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Objective:To define the significance of soluble triggering receptor expressed on myeloid cells 1 (sTREM-1) in the septic cascade by comparing its kinetics to those of other proinflammatory mediators and of interleukin (IL) 10.Design:Prospective study in a tertiary unit.Patients:Blood was sampled from 90 patients with septic syndrome due to ventilator-associated pneumonia for 7 days after the appearance of symptoms. Concentrations of tumor necrosis factor (TNF) alpha, IL-6, IL-8, IL-10, and sTREM-1 were determined by enzyme-linked immunosorbent assay.Results:Serum levels of TNF alpha, IL-6, IL-10, and sTREM-1 were higher in nonsurvivors than in survivors; similar differences were not found for IL-8. Positive correlations were found between the ratios IL-10/TNF alpha and sTREM-1/TNF alpha, between IL-10/IL-6 and sTREM-1/IL-6, and between IL-10/IL-8 and sTREM-1/IL-8. Median values of IL-10/TNF alpha upon presentation of sepsis, severe sepsis, and septic shock were 3.21, 2.16, and 2.86, respectively (NS). Respective values for sTREM-1/TNF alpha were 21.28, 7.33, and 27.78 (p = 0.047 between sepsis and severe sepsis, p = 0.003 between severe sepsis and septic shock).Conclusions:sTREM-1 follows the kinetics of IL-10 and should therefore be considered an anti-inflammatory mediator in sepsis. Decreased ratios of sTREM-1/TNF alpha might determine transition from sepsis to severe sepsis and from severe sepsis to septic shock.

Background: To apply clarithromycin as an immunomodulatory treatment in experimental urosepsis by multidrug-resistant Pseudomonas aeruginosa. Methods: Acute pyelonephritis was induced in 40 rabbits after inoculation of the test isolate in the renal pelvis. Therapy was administered upon signs of sepsis in four groups: A, controls; B, intravenous clarithromycin; C, amikacin; and D, both agents. Survival and vital signs were recorded; blood was sampled for culture and estimation of pro-inflammatory mediators; monocytes were isolated for determination of apoptotic rate and ex vivo TNF alpha secretion. Quantitative cultures and biopsies of organs were performed after death. Results: Increased rectal temperature and oxygen saturation were found in groups B and D compared to A and C. Mean survival of groups A, B, C and D was 2.65, 7.15, 4.25 and 8.70 days respectively. No differences were noted between groups concerning bacterial load in blood and tissues and serum endotoxins. Serum MDA and total caspase-3 activity of monocytes of group D decreased following treatment compared to other groups. Negative correlation was detected between cytoplasmic caspase-3 and ex vivo secretion of TNF alpha of blood monocytes of group A; similar correlation was not found for any other group. Pathology scores of liver and lung of group B were lower than group A. Conclusion: Clarithromycin administered late in experimental urosepsis by multidrug-resistant P. aeruginosa prolonged survival and ameliorated clinical findings. Its effect is probably attributed to immunomodulatory intervention on blood monocytes.

The application of antimicrobial combinations on multidrug-resistant Pseudomonas aeruginosa might be of clinical relevance if they possess a significant postantibiotic effect (PAE). Twenty-two nosocomial isolates were exposed over time to ceftazidime, imipenem, or ciprofloxacin, and to their interaction with amikacin; all were applied at concentrations equal to their average serum level. After 24 h of exposure, live cells were washed and resuspended into fresh broth, and bacterial growth was monitored. PAE was found only for isolates subjected to the synergistic effect of the applied interactions. For these isolates, the mean PAEs (+/- SE) were 3.10 +/- 0.71 h for ceftazidime and amikacin, 4.38 +/- 0.83 h for imipenem and amikacin, and 3.33 +/- 2.83 h for ciprofloxacin and amikacin. The prolonged PAE documented after exposure to the interactions of the studied drugs strengthens the application of their combination for the management of infections by multidrug-resistant P. aeruginosa. (c) 2005 Elsevier Inc. All rights reserved.

In order to define the significance of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) upon progression from sepsis or severe sepsis to septic shock a prospective study was designed with 90 enrolled patients with septic syndrome due to ventilator-associated pneumonia. Blood was sampled on seven consecutive days upon initiation of symptoms and concentrations of tumour necrosis factor-alpha (TNF alpha), interleukin-6 (IL-6), IL-8 and sTREM-1 were estimated in serum by an enzymeimmunoassay. No differences in concentrations of TNF alpha, IL-6 and IL-8 were found between patients with sepsis, severe sepsis and septic shock on the first day of presentation of symptoms. Patients presenting with septic shock had concentrations of sTREM-1 significantly higher than both patients with sepsis and severe sepsis on the first day; no difference was found between patients with sepsis and severe sepsis. A positive correlation was detected between sTREM-1 and the white blood cell count. Serum levels of sTREM-1 were significantly lower in patients where VAP resolved compared to those where VAP did not resolve; similar findings were noted between patients who eventually survived and those who died. IL-6 followed the kinetics of sTREM-1 in correlation to patients’s prognosis; levels of TNF alpha and IL-8 were unrelated to prognosis. It is concluded that sTREM-1 is particularly increased upon evolution from sepsis or severe sepsis to septic shock. Its sustained increase is an indication of poor outcome. The underlined pathophysiological role of sTREM-1 for the transition from sepsis or severe sepsis to septic shock might constitute a novel target for immunomodulatory therapy.

