A study of potential serum markers for a diagnosis of gram-positive and gram-negative bacterial sepsis

Sepsis continues to be a major cause of morbidity and mortality as it can readily lead tosevere sepsis, septic shock, multiple organ failure and death. The onset can be rapid and difficult to define clinically. Despite the numerous candidate markers proposed in the literature, to date a serum marker for sepsis has not been found. The aim of this study was to assay the serum of clinically diagnosed patients with eithera Gram-negative or Gram- positive bacterial sepsis for elevated levels of nine potentialmarkers of sepsis, using commercially produced enzyme linked immunosorbent assays(ELISA). The purpose was to find a test marker for sepsis that would be helpful toclinicians in cases of uncertain sepsis and consequently expose false positive BC'scaused by skin or environmental contaminants. Nine test markers were assayed including IL-6, IL-I 0, ILI2, TNF-α, lipopolysaccharide binding protein, procalcitonin, sE-selectin, sICAM -1 and a potential differential marker for Gram-positive sepsis- anti-lipid S antibody. A total of 445 patients were enrolled into this study from the Queen Elizabeth Hospital and Selly Oak Hospital (Birmingham). The results showed that all the markers were elevated in patients with sepsis and that patients with a Gram-negative sepsis consistently produced higher median/range serum levels than those with a Gram-positive sepsis. No single marker was able to identify all the septic patients. Combining two markers caused the sensitivities and specificities for a diagnosis of sepsis to increase to within a 90% to 100% range. By a process of elimination the markers that survived into the last phase were IL-6 with sICAM -1, and anti-lipid S IgG assays Defining cut-off levels for a diagnosis of sepsis became problematic and a semi-blind trial was devised to test the markers in the absence of both clinical details and positive blood cultures. Patients with pyrexia of unknown origin and negative BC were included in this phase (4). The results showed that IL-6 with sICAM-l are authentic markers of sepsis. There was 82% agreement between the test marker diagnosis and the clinical diagnosis for sepsis in patients with a Gram-positive BC and 78% agreement in cases of Gram-negative Be. In the PUO group the test markers identified 12 cases of sepsis and the clinical diagnosis 15. The markers were shown to differentiate between early sepsis and sepsis, inflammatory responses and infection. Anti-lipid S with IL-6 proved be a sensitive marker for Gram-positive infections/sepsis.

Mediators of gram-positive septic shock

Septic shock can occur as a result of Gram-negative or Gram-positive infection and involves a complex interaction between bacterial factors and the host immune system producing a systemic inflammatory state that may progress to multiple organ failure and death. Gram-positive bacteria are increasingly becoming more prevalent especially Staphylococcus epidermidis in association with indwelling devices. Lipopolysaccaride (LPS) is the key Gram-negative component involved in this process, but it is not clear which components of Gram-positive bacteria are responsible for progression of this often fatal disease. The aim of this thesis was to investigate the effect of bacterial components on the immune systems. Lipid S, a short chain form of lipoteichoic acid (LTA) found to be excreted from bacteria during growth in culture medium was examined along with other Gram-positive cell wall components: LTA, peptidoglycan (PG) and wall teichoic acids (WTA) and LPS from Gram-negative bacteria. Lipid S, LTA, PG and LPS but not WTA all stimulated murine macrophages and cell lines to produce significant amounts of NO, TNF-a, IL-6 and IL-1 and would induce fever and tissue damage seen in inflammatory diseases. Lipid S proved to be the most potent out of the Gram-positive samples tested. IgG antibodies in patients serum were found to bind to and cross react with lipid S and LTA. Anti-inflammatory antibiotics, platelet activating factor (PAF), PAF receptor antagonists and monoclonal antibodies (mAbs) directed to LTA, CD14 and toll-like receptors were utilised to modulate cytokine and NO production. In cell culture the anti-LTA and the anti-CD14 mAbs failed to markedly attenuate the production of NO, TNF-a, IL-6 or IL-1, the anti-TLR4 antibody did greatly inhibit the ability of LPS to stimulate cytokine production but not lipid S. The tetracyclines proved to be the most effective compounds, many were active at low concentrations and showed efficacy to inhibit both lipid S and LPS stimulated macrophages to produce NO.

