(特集：PIVMECILLINAMによる尿路感染症の治療) 実験的感染マウスにおけるMecillinamとSulbenicillinとの併用作用について

Abstract

Combined effects of sulbenicillin (SBPC) and mecillinam (MPC) were investigated in the mice which were experimentally infected with E. coli, P. rettgeri, K. pneumoniae NH 31 or K. pneumoniae TN 1697. The bacilli and drugs were injected i.p. The protecting effects against the infections were expressed as ED0, ED2S, ED50 and ED75. Combined doses of the drugs used were less than that of the ED50 or ED75 of each drug, and the ED0, ED2S , ED50 and ED, s in the combined doses were compared with those in the single doses. 1) In the case of the infected mice with E. coli, ED50's of SBPC and MPC were 470 mg/kg and 520 mg/kg, respectively. The ED50 in the combined doses was calculated as that in 100 mg/kg of SBPC and 40 mg/kg of MPC (2.5: 1). 2) In the case of the infected mice with P. rettgeri, ED50's of SBPC and MPC were 27 mg/kg and more than 2, 000 mg/kg, respectively. The ED50 in the combined doses was calculated as that in 12.5 mg/kg of SBPC and 100 mg/kg of MPC (1: 8.0). 3) In the case of the infected mice with K. pneumoniae NK 31, ED'50s of SBPC and MPC were 90 mg/kg and 420 mg/kg, respectively. The ED50 in the combined doses was calculated as that in 12.5 mg/kg of SBPC and 100 mg/kg of MPC (1 : 8.0). 4) In the case of the infected mice with K.pneumoniae TN 1697, ED50's of SBPC and MPC were 130 mg/kg and 33 mg/kg, respectively. The ED50's in the combined doses were calculated as the doses of SBPC and MPC in combinations with 17.5 mg/kg and 3.1 mg/kg, 9.6 mg/kg and 6.25 mg/kg, and 6.25 mg/kg and 8.8 mg/kg (5.81: 1, 1.54: 1 and 1: 1.41), respectively. Therefore, as ED 50's in the combined doses of SBPC and MPC were less than 50% of those in single doses of each drug, it is concluded that the combined effects of these drugs are synergetic or additive.