Objective: The significance of lipid peroxidation as an independent factor leading to sepsis by multidrug-resistant Pseudomonas aeruginosa. Design experimental study Methods: Twenty-six rabbits were applied. They were divided into two groups; A (n = 6) comprising controls, and B (n = 20) comprising animals infected by the injection of 1 x 10(8) cfu/kg inoculum of the test pathogen into the left inner jugular vein. Six rabbits of group B were followed-up to estimate survival; all of the remaining were sacrificed. Blood was sampled for the determination of serum malondialdehyde (MDA) by the thiobarbiturate assay, total antioxidant status (TAS) by a chromogenic assay, tumor necrosis factor alpha by a bioassay on fibrosarcoma L929 cell line, and endotoxins (LPS) by the QCL-1000 LAL assay. Results: Mean survival of group B was 60.0 +/- 15.8 h. MDA was significantly higher in group B compared to group A at 30, 60, 120 and 150 min. TAS was statistically decreased in group B compared to group A at 30 and 60 min. Increases of MDA in group B were followed by reciprocal decreases of TAS (P of correlation < 0.001). Hemodynamic instability was recorded in group B compared to group A 160 min after bacterial challenge. Conclusions: Early alterations of oxidant/antioxidant balance occur in experimental sepsis by multidrug-resistant P. aeruginosa followed by hemodynamic instability. Results highlight the perspective of the administration of antioxidants as immunomodulatory treatment of sepsis in animal studies. (C) 2004 Elsevier Ltd. All rights reserved.

The potency of clarithromycin as immunomodulator was assessed in an experimental model of sepsis based on acute pyelonephritis by susceptible Escherichia coli. 55 rabbits were utilized; 5 for preliminary pharmacokinetic study and 50 for treatment. The latter were divided into 5 groups of treatment, A: controls; B: clarithromycin pretreatment; C: amikacin pretreatment; D: clarithromycin treatment on presentation of pulmonary oedema; and E; amikacin treatment on presentation of pulmonary oedema. Survival was recorded; tumour necrosis factor-alpha (TNFalpha), and malondialdehyde (MDA) were estimated in serum; activities of caspase-3 in monocyte cytosolic extracts were studied; and bacterial counts made in various organs. Median survival of animals of groups A, B, C, D and E was 1.0, 21.0, 12.5, 2.0 and 5.0 d, respectively. TNFa and MDA and monocyte caspase-3 activity of group A increased over time; no increases were detected in groups B and C. Concentrations of MDA and activities of monocytic caspase-3 were decreased after administration of clarithromycin in group D, an effect not occurring in group E. Bacterial load was decreased in renal tissue of group D compared to group A. It is concluded that intravenous clarithromycin might constitute a promising immunomodulator in sepsis even in the advent of pulmonary oedema.

Immunonutrition with diets enriched in polyunsaturated fatty acids (PUFAs) are becoming mandatory for multiple trauma patients. Solutions containing single n-6 PUFAs were administered intravenously in an experimental model of trauma. Thirty-five rabbits were studied; 13 controls; 10 administered gamma-linolenic acid (GLA) 30 min after fracture of the right femor; and 12 arachidonic acid (AA). Systolic, diastolic and mean arterial pressures and heart rate were recorded; serum levels of tumor necrosis factor-alpha (TNF alpha), malondialdehyde (MDA) and nitrate were estimated before and after therapy. Mean survival of controls, of animals treated with GLA and of animals treated with AA was 0.80, 1.41 and 3.60 days, respectively. Administration of PUFAs induced higher levels of blood pressure; that of AA decreased serum TNF alpha and tissue bacterial load compared to controls. Intravenous administration of n-6 PUFAs conferred hemodynamic stability and increased survival in a model of trauma rendering further research mandatory. (c) 2005 Elsevier Ltd. All rights reserved.

To assess the efficacy of clarithromycin as an immunomodulator in experimental sepsis with Escherichia coli, acute pyelonephritis was induced after ligation of the right ureter and injection of the test isolate into the renal pelvis in 40 rabbits. Four groups of treatment were applied with administration of therapy on advent of sepsis-associated pulmonary oedema, as follows: A: controls; B: clarithromycin; C: amikacin, D: both agents. Survival was recorded along with estimation of serum levels of endotoxins (LPS), of tumour necrosis factor-alpha (TNFalpha), malondialdehyde (MDA) and of bacterial counts. Mean survival of groups A, B, C and D was 2.51, 7.60, 10.25 and 11.40 days, respectively. Serum levels of TNFalpha and of MDA of group A increased over-time. Pulmonary oedema at 6 h after bacterial challenge was accompanied by increase of TNFalpha and MDA; administration of clarithromycin decreased their values. It is concluded that intravenous clarithromycin might constitute a promising immunomodulatory agent for the management of sepsis since its efficacy was proved after administration on presentation of sepsis-associated pulmonary oedema. The presented findings emphasise the need for further clinical research of the use of clarithromycin for the therapy of Gram-negative sepsis. (C) 2004 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Background: Thalidomide is an inhibitor of tumour necrosis factor-alpha (TNF alpha) that has been proven effective for the treatment of experimental sepsis by Escherichia coli. It was tested whether it might behave as an effective immunomodulator in experimental sepsis by multidrug-resistant (MDR) Pseudomonas aeruginosa. Methods: Sepsis was induced by the intraperitoneal injection of 1 x 10(8) cfu/kg inoculum of the test isolate in a total of 109 Wistar rats divided in three groups as follows: group A controls; group B administered seed oil 30 minutes before bacterial challenge; and group C administered 50 mg/ kg of thalidomide diluted in seed oil 30 minutes before bacterial challenge. Blood was sampled for estimation of endotoxins (LPS), TNF alpha, interferon-gamma (IFN gamma), nitric oxide ( NO) and malondialdehyde (MDA). LPS was measured by the QCL-1000 LAL assay, TNF alpha and IFN gamma by ELISA, NO by a colorimetric assay and MDA by the thiobarbiturate assay. Results: Mean ( +/- SE) survival of groups A, B and C were 18.60 +/- 1.84, 12.60 +/- 0.60 and 30.50 +/- 6.62 hours ( p of comparisons A to C equal to 0.043 and B to C equal to 0.002). Decreased TNF alpha and NO levels were found in sera of animals of group C compared to group A. Plasma levels of LPS, MDA and IFN gamma did not differ between groups. Conclusion: Intake of thalidomide considerably prolonged survival in experimental sepsis by MDR P. aeruginosa an effect probably attributed to decrease of serum TNF alpha.

