Short-chain fatty acids inhibit bacterial plasmid transfer through conjugation in vitro and in ex vivo chicken tissue explants

The animal gut acts as a potent reservoir for spreading and maintaining conjugative plasmids that confer antimicrobial resistance (AMR), fitness, and virulence attributes. Interventions that inhibit the continued emergence and expansion of AMR and virulent strains in agricultural and clinical environments are greatly desired. This study aims to determine the presence and efficacy of short-chain fatty acids (SCFA) inhibitory effects on the conjugal transfer of AMR plasmids. In vitro broth conjugations were conducted between donor Escherichia coli strains carrying AMP plasmids and the plasmid-less Escherichia coli HS-4 recipient strain. Conjugations were supplemented with ddH2O or SCFAs at 1, 0.1, 0.01, or 0.001 molar final concentration. The addition of SCFAs completely inhibited plasmid transfer at 1 and 0.1 molar and significantly (p < 0.05) reduced transfer at 0.01 molar, regardless of SCFA tested. In explant models for the chicken ceca, either ddH2O or a final concentration of 0.025 M SCFAs were supplemented to the explants infected with donor and recipient E. coli. In every SCFA tested, significant decreases in transconjugant populations compared to ddH2O-treated control samples were observed with minimal effects on donor and recipient populations. Finally, significant reductions in transconjugants for plasmids of each incompatibility type (IncP1ε, IncFIβ, and IncI1) tested were detected. This study demonstrates for the first time the broad inhibition ability of SCFAs on bacterial plasmid transfer and eliminates AMR with minimal effect on bacteria. Implementing interventions that increase the concentrations of SCFAs in the gut may be a viable method to reduce the risk, incidence, and rate of AMR emergence in agricultural and human environments.

Inflammaging in Multidrug-Resistant Sepsis of Geriatric ICU Patients and Healthcare Challenges

Multidrug-resistant sepsis (MDR) is a pressing concern in intensive care unit (ICU) settings, specifically among geriatric patients who experience age-related immune system changes and comorbidities. The aim of this review is to explore the clinical impact of MDR sepsis in geriatric ICU patients and shed light on healthcare challenges associated with its management. We conducted a comprehensive literature search using the National Center for Biotechnology Information (NCBI) and Google Scholar search engines. Our search incorporated keywords such as "multidrug-resistant sepsis" OR "MDR sepsis", "geriatric ICU patients" OR "elderly ICU patients", and "complications", "healthcare burdens", "diagnostic challenges", and "healthcare challenges" associated with MDR sepsis in "ICU patients" and "geriatric/elderly ICU patients". This review explores the specific risk factors contributing to MDR sepsis, the complexities of diagnostic challenges, and the healthcare burden faced by elderly ICU patients. Notably, the elderly population bears a higher burden of MDR sepsis (57.5%), influenced by various factors, including comorbidities, immunosuppression, age-related immune changes, and resource-limited ICU settings. Furthermore, sepsis imposes a significant economic burden on healthcare systems, with annual costs exceeding $27 billion in the USA. These findings underscore the urgency of addressing MDR sepsis in geriatric ICU patients and the need for tailored interventions to improve outcomes and reduce healthcare costs.

Multidrug-Resistant Sepsis: A Critical Healthcare Challenge

Sepsis globally accounts for an alarming annual toll of 48.9 million cases, resulting in 11 million deaths, and inflicts an economic burden of approximately USD 38 billion on the United States healthcare system. The rise of multidrug-resistant organisms (MDROs) has elevated the urgency surrounding the management of multidrug-resistant (MDR) sepsis, evolving into a critical global health concern. This review aims to provide a comprehensive overview of the current epidemiology of (MDR) sepsis and its associated healthcare challenges, particularly in critically ill hospitalized patients. Highlighted findings demonstrated the complex nature of (MDR) sepsis pathophysiology and the resulting immune responses, which significantly hinder sepsis treatment. Studies also revealed that aging, antibiotic overuse or abuse, inadequate empiric antibiotic therapy, and underlying comorbidities contribute significantly to recurrent sepsis, thereby leading to septic shock, multi-organ failure, and ultimately immune paralysis, which all contribute to high mortality rates among sepsis patients. Moreover, studies confirmed a correlation between elevated readmission rates and an increased risk of cognitive and organ dysfunction among sepsis patients, amplifying hospital-associated costs. To mitigate the impact of sepsis burden, researchers have directed their efforts towards innovative diagnostic methods like point-of-care testing (POCT) devices for rapid, accurate, and particularly bedside detection of sepsis; however, these methods are currently limited to detecting only a few resistance biomarkers, thus warranting further exploration. Numerous interventions have also been introduced to treat MDR sepsis, including combination therapy with antibiotics from two different classes and precision therapy, which involves personalized treatment strategies tailored to individual needs. Finally, addressing MDR-associated healthcare challenges at regional levels based on local pathogen resistance patterns emerges as a critical strategy for effective sepsis treatment and minimizing adverse effects.

