Ofloxacin and penicillin G combination therapy in prevention of bacterial translocation and animal mortality after irradiation.

The efficacies of 40 mg of ofloxacin per kg/day given orally and 250 mg of penicillin per kg/day given intramuscularly, alone or in combination, were evaluated in the prevention of mortality of C3H/HeN female mice given 8.2 Gy of 60Co radiation. Mortalities were 51 of 60 mice (85%) in the control group, 46 of 60 mice (77%) among those treated with penicillin, 32 of 60 mice (53%) among those treated with ofloxacin (P less than 0.05), and 5 of 60 mice (8%) among those treated with ofloxacin and penicillin (P less than 0.001). The organisms recovered from the livers of control mice were members of the family Enterobacteriaceae and Streptococcus spp. A reduction in the number of the Enterobacteriaceae was noted only in ofloxacin-treated mice, and a reduction in the number of Streptococcus spp. was noted only in the penicillin-treated mice. Reductions in the numbers of both groups of organisms were noted only in the animals treated with both agents. This study shows the advantage of the combination of ofloxacin and penicillin in the prevention of bacterial translocation and animal mortality after irradiation.