Aim of the study: To evaluate the early effect of inguinal hernia repair by the tension-free method compared to the conventional Andrew’s technique on lipid peroxidation. Patients-methods: Thirty-four patients subjected to elective hernia repair were enrolled in the study divided in two groups. Group A (n = 18) underwent hernia repair by the tension-free method using a polypropylene mesh. Group B (n = 16) underwent hernia repair by the Andrew’s technique (i.e. a modification of the Bassini’s technique). Venous blood samples were drawn preoperatively and at 12, 24 and 48 h postoperatively. Malondialdehyde (MDA) was estimated by the thiobarbiturate assay. Results: Neutrophil counts were significantly higher in patients of group B compared to group A at 12 and 48 h postoperatively. Concentrations of fibrinogen were similar between the two groups. MDA was significantly higher in patients of group B hours compared to group A at 12, 24 and 48 h postoperatively. Positive correlation was found between neutrophil counts and MDA at 12 h (r: + 0.43, P: 0.015) and 48 h (r: + 0.496, P: 0.005) but not at 24 h. No correlation was found between serum fibrinogen and MDA. Conclusion: Hernia repair by the Andrews’s technique elicits a sustained triggering of lipid peroxidation, compared to the tension-free method. (C) 2004 Elsevier Ltd. All rights reserved.

Purpose : To define whether procalcitonin should be introduced in the diagnostic criteria of sepsis. Methods: Procalcitonin was estimated in sera of 105 critically ill patients by an immunochemiluminometric assay. Diagnosis was settled by 3 types of criteria: A, the American College of Chest Physicians/Society of Critical Care Medicine (ACCP/SCCM) 1992 criteria; B, the ACCP/SCCM criteria and concentrations of procalcitonin above 1.0 ng/mL as indicative of SIRS/sepsis; and C, the ACCP/SCCM criteria and concentrations of procalcitonin 0.5 to 1.1 ng/mL for SIRS and above 1.1 ng/mL for sepsis. Results: Criteria A identified 50.5% of patients with SIRS, 18.1% with sepsis, 0.9% with severe sepsis and 22.9% with septic shock; respective diagnosis by criteria B were 26.7%, 9.5%, 10.5% and 25.7%; and respective diagnosis by criteria C were 19.0%, 25.7%, 9.5%, and 25.7%. Sensitivity of concentrations between 0.5 ng/mL and 1.1 ng/mL was 25.6% for Systemic Inflammatory Response Syndrome (SIRS); and above 1.1 ng/mL 92.8% for sepsis. Sepsis-related death was associated with elevated procalcitonin upon presentation of a clinical syndrome. Conclusions: Despite the limited diagnostic value of procalcitonin for SIRS, concentrations of procalcitonin above 1.1 ng/mL are highly indicative for sepsis without, however, excluding the presence of SIRS. (C) 2004 Elsevier Inc. All rights reserved.

Polyunsaturated fatty acids (PUFAs) have been shown to possess a considerable anti-tumor and anti-bacterial effect in vitro. In an attempt to achieve serum concentrations of these acids similar to those applied in vitro, a solution of ethyl ester of arachidonic acid (AA) was administered intravenously at 25 mg/kg within 10 min in six male rabbits. Blood samples were collected before and 60 min after infusion from catheters inserted in the hepatic veins and in the carotid artery. Analysis of serum fatty acids was performed by gas chromatography mass spectrometry. Elevated concentrations of elongated fatty acids were detected in the hepatic veins after infusion. Mean concentrations of arachidonate in the hepatic veins and the carotid arteries after infusion of AA were 2.77 and 3.73 muM, respectively. It is concluded that the intravenous administration of a solution of AA might result in increased hepatic biosynthesis of serum saturated and unsaturated fatty acids of elongated carbon chains. The increasing interest for the application of PUFAs in therapeutics renders further study mandatory to clarify the significance of these findings. (C) 2003 Elsevier Ltd. All rights reserved.

