OBJECTIVE To observe the anti
anaerobic activities of
secnidazole (SNZ) in vitro and in vivo. METHOD MIC 50
and MIC 90 of
secnidazole against 200 strains of
anaerobic bacteria were detected by using agar disk dilution assay the in viv anti anaerobic activity of secnidazole through oral administration or tail vein injection was determined by the mouse models infected by Peptostreptococcus anaerobius, Clostridum perfringens, Bacteriodes fragilis or Porphyron monas gingivalis. Tinidazole (TNZ) and/or meronidazole (MTZ) were used as control drugs in this study. RESULTS MIC 90 values of SNZ and TNZ to 120 strains of Gram negative anaerobic bacteria were 1～4 and 1～2 mg/mL, and were 4～8 and 4～16 mg/mL to 80 strains of Gram positive anaerobic bacteria, respectively ( t =0.36～0.67, P >0.05). MIC90 values of MTZ against the Gram negative and Gram positive anaerobic bacteria were 4～8 and 16～32mg/mL, respectively, which were obviously higher than that of SNZ and TNZ ( t =2.46～2.82, P <0.01). In the mouse models infected with the four bacteria mentioned above, the ED 50 values of SNZ and TNZ with oral taking were 6.287～12.912 mg/kg and 6.943～14.726 mg/kg, and were 4.448～8.398 mg/kg and 4.380～8.872 mg/kg by way of drug tail vein injection. CONCLUSION The activities against anaerobic bacteria of SNZ and in vitro and in vivo were similar to that of TNZ. The activity against the anaerobic bacteria of MTZ in vitro was obviously lower compared with SNZ and TNZ, respectively.