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.

Conserved Bacterial-Binding Peptides of the Scavenger-Like Human Lymphocyte Receptor CD6 Protect From Mouse Experimental Sepsis

Sepsis is an unmet clinical need constituting one of the most important causes of death worldwide, a fact aggravated by the appearance of multidrug resistant strains due to indiscriminate use of antibiotics. Host innate immune receptors involved in pathogen-associated molecular patterns (PAMPs) recognition represent a source of broad-spectrum therapies alternative or adjunctive to antibiotics. Among the few members of the ancient and highly conserved scavenger receptor cysteine-rich superfamily (SRCR-SF) sharing bacterial-binding properties there is CD6, a lymphocyte-specific surface receptor. Here, we analyze the bacterial-binding properties of three conserved short peptides (11-mer) mapping at extracellular SRCR domains of human CD6 (CD6.PD1, GTVEVRLEASW; CD6.PD2 GRVEMLEHGEW; and CD6.PD3, GQVEVHFRGVW). All peptides show high binding affinity for PAMPs from Gram-negative (lipopolysaccharide; K_d from 3.5 to 3,000 nM) and Gram-positive (lipoteichoic acid; K_d from 36 to 680 nM) bacteria. The CD6.PD3 peptide possesses broad bacterial-agglutination properties and improved survival of mice undergoing polymicrobial sepsis in a dose- and time-dependent manner. Accordingly, CD6.PD3 triggers a decrease in serum levels of both pro-inflammatory cytokines and bacterial load. Interestingly, CD6.PD3 shows additive survival effects on septic mice when combined with Imipenem/Cilastatin. These results illustrate the therapeutic potential of peptides retaining the bacterial-binding properties of native CD6.

Anti-inflammatory Properties of Antimicrobial Peptides and Peptidomimetics: LPS and LTA Neutralization

Lipopolysaccharide (LPS) and lipoteichoic acid (LTA) neutralization constitute potential non-antibiotic treatment strategies for sepsis - a systemic infection-induced inflammatory response. Studies on LPS- and LTA-neutralizing compounds are abundant in literature, and a number of peptides and peptidomimetics appear to display promising activity. However, in this ongoing search for potential antisepsis drug leads, it will be preferable that the assays used by different research groups lead to readily comparable data for the most efficient compounds. Here, we propose and describe standardized methods to be used for testing of novel compounds for their LPS- and LTA-neutralizing capacity with a focus on functional suppression of pro-inflammatory responses in cell-based systems. To best mimic the human in vivo conditions, we suggest the use of freshly isolated human leukocytes combined with an appropriate method for the chosen cytokine (e.g., IL-6 or TNF-α). The described protocols comprise isolation, stimulation, and viability test of the human leukocytes.

Protective Effects of Human and Mouse Soluble Scavenger-Like CD6 Lymphocyte Receptor in a Lethal Model of Polymicrobial Sepsis

Sepsis still constitutes an unmet clinical need, which could benefit from novel adjunctive strategies to conventional antibiotic therapy. The soluble form of the scavenger-like human CD6 lymphocyte receptor (shCD6) binds to key pathogenic components from Gram-positive and -negative bacteria and shows time- and dose-dependent efficacy in mouse models of monobacterial sepsis. The objective of the present work was to demonstrate the effectiveness of infusing mouse and human sCD6 by different systemic routes, either alone or as adjunctive therapy to gold standard antibiotics, in a lethal model of polymicrobial sepsis. To this end, C57BL/6 mice undergoing high-grade septic shock induced by cecal ligation and puncture (CLP; ≥90% lethality) were infused via the intraperitoneal (i.p.) or intravenous (i.v.) route with shCD6 at different doses and time points, either alone or in combination with imipenem/cilastatin (I/C) at a dose of 33 mg/kg of body weight every 8 h. Significantly reduced mortality and proinflammatory cytokine levels were observed by i.p. infusion of a single shCD6 dose (1.25 mg/kg) 1 h pre- or post-CLP. When using the i.v. route, mice survival was significantly extended by starting shCD6 infusion at later time points post-CLP (up to 6 h after CLP). Significant adjunctive effects on mouse survival were observed by i.p. or i.v. infusion of shCD6 in combination with i.p. I/C post-CLP. Similar results were obtained in mice expressing high sustained levels (5 to 10 μg/ml) of mouse sCD6 in serum by means of transduction with hepatotropic adeno-associated virus (AAV). Taken together, the data support the conserved antibacterial effects of human and mouse sCD6 and their use as adjunctive therapy in experimental models of complex and severe polymicrobial sepsis.

