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Biomedical subjects

O D Rotstein

Publications and source records attributed to O D Rotstein.

At least 55 records · Page 3Linked to original sources
PubMed1998

MAP-kinase dependent induction of monocytic procoagulant activity by beta2-integrins.

beta2-Integrin adhesion molecules play crucial roles in monocyte transmigration and adherence to the inflamed extracellular matrix. While integrin engagement contributes to inflammatory cell activation, little is known about the precise signaling pathways that are important to integrin-dependent monocyte activation. We examined the role of tyrosine phosphorylation and extracellular-signal regulated kinase (ERK) activity in beta2-integrin signaling in monocytes. Cross-linking of the LFA-1 (CD11a/CD18) and MAC-1 (CD11b/CD18) integrins on the surface of THP-1 monocytic cells induced the accumulation of tyrosine phosphoproteins. As part of this signal both ERK-1 and ERK-2 are tyrosine phosphorylated. In vitro kinase assays documented an increase in ERK-2 activity following both LFA-1 and MAC-1 cross-linking. beta2-Integrin cross-linking also led to a marked increase in 4-h procoagulant activity (PCA) in THP-1 cells and purified human monocytes. Inhibition of tyrosine phosphorylation by genistein (10 microg/ml), or selective ERK inhibition with PD98059 (10 microM), was able to block the integrin-dependent induction of PCA in both THP-1 cells and human monocytes. Thus, beta2 integrin signaling in monocytic cells can flow through the tyrosine phosphorylation and activation of the ERK mitogen activated protein kinases, which is essential for the subsequent expression of tissue factor. These results suggest that the ERK proteins likely function to integrate various adhesion-dependent signals during the process of monocyte transmigration.

Blood Coagulation Factors↗
PubMed1998

The glutathione depleting agent diethylmaleate prolongs renal allograft survival.

INTRODUCTION: Intercellular adhesion molecule 1 (ICAM-1) plays an important role in mediating allograft rejection through its role in cellular trafficking and as an important costimulatory signal mediating T cell activation. We have previously reported that systemic administration of the glutathione (GSH) depleting agent diethylmaleate (DEM) prevents upregulation of ICAM-1 in various inflammatory models, suggesting that this agent may offer benefit in preventing allograft rejection. Thus we evaluated the effects of DEM in a murine model of renal transplantation. METHODS: Kidneys from C57BL/6 mice were transplanted into MHC incompatible C3H mice. Donors were treated with DEM 1 h prior to sacrifice, whereas recipients received DEM 1 h following transplantation. Animals were followed until the time of death. In separate studies, renal ICAM-1 mRNA expression was evaluated by polymerase chain reaction and the CD4(+) T cell cytokine profile evaluated in a mixed lymphocyte reaction using C3H responder splenocytes and C57BL/6 stimulator cells. RESULTS: Pretreatment with DEM increased survival from 18.9 +/- 3.6 to 30.6 +/- 10 days (P < 0.05). This increase in survival was associated with a reduction in renal ICAM-1 mRNA expression. Mixed lymphocyte cultures derived from animals pretreated with DEM demonstrated a reduction in the Th1 cytokines IFN-gamma and IL-2 and an increase in the Th2 cytokines IL-4 and IL-10. CONCLUSION: Administration of DEM with consequent systemic GSH depletion significantly reduces allograft ICAM-1 expression and prolongs graft survival. Although speculative, a shift from a Th1 to a Th2 cytokine response raises the possibility that tolerance induction plays a role in prolonged allograft survival.

Animals↗
PubMed1998

Tertiary peritonitis: clinical features of a complex nosocomial infection.

The objective of this study was to define risk factors for and the clinical course of recurrent or tertiary peritonitis. Intensive supportive care of patients with life-threatening intraabdominal infections has led to the emergence of a new clinical syndrome, tertiary peritonitis, defined as the persistence or recurrence of intraabdominal infection following apparently adequate therapy of primary or secondary peritonitis. We undertook a retrospective study of 59 patients admitted with intraabdominal infection to a surgical intensive care unit (ICU). Tertiary peritonitis developed in 74% (44/59) of patients. Despite comparable premorbid health status, source of peritonitis, and admission APACHE II scores, patients with tertiary peritonitis had a significantly longer ICU stay (21.8 +/- 14.9 vs. 8.5 +/- 7.9 days), more advanced organ dysfunction reflected in higher organ dysfunction scores (13.3 +/- 5.1 vs. 7.7 +/- 3.3), and higher ICU mortality (64% vs. 33%) than patients with uncomplicated secondary peritonitis. The most common infecting organisms in patients with tertiary peritonitis were Enterococcus, Candida, Staphylococcus epidermidis, and Enterobacter. Infectious foci were rarely amenable to percutaneous drainage and were found to be poorly localized at laparotomy. Recurrent, or tertiary, peritonitis is a common complication of intraabdominal infection in patients admitted to an ICU. It differs from uncomplicated secondary peritonitis in its microbial flora and lack of response to appropriate surgical and antibiotic therapy. Like nosocomial pneumonia in the critically ill patient, the syndrome appears to be more a reflection than a cause of adverse outcome.

