Gram-negative Bacterial Sepsis Research Articles

A Neonatal Imaging Model of Gram-Negative Bacterial Sepsis

A Neonatal Imaging Model of Gram-Negative Bacterial Sepsis

CRP/albumin ratio: A promising marker of gram-negative bacteremia in late-onset neonatal sepsis.

Neonatal sepsis is a clinical condition that results in serious morbidity and mortality unless urgently diagnosed and treated. Obtaining the results of blood cultures to determine the causative agent in sepsis is a time-consuming process. The CRP/albumin ratio is an inflammatory marker that has started to be used in recent years. The aim of our study was to investigate the relationship between CRP/albumin and Gram-negative bacterial sepsis in neonates. This study was conducted on 112 premature neonates with sepsis. The patients were divided into two groups according to culture results as Gram-negative and Gram-positive bacterial sepsis. The laboratory and demographic features of the patients were obtained from the hospital records. A receiver operating characteristic curve was plotted to evaluate the predictive value of the CRP/albumin ratio for Gram-negative sepsis. CRP/albumin was significantly higher in the Gram-negative group (p<0.001). According to the receiver operating characteristic curve, the optimal cut-off value of CRP/albumin for the prediction of Gram-negative sepsis was >35.17, which had a specificity of 97% and sensitivity of 56% (AUC=0.839; 95% CI: 0.743-0.944; p<0.001). A multivariate logistic regression analysis revealed that CRP/albumin (OR=1.082, 95% CI: 1.033-1.134, p=0.001) and absolute neutrophil count (OR=1.145, 95% CI: 1.000-1.312, p=0.049) were still associated with Gram-negative sepsis after adjustment for variables found to be statistically significant in univariate analysis and correlated with Gram-negative sepsis. The CRP/albumin ratio is independently related to Gram-negative sepsis in neonatal sepsis and may be useful in predicting Gram-negative bacteremia.

IL-10-producing regulatory B cells exhibit functional defects and play a protective role in severe endotoxic shock

Dysregulated host immune homeostasis in sepsis is life-threatening even after a successfully treated bacterial infection. Lipopolysaccharide (LPS) is an endotoxin that is a major contributor to the aberrant immune responses and endotoxic shock in gram-negative bacterial sepsis. However, the current knowledge of the role of B cells in endotoxic shock is limited. Here, we report that CD1d expression in B cells and the percentage of CD5+CD1dhi regulatory B (Breg) cells decreased in a mouse model of endotoxic shock. Interestingly, IL-10 but not FasL expression in CD5+CD1dhi Breg cells in response to endotoxin was dramatically reduced in severe septic shock mice, and the regulatory function of CD5+CD1dhi Breg cells in vitro to control the Th1 response was also diminished. Adoptive transfer of CD5+CD1dhi Breg cells from healthy WT mice but not IL-10 deficient mice downregulated the IFN-γ secretion in CD4+ T cells and conferred protection against severe endotoxic shock in vivo. Our findings demonstrate the change and notable therapeutic potential of IL-10-producing Breg cells in endotoxic shock.

TOLL LIKE RECEPTOR TYPE FOUR GENE POLYMORPHISM IN NEONATAL SEPSIS IN ZAGAZIG UNIVERSITY CHILDREN’S HOSPITAL

Introduction: The immune response constitutes the first-line defense against microbial infections. Toll like receptors (TLRs) play a fundamental role in neonatal innate immunity, and one of them, toll like receptor 4 (TLR4) is considered a major pattern recognition receptor (PRR) in recognizing lipopolysaccharide (LPS) of gram-negative bacteria. Single nucleotide polymorphisms (SNPs) among various TLR genes have been identified and maybe related to susceptibility/resistance to certain infections and other inflammatory diseases.Objective: The purpose of this study was to find a relation between sepsis-related outcomes in neonates and TLR4 Asp299Gly gene polymorphism.Method: we carried out a case control study on 72 neonates. 36 neonates with culture proven gram-negative sepsis and 36 neonates as controls. Both groups were genotyped for TLR4 Asp299Gly gene polymorphism, by polymerase chain reaction (PCR), and restriction fragment length polymorphism analysis (RFLP) by using BccI enzyme.Results: No statistically significant association between TLR4 Asp299Gly gene polymorphism and severity of neonatal sepsis (P>.99).Conclusion: TLR4 Asp299Gly gene polymorphism is not associated with increased severity of gram-negative bacterial sepsis in neonates.

