Antimicrobial activity of silver nitrate against periodontal pathogens.
Metal ions were evaluated as potential antimicrobial agents suitable for local delivery in the oral cavity for the treatment of periodontitis. Silver nitrate, copper chloride, and zinc chloride were tested for antimicrobial activity in in vitro killing assays conducted in phosphate buffered saline with a series of oral bacteria including gram-negative periodontal pathogens and gram-positive streptococci. Copper and zinc salts failed to exhibit strong and consistent activity against periodontal pathogens. In contrast, silver at a concentration of 0.5 microg/mL produced a 3 log10 reduction in colony forming units (CFU)/mL or greater against all periodontal pathogens tested including Porphyromonas gingivalis, Prevotella intermedia, Prevotella denticola, Bacteroides forsythus, Fusobacterium nucleatum vincentii, Campylobacter gracilis, Campylobacter rectus, Eikenella corrodens, and Actinobacillus actinomycetemcomitans. In comparison, substantially higher concentrations of silver nitrate failed to kill oral streptococci. A silver nitrate concentration of 25 microg/mL produced log10 reductions in CFU/mL of 3.5-5 in killing assays performed in human serum against P. gingivalis, demonstrating the ability of silver to retain activity in a biological medium similar to that encountered in vivo in the periodontal pocket. These results identify silver nitrate, an antimicrobial that may possess advantages over traditional antibiotics, as a potential agent for controlled release local delivery in the oral cavity for the treatment of periodontitis.
Spacciapoli
P
P
Periodontix Inc, Watertown, Massachusetts 02472, USA. pspacciapoli@periodontix.com
Buxton
D
D
Rothstein
D
D
Friden
P
P
D000287:Administration, Topical; D016976:Aggregatibacter actinomycetemcomitans / Q000187:drug effects; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001439:Bacteroides / Q000187:drug effects; D001769:Blood; D002167:Campylobacter / Q000187:drug effects; D002712:Chlorides / Q000494:pharmacology; D015169:Colony Count, Microbial; D003300:Copper / Q000494:pharmacology; D003470:Culture Media; D016124:Eikenella corrodens / Q000187:drug effects; D016967:Fusobacterium nucleatum / Q000187:drug effects; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006801:Humans; D009055:Mouth / Q000382:microbiology; D010514:Periodontal Pocket / Q000382:microbiology; D010518:Periodontitis / Q000382:microbiology*; D016966:Porphyromonas gingivalis / Q000187:drug effects; D018720:Prevotella / Q000187:drug effects; D018713:Prevotella intermedia / Q000187:drug effects; D012835:Silver Nitrate / Q000008:administration & dosage / Q000494:pharmacology*; D013291:Streptococcus / Q000187:drug effects; D013295:Streptococcus mutans / Q000187:drug effects; D016986:Streptococcus sobrinus / Q000187:drug effects; D017967:Zinc Compounds / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D002712:Chlorides; D003470:Culture Media; D017967:Zinc Compounds; D003300:Copper; C016837:zinc chloride; D012835:Silver Nitrate; C028419:cuprous chloride