Adult↗
PubMed1998

Role of the coagulation system in the local and systemic inflammatory response.

Activation of the coagulation cascade during the inflammatory response is an essential component of the host response to infection. Coagulation represents a double-edged sword. Necessary for hemostasis and the acute containment of an infective focus, it also amplifies the inflammatory response, decreases bacterial clearance, and in the critically ill patient contributes to end-organ damage and death. Evidence for these concepts is found in the fact that critically ill and septic patients consistently demonstrate marked abnormalities in their biochemical indices of coagulation. Moreover, there is excellent experimental evidence to suggest that replacement or inhibition of individual coagulation factors, either consumed or up-regulated during the inflammatory response, can attenuate both local and systemic injury and protect animals from otherwise fatal outcomes. Based on these facts, novel therapeutic approaches to the treatment of the systemic response to infection have been developed and tested in intensive care settings. Although promising results have been obtained, much work remains to be done in defining exactly which coagulation factors (or combination of factors) should be inhibited or replaced during treatment of the septic, critically ill patient. The experimental and clinical evidence linking the coagulation cascade to local and systemic inflammation is reviewed, and the status of the clinical trials performed to date is overviewed.

Animals↗
PubMed1998

Inhibition of amiloride-sensitive sodium-channel activity in distal lung epithelial cells by nitric oxide.

Distal lung epithelial cells (DLECs) play an active role in fluid clearance from the alveolus by virtue of their ability to actively transport Na+ from the alveolus to the interstitial space. The present study evaluated the ability of activated macrophages to modulate the bioelectric properties of DLECs. Low numbers of lipopolysaccharide (LPS)-treated macrophages were able to significantly reduce amiloride-sensitive short-circuit current (Isc) without affecting total Isc or monolayer resistance. This was associated with a rise in the flufenamic acid-sensitive component of the Isc. The effect was reversed by the addition of N-monomethyl-L-arginine to the medium, implying a role for nitric oxide. We hypothesized that macrophages exerted their effect by expressing inducible nitric oxide synthase (iNOS) in DLECs. The products of LPS-treated macrophages increased the levels of iNOS protein and mRNA transcripts in DLECs as well as causing a rise in iNOS activity. Immunofluorescence microscopy of LPS-stimulated macrophage-DLEC cocultures with anti-nitrotyrosine antibodies provided evidence for the generation of peroxynitrite in macrophages but not in DLECs. These data indicate that activated macrophages in the lung may contribute to impaired resolution of acute respiratory distress syndrome and suggest a novel mechanism whereby nitric oxide might alter cell function by altering its ion-transporting phenotype.

Amiloride↗
PubMed1998

Host response to laparoscopic surgery: mechanisms and clinical correlates.

Minimal access surgery has revolutionized the treatment of a variety of surgical diseases, partly because it is associated with less patient morbidity than nonlaparoscopic surgical procedures. Emerging evidence suggests that alteration in the host response after laparoscopic procedures has significantly contributed to the improved postoperative course. Laparoscopy modulates both afferent stimuli (including tissue trauma, pain and wound size) and efferent responses (via neuroendocrine, metabolic, immunologic and cardiorespiratory systems). These effects lead to a decrease in postoperative pain, fever and disability. Laparoscopy mediates these effects through reduced wound size, the activities of endotoxin and immunomodulatory actions of the insufflated gas, resulting in impaired macrophage activity. Although clearly beneficial in reducing postoperative morbidity after elective surgery, this immunosuppression could increase the risk of complications during procedures for infection or neoplasia.

Humans↗
PubMed1997

Regulation of phagosomal acidification. Differential targeting of Na+/H+ exchangers, Na+/K+-ATPases, and vacuolar-type H+-atpases.