Drug repositioning of TANK-binding kinase 1 inhibitor CYT387 as an alternative for the treatment of Gram-negative bacterial sepsis

There is currently no specific drug for the treatment of sepsis and antibiotic administration is considered the best option, despite numerous issues. Therefore, the development of drugs to control the pathogen-induced inflammatory responses associated with sepsis is essential. To address this, our study examined the transcriptomes of lipopolysaccharide (LPS)-induced dendritic cells (DCs), identifying TANK-binding kinase1 (Tbk1) as a key factor involved in the inflammatory response. These data suggested drug repositioning of the Tbk1 inhibitor CYT387, currently used for the treatment of myelofibrosis and some cancers, as a candidate for regulating the LPS-induced inflammatory response. CYT387 also inhibited pro-inflammatory cytokine and surface molecule expression by mature DCs after LPS exposure. These effects correlated with both Akt phosphorylation and IκBα degradation. Finally, CYT387 demonstrated therapeutic effects in LPS-induced endotoxemia and Escherichia coli K1-induced mouse models of sepsis and decreased the expression of pro-inflammatory cytokines. In conclusion, our study suggests that drug repositioning of CYT387 may serve as a potential therapeutic for sepsis.

Novel Chitohexaose Analog Protects Young and Aged mice from CLP Induced Polymicrobial Sepsis

In Gram-negative bacterial sepsis, production of excess pro-inflammatory cytokines results in hyperinflammation and tissue injury. Anti-inflammatory cytokines such as IL-10 inhibit inflammation and enhance tissue healing. Here, we report a novel approach to treat septicemia associated with intra-abdominal infection in a murine model by delicately balancing pro- and anti-inflammatory cytokines. A novel oligosaccharide compound AVR-25 selectively binds to the TLR4 protein (IC50 = 0.15 µM) in human peripheral blood monocytes and stimulates IL-10 production. Following the cecal ligation and puncture (CLP) procedure, intravenous dosing of AVR-25 (10 mg/kg, 6–12 h post-CLP) alone and in combination with antibiotic imipenem protected both young adult (10–12 week old) and aged (16–18 month old) mice against polymicrobial infection, organ dysfunction, and death. Proinflammatory cytokines (TNF-α, MIP-1, i-NOS) were decreased significantly and restoration of tissue damage was observed in all organs. A decrease in serum C-reactive protein (CRP) and bacterial colony forming unit (CFU) confirmed improved bacterial clearance. Together, these findings demonstrate the therapeutic ability of AVR-25 to mitigate the storm of inflammation and minimize tissue injury with high potential for adjunctive therapy in intra-abdominal sepsis.

Increased TLR4 Expression Aggravates Sepsis by Promoting IFN-γ Expression in CD38-/- Mice.

Gram-negative bacterial sepsis accounts for up to 50% worldwide sepsis that causes hospital mortality. Acute kidney injury (AKI), a common complication of Gram-negative bacterial sepsis, is caused by Toll-like receptor 4 (TLR4) activation. Lipopolysaccharide (LPS) is an endotoxin in Gram-negative bacteria and is recognized specifically by TLR4, which initiates innate immune response. Also, TLR4 signaling pathway activation is essential in response to LPS infection. CD38 is one of the well-known regulators of innate immunity, whose dysregulation contributes to sepsis. Many studies have proven that an attenuated Gram-positive bacterium induces sepsis in a CD38-blocking model. However, the pathogenesis of Gram-negative bacteria-induced sepsis in a CD38−/− mouse model remains unclear. The aim of this study is to investigate whether kidney injury is still attenuated in a LPS-induced CD38−/− sepsis model and identify the potential mechanism. We assess the severity of kidney injury related to proinflammatory cytokine expressions (IFN-γ, TNF-α, IL-1β, and IL-6) in WT and CD38−/− mice. Our results showed more aggravated kidney damage in CD38−/− mice than in WT mice, accompanied with an increase of proinflammatory cytokine expression. In addition, compared with CD38−/−TLR4mut mice, we found an increase of TLR4 expression and mRNA expression of these cytokines in the kidney of CD38−/− mice, although only increased IFN-γ level was detected in the serum. Taken together, these results demonstrated that an increased TLR4 expression in CD38−/− mice could contribute to the aggravation of AKI through boosting of the production of IFN-γ.

