title: Antibiotic resistance in human chronic periodontitis microbiota.
abstract: BACKGROUND
  Patients with chronic periodontitis (CP) may yield multiple species of putative periodontal bacterial pathogens that vary in their antibiotic drug susceptibility. This study determines the occurrence of in vitro antibiotic resistance among selected subgingival periodontal pathogens in patients with CP.
  
  
  METHODS
  Subgingival biofilm specimens from inflamed deep periodontal pockets were removed before treatment from 400 adults with CP in the United States. The samples were cultured, and selected periodontal pathogens were tested in vitro for susceptibility to amoxicillin at 8 mg/L, clindamycin at 4 mg/L, doxycycline at 4 mg/L, and metronidazole at 16 mg/L, with a post hoc combination of data for amoxicillin and metronidazole. Gram-negative enteric rods/pseudomonads were subjected to ciprofloxacin disk-diffusion testing.
  
  
  RESULTS
  Overall, 74.2% of the patients with CP revealed subgingival periodontal pathogens resistant to at least one of the test antibiotics. One or more test species, most often Prevotella intermedia/nigrescens, Streptococcus constellatus, or Aggregatibacter actinomycetemcomitans, were resistant in vitro to doxycycline, amoxicillin, metronidazole, or clindamycin, in 55%, 43.3%, 30.3%, and 26.5% of the patients with CP, respectively. Fifteen percent of patients harbored subgingival periodontal pathogens resistant to both amoxicillin and metronidazole, which were mostly either S. constellatus (45 individuals) or ciprofloxacin-susceptible strains of Gram-negative enteric rods/pseudomonads (nine individuals).
  
  
  CONCLUSIONS
  Patients with CP in the United States frequently yielded subgingival periodontal pathogens resistant in vitro to therapeutic concentrations of antibiotics commonly used in clinical periodontal practice. The wide variability found in periodontal pathogen antibiotic-resistance patterns should concern clinicians empirically selecting antibiotic treatment regimens for patients with CP.
authors.affiliation: Department of Periodontology and Oral Implantology, and Oral Microbiology Testing Service Laboratory, Temple University School of Dentistry, Philadelphia, PA.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Rams
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; D016976:Aggregatibacter actinomycetemcomitans / Q000187:drug effects; D000658:Amoxicillin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D058491:Bacterial Load; D002175:Candida / Q000187:drug effects; D055113:Chronic Periodontitis / Q000382:microbiology*; D002939:Ciprofloxacin / Q000494:pharmacology; D002981:Clindamycin / Q000494:pharmacology; D003773:Dental Plaque / Q000382:microbiology; D004318:Doxycycline / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D013293:Enterococcus faecalis / Q000187:drug effects; D005260:Female; D016967:Fusobacterium nucleatum / Q000187:drug effects; D006801:Humans; D008297:Male; D008795:Metronidazole / Q000494:pharmacology; D008875:Middle Aged; D010514:Periodontal Pocket / Q000382:microbiology; D018713:Prevotella intermedia / Q000187:drug effects; D045242:Prevotella nigrescens / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects; D034365:Streptococcus constellatus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D008795:Metronidazole; D002981:Clindamycin; D002939:Ciprofloxacin; D000658:Amoxicillin; D004318:Doxycycline