effect of minocycline, doxycycline and tetracycline on plaque bacteria associated with periodontitis

ABSTRACT

The aim of this study was to evaluate the antibacterial activity of three antibiotics, Minocycline, Tetracycline and Doxycycline against the representative strains of plaque bacteria, particularly of species related to periodontitis. Nineteen strains of bacteria isolated from human periodontal pockets were used as test organism with B fragalis as control, all strains were maintained in 20 ml of Brain Heart inforsin at 37°C and subcultured weekly. Three antibiotics Minocycline, Tetracycline and Doxycycline were tested against these bacteria minimum inhibitory concentration was taken as the lowest antibiotic concentration that yield no visible growth. Of the 3 antibiotics, minocycline invariably showed a lower minimum inhibitory concentration, than tetracycline or doxycycline. The gram-negative organisms involved in adult periodontitis including those organism with localized juvenile periodontitis were most susceptible to minocycline at a lower concentration than tetracycline and doxycycline. This indicates that minocycline is likely to be a good choice for antibiotic treatment and prevention of periodontal inflammation in which these organisms are implicated