Evaluation of Procalcitonin Accuracy for the Distinction Between Gram-Negative and Gram-Positive Bacterial Sepsis in Burn Patients.

Sepsis is the main cause of death in burns. Early institution of antimicrobial therapy is crucial to optimize outcomes but superfluous therapy increases adverse events, microbial resistance, and costs. Blood cultures are the gold standard for diagnosis but can take 48 to 72 hours. Biomarkers are used to help sepsis diagnosis and distinction between Gram-negative and Gram-positive bacterial cause. The aim of this work is to evaluate procalcitonin (PCT) accuracy for this distinction in burn patients. Retrospective observational study of adult septic burn patients with ≥15% total burn surface area admitted from January 2011 to December 2014 at a Burn Unit in Portugal. A statistical analysis was done, evaluating the correlation between PCT levels on the day of the first positive blood culture and microbiological data for Gram-negative and Grand-positive bacteria. Patients with mixed bacterial and/or fungal blood cultures were excluded. Data were summarized by quartiles statistics. Blood cultures were positive in 189 patients: 75 (39.7%) showed growth for Gram-negative and 114 (60.3%) for Gram-positive bacteria. Patients with Gram-negative bacteria have significantly higher PCT levels. Receiver operating characteristic curve analysis showed accuracy for Gram-negative discrimination with area under the curve = 0.687. Most elevated levels were related to nonfermentative Gram-negative bacteria and by Klebsiella pneumoniae and other Enterobacteriaceae. PCT levels were significantly higher in burn patients with Gram-negative sepsis comparing to patients with Gram-positive sepsis and controls. The determination of PCT levels may help the choice of empirical antimicrobial therapy while microbiological culture results are not available, despite not fully ensuring the desirable degree of precision.

The oxidized phospholipid oxPAPC ameliorates septic shock by targeting the non-canonical inflammasome in macrophages

Abstract Inflammasomes are signaling complexes that link the recognition of pathogen and danger associated molecular patterns (PAMPs and DAMPs) by cytosolic pattern-recognition receptors (PPRs) to the activation of Caspase-1, leading to the release of the pro-inflammatory cytokines interleukin (IL)-1β and IL-18, and the induction of pyroptosis. In addition to the canonical inflammasome activation by Caspase-1, other inflammatory caspases including murine Caspase-11 and its human orthologs Caspase-4 and Caspase-5 participate in the non-canonical pathway in response to intracellular LPS and Gram negative bacteria escaping the phagosomes, resulting in pyroptotic cell death as well as NLRP3 inflammasome-dependent cytokine release. Contrary to the highly regulated multiprotein platform required for Caspase-1 activation in the canonical inflammasomes, non-canonical inflammatory caspases are directly activated by binding to LPS thus simultaneously act as innate sensors and effectors. It is still largely unknown how the activity of these caspases is regulated. Here we identified the oxidized phospholipid 1-Palmitoyl-2-arachidonoyl-sn- glycero-3-phosphorylcholine (oxPAPC) as a negative regulator of the non-canonical inflammasome in macrophages. In addition to its previously reported TLR4 antagonistic role, oxPAPC directly binds to Caspase-4 and Caspase-11, competes with LPS binding and consequently, inhibits LPS-induced pyroptosis, IL-1β release and septic shock in vivo. Therefore, oxPAPC and its derivatives could provide a basis for novel therapies targeting non-canonical inflammasomes during Gram-negative bacterial sepsis.