Sepsis: the LightCycler SeptiFast Test MGRADE®, SepsiTest™ and IRIDICA BAC BSI assay for rapidly identifying bloodstream bacteria and fungi – a systematic review and economic evaluation

Background: Sepsis can lead to multiple organ failure and death. Timely and appropriate treatment can reduce in-hospital mortality and morbidity. Objectives: To determine the clinical effectiveness and cost-effectiveness of three tests [LightCycler SeptiFast Test MGRADE® (Roche Diagnostics, Risch-Rotkreuz, Switzerland); SepsiTest™ (Molzym Molecular Diagnostics, Bremen, Germany); and the IRIDICA BAC BSI assay (Abbott Diagnostics, Lake Forest, IL, USA)] for the rapid identification of bloodstream bacteria and fungi in patients with suspected sepsis compared with standard practice (blood culture with or without matrix-absorbed laser desorption/ionisation time-offlight mass spectrometry). Data sources: Thirteen electronic databases (including MEDLINE, EMBASE and The Cochrane Library) were searched from January 2006 to May 2015 and supplemented by hand-searching relevant articles. Review methods: A systematic review and meta-analysis of effectiveness studies were conducted. A review of published economic analyses was undertaken and a de novo health economic model was constructed. A decision tree was used to estimate the costs and quality-adjusted life-years (QALYs) associated with each test; all other parameters were estimated from published sources. The model was populated with evidence from the systematic review or individual studies, if this was considered more appropriate (base case 1). In a secondary analysis, estimates (based on experience and opinion) from seven clinicians regarding the benefits of earlier test results were sought (base case 2). A NHS and Personal Social Services perspective was taken, and costs and benefits were discounted at 3.5% per annum. Scenario analyses were used to assess uncertainty. Results: For the review of diagnostic test accuracy, 62 studies of varying methodological quality were included. A meta-analysis of 54 studies comparing SeptiFast with blood culture found that SeptiFast had an estimated summary specificity of 0.86 [95% credible interval (CrI) 0.84 to 0.89] and sensitivity of 0.65 (95% CrI 0.60 to 0.71). Four studies comparing SepsiTest with blood culture found that SepsiTest had an estimated summary specificity of 0.86 (95% CrI 0.78 to 0.92) and sensitivity of 0.48 (95% CrI 0.21 to 0.74), and four studies comparing IRIDICA with blood culture found that IRIDICA had an estimated summary specificity of 0.84 (95% CrI 0.71 to 0.92) and sensitivity of 0.81 (95% CrI 0.69 to 0.90). Owing to the deficiencies in study quality for all interventions, diagnostic accuracy data should be treated with caution. No randomised clinical trial evidence was identified that indicated that any of the tests significantly improved key patient outcomes, such as mortality or duration in an intensive care unit or hospital. Base case 1 estimated that none of the three tests provided a benefit to patients compared with standard practice and thus all tests were dominated. In contrast, in base case 2 it was estimated that all cost per QALY-gained values were below £20,000; the IRIDICA BAC BSI assay had the highest estimated incremental net benefit, but results from base case 2 should be treated with caution as these are not evidence based. Limitations: Robust data to accurately assess the clinical effectiveness and cost-effectiveness of the interventions are currently unavailable. Conclusions: The clinical effectiveness and cost-effectiveness of the interventions cannot be reliably determined with the current evidence base. Appropriate studies, which allow information from the tests to be implemented in clinical practice, are required.

Do simple ventilation and gas exchange measurements predict early successful weaning from respiratory support in unselected general intensive care patients?

Background. The value of respiratory variables as weaning predictors in the intensive care unit (ICU) is controversial. We evaluated the ability of tidal volume (Vtexp), respiratory rate ( f ), minute volume (MVexp), rapid shallow breathing index ( f/Vt), inspired–expired oxygen concentration difference [(I–E)O2], and end-tidal carbon dioxide concentration (PE′CO2) at the end of a weaning trial to predict early weaning outcomes. Methods. Seventy-three patients who required .24 h of mechanical ventilation were studied. A controlled pressure support weaning trial was undertaken until 5 cm H2O continuous positive airway pressure or predefined criteria were reached. The ability of data from the last 5 min of the trial to predict whether a predefined endpoint indicating discontinuation of ventilator support within the next 24 h was evaluated. Results. Pre-test probability for achieving the outcome was 44% in the cohort (n¼32). Non-achievers were older, had higher APACHE II and organ failure scores before the trial, and higher baseline arterial H+ concentrations. The Vt, MV, f, and f/Vt had no predictive power using a range of cut-off values or from receiver operating characteristic (ROC) analysis. The [I–E]O2 and PE′CO2 had weak discriminatory power [areaunder the ROC curve: [I–E]O2 0.64 (P¼0.03); PE′CO2 0.63 (P¼0.05)]. Using best cut-off values for [I–E]O2 of 5.6% and PE′CO2 of 5.1 kPa, positive and negative likelihood ratios were 2 and 0.5, respectively, which only changed the pre- to post-test probability by about 20%. Conclusions. In unselected ICU patients, respiratory variables predict early weaning from mechanical ventilation poorly.

