolates, and would likely be ineffective therapeutic agents against these species in periodontal pockets. Among orally administered antibiotics, ampicillin, amoxicillin/clavulanate, and ciprofloxacin exhibited marked in vitro inhibitory activity against periodontal E. faecalis, and may be clinically useful in treatment of periodontal infections involving enterococci.
authors.affiliation: Department of Periodontology and Oral Implantology, Oral Microbiology Testing Service Laboratory, Temple University School of Dentistry, Philadelphia, PA 19140, USA. trams@temple.edu
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Rams
authors.forename: Diane
authors.initials: D
authors.lastname: Feik
authors.forename: Joel E
authors.initials: JE
authors.lastname: Mortensen
authors.forename: John E
authors.initials: JE
authors.lastname: Degener
authors.forename: Arie J
authors.initials: AJ
authors.lastname: van Winkelhoff
mesh_terms: D000328:Adult; D000368:Aged; D019980:Amoxicillin-Potassium Clavulanate Combination / Q000494:pharmacology; D000667:Ampicillin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000890:Anti-Infective Agents / Q000494:pharmacology; D001431:Bacteriological Techniques; D055113:Chronic Periodontitis / Q000188:drug therapy / Q000382:microbiology; D002939:Ciprofloxacin / Q000494:pharmacology; D002981:Clindamycin / Q000494:pharmacology; D003773:Dental Plaque / Q000382:microbiology; D024881:Drug Resistance, Bacterial; D013293:Enterococcus faecalis / Q000145:classification / Q000187:drug effects*; D004917:Erythromycin / Q000494:pharmacology; D005260:Female; D005881:Gingiva / Q000382:microbiology; D016908:Gram-Positive Bacterial Infections / Q000382:microbiology; D006801:Humans; D008297:Male; D008795:Metronidazole / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D010514:Periodontal Pocket / Q000188:drug therapy / Q000382:microbiology; D010518:Periodontitis / Q000382:microbiology*; D017334:Teicoplanin / Q000494:pharmacology; D013753:Tetracycline Resistance; D014640:Vancomycin / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D008795:Metronidazole; D002981:Clindamycin; D002939:Ciprofloxacin; D017334:Teicoplanin; D004917:Erythromycin; D014640:Vancomycin; D019980:Amoxicillin-Potassium Clavulanate Combination; D000667:Ampicillin