The oxidized phospholipid oxPAPC protects from septic shock by targeting the non-canonical inflammasome in macrophages

Lipopolysaccharide (LPS) of Gram-negative bacteria can elicit a strong immune response. Although extracellular LPS is sensed by TLR4 at the cell surface and triggers a transcriptional response, cytosolic LPS binds and activates non-canonical inflammasome caspases, resulting in pyroptotic cell death, as well as canonical NLRP3 inflammasome-dependent cytokine release. Contrary to the highly regulated multiprotein platform required for caspase-1 activation in the canonical inflammasomes, the non-canonical mouse caspase-11 and the orthologous human caspase-4 function simultaneously as innate sensors and effectors, and their regulation is unclear. Here we show that the oxidized phospholipid 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (oxPAPC) inhibits the non-canonical inflammasome in macrophages, but not in dendritic cells. Aside from a TLR4 antagonistic role, oxPAPC binds directly to caspase-4 and caspase-11, competes with LPS binding, and consequently inhibits LPS-induced pyroptosis, IL-1β release and septic shock. Therefore, oxPAPC and its derivatives might provide a basis for therapies that target non-canonical inflammasomes during Gram-negative bacterial sepsis.

O-2 Population and developmental pharmacokinetic analysis to evaluate and optimise cefotaxime dosing regimen in neonates and young infants

Background Cefotaxime is one of the most frequently prescribed antibiotics for the treatment of Gram-negative bacterial sepsis in neonates. However, the dosing regi-mens routinely used in clinical practice vary considerably. The objective of the present study was to conduct a population pharmacokinetic study of cefotaxime in neonates and young infants in order to evaluate and optimise the dosing regimen. Methods An opportunistic sampling strategy com-bined with population pharmacokinetic analysis using NONMEM software was performed. Cefotaxime concentrations were measured by high-performance liquid chromatography tandem mass spectrometry. Developmental pharmacokinetics-pharmacodynamics, the microbiological pathogens, and safety aspects were taken into account to optimise the dose. Results The pharmacokinetic data from 100 neonates (gestational age [GA] range, 23 to 42 weeks) were modeled with an allometric two compartment model with first-order elimination. The median values for clearance and volume of distribution at steady state were 0.12 litre/h/kg of body weight and 0.64 litre/kg, respectively. The covariate analysis showed that current weight, GA, and postnatal age [PNA] had significant impacts on ce-fotaxime pharmacokinetics. Monte Carlo simulations demonstrated that the current dose recommendations underdosed the older newborns. A model-based dosing regimen of 50 mg/kg twice a day to four times a day, according to GA and PNA, was established. The associated risk of overdose for the proposed dosing regimen was 0.01%. Conclusion We determined the population pharma cokinetics of cefotaxime and established a model based dosing regimen to optimise treatment for neonates and young infants.

High Efficiency Binding Aptamers for a Wide Range of Bacterial Sepsis Agents.

Sepsis is a major health problem worldwide, with an extremely high rate of morbidity and mortality, partly due to delayed diagnosis during early disease. Currently, sepsis diagnosis requires bacterial culturing of blood samples over several days, whereas PCR-based molecular diagnosis methods are faster but lack sensitivity. The use of biosensors containing nucleic acid aptamers that bind targets with high affinity and specificity could accelerate sepsis diagnosis. Previously, we used the systematic evolution of ligands by exponential enrichment technique to develop the aptamers Antibac1 and Antibac2, targeting the ubiquitous bacterial peptidoglycan. Here, we show that these aptamers bind to four gram-positive and seven gram-negative bacterial sepsis agents with high binding efficiency. Thus, these aptamers could be used in combination as biological recognition elements in the development of biosensors that are an alternative to rapid bacteria detection, since they could provide culture and amplification-free tests for rapid clinical sepsis diagnosis.

A Population and Developmental Pharmacokinetic Analysis To Evaluate and Optimize Cefotaxime Dosing Regimen in Neonates and Young Infants.

