In vitro antimicrobial sensitivity of enteric rods and pseudomonads from advanced adult periodontitis.

The prevalence and in vitro antimicrobial sensitivity of isolates of enteric rods and pseudomonads was examined in 844 adult periodontitis patients. These organisms were recovered from 13.5% of the study subjects. Ciprofloxacin exhibited the highest inhibitory activity of the 14 oral antimicrobial agents tested. Beta-lactam antibiotics were largely ineffective, and tetracycline failed to inhibit most Pseudomonas species. In vitro sensitivity data suggest that a subgingival microbiota comprising mainly streptococci would result from therapy that combined ciprofloxacin and metronidazole. Since streptococci may inhibit the growth of several putative periodontal pathogens, populations of "beneficial" streptococci in the periodontal pocket might constitute a very attractive therapeutic outcome. Controlled clinical studies are needed to clarify the possible role of ciprofloxacin in the treatment of destructive periodontitis.