Total and free endotoxin release in time from cultures of Escherichia coli by different antibiotics was studied in vitro for 4 h in relation to the antibiotic effect on viable counts and morphological features of the test cultures. The most rapid fall in viable counts was seen after treatment with imipenem or the combination of imipenem with tobramycin, accompanied by an early, but minimal increase (1.8-fold) of the total (free plus cell-bound) endotoxin level at 1 h. Total endotoxin levels increased approximately 5-fold upon incubation with ceftazidime, tobramycin or the combination of tobramycin with cefuroxime, whereas incubation with cefuroxime or aztreonam alone caused a late 22-and 49-fold increase in total endotoxin, respectively, at 4 h. In chloramphenicol treated cultures there was still an increase in viable counts during therapy, resulting in an ultimately 78-fold increase of mean levels of total endotoxin. Free endotoxin levels increased approximately 6-fold within 1 h upon treatment with imipenem, alone or in combination with tobramycin, or ceftazidime as the result of rapid lysis of bacteria. Treatment with cefuroxime or aztreonam induced a relatively late but much higher release of free endotoxin (118-and 222-fold, respectively), which was due to the formation of long filamentous structures during the first 2 h of incubation and eventually cell lysis. Both tobramycin and the combination of tobramycin with cefuroxime caused a more gradual rise in free endotoxin, with a +/- 15-fold increase in free endotoxin at 4 h. In chloramphenicol treated cultures, as in the control cultures, the level of free endotoxin remained proportional to the amount of viable organisms. We also studied plasma endotoxin levels in 20 patients with septic shock. 10 out of these 20 patients had a detectable endotoxemia (greater than 5 ng/l) on admission. We describe the patterns of plasma endotoxin in these patients during the first 24 h of antibiotic treatment. We conclude that, in the in-vitro study, values of total endotoxin, free endotoxin, and the rate of release of endotoxin varies with the antibiotic used. We also demonstrate that in patients under treatment for septic shock endotoxin release can be related to the administration of antibiotics.

No abstract

Twelve febrile patients with severe neutropenia, who had undergone aggressive chemotherapy for acute myeloid leukemia, were treated empirically with a continuous infusion of ceftazidime 100 mg/kg/day after a 500 mg loading dose, in order to study the pharmacokinetics of ceftazidime after continuous infusion and to examine the clinical applicability of continuous infusion in this patient population. Three patients had a slight decrease in renal function. All patients attained a steady-state ceftazidime serum level of > 20 micrograms/ml within 180 to 240 min, which was considered effective against most pathogens in neutropenic patients. The median volume of distribution for the patient group was 29.1 l, the elimination half-life was 2.5 h and the clearance of ceftazidime was 7.7 l/h. A subnormal kidney function influenced half-lives and clearance (but not volume of distribution), as expected. When precautions were taken to avoid known interactions between ceftazidime and other compounds to be infused simultaneously, continuous infusion of ceftazidime was applicable for treatment of neutropenic patients without major side effects.

Sepsis or septic shock is frequently associated with activation of the complement system, coagulation and fibrinolytic changes and the release of several cytokines. In this study we analyzed the relation of complement activation to the inflammatory mediators, hemodynamic and biochemical parameters and severity of illness and outcome in 20 consecutive patients with clinically defined sepsis. Levels of C3a and C3d were elevated in 90% of the patients (median levels 0.19 mg/l and 8.6 mg/l respectively) in comparison to 14% and 42%, respectively of 7 patients with non-septic shock. Levels of C4 were decreased in only 1 of the 20 septic patients. Levels of TNF and IL-6 were elevated in 94% and 100% of the patients, Levels of TNF and IL-6 were elevated in 94% and 100% of the patients, respectively (median levels 122 ng/l and 1300 U/ml) and were clearly interrelated (r = 0.67, p less than 0.01). C3a levels correlated with the APACHE II score (r = 0.57, p less than 0.05) and high C3a levels were associated with fatal outcome (p less than 0.05). C3a was also correlated inversely with mean arterial pressure (r = 0.50, p less than 0.01). Levels of complement C3a and C3d significantly correlated with levels of plasminogen activator inhibitor-1 (PAI) and correlated inversely with AT-III levels. We found no correlation between these complement products and leukocyte counts or lactate levels, nor was there a correlation between C3a or C3d and the cytokines TNF and IL-6. Levels of C3a and C3d did not decrease significantly during the first 24 h of treatment, in contrast to a clear decrease in IL-6 levels in all patients and a decrease in TNF in the surviving patients. TNF levels remained stable or increased in the non-survivors. We conclude that both the complement system and the cytokine system are involved in the pathogenesis of septic shock and may be involved in the development of some of the fatal complications like hypotension and disseminated intravascular coagulation.

In a prospective study patients with acute leukemia undergoing remission induction therapy were randomized to receive either a regimen of non-absorbable antimicrobial drugs (colistin and neomycin) or of absorbable and non-absorbable drugs (trimethoprim-sulfamethoxazole [TMP-SMZ] and colistin) for antibacterial prophylaxis. For antifungal prophylaxis patients in both groups were given oral amphotericin B. The proportion of patients without acquired infections and the median of study time to the first acquired infection did not differ significantly between the two treatment groups (p greater than 0.05). Septicemias occurred in nine out of 49 recipients of colistin and neomycin and in one out of 56 patients receiving TMP-SMZ and colistin (p = 0.03). Localized infections and fever episodes without proven infections were equally distributed between the two groups. The incidence of febrile days and of days on parenteral antibiotic therapy was significantly lower in the group given TMP-SMZ and colistin (p less than 0.05). The duration of severe granulocytopenia and thrombocytopenia did not differ significantly between the two groups (p greater than 0.05).