Cefotaxime is one of the most frequently prescribed antibiotics for the treatment of Gram-negative bacterial sepsis in neonates. However, the dosing regimens routinely used in clinical practice vary considerably. The objective of the present study was to conduct a population pharmacokinetic study of cefotaxime in neonates and young infants in order to evaluate and optimize the dosing regimen. An opportunistic sampling strategy combined with population pharmacokinetic analysis using NONMEM software was performed. Cefotaxime concentrations were measured by high-performance liquid chromatography-tandem mass spectrometry. Developmental pharmacokinetics-pharmacodynamics, the microbiological pathogens, and safety aspects were taken into account to optimize the dose. The pharmacokinetic data from 100 neonates (gestational age [GA] range, 23 to 42 weeks) were modeled with an allometric two-compartment model with first-order elimination. The median values for clearance and the volume of distribution at steady state were 0.12 liter/h/kg of body weight and 0.64 liter/kg, respectively. The covariate analysis showed that current weight, GA, and postnatal age (PNA) had significant impacts on cefotaxime pharmacokinetics. Monte Carlo simulations demonstrated that the current dose recommendations underdosed older newborns. A model-based dosing regimen of 50 mg/kg twice a day to four times a day, according to GA and PNA, was established. The associated risk of overdose for the proposed dosing regimen was 0.01%. We determined the population pharmacokinetics of cefotaxime and established a model-based dosing regimen to optimize treatment for neonates and young infants.

Clinical Features Before Hematopoietic Stem Cell Transplantation or Enzyme Replacement Therapy of Children With Combined Immunodeficiency.

Survival of children with combined immunodeficiency is strongly related to patient's age and clinical situation at the time of hematopoietic stem cell transplantation (HSCT). We describe the clinical features before HSCT or enzyme replacement therapy (ERT) in a cohort of children treated in a National Reference Unit. A retrospective study of children with CIDs treated in our Hospital during a 20-year period (1995-2014) was performed, analyzing their clinical situation before HSCT/ERT. Thirty-one children were included. Risk factors such as family history or consanguinity were present in 35% of cases, but only 3 children (9%) were initially studied because of family history. Median ages at clinical onset, diagnosis and HSCT/ERT were 3.3, 5.6 and 8.1 months, respectively. All patients had lymphopenia before HSCT/ERT. At the time of admission to our unit, 68% of cases had abnormal lung auscultation, 72% were malnourished, 45% reported chronic gastroenteritis and 35% had hepatosplenomegaly. Before HSCT/ERT, respiratory infections and sepsis episodes were documented in 80% and 42% of cases, respectively. In 23% of children, a viral systemic infection was confirmed. The mortality rate was 35%, and 72% of children who died had Gram-negative bacterial sepsis or a viral infection. The present study shows the characteristics and outcome of children with CIDs in the absence of neonatal screening. Although all our patients had lymphopenia and most of them had suffered relevant infections or had a positive family history, these factors were not identified early. Respiratory and systemic viral infections were the main source of infection with important implications in clinical outcome. Our results highlight the importance of the implementation of neonatal screening, to improve survival rates.

Autophagy Limits Endotoxemic Acute Kidney Injury and Alters Renal Tubular Epithelial Cell Cytokine Expression.

Sepsis related acute kidney injury (AKI) is a common in-hospital complication with a dismal prognosis. Our incomplete understanding of disease pathogenesis has prevented the identification of hypothesis-driven preventive or therapeutic interventions. Increasing evidence in ischemia-reperfusion and nephrotoxic mouse models of AKI support the theory that autophagy protects renal tubular epithelial cells (RTEC) from injury. However, the role of RTEC autophagy in septic AKI remains unclear. We observed that lipopolysaccharide (LPS), a mediator of gram-negative bacterial sepsis, induces RTEC autophagy in vivo and in vitro through TLR4-initiated signaling. We modeled septic AKI through intraperitoneal LPS injection in mice in which autophagy-related protein 7 was specifically knocked out in the renal proximal tubules (ATG7KO). Compared to control littermates, ATG7KO mice developed more severe renal dysfunction (24hr BUN 100.1mg/dl +/- 14.8 vs 54.6mg/dl +/- 11.3) and parenchymal injury. After injection with LPS, analysis of kidney lysates identified higher IL-6 expression and increased STAT3 activation in kidney lysates from ATG7KO mice compared to controls. In vitro experiments confirmed an altered response to LPS in RTEC with genetic or pharmacological impairment of autophagy. In conclusion, RTEC autophagy protects against endotoxin induced injury and regulates downstream effects of RTEC TLR4 signaling.

