Antibacterial Activities Of Secnidazole Against Periodontal Pathogen In Vitro

Periodontal disease is a familiar oral disease. It has been proved that the bacterium and its productions in the dental plaque are the imperative initiation factor to initiation periodontal disease,and other local factors and the defence reaction of host have important influences,too. Scaling and root planing (SRP) remains the "gold standard" treatment for periodontitis as against other treatments they have used. However, in the cases of conventional treatment fail or have more aggressive disease , anti-microbial agents have been used as adjuncts to mechanical therapy. Nitroimidazole is one of the common drugs used in the clinic which has evident curative effect, but the drug resistant strain is increasing gradually with the common use of metronidazole. Secnidazole is a new drug to resist anaerobia which has the same chemistry structure as nitroimidazole , metronidazole and tinidazole. It has long half life in corpore, and evident curative effect agaist anaerobic bacteria . The objective of this study is to compare with three nitroimidazole's anti-bacteria activity. These results will offer substantial evidence for using secinidazole in the further oral clinic . First part: The liquid dilution was used to detect the minimal inhibition concentration(MIC) of secnidazole against six bacterium from lab P.gingivalisATCC33277, P.gingivalis381, P.endodentalisAT CC34506 , P.intermedia ATCC25611, P.melaninogenicaATCC13041 and F. nucleatumATCC10953 were diluted in BHI liquid medium, thelast concentration were 10~8 CFU/ml. Then we detected the MIC of secnidazole against six bacterium from lab.Second part: We chose the clinical periodontitis patient which the probing depth was more than or equal to 5mm. After removal of suprgingival plaque, paper point were inserted into a periodontal pocket for 20s. Then the specimens were anaerobic cultured immediately. Base on its form of colony and the biochemistry identification , isolated the bacterium and save the pure strain. We collected 43 strains which isolated from patients and used the method agar-dilution to detect the mimimal inhibition concentration(MIC) of secnidazole against them.Result: (1) three kinds of nitroimidazole can obviously inhibit the 43 strains which isolated from patients. The activities against anaerobic bacteria of secnidazole in vitro were similar with tinidazole ,there ia no statistical difference .Secnidazole and tinidazole were stronger than that of metronidazole, and it has statistical difference. MIC of three kinds of nitroimidazole of secnidazole, tinidazole and metronidazole against 43 strains which isolated from patients separate is 0.359±0.451,0.353±0.399 and 0.602±0.378.(2) Result shows that the effect of the three kinds of nitroimidazole inhibiting the G strain is stronger than its inhibiting the G strain, andSNZ has the strongest inhibiting effect against the G strain among them.(3) The MIC of strains which isolated from patients is higher than that of the bacterium from lab.Based on these findings, three kinds of nitroimidazole all have activities against periodontal pathogen. From this study we know that the periodontal pathogen were susceptible to secnidazole ,can be used as oral clinical drug for periodontitis.