Clarithromycin was administered intravenously to 55 rabbits to evaluate its effect on experimental sepsis caused by multidrug-resistant Pseudomonas aeruginosa. Acute pyelonephritis was induced after ligation of the right ureter and injection of 10(8) CFU of the test isolate per kg of body weight into the renal pelvis. The animals were divided into six groups: group A, controls; group B, rabbits that received one intravenous dose of 80 mg of clarithromycin per kg concomitantly with bacterial challenge; group C, rabbits that received two doses of clarithromycin, the second one of which was given 2 h after the first one; group D, rabbits that received 15 mg of amikacin per kg; group E, rabbits that received one dose of clarithromycin and amikacin; and group F, rabbits that received two doses of clarithromycin and amikacin. Serum endotoxin levels were estimated by the QCL-1000 Limulus amoebocyte lysate assay, tumor necrosis factor alpha (TNF-alpha) levels were measured by a bioassay, and malondialdehyde (NIDA) levels were measured by the thiobarbiturate assay. Viable bacterial counts in various tissue samples were also assessed. The mean survival times of the animals in groups A, B, C, D, E, and F were 4.50, 7.69, 4.07, 4.55, 11.55, and 11.60 days, respectively (P = 0.033 for group D versus group F, P = 0.006 for group D versus group E, P = not significant for group B versus group E, P = 0.042 for group C versus group F). Serum endotoxin levels were similar between groups at all sampling times; TNF-alpha and NIDA levels in groups B, C, E, and F decreased significantly over follow-up. The numbers of viable bacterial cells in the infected kidney were similar among the groups; those in the liver, spleen, lungs, and mesenteral lymph nodes were significantly decreased in groups B, E, and F compared to those in groups A and D. It is concluded that a prolongation of survival in animals with experimental sepsis caused by multidrug-resistant P. aeruginosa was achieved after coadministration of clarithromycin and amikacin and that the increased survival was probably attributable to the immunomodulatory properties of clarithromycin.

Background: To evaluate whether histopathologic findings of skin in sepsis by Pseudomonas aeruginosa correlate with the clinical course. Methods: Histological alterations after bacterial challenge by one susceptible (A) and two multidrug-resistant isolates (B and C) of P. aeruginosa were studied in 18 rabbits. Sepsis was induced by the intravenous infusion of 1 x 10(8) CFU by a catheter in the right jugular vein; blood was sampled for the estimation of tumor necrosis factor alpha (TNF-alpha) and malondialdehyde (MDA). Skin biopsies were collected along with a subcutaneous fat specimen for culture. Results: The mean survival was 0.85, 1.75 and 11.00 days after challenge by isolates A, B and C, respectively. The main histologic findings of skin were: inflammation and swelling of the dermis; thickening of the endothelium and infiltration of vessel wall and lumen by polymorphonuclear leukocytes; extravasation of red blood cells, and necrobiotic changes of the hair follicles. Serum TNF-alpha was elevated in animals challenged by isolate A compared to challenge by isolates B and C. Concentrations of MDA were similar for all isolates. Mean log(10) of viable cells isolated from subcutaneous fat were 5.74, 2.74 and 1.40 after challenge by isolates A, B and C, respectively. Conclusions: Prolongation of survival was accompanied by lower serum TNF-alpha, decreased viable cells from subcutaneous fat and intensified inflammatory response in the dermis and subcutaneous tissue. These findings might be of importance for immunomodulatory intervention. Copyright (C) 2004 S. Karger AG, Basel.

The possible increase of ofloxacin levels in serum and cerebrospinal fluid (CSF) by concomitant indomethacin administration was investigated in 120 healthy adult rats. The animals were administered intramuscular doses of ofloxacin 30 mg/kg alone (Group A, n = 60) or with indomethacin 2 mg/kg (Group B, n = 60). Blood and CSF samples were obtained from both groups at 30, 45, 60 and 90 min post-administration. Concentrations of ofloxacin were estimated using a microbiological assay. Co-administration of indomethacin did not affect plasma levels of ofloxacin significantly; however, higher levels were found in all CSF samples after co-administration with indomethacin, particularly after 90 min with 0.59 mug/ml versus zero median values when only ofloxacin was administered (P = 0.05). No central nervous system adverse effects were observed clinically. No correlation between levels of ofloxacin in plasma and CSF could be established either in rats administered only ofloxacin or in rats administered both drugs. The presented pharmacokinetic findings revealed that co-administration of ofloxacin and indomethacin may result in protracted quinolone levels in the CSF. However, the absence of significant correlation between concentrations of ofloxacin in plasma and CSF upon co-administration of indomethacin, as well as of central nervous system adverse effects, make the probability of an epileptogenic interaction between them unlikely. These results merit further clinical evaluation. (C) 2004 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

In order to clarify whether susceptible and multidrug-resistant Pseudomonas aeruginosa differ in the mechanism of induction of sepsis, three different isolates were used; one susceptible (isolate A) and two (isolates B and C) multidrug-resistant. Isolate B had moderately elevated MICs of antipseudomonal antimicrobials and isolate C highly elevated MICs. Each isolate was infused by a catheter inserted into the right jugular vein of six rabbits. Survival was recorded; blood was sampled at regular time intervals for estimation of bacterial blood counts, malondialdehyde (MDA) and turnout necrosis factor-alpha (TNFalpha). Quantitative cultures of various organs were performed after death or sacrifice. Mean survival after challenge by isolates A, B and C was 0.73, 2.58 and 11.00 days, respectively (P of comparisons A versus B, 0.0048; A versus C, 0.0012; B versus C, 0.0005). The number of viable organisms in the blood after challenge using isolates A and B was greater than the viable counts of C. Serum MDA was lower after challenge with B and C compared with A. Serum TNFalpha levels were higher after challenge by isolate A compared with isolate C. The bacterial loads of the liver, lower right lung lobe, spleen and mesenteric lymph nodes were greater after challenge by isolate A than the other isolates. It is concluded that infection by multidrug-resistant P. aeruginosa is accompanied by increased survival compared with infection by Susceptible isolates; that finding might be explained by the different mechanisms leading to sepsis. Further studies must be done to clarify the significance of these observations for therapeutics. (C) 2004 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