Epidemiology of invasive aspergillosis in critically ill patients: clinical presentation, underlying conditions, and outcomes

INTRODUCTION: Invasive aspergillosis (IA) is a fungal infection that particularly affects immunocompromised hosts. Recently, several studies have indicated a high incidence of IA in intensive care unit (ICU) patients. However, few data are available on the epidemiology and outcome of patients with IA in this setting.

Predictors of maternal mortality among critically ill obstetric patients

Aim Evaluation of the predictors of maternal mortality among critically ill obstetric patients managed at the intensive care unit (ICU). Methods A case control study to evaluate the predictors of maternal mortality among critically ill obstetric patients managed at the intensive care unit (ICU) of the University of Ilorin Teaching Hospital, Ilorin, Nigeria from 1st January 2010 to 30th June 2013. Participants were critically ill obstetric patients who were admitted and managed at the ICU during the study period. Subjects were those who died while controls were age and parity matched survivors. Statistical analysis was with SPSS-20 to determine chi square, Cox-regression and odds ratio; p value < 0.05 was significant. Results The mean age of subjects and controls were 28.92 ± 5.09 versus 29.44 ± 5.74 (p = 0.736), the level of education was higher among controls (p = 0.048) while more subjects were of low social class (p = 0.321), did not have antenatal care (p = 0.131) and had partners with lower level of education (p = 0.156) compared to controls. The two leading indications for admission among subjects and controls were massive postpartum haemorrhage and severe preeclampsia or eclampsia. The mean duration of admission was higher among controls (3.32 ± 2.46 versus 3.00 ± 2.58; p = 0.656) while the mean cost of ICU care was higher among the subjects (p = 0.472). The statistical significant predictors of maternal deaths were the patient’s level of education, Glasgow Coma Scale (GCS) score, oxygen saturation, multiple organ failure at ICU admission and the need for mechanical ventilation or inotrophic drugs after admission. Conclusion The clinical state at ICU admission of the critically ill obstetric patients is the major outcome determinant. Therefore, early recognition of the need for ICU care, adequate pre-ICU admission supportive care and prompt transfer will improve the outcome.

Red blood cell rheology in sepsis

Changes in red blood cell (RBC) function can contribute to alterations in microcirculatory blood flow and cellular dysoxia in sepsis. Decreases in RBC and neutrophil deformability impair the passage of these cells through the microcirculation. While the role of leukocytes has been the focus of many studies in sepsis, the role of erythrocyte rheological alterations in this syndrome has only recently been investigated. RBC rheology can be influenced by many factors, including alterations in intracellular calcium and adenosine triphosphate (ATP) concentrations, the effects of nitric oxide, a decrease in some RBC membrane components such as sialic acid, and an increase in others such as 2,3 diphosphoglycerate. Other factors include interactions with white blood cells and their products (reactive oxygen species), or the effects of temperature variations. Understanding the mechanisms of altered RBC rheology in sepsis, and the effects on blood flow and oxygen transport, may lead to improved patient management and reductions in morbidity and mortality.