A retrospective comparative study to evaluate the use of a new beta-lactam + beta-lactamase inhibitor (ceftriaxone + sulbactam + disodium edetate) in comparison to meropenem in the management of gram-negative bacterial sepsis

Introduction and Objective: Gram-negative bacterial sepsis and anti-microbial resistance are global health concerns. The present study is a comparative retrospective analysis of the outcome of two antibacterial therapies (Ceftriaxone + Sulbactam + adjuvant Disodium edetate [FDC] and Meropenem) used for management of patients suffering from gram-negative bacterial sepsis. Materials and Methods: Both the therapies (FDC or Meropenem) were initiated empirically on the basis of clinical presentation of the patients and treating physician's decision and continued based on the results of the in vitro microbiological susceptibility testing pattern and clinical outcome. Results: 70 patients with known Gram-negative bacterial infections showing sensitivity to FDC and Meropenem were included in the study. Fifty-seven (81.42%) out of 70 cultures isolated from the patients showed susceptibility towards FDC, whereas the isolates showed comparatively lower susceptibility (45 [64.28%]) towards Meropenem. Twenty (54.05%) out of 37 patients treated with FDC were cured, while the remaining patients achieved clinical success with FDC + Colistin combination therapy. On the other hand, only 11 (33.33%) out of 33 patients to whom Meropenem was given empirically were cured, and the remaining 22 patients required Meropenem and Colistin combination therapy to achieve clinical cure. Conclusion: This new FDC exhibits better antimicrobial susceptibility than Meropenem and a better efficacy in gram-negative sepsis management. This new FDC in combination with Colistin can be used to treat severe sepsis patients, which often fails to respond to monotherapy. This new FDC and Colistin can be an effective alternate therapy to Meropenem and Colistin.

Serum procalcitonin levels distinguish Gram-negative bacterial sepsis from Gram-positive bacterial and fungal sepsis.

Background:Serum procalcitonin (PCT) levels differ in patients with bacterial or fungal infections and are significantly elevated in patients with Gram-negative bacteremia. We evaluated the diagnostic accuracy of different inflammatory markers to discriminate sepsis caused by different pathogens.Materials and Methods:We included 328 episodes of bacteremia from 292 patients with sepsis and 31 patients with suspected sepsis in this study. Medical records of patients who had bacteremia caused by Gram-negative bacteria (Gram-negative), Gram-positive bacteria (Gram-positive) or fungi were reviewed, and information about PCT and other inflammatory markers was recorded. The diagnostic performance of inflammatory markers was calculated via receiver operating characteristic (ROC) curves.Results:Serum PCT levels in Gram-negative, Gram-positive, and fungal sepsis were 7.47 (interquartile range [IQR]: 1.09–41.26) ng/mL, 0.48 (IQR: 0.15–2.16) ng/mL, and 0.60 (IQR: 0.14–2.06) ng/mL, respectively (P < 0.001). ROC analysis revealed an optimal cut-off value of 2.44 ng/mL for PCT in discriminating Gram-negative sepsis from Gram-positive sepsis, which yielded a sensitivity of 68.4% and a specificity of 77.1%. An optimal cut-off value of 3.11 ng/mL for PCT in discriminating Gram-negative sepsis from fungal sepsis, led to a sensitivity of 63.9% and specificity of 93.3%. Neither PCT nor other inflammatory markers could be used to distinguish between Gram-positive and fungal sepsis.Conclusion:Serum PCT levels were significantly higher in patients with Gram-negative sepsis than in those with Gram-positive or fungal sepsis. PCT is a potential sensitive biomarker for distinguishing Gram-negative sepsis from Gram-positive and fungal sepsis.

Soluble Heparan Sulfate in Serum of Septic Shock Patients Induces Mitochondrial Dysfunction in Murine Cardiomyocytes.