Vacuolar-type (V) ATPases are thought to be the main determinant of phagosomal acidification. In phagosomes containing mycobacteria, which ostensibly impair the delivery of V-ATPases to the phagosomal membrane, the pH would be expected to be near neutral. This prediction was tested by microfluorescence ratio imaging using macrophages from mice susceptible to mycobacterial infection. Although less acidic than their counterparts containing dead bacteria, phagosomes containing live Mycobacteria bovis were nearly 1 pH unit more acidic than the cytosol, suggesting the existence of alternate H+ transport mechanisms. We therefore investigated whether Na+/H+ exchange (NHE) contributes to phagosomal acidification. Immunoblotting, reverse transcriptase-polymerase chain reaction, and pharmacological studies indicated that NHE1 is the predominant isoform of the exchanger in macrophages. Fractionation revealed that NHE1 is incorporated into the phagosomal membrane, and measurements of pH indicated that it is functional in this location. Nevertheless, acidification of the lumen of phagosomes containing either latex beads or live M. bovis was insensitive to (3-methylsulfonyl-4-piperidinobenzoyl)-guanidine methanesulfonate, a potent inhibitor of NHE1. This may have been due to the absence of an appropriate lumen to cytosol Na+ gradient, because the phagosomal membrane was found to be devoid of Na+/K+ pumps. Unexpectedly, the acidification of M. bovis phagosomes was fully reversed by specific inhibitors of the vacuolar H+-ATPase, suggesting that ATPases are present only transiently or in reduced quantities in the phagosomal membrane. Alternatively, acid equivalents accumulated in endosomes by V-ATPases may be delivered to the mycobacterial phagosome by carrier vesicles devoid of ATPases.

Animals↗
PubMed1997

Rho is required for the initiation of calcium signaling and phagocytosis by Fcgamma receptors in macrophages.

Phagocytosis of bacteria by macrophages and neutrophils is an essential component of host defense against infection. The mechanism whereby the interaction of opsonized particles with Fcgamma receptors triggers the engulfment of opsonized particles remains incompletely understood, although activation of tyrosine kinases has been recognized as an early step. Recent studies in other systems have demonstrated that tyrosine kinases can in turn signal the activation of small GTPases of the ras superfamily. We therefore investigated the possible role of Rho in Fc receptor-mediated phagocytosis. To this end we microinjected J774 macrophages with C3 exotoxin from Clostridium botulinum, which ADP-ribosylates and inactivates Rho. C3 exotoxin induced the retraction of filopodia, the disappearance of focal complexes, and a global decrease in the F-actin content of J774 cells. In addition, these cells exhibited increased spreading and the formation of vacuolar structures. Importantly, inactivation of Rho resulted in the complete abrogation of phagocytosis. Inhibition of Fcgamma receptor-mediated phagocytosis by C3 exotoxin was confirmed in COS cells, which become phagocytic upon transfection of the FcgammaRIIA receptor. Rho was found to be essential for the accumulation of phosphotyrosine and of F-actin around phagocytic cups and for Fcgamma receptor-mediated Ca2+ signaling. The clustering of receptors in response to opsonin, an essential step in Fcgamma-induced signaling, was the earliest event shown to be inhibited by C3 exotoxin. The effect of the toxin was specific, since clustering and internalization of transferrin receptors were unaffected by microinjection of C3. These data identify a role for small GTPases in Fcgamma receptor-mediated phagocytosis by leukocytes.

Actins↗
PubMed1997

Granulocytic differentiation of HL-60 cells results in spontaneous apoptosis mediated by increased caspase expression.

HL-60 cells differentiating into neutrophil-like cells die an apoptotic death in vitro. Susceptibility to apoptosis is associated with decreased Bcl-2 protein and mRNA expression; however, the effect of differentiation on the expression of pro-apoptotic caspases is unknown. Spontaneous apoptosis occurred 6 days after retinoic acid treatment. Western blotting showed loss of Bcl-2 by day 7, and new expression of ICE (caspase 1) and CPP32 (caspase 3) protein by day 2. Northern analysis demonstrated loss of Bcl-2 mRNA and increases in ICE mRNA by day 2; CPP32 mRNA was unchanged. Differential Bcl-2 and ICE mRNA expression was also found when granulocytic differentiation was stimulated by DMSO. Differentiated HL-60 cell lysates exhibited functional ICE proteolytic activity. De novo caspase expression was responsible for the development of spontaneous apoptosis, since specific inhibitors of ICE (YVAD-CMK) and CPP32 (DEVD-CHO), inhibited retinoic acid induced spontaneous apoptosis. Functional maturation and susceptibility to apoptosis are both inducible and linked in this granulocyte precursor cell line.