Experiencia y porcentaje de complicaciones de las derivaciones portosistémicas intrahepáticas transyugulares en la Fundación Cardioinfantil

La derivación portosistémica intrahepática transyugular (TIPS) es una técnica importante en el manejo de las complicaciones de la hipertensión portal, en especial en aquellos pacientes candidatos a trasplante hepático. Se trata de un estudio observacional analítico, sin riesgo, en el cual se emplearon técnicas y métodos de investigación documental retrospectivo, y no se realizó ningún tipo de intervención sobre las variables fisiológicas, psicológicas y sociales de la población incluida. Se realizó la descripción demográfica de los pacientes, características clínicas, hallazgos imageneológicos y aspectos técnicos asociados al procedimiento de los pacientes con hipertensión portal que han sido manejados con TIPS en la Fundación CardioInfantil desde Enero 1 de 2007 hasta Junio 30 de 2016. Se incluyeron 54 pacientes de los cuales el 66,7% no presentaron complicaciones inmediatas, tenidas en cuenta desde la terminación del procedimiento y hasta las siguientes 24 horas; sin embargo, 16,9% debutaron con encefalopatía durante este periodo. De las complicaciones tardías, la más frecuente fue la ascitis con un 66,7%, con una mortalidad de 20,4% de los cuales, el 45% de estos fue por shock séptico y falla orgánica secundaria. Aunque el porcentaje de complicaciones asociadas al procedimiento fue alto en nuestros pacientes, se encuentra dentro de los valores reportados en la literatura. Los resultados presentados son un punto de partida para la evaluación del procedimiento en nuestra población y permiten implementar estrategias de mejora que conlleven a incidir de manera positiva en el porcentaje de complicaciones y mortalidad derivadas del procedimiento.

Direct molecular and spectroscopic evidence for increased ammonia removal capacity of skeletal muscle in acute liver failure.

BACKGROUND/AIMS: It has been proposed that, in acute liver failure, skeletal muscle adapts to become the principle organ responsible for removal of blood-borne ammonia by increasing glutamine synthesis, a reaction that is catalyzed by the cytosolic ATP-dependent enzyme glutamine synthetase. To address this issue, glutamine synthetase expression and activities were measured in skeletal muscle of rats with acute liver failure resulting from hepatic devascularization. METHODS: Glutamine synthetase protein and gene expression were investigated using immunoblotting and semi-quantitative RT-PCR analysis. Glutamine synthetase activity and glutamine de novo synthesis were measured using, respectively, a standard enzymatic assay and [13C]-nuclear magnetic resonance spectroscopy. RESULTS: Glutamine synthetase protein (but not gene) expression and enzyme activities were significantly up-regulated leading to increased de novo synthesis of glutamine and increased skeletal muscle capacity for ammonia removal in acute liver failure. In contrast to skeletal muscle, expression and activities of glutamine synthetase in the brain were significantly decreased. CONCLUSIONS: These findings demonstrate that skeletal muscle adapts, through a rapid induction of glutamine synthetase, to increase its capacity for removal of blood-borne ammonia in acute liver failure. Maintenance of muscle mass together with the development of agents with the capacity to stimulate muscle glutamine synthetase could provide effective ammonia-lowering strategies in this disorder.

HAWAIIAN SKIRT: an F-box gene that regulates organ fusion and growth in arabidopsis

A fast neutron-mutagenized population of Arabidopsis ( Arabidopsis thaliana) Columbia-0 wild-type plants was screened for floral phenotypes and a novel mutant, termed hawaiian skirt ( hws), was identified that failed to shed its reproductive organs. The mutation is the consequence of a 28 bp deletion that introduces a premature amber termination codon into the open reading frame of a putative F-box protein ( At3g61590). The most striking anatomical characteristic of hws plants is seen in flowers where individual sepals are fused along the lower part of their margins. Crossing of the abscission marker, Pro(PGAZAT):beta-glucuronidase, into the mutant reveals that while floral organs are retained it is not the consequence of a failure of abscission zone cells to differentiate. Anatomical analysis indicates that the fusion of sepal margins precludes shedding even though abscission, albeit delayed, does occur. Spatial and temporal characterization, using Pro(HWS):beta-glucuronidase or Pro(HWS):green fluorescent protein fusions, has identified HWS expression to be restricted to the stele and lateral root cap, cotyledonary margins, tip of the stigma, pollen, abscission zones, and developing seeds. Comparative phenotypic analyses performed on the hws mutant, Columbia-0 wild type, and Pro(35S):HWS ectopically expressing lines has revealed that loss of HWS results in greater growth of both aerial and below-ground organs while overexpressing the gene brings about a converse effect. These observations are consistent with HWS playing an important role in regulating plant growth and development.

