Metronidazol susceptibility testing of porphyromonas gingivalis associated with adult periodontitis (An invitro study)

A variety of systemic agents being able to arrest the progression of periodontal disease have been studied for progression in periodontal therapy. Metronidazole usually used as a systemic and local antibiotic for treating periodontitis in Iran. During recent years an increasing number in antibiotic resistance has been documented. The purpose of the present study was to evaluate the minimal inhibitory concentration of metronidazole against clinical isolates of Porphyromonas gingivalis from adult periodontitis in Iran. This experimental study was performed on samples of 62 patients. The samples were taken by sterile paper points. Isolated bacteria were determined by conventional methods and MIC (minimal inhibitory concentration) determination was carried out according to the agar dilution method recommended for anaerobic bacteria by NCCLS (M11-A5). The range of final antibiotic concentration was 0.0625μg/ml to 16μg/ml. The results were analyzed by interval estimates. Thirty six strains of P. gingivalis were isolated from 62 patients. 16.7%, 55.5% and 27.8% of isolated strains were susceptible to the metronidazole with final concentration of 1, 0.5 and 0.25μg/ml of metronidazole, respectively. Therefore, all strains were susceptible to metronidazole. This is the first report to testing the sensitivity of P. gingivalis to Metronidazole in Iran. Fortunately, all 36 isolated strains of P. gingivalis were sensitive to metronidazole and this antibiotic may be used for treating P. gingivalis related infection in Iran.