Abstract: | Investigation on the etiology of septicemia occurring among the immunocompromised patients was performed by using experimental model of the mouse with leukocytopenia. The ddY conventional mice of 4 weeks of age were inoculated with cyclophosphamide (CPM) intraperitoneally 3 to 5 times every other day with a dose of 3 mg/mouse once to make an agranulocytic status. Then, intraperitoneal administrations of various antibiotic regimens consisting of ampicillin (ABPC) alone, ABPC + ceftazidime (CAZ), ABPC + CAZ + cloxacillin (MCIPC), ABPC + CAZ + MCIPC + minocycline (MINO) and saline as a control to these immunosuppressed mice were begun once every day for 10 days after the second inoculation of CPM. The mortality rate of the mice given saline as a control was very high with a frequency of 43.3% and there were significant differences between the saline group and another antibiotic groups other than ABPC (p less than 0.01). On the other hand, the mortality rate of the group given APBC showed the highest rate of 70% and it was significantly higher than that of the saline control group (p less than 0.05). The main cause of most of the dead mice was septicemia due to P. aeruginosa and which were isolated from the feces of all these mice and serotype of the strains isolated from the heart blood and feces in the same host corresponded to each other. Moreover, intestinal bacterial flora in mice treated by saline and ABPC which highly showed Pseudomonas sepsis, was occupied dominantly by P. aeruginosa, although P. aeruginosa was not detectable from the experimental environments.(ABSTRACT TRUNCATED AT 250 WORDS) |