Differential morphofunctional characteristics and gene expression in fast and slow muscle of rats with monocrotaline-induced heart failure

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effects of Continuous Erythropoietin Receptor Activator in Sepsis-Induced Acute Kidney Injury and Multi-Organ Dysfunction

Background: Despite advances in supportive care, sepsis-related mortality remains high, especially in patients with acute kidney injury (AKI). Erythropoietin can protect organs against ischemia and sepsis. This effect has been linked to activation of intracellular survival pathways, although the mechanism remains unclear. Continuous erythropoietin receptor activator (CERA) is an erythropoietin with a unique pharmacologic profile and long half-life. We hypothesized that pretreatment with CERA would be renoprotective in the cecal ligation and puncture (CLP) model of sepsis-induced AKI. Methods: Rats were randomized into three groups: control; CLP; and CLP+CERA (5 mu g/kg body weight, i.p. administered 24 h before CLP). At 24 hours after CLP, we measured creatinine clearance, biochemical variables, and hemodynamic parameters. In kidney tissue, we performed immunoblotting-to quantify expression of the Na-K-2Cl cotransporter (NKCC2), aquaporin 2 (AQP2), Toll-like receptor 4 (TLR4), erythropoietin receptor (EpoR), and nuclear factor kappa B (NF-kappa B)-and immunohistochemical staining for CD68 (macrophage infiltration). Plasma interleukin (IL)-2, IL-1 beta, IL-6, IL-10, interferon gamma, and tumor necrosis factor alpha were measured by multiplex detection. Results: Pretreatment with CERA preserved creatinine clearance and tubular function, as well as the expression of NKCC2 and AQP2. In addition, CERA maintained plasma lactate at normal levels, as well as preserving plasma levels of transaminases and lactate dehydrogenase. Renal expression of TLR4 and NF-kappa B was lower in CLP+CERA rats than in CLP rats (p<0.05 and p<0.01, respectively), as were CD68-positive cell counts (p<0.01), whereas renal EpoR expression was higher (p<0.05). Plasma levels of all measured cytokines were lower in CLP+CERA rats than in CLP rats. Conclusion: CERA protects against sepsis-induced AKI. This protective effect is, in part, attributable to suppression of the inflammatory response.

[Surgical treatment options in end-stage heart failure]

Despite significant improvements in pharmacological therapy heart failure is still one of the leading causes for death in the Western World. The gold standard treatment of end-stage heart failure remains cardiac transplantation, but there is a great excess of eligible candidates compared with the low number of suitable donor organs. The variety of surgical organ preserving treatment strategies has significantly increased during the last 20 years, intenting either to delay or even to prevent the need for cardiac transplantation. An individually tailored surgical concept should be considered as an alternative in any heart failure patient who has reached the limits of pharmacologic therapy. This article gives an overview about current and potential future therapeutic options in end-stage heart failure.

Bridging hyperacute liver failure by ABO-incompatible auxiliary partial orthotopic liver transplantation

Uncontrollable intracranial pressure elevation in hyperacute liver failure often proves fatal if no suitable liver for transplantation is found in due time. Both ABO-compatible and auxiliary partial orthotopic liver transplantation have been described to control such scenario. However, each method is associated with downsides in terms of immunobiology, organ availability and effects on the overall waiting list.

Beneficial cardiovascular effects of endothelin ET(A) receptor blockade in established long-term heart failure after myocardial infarction

Although experimental prevention studies have suggested therapeutic potential of endothelin (ET) antagonists for the treatment of heart failure, the results of clinical trials using ET antagonists on top of standard heart failure medications have been largely disappointing. This experimental study investigated the effects of chronic ET(A) receptor blockade in long-term survivors of myocardial infarction who had developed stable chronic heart failure in the absence of other treatments. Systolic blood pressure, heart rate, organ weights of the right atrium and ventricle, and the lungs were determined, and tissue ET-1 peptide levels were measured in cardiac tissue, lung, and aorta. The results show that chronic blockade of ET(A) receptors stabilizes systolic blood pressure and reverses the heart failure-induced weight increases of right heart chambers and lung. The changes observed occurred independently of tissue ET-1 concentrations and heart rate, suggesting mechanisms independent of local cardiac or pulmonary ET-1 synthesis, which are yet to be identified.