Apoptosis↗
PubMed1997

Augmented intracellular glutathione inhibits Fas-triggered apoptosis of activated human neutrophils.

Agonist signals delivered through cell surface Fas induce apoptosis. However, the apoptotic program can be modulated by signals from the environment, and in particular, by signals delivered through adhesion molecules. Because neutrophil functional activity in inflammation is contingent on cell survival, and because circulating neutrophils normally die rapidly through a constitutively expressed apoptotic program, we evaluated Fas-mediated apoptosis in resting and inflammatory human neutrophils. We show that normal neutrophils respond to Fas engagement with accelerated rates of apoptosis, but cross-linking of beta2 integrins or priming with bacterial lipopolysaccharide (LPS) prevents this increase. Adhesion molecule cross-linking results in increased intracellular glutathione (GSH). Augmentation of intracellular GSH with exogenous GSH or N-acetylcysteine is sufficient to reduce the Fas-triggered increase in apoptotic rates. Prevention of the activation induced GSH increase by buthionine sulfoximine, a cell permeable inhibitor of GSH biosynthesis, restored Fas responsiveness in activated neutrophils, an effect that could be blocked with exogenous GSH. Taken together, these data show that Fas-induced signaling for neutrophil apoptosis is blocked in a redox sensitive manner by costimulatory signals delivered through beta2 integrins or activation by LPS, and provide a biologic explanation for sustained neutrophil survival in the inflammatory environment.

Apoptosis↗
PubMed1997

VLA-4 integrin cross-linking on human monocytic THP-1 cells induces tissue factor expression by a mechanism involving mitogen-activated protein kinase.

Adhesion molecules such as VLA-4 are important not only for monocyte adhesion to extracellular matrix proteins, but also for subsequent cell activation. Monocyte adherence to fibronectin or engagement of VLA-4 has been demonstrated to stimulate production of potent inflammatory mediators such as tumor necrosis factor-alpha, interleukin-1, and the procoagulant tissue factor protein. However, the intracellular signaling cascades leading to gene expression have not been elucidated. Using the human monocytic THP-1 cell line, VLA-4 cross-linking by monoclonal antibodies directed against its alpha4 and beta1 subunits produced a time-dependent increase in tyrosine phosphorylation of a broad range of cellular proteins. Using Western blot analysis directed against the phosphorylated form of the extracellular signal-related kinase (ERK) mitogen-activated protein (MAP) kinase proteins, as well as immunoprecipitation and in vitro kinase assays, we found that VLA-4 cross-linking increased ERK1/ERK2 tyrosine phosphorylation and activity. In conjunction, integrin cross-linking also increased NF-kappaB nuclear translocation and 4-h expression of tissue factor. Inhibition of tyrosine kinase activity with genistein (10 microg/ml) as well as selective MAP kinase inhibition with the MEK-1 inhibitor PD98059 abolished the VLA-4-dependent ERK tyrosine phosphorylation, inhibited NF kappaB nuclear binding, and abrogated tissue factor expression induced by both VLA-4 cross-linking and adhesion to fibronectin in THP-1 cells and human peripheral blood monocytes. These studies point to the involvement of the MAP kinase pathway in the activation of monocytic cells during transmigration to inflammatory sites.

Calcium-Calmodulin-Dependent Protein Kinases↗
PubMed1997

Chronic extracellular acidosis induces plasmalemmal vacuolar type H+ ATPase activity in osteoclasts.

Proton extrusion into an extracellular resorption compartment is an essential component of bone degradation by osteoclasts. Chronic metabolic acidosis is known to induce negative calcium balance and bone loss by stimulating osteoclastic bone resorption, but the underlying mechanism is not known. The present studies were undertaken to evaluate whether chronic acidosis affects proton extrusion mechanisms in osteoclasts cultured on glass coverslips. Acidosis, mimicked experimentally by maintaining the cells at extracellular pH 6.5, rapidly lowered intracellular pH to 6.8. However, after 2 hours, a proportion of cells demonstrated the capacity to restore intracellular pH to near normal levels. To define the mechanism responsible for this recovery, the activity of individual H+ transport pathways was analyzed. We found that chronic acid treatment for up to 6 h did not significantly affect the cellular buffering power or Na+/H+ antiport activity. In contrast, chronic acidosis activated vacuolar H+ pumps in the osteoclasts. Although only approximately 5% of the control cells displayed proton pump activity, about 40% of cells kept at extracellular pH 6. 5 for 4-6 h were able to recover from the acute acid load by means of bafilomycin A1-sensitive proton extrusion. Conversely, the H+-selective conductance recently described in the plasma membrane of osteoclasts was clearly inhibited in the cells exposed to chronic acidosis. Following acid treatment, the activation threshold of the H+ conductance was shifted to more positive potentials, and the current density was significantly reduced. Considered together, these results suggest that induction of plasmalemmal vacuolar type ATPase activity by chronic acidosis, generated either systemically due to metabolic disease or locally at sites of inflammation, is likely to stimulate osteoclastic bone resorption and thus to promote bone loss.