In order to assess the diagnostic value of procalcitonin, 158 patients with febrile neutropenia from centres across Europe were studied. Patients with fever were diagnosed on the basis of either: (1) clinical, radiological and microbiological criteria; or (2) the procalcitonin value. In the latter case, concentrations of 0.5-1.0 ng/mL were considered diagnostic of localised infection, concentrations of 1.0-5.0 ng/mL of bacteraemia, and concentrations of > 5.0 ng/mL of severe sepsis. Procalcitonin and C-reactive protein were estimated daily in serum by immunochemiluminescence and nephelometry, respectively. Overall, the sensitivity (specificity) of procalcitonin for bacteraemia was 44.2% (64.3%) at concentrations of 1.0-5.0 ng/mL, and 83.3% (100%) for severe sepsis at concentrations of > 5.0 ng/mL. It was concluded that procalcitonin is a marker strongly suggestive of severe sepsis at concentrations of > 5.0 ng/mL. Estimated concentrations of < 0.5 ng/mL indicate that infection is unlikely, but it was observed that bacteraemia associated with coagulase-negative staphylococci may fail to elevate serum procalcitonin levels.

To assess the effectiveness of calcium phosphate as a delivery system of teicoplanin, methicillin-resistant Staphylococcus aureus osteomyelitis was induced in 36 rabbits. Osteomyelitis was induced by inoculating 10(7) cfu of methicillin-resistant Staphylococcus aureus isolate into a 2-mm hole at the upper 1/3 of the femur for 3 weeks, when all animals had reoperations, and calcium phosphate cement with 3% teicoplanin was implanted. Animals were divided into six groups of six animals each, sacrificed at Weeks 1, 2, 3, 4, 5, and 6, respectively, after implantation. One rabbit in each group was used as a control. Substantial clinical improvement of the rabbits was observed after implantation, accompanied with sterile cultures of bone after the second week of treatment. Throughout the same period, 10(5) to 10(8) cfu/g of methicillin-resistant Staphylococcus aureus isolate was cultured from the control samples. Bacterial eradication signified a considerable decrease of the total histologic scores of osteomyelitis compared with controls, accompanied with newly growing host bone. The calcium phosphate with teicoplanin delivery system seems promising for treatment of bone infection attributable to methicillin-resistant Staphylococcus aureus. In addition, this mixture allows filling of bone defects by new host bone.

To evaluate the penetration of cefepime in the inflamed pancreas, three doses of 50 mg/kg were administered intramuscularly at 8-h intervals after induction of acute necrotizing pancreatitis using intraperitoneal injection of DL-ethionine in 35 rabbits and in 33 controls. Animals were sacrificed and concentrations of cefepime were determined by a microbiological assay. Cefepime reached its peak concentrations 60 min after the last drug dose when mean values of 46.05 mug/ml, 22.34 mug/g and 34.74 mug/ml were found in serum, pancreas and bile, respectively, in rabbits with acute necrotizing pancreatitis and 45.19 mug/ml, 12.68 mug/g and 20.77 mug/ml respectively in controls. Tissue/serum ratios of cefepime were 0.48, 0.23, 0.15 and 0.09 at 60, 90, 120 and 180 min, respectively, after the last dose of cefepime in rabbits with acute necrotizing pancreatitis and 0.28, 0.18, 0.16 and 0.16, respectively at 60, 90, 120 and 180 min in controls. It is concluded that the administration of cefepime in rabbits with acute necrotizing pancreatitis resulted in pancreatic tissue levels well above the MIC(90)s of the common pathogens involved in pancreatic superinfection, so that its administration might be proposed for the therapy of superinfection following acute necrotizing pancreatitis in humans.

The administration of colistin is considered as the last alternative for infections by multidrug-resistant isolates of Pseudomonas aeruginosa; however its use is limited due to its considerable toxicity and poor pharmacokinetics. In order to define the in vitro activity of colistin combined with rifampin, 28 isolates resistant to piperacillin, ceftazidime, imipenem, meropenem, ciprofloxacin, amikacin, rifampin and colistin were tested. Seventeen of them that were found by PFGE to be genetically distinct were over time exposed to 2 mug/ml of colistin, to 2 mug/ml of rifampin and to their combination. Applied concentrations were selected to correspond to the mean serum level of the tested antimicrobials. Synergy between colistin and rifampin was found in four (23.5%), six (35.3%), seven (41.7%) and two (11.8%) isolates after 2 4, 6 and 24 hours of growth, respectively. Bacterial re-growth was detected after 24 hours of exposure to the tested interaction. It is concluded that colistin and rifampin express a considerable in vitro synergistic effect on multidrug-resistant P. aeruginosa. The reported interaction should be tested in animal studies before introduction in clinical practice.

