Immune response in patients with intraabdominal infections treated with imipenem. Swedish Study Group.

In the present investigation the humoral immune response against isolated microorganisms in patients treated with imipenem was studied. Sixty-six patients (34 men and 32 women, 18-86 years of age) with suspicion of intraabdominal infections entered the study. Five patients were excluded for various reasons and the remaining 61 patients were treated with imipenem/cilastatin 0.5-1.0 g t.i.d. for 5-29 days (median nine days). Three serum samples were taken from each patient, the first sample at admission, the second between three and seven days after the first dose of imipenem/cilastatin and the third between 14 and 31 days after the first dose. One third of the patients had a malignant disease and the verified intraabdominal infections were judged to be severe in 23 and moderately severe in 33 of the patients. Fifty-six patients (92%) were cured and five patients (8%) were considered improved after the treatment. The immune response against isolated microorganisms was measured in the three serum samples by indirect immunofluorescence tests and enzyme-linked immunosorbent assays. Among the aerobic microorganisms isolated Escherichia coli (46 strains) Staphylococcus epidermidis (22 strains), Streptococcus milleri (15 strains) and Enterococcus faecalis (11 strains) dominated and among the anaerobic bacteria Bacteroides fragilis (39 strains). Thirty-two patients had significant immune responses against one or more of the isolated microorganisms. E. coli and B. fragilis gave rises in antibody titers in 13 and 20 cases respectively, while significant titers against S. epidermidis were noticed in only three cases, against S. milleri in two cases and against E. faecalis in three cases.(ABSTRACT TRUNCATED AT 250 WORDS)