Acidosis↗
PubMed1997

Neutrophil apoptosis is modulated by endothelial transmigration and adhesion molecule engagement.

Termination of a neutrophil-mediated inflammatory response occurs through the activation of the endogenous cell death program, apoptosis. Neutrophil apoptosis is a constitutive process that can be accelerated or delayed by signals from the microenvironment. Since cellular localization at the site of an inflammatory challenge is the critical first step in a neutrophil response, we investigated the effects of neutrophil transendothelial transmigration on the kinetic expression of apoptosis. Neutrophils isolated from rat lung following challenge with LPS demonstrated a significant delay in spontaneous apoptosis. This delay was a consequence of transmigration, since a comparable delay was seen when TNF-alpha, a potent inducer of apoptosis in vitro, was used as the inflammatory stimulus. Human neutrophils demonstrated comparable delays in apoptosis in vitro following migration across an endothelial monolayer in response to FMLP. Delayed apoptosis only occurred in cells that had first been primed by LPS, a stimulus shown to up-regulate beta2 integrins and down-regulate L-selectin. Finally, crosslinking of CD11a or CD11b, but not of CD18, with mAbs and F(ab')2 fragments produced a delay in spontaneous apoptosis, whereas crosslinking of L-selectin with mAb or its natural ligand, sulfatides, accelerated the apoptotic process. Cells in which apoptosis was inhibited demonstrated persistent functional respiratory burst activity. These observations establish a role for endothelial transmigration in the regulation of neutrophil apoptosis, and suggest that adhesion molecules serve a modulatory role in the expression of neutrophil programmed cell death.

Animals↗
PubMed1997

Glutathione depletion prevents lipopolysaccharide-induced local skin inflammation.

BACKGROUND: We have previously shown that the thiol-oxidizing agent diethyl maleate prevents lipopolysaccharide (LPS)-induced up-regulation of endothelial cell intercellular adhesion molecule-1 (ICAM-1) in vitro. OBJECTIVE: To determine the effect of glutathione depletion on the development of local skin inflammation in vivo, a model known to be dependent on ICAM-1. DESIGN: Swiss Webster mice were injected with intradermal LPS (30 micrograms) or isotonic saline solution. INTERVENTION: Mice were pretreated for 1 hour with intraperitoneal diethyl maleate (6 mmol/kg) or corn oil vehicle. MAIN OUTCOME MEASURES: Injection sites were harvested after 12 and 24 hours and evaluated for changes in vascular permeability and histological characteristics. To determine the mechanism underlying our findings, we evaluated skin ICAM-1 immunohistochemistry, levels of ICAM-1 protein and messenger RNA (mRNA), and neutrophil CD11b expression at the 24-hour point. RESULTS: Diethyl maleate significantly decreased the skin permeability index in a dose-dependent fashion at 24 hours but not at 12 hours. Skin histological examination under light microscopy showed a marked LPS-induced neutrophil infiltration at 24 hours, which was inhibited with diethyl maleate pretreatment. Immunohistochemical examination showed that diethyl maleate reduced ICAM-1 expression. In keeping with the hypothesized mechanism, diethyl maleate attenuated the LPS-induced up-regulation of ICAM-1 mRNA by 44%. Diethyl maleate also slightly but insignificantly reduced CD11b expression in vivo. CONCLUSIONS: Diethyl maleate markedly attenuates LPS-induced dermal inflammation, primarily through a reduction in ICAM-1 protein and mRNA expression. These data suggest that manipulation of the intracellular redox state may have a beneficial role in neutrophil-mediated inflammation.

Animals↗
PubMed1997

Dysregulated expression of neutrophil apoptosis in the systemic inflammatory response syndrome.