Thalidomide, an agent which inhibits biosynthesis of tumor necrosis factor alpha (TNF-alpha) and which is used to treat a variety of chronic inflammatory conditions, was investigated as therapy for experimental sepsis. Sepsis was induced by intraperitoneal injection of 10(7) CFU of Escherichia coli per kg of body weight to 80 Wistar rats divided into four groups. Group A consisted of 24 control animals that did not receive any pretreatment, group B consisted of 18 vehicle-treated control animals pretreated with seed oil, group C consisted of 30 rats administered thalidomide diluted in seed oil at a dose of 50 mg/kg 30 min before bacterial challenge, and group D consisted of eight animals that were not challenged with E. coli but that were used for white blood cell count determination. Sepsis was determined by measurement of vital signs before and 6 h after bacterial challenge. After 6 h the animals were killed and blood was sampled for culture; white blood cell count determination; and determination of endotoxin (lipopolysaccharide), TNF-alpha, interleukin-1beta (IL-1beta), and IL-6 levels. The levels of these cytokines were also estimated in the supernatants of human monocytes pretreated with thalidomide after exposure to the isolate. Sepsis developed in all vehicle-treated control animals and controls by 6 h after bacterial challenge but in only 10 animals (33.3%) pretreated with thalidomide (P < 0.0001). Six hours after bacterial challenge all animals had similar levels of endotoxemia, IL-10, and IL-6. The mean white blood cell count for groups A, B, and C were 5,631.1, 2,638.9, and 8,169.3 cells/mu l, respectively (P value between groups

Background. Obstructive jaundice is often accompanied by bacterial translocation and subsequent sepsis. The effect of lactulose in preventing that process was evaluated in an experimental model. Obstructive jaundice was induced in 23 rabbits after common bile duct ligation. Methods. Animals were divided into two groups. Group A of 11 animals-controls and group B of 12 rabbits, which received 2 ml/kg of lactulose p.o. by a nasogastric tube. Blood was sampled daily, before and after operation. Samples were applied for culture and for estimation of endotoxins (LPS), tumor necrosis factor (TNFa), and malondialdehyde (MDA). Results. Mean (+/-SD) survival of animals of group A was 3.08 +/- 0.19 days compared to 5.36 +/- 0.41 days of animals of group B. Serum concentrations of LPS and TNFa of each day of treatment remain constant in animals of group A; they were steadily decreased in animals of group B reaching statistical significance on the fourth day. Similar changes were not found for MDA. Conclusion. The administration of lactulose may prevent systemic endotoxaemia and the subsequent inflammatory response in an experimental model of obstructive jaundice, so as to extend survival. These results merit further clinical evaluation. (C) 2003 Elsevier Inc. All rights reserved.

Background/Aims: To define whether bacterial translocation occurs over the course of acute edematous pancreatitis and to correlate its presence to the advent of an infection since data in humans are lacking. Methods: Thirty-three patients hospitalized over the period January 2000-January 2001 were subjected to venipuncture at regular time intervals for the collection of blood samples for blood culture and for determination of endotoxins and of C-reactive protein. Endotoxins were measured by the Limulus assay and C-reactive protein by nephelometry. Results: A wide range of concentrations of endotoxins was observed over the first 3 days of the disease. Mean (+/-SE) of endotoxins was 4.01 +/- 1.36 and 2.42 +/- 0.95 EU/ml 3 and 6 h, respectively, after admission of afebrile patients. Respective values 3 and 6 h after admission of febrile patients were 3.03 +/- 1.14 and 5.84 +/- 2.28 EU/ml (normal

In an attempt to achieve the safe intravenous administration of two n-6 polyunsaturated fatty acids (PUFAs), gamma-linolenic acid (GLA) and arachidonic acid (AA), and to study the subsequent changes on the total oxidant and antioxidant status, various steadily increasing doses of each acid were injected intravenously at different infusion times in 28 male rabbits. Blood samples were collected at 15-min time intervals by the hepatic veins and from the carotid artery; oxidant status was determined by the thiobarbiturate assay and total antioxidant status (TAS) was assessed by a colorimetric assay. Both n-6 PUFAs were administered with safety at a dose of 25 mg/kg within 10 min accompanied by an increase of malonodialdehyde concentrations in the hepatic veins and in the carotid artery 30-45 min, respectively, after the end of the infusion of GLA and/or AA. Similar changes did not occur in red cell membranes after the infusion of AA. TAS presented reciprocal changes to malonodialdehyde production; the main consumption of TAS was observed in all samples 30-60 min after the end of the infusion of n-6 PUFAs. The above-mentioned rapid alterations occurring in both serum oxidant and antioxidant status after GLA might have a future clinical therapeutic significance in conditions like cancer and disseminated infectious diseases. (C) 2002 Elsevier Science Ltd. All rights reserved.

Stenotrophomonas maltophilia is characterized by intrinsic resistance to a variety of antimicrobials. Therapeutic options are often limited particularly after the emergence of isolates resistant to trimethoprim/sulfamethoxazole, The application of colistin for infections caused by multidrug-resistant Gram-negative pathogens is limited due to its toxicity. In order to evaluate the activity of the interaction of colistin with rifampin or trimethoprim/sulfamethoxazole on S. maltophilia. 24 different isolates resistant to trimethoprim/sulfamethoxazole were in vitro exposed over-time to the combination of I X and 4 X MIC of colistin with 2 mug/ml of rifampin or 2/38 mug/ml of trimethoprim/sulfamethoxazole. The applied concentrations for rifampin and trimethoprim/sulfamethoxazole reflect their mean serum levels. Synergy of colistin and rifampin was documented after the first two hours of bacterial growth for approximately 60% of isolates and it occurred with both applied concentrations of colistin. The interaction of colistin and rifampin prevented regrowth observed when single colistin was applied. Synergy of colistin and trimethoprim/sulfamethoxazole was mainly found when colistin was applied at a concentration of 4 X MIC involving 41.7% of isolates after 24 h of growth. In the presence of trimethoprim/sulfamethoxazole bacterial regrowth, observed when single colistin was applied, was prevented. It is concluded that growth of multidrug-resistant S. maltophilia is significantly inhibited by the interaction of colistin and rifampin and to a lesser extent of colistin and trimethoprim/sulfamethoxazole. These results merit further study in both the animal model and the clinical setting. (C) 2002 Elsevier Science Inc. All rights reserved.