The heart is one of the most frequently affected organs in sepsis. Recent studies focused on lipopolysaccharide-induced mitochondrial dysfunction; however myocardial dysfunction is not restricted to gram-negative bacterial sepsis. The purpose of this study was to investigate circulating heparan sulfate (HS) as an endogenous danger associated molecule causing cardiac mitochondrial dysfunction in sepsis. We used an in vitro model with native sera (SsP) and sera eliminated from HS (HS-free), both of septic shock patients, to stimulate murine cardiomyocytes. As determined by extracellular flux analyzing, SsP increased basal mitochondrial respiration, but reduced maximum mitochondrial respiration, compared with unstimulated cells (P < 0.0001 and P < 0.0001, respectively). Cells stimulated with HS-free serum revealed unaltered basal and maximum mitochondrial respiration, compared with unstimulated cells (P = 0.1174 and P = 0.8992, respectively). Cellular ATP-level were decreased in SsP-stimulated cells but unaltered in cells stimulated with HS-free serum compared with unstimulated cells (P < 0.0001 and P = 0.1593, respectively). Live-cell imaging revealed an increased production of mitochondrial reactive oxygen species in cells stimulated with SsP compared with cells stimulated with HS-free serum (P < 0.0001). Expression of peroxisome proliferator-activated receptors (PPARα and PPARγ) and their co-activators PGC-1α, which regulate mitochondrial function, were studied using PCR. Cells stimulated with SsP showed downregulated PPARs and PGC-1α mRNA-levels compared with HS-free serum (P = 0.0082, P = 0.0128, and P = 0.0185, respectively). Blocking Toll-like receptor 4 revealed an inhibition of HS-dependent downregulation of PPARs and PGC-1α (all P < 0.0001). In conclusion, circulating HS in serum of septic shock patients cause cardiac mitochondrial dysfunction, suggesting that HS may be targets of therapeutics in septic cardiomyopathy.

Diagnostic and prognostic roles of soluble CD22 in patients with Gram-negative bacterial sepsis

Soluble CD22 (sCD22) is a fragment of CD22, a B cell-specific membrane protein that negatively regulates B-cell receptor signaling. To date, sCD22 has only been regarded as a tumor marker of B-cell malignancies. Its expression in infectious diseases has not yet been assessed. Serum concentrations of sCD22, procalcitonin (PCT) and interleukin-6 (IL-6) were measured by enzyme-linked immunosorbent assays in patients with intra-abdominal Gram-negative bacterial infection. Receiver operating characteristic curve analysis was performed to evaluate the diagnostic accuracy of these biomarkers in this type of infection. The correlations between biomarkers and the Acute Physiology and Chronic Health Evaluation (APACHE) II scores were also analyzed. Concentrations of sCD22 were significantly elevated in patients with sepsis and the elevation is correlated with the severity of sepsis. sCD22 was also slightly elevated in patients with non-infected systemic inflammatory response syndrome or local infection. The diagnostic accuracy of sCD22 for sepsis was equivalent to that of PCT or IL-6. In addition, the correlation of sCD22 with APACHE II scores was stronger than that of PCT or IL-6. Serum sCD22 is a novel inflammatory mediator released during infection. This soluble biomarker plays a potential role in the diagnosis of Gram-negative bacterial sepsis, with a diagnostic accuracy as efficient as that of PCT or IL-6. Furthermore, sCD22 is more valuable to predict the outcomes in patients with sepsis than PCT or IL-6. The present study suggested that sCD22 might be potentially useful in supplementing current criteria for sepsis.

Detecting endotoxin activity in raw milk using an automated testing system

Gram-negative bacteria are among the most common environmental pathogens causing mastitis. Endotoxin plays a major role in the pathophysiology of gram-negative bacterial sepsis; therefore, attempts have been made to detect and quantify it, with conflicting findings, in various states of infection. The simple and easy portable test system (PTS) for endotoxin activity offers several advantages over the traditional microplate kinetic limulus amebocyte lysate (LAL)-based test used by diagnostic laboratories. It is small, inexpensive and portable, requires only small quantities of raw milk, and provides results relatively rapidly in comparison to traditional methods. Thus the portability and ready availability of this cartridge system adds to its attractiveness for use in acute coliform mastitis (ACM). However, since the results obtained using this portable test will often dictate the course of clinical care and hygiene management, it is important that the cartridge system provides accurate information. The aim of the present study was to compare endotoxin activities detected in raw milk samples obtained from healthy dairy cattle without mastitis by a commercially available PTS™ and traditional microplate LAL-based assay, which determined activities using a kinetic turbidimetric (KT) assay.