OBJECTIVE: To study the effect of the systemic inflammatory response syndrome (SIRS) or major elective surgery on the apoptosis of circulating polymorphonuclear neutrophils because an activated inflammatory response is terminated, in part, through the programmed cell death, or apoptosis, of its effector cells. DESIGN: A prospective inception cohort study. SETTING: A mixed surgical and medical intensive care unit of an adult tertiary care hospital. PATIENTS: Sixteen patients with SIRS, 7 uninfected patients who had undergone elective aortic aneurysmectomy, and 8 healthy laboratory control subjects. INTERVENTIONS: Serial blood samples were drawn for evaluation of neutrophil apoptosis, activational state, and surface receptor expression by flow cytometry. MAIN OUTCOME MEASURES: Spontaneous apoptosis was significantly delayed in neutrophils from patients with SIRS (8.6%+/-6.8%) and patients who had undergone elective aortic aneurysmectomy (11.0%+/-5.0%) when compared with controls (34.9%+/-6.8%). These neutrophils were activated as evidenced by enhanced respiratory burst activity and augmented surface expression of CD11b. Apoptosis in response to engagement of cell surface Fas (also known as CD95 or APO-1) with an agonistic antibody was blunted. Plasma from patients with SIRS or patients who had undergone elective aortic aneurysmectomy suppressed the apoptotic responses of control neutrophils (plasma from patients with SIRS, 18.8%+/-10.3%; plasma from patients who had undergone elective aortic aneurysmectomy, 20.0%+/-6.1%; P<.01). Western blot analysis showed normal expression of the key proapoptotic proteases, interleukin 1beta converting enzyme and CPP32 (also known as YAMA, apopain, and caspase 3), indicating that delayed apoptosis was not a consequence of decreased levels of proapoptotic enzymes. CONCLUSIONS: Circulating neutrophils from patients with SIRS or from patients who have undergone major elective surgery show delayed expression of constitutive programmed cell death, and antiapoptotic factors are present in the general circulation. While prolonged neutrophil survival may represent an appropriate adaptive response to injury, the presence of activated and apoptosis-resistant cells in an antiapoptotic environment may contribute to the systemic inflammatory injury characteristic of SIRS and predispose to the development of the multiple organ dysfunction syndrome.

APACHE↗
PubMed1997

A randomized, double-blind clinical trial comparing cefepime plus metronidazole with imipenem-cilastatin in the treatment of complicated intra-abdominal infections. Cefepime Intra-abdominal Infection Study Group.

OBJECTIVE: To evaluate the safety and efficacy of cefepime hydrochloride plus metronidazole vs the combination of imipenem and cilastatin sodium in the treatment of complicated intra-abdominal infections in adult patients. DESIGN: Prospective, randomized, double-blind multicenter study. SETTING: University-affiliated hospitals in the United States and Canada. PATIENTS: Three hundred twenty-three patients with complicated intra-abdominal infections in whom an operative procedure or percutaneous drainage was required for diagnosis and management. INTERVENTION: Cefepime, 2 g, was administered intravenously every 12 hours (n= 164) in addition to metronidazole, 500 mg (or 7.5 mg/kg) intravenously every 6 hours. Imipenen-cilastatin sodium, 500 mg, was administered intravenously every 6 hours (n= 159). Surgical infection management was determined by the patients' surgeons. MAIN OUTCOME ASSESSMENTS: Clinical cure, defined as elimination of all signs and symptoms relevant to the original infection; and treatment failure, defined as persistence, increase or worsening of signs and symptoms resulting in an antibiotic change, requirement of an additional surgical procedure to cure the infection, or a wound infection with fever. RESULTS: Of the initial isolates, 84% were susceptible to cefepime and 92% were susceptible to imipenem-cilastatin. Among the 217 protocol-valid patients, those treated with cefepime+metronidizole were deemed clinical cures (88%) more frequently than were imipenem-cilastatin-treated patients (76%) (P=.02). Using multivariate analysis to adjust for identified clinical risk factors for an adverse outcome (severity of presenting illness, isolation of enterococcus, type of infection, and duration of prestudy hospitalization), there was a trend (P=.06) toward a higher cure rate favoring cefepime+metronidazole. Pathogens were eradicated in significantly (P=.01) more patients treated with combined cefepime and metronidazole (89%) than with imipenem-cilastatin (76%). CONCLUSION: The combination of cefepime plus metronidazole is safe and effective therapy for patients with severe intra-abdominal infections.

Abdomen↗