The increased incidence of nosocomial infections by multidrug-resistant Acinetobacter spp creates demand on the application of some combinations of older antimicrobials on that species. The in vitro activities of colistin and of rifampin and of their interaction were tested on 39 nosocomial isolates of Acinetobacter baumannii. All isolates were resistant to ampicillin/sulbactam, to 3rd and 4th generation cephalosporins, to amikacin and to ciprofloxacin. MICs were determined by a microdilution technique and interactive studies between 1X or 4X MIC of colistin and rifampin were performed by the time-kill assay. Rifampin was applied at a concentration of 2 mug/mL which is equal to its mean serum level. All isolates were inhibited by colistin and only 15.2% by rifampin. Synergy between 1X MIC of colistin and rifampin was detected in 15.4% of isolates et 6 h of growth and in 51.3% of isolates at 24 h of growth. Synergy between 4X MIC of colistin and rifampin was detected in 15.4% of isolates at 6 h of growth and in 66.7% of isolates at 24 h of growth. It is concluded that colistin is highly active on multidrug-resistant Acinetobacter spp and its activity on A.baumannii is increased in the presence of rifampin, so that their administration might be proposed for nosocomial infections by these isolates. (C) 2001 Elsevier Science Inc. All rights reserved.

Purpose: We studied the pharmacokinetics of orally administered clarithromycin in prostatic tissue to define its role in the treatment of chronic abacterial prostatitis caused by intracellular pathogens. Materials and Methods: A total of 45 men receiving 3 oral doses of 750 mg. clarithromycin at 12-hour intervals underwent suprapubic prostatectomy for benign prostate hyperplasia 4, 5, 6 and 7 hours after the last drug dose in 13, 12, 10 and 10 patients, respectively. Concentrations were determined in the prostate tissue and in plasma by an agar diffusion assay. Results: A mean peak level of clarithromycin of 3.22 and 3.08 mug./gm. of tissue was achieved 4 hours after the third drug dose at the center and periphery of the adenoma, respectively. Tissue levels remained statistically superior to plasma levels at all intervals. Conclusions: The oral administration of clarithromycin achieved a prostate level much higher than the minimal inhibitory concentration of clarithromycin for the intracellular pathogens of chronic prostatitis. Thus, clarithromycin may be considered for treating chronic abacterial prostatitis.

The novel inflammatory marker procalcitonin (PCT) was assessed as an index of infection in patients with febrile neutropenia. Blood samples were obtained from 115 patients with febrile neutropenia for determination of PCT levels before onset of fever and daily until the resolution of fever. The median PCT level on the first day of fever was 8.23 ng/mL in patients with bacteremia, compared with 0.86 ng/mL in patients with localized bacterial infections (P =.017). The median PCT level on the first day of fever was 2.62 ng/mL in patients with severe sepsis, compared with 0.57 ng/mL in patients with clinically localized infections (P

In an attempt to define whether intravenously administered pefloxacin might be appropriate for surgical prophylaxis in prostatectomy. 50 patients undergoing transvesical prostatectomy for benign prostate hyperplasia were given a single intravenous dose of 800 mg, surgery was then performed after 2. 4, 6, 8 or 10 h. Concentrations of perfloxacin were determined in serum and in both the centre and periphery of the prostate adenoma using a microbiological plate assay. Elevated concentrations of pefloxacin were found in the adenoma from 2 h onwards. The central and peripheral concentrations were similar and had a mean value of 4.39 mug/g of tissue. These concentrations were similar to those achieved in serum. Although concentrations of pefloxacin were not determined separately in the intercellular, interstitial or excreted fluid, the tissue levels found were well above the MICs of perfloxacin for the bacteria commonly causing acute and chronic prostatitis. These data suggest the intravenous administration of pefloxacin to be a satisfactory alternative for the surgical prophylaxis before prostatectomy as well as in the therapy of acute prostatitis. (C) 2001 Elsevier Science B.V. and International Society of Chemotherapy All rights reserved.

A novel biodegradable system of D-,L-dilactide delivering pefloxacin was implanted in 104 rabbits with experimental osteomyelitis caused by methicillin-resistant Staphylococcus aureus (MRSA), 26 serving as controls. Animals were killed on each third day and viable bacterial counts and levels of pefloxacin in bone tissue were determined. A 99.9% decrease in viable count of bacteria was achieved by day 12 and complete bacterial eradication on day 33. Pefloxacin was released gradually, reaching its peak on day 15 at levels 100 times the MIC of pefloxacin for MRSA. The biodegradable system described may have a future role in the therapeutic approach to osteomyelitis.

Twenty-six multidrug-resistant Pseudomonas aeruginosa isolates were exposed over time to 300 mu g of gammalinolenic acid or arachidonic acid per mi or to the combination of both acids at 150 mu g/ml each with ceftazidime and amikacin with or without albumin to observe the in vitro interactions of the antibiotics. Antibiotics and albumin were applied at their levels found in serum. Synergy between acids and antibiotics was found against 13 isolates, and it was expressed after 5 h of growth in the presence of albumin. The results indicate that further application in experimental infection models is merited.

Carriers used for the local delivery of antibacterial agents may be classified as nonbiodegradable or biodegradable. A major representative of the former category are the polymethylmethacrylate (PMMA) beads often impregnated with gentamicin which have been commercially available for the last 2 decades. Examples of the latter category include the collagen-gentamicin sponge, apatite-wollastonite glass ceramic blocks, hydroxyapatite blocks, polylactide/polyglycolide implants and the polylactate polymers. All of the above systems release antibiotics at concentrations exceeding those of the minimum inhibitory concentrations (MICs) for the most common pathogens of chronic osteomyelitis without releasing any antibiotic in the systemic circulation and without producing adverse effects. The major disadvantage of the PMMA beads is the need for their surgical removal at the completion of antibiotic release, which usually takes place 4 weeks after their implantation. The biodegradable carriers do not require surgical removal, and of those listed, the collagen-gentamicin sponge has been applied successfully over the last decade for bone infections. Among the other biodegradable systems which are still in experimental stages, polylactate polymers carrying quinolones seem very promising, since they are characterised by prolonged duration of release at concentrations 100 to 1000 times the MICs of the causative bacteria implicated in bone infections; preliminary results have shown these carriers to be very effective in the management of experimental osteomyelitis caused by methicillin-resistant Staphylococcus aureus. Further development of such biodegradable systems will provide a novel approach in the future for the eradication of chronic osteomyelitis.

A biodegradable polymer of DL-dilactide that facilitates release of ciprofloxacin or pefloxacin at levels exceeding MICs for the causative microorganisms of chronic osteomyelitis is described. Duration and peak of release were found to depend on the molecular weight of the polymer. Its characteristics make it promising for treating chronic bone infections.

Quinupristin/dalfopristin (RP59500) is a novel streptogramin and a semisynthetic derivative of pristinamycins I-A and IIB. The following properties of RP59500 were investigated: (i) its in-vitro activity against 164 hospital isolates of Staphylococcus aureus, 101 of which were methicillin-resistant (MRSA); (ii) its killing effect against 24 MRSA and seven methicillin-susceptible (MSSA) isolates; (iii) its interactions with rifampicin and ciprofloxacin against 18 MRSA isolates, six susceptible to both rifampicin and ciprofloxacin and 12 resistant to both, at 1 x MIG, 2 x MIC and 4 x MIG. Rifampicin and ciprofloxacin were applied at a concentration equal to their mean serum levels in order to establish the clinical relevance of the results. The MIG,,, MIC90, MBC50 and MBC90 of quinupristin/dalfopristin were, respectively, less than or equal to 0.015, 2, 0.12 and 2 mg/L for MRSA isolates and less than or equal to 0.015, 0.06, less than or equal to 0.015 and 0.25 mg/L for MSSA isolates. All isolates were inhibited by quinupristin/dalfopristin. Its killing effect varied with concentration and time, being optimal at 4 x MIC and after 24 h growth. Strains surviving 24 h exposure to this agent had much higher MICs than the parent strain, but only a limited number of them became resistant. Quinupristin/dalfopristin at 2 x MIC and 4 x MIC showed in-vitro synergy with rifampicin against highly resistant isolates mainly at 6 h and 24 h of growth involving 50-83% of MRSA isolates, and showed synergy with ciprofloxacin at 24 h involving 42-75% of isolates. The MIC increase in colonies surviving at 24 h was restricted by the presence of rifampicin or ciprofloxacin. In contrast, the above combinations acted synergically over the total number of MRSA strains susceptible to both rifampicin and ciprofloxacin. The above findings show that quinupristin/dalfopristin is a very potent antistaphylococcal agent, and that its activity against MRSA isolates is enhanced when it is combined with rifampicin or ciprofloxacin.

Based on previous findings that gamma-linolenic acid (GLA) inhibits Escherichia coli growth and provokes the induction of strains resistant to aminoglycosides, 19 Pseudomonas aeruginosa strains were exposed in vitro over time to GLA, to arachidonic acid (AA) and to their combination in the presence or absence of vitamin E. AII acids were used at a 300 mu g/ml concentration, whereas vitamin E was added as an antioxidant. Lipid peroxidation was evaluated by the thiobarbiturate assay measuring malonodialdehyde (MDA) production. It was found that GLA or AA killed 5-10% of strains at 24 h of growth, whereas when applied in combination their effect involved 100% of strains at 24 h and was limited to 68% of strains in the presence of vitamin E (P < 0.01). MDA production was time-dependent and it was restrained by vitamin E (P < 0.01). Post acid exposure, 27% to 37% of the survived strains became resistant to diverse antimicrobial agents and mainly to ticarcillin, to ceftazidime and to amikacin; no strain developed resistance in the presence of vitamin E. It is concluded that GLA and AA interact bactericidally on P. aeruginosa isolates, inducing the development of strains resistant to beta-lactams and to aminoglycosides; their action might be mediated through their peroxides, Further research is necessary to establish the clinical application of these in vitro findings.

In a study designed to obtain data on compounds active against enterococci, the minimum inhibitory concentrations (MICs) of quinupristin/dalfopristin (RP 59500) and the novel quinolones DU-6859a, trovafloxacin, levofloxacin, and sparfloxacin were determined for 122 Enterococcus faecalis and seven Enterococcus faecium isolates. In addition, 15 Enterococcus faecalis isolates resistant to gentamicin, DU6859a, and trovafloxacin were exposed over time to combinations of DU-6859a plus gentamicin and trovafloxacin plus gentamicin. DU-6859a and trovafloxacin were found to be the most active compounds against Enterococcus faecalis and DU-6859a and RP59500 against Enterococcus faecium. Synergy between either DU-6859a or trovafloxacin and gentamicin was observed with 27 to 35% of the isolates. It is concluded that DU-6859a and trovafloxacin are very potent against enterococci, especially when combined with gentamicin.