Similarly Lethal Strains of Extraintestinal Pathogenic Escherichia coli Trigger Markedly Diverse Host Responses in a Zebrafish Model of Sepsis

In individuals with sepsis, the infecting microbes are commonly viewed as generic inducers of inflammation while the host background is considered the primary variable affecting disease progression and outcome. To study the effects of bacterial strain differences on the maladaptive immune responses that are induced during sepsis, we employed a novel zebrafish embryo infection model using extraintestinal pathogenic Escherichia coli (ExPEC) isolates. These genetically diverse pathogens are a leading cause of sepsis and are becoming increasingly dangerous because of the rise of multidrug-resistant strains. Zebrafish infected with ExPEC isolates exhibit many of the pathophysiological features seen in septic human patients, including dysregulated inflammatory responses (cytokine storms), tachycardia, endothelial leakage, and progressive edema. However, only a limited subset of ExPEC isolates can trigger a sepsis-like state and death of the host when introduced into the bloodstream. Mirroring the situation in human patients, antibiotic therapy reduced ExPEC titers and improved host survival rates but was only effective within limited time frames that varied, depending on the infecting pathogen. Intriguingly, we find that phylogenetically distant but similarly lethal ExPEC isolates can stimulate markedly different host transcriptional responses, including disparate levels of inflammatory mediators. These differences correlate with the amounts of bacterial flagellin expression during infection, as well as differential activation of Toll-like receptor 5 by discrete flagellar serotypes. Altogether, this work establishes zebrafish as a relevant model of key aspects of human sepsis and highlights the ability of genetically distinct ExPEC isolates to induce divergent host responses independently of baseline host attributes. IMPORTANCE Sepsis is a life-threatening systemic inflammatory condition that is initiated by the presence of microorganisms in the bloodstream. In the United States, sepsis due to ExPEC and other pathogens kills well over a quarter of a million people each year and is associated with tremendous health care costs. A high degree of heterogeneity in the signs and symptomology of sepsis makes this disease notoriously difficult to effectively diagnose and manage. Here, using a zebrafish model of sepsis, we find that similarly lethal but genetically distinct ExPEC isolates can elicit notably disparate host responses. These variances are in part due to differences in the levels and types of flagellin that are expressed by the infecting ExPEC strains. A better understanding of the variable impact that bacterial factors like flagellin have on host responses during sepsis could lead to improved diagnostic and therapeutic approaches to these often deadly infections. Podcast: A podcast concerning this article is available.

Therapeutical Administration of Peptide Pep19-2.5 and Ibuprofen Reduces Inflammation and Prevents Lethal Sepsis

Sepsis is still a major cause of death and many efforts have been made to improve the physical condition of sepsis patients and to reduce the high mortality rate associated with this disease. While achievements were implemented in the intensive care treatment, all attempts within the field of novel therapeutics have failed. As a consequence new medications and improved patient stratification as well as a thoughtful management of the support therapies are urgently needed. In this study, we investigated the simultaneous administration of ibuprofen as a commonly used nonsteroidal anti-inflammatory drug (NSAID) and Pep19-2.5 (Aspidasept), a newly developed antimicrobial peptide. Here, we show a synergistic therapeutic effect of combined Pep19-2.5-ibuprofen treatment in an endotoxemia mouse model of sepsis. In vivo protection correlates with a reduction in plasma levels of both tumor necrosis factor α and prostaglandin E, as a likely consequence of Pep19-2.5 and ibuprofen-dependent blockade of TLR4 and COX pro-inflammatory cascades, respectively. This finding is further characterised and confirmed in a transcriptome analysis of LPS-stimulated human monocytes. The transcriptome analyses showed that Pep19-2.5 and ibuprofen exerted a synergistic global effect both on the number of regulated genes as well as on associated gene ontology and pathway expression. Overall, ibuprofen potentiated the anti-inflammatory activity of Pep19-2.5 both in vivo and in vitro, suggesting that NSAIDs could be useful to supplement future anti-sepsis therapies.

Community-acquired pneumonia: identification and evaluation of nonresponders

Community acquired pneumonia (CAP) is a relevant public health problem, constituting an important cause of morbidity and mortality. It accounts for a significant number of adult hospital admissions and a large number of those patients ultimately die, especially the population who needed mechanical ventilation or vasopressor support. Thus, early identification of CAP patients and its rapid and appropriate treatment are important features with impact on hospital resource consumption and overall mortality. Although CAP diagnosis may sometimes be straightforward, the diagnostic criteria commonly used are highly sensitive but largely unspecific. Biomarkers and microbiological documentation may be useful but have important limitations. Evaluation of clinical response is also critical especially to identify patients who fail to respond to initial treatment since these patients have a high risk of in-hospital death. However, the criteria of definition of non-response in CAP are largely empirical and frequently markedly diverse between different studies. In this review, we aim to identify criteria defining nonresponse in CAP and the pitfalls associated with this diagnosis. We also aim to overview the main causes of treatment failure especially in severe CAP and the possible strategies to identify and reassess non-responders trying to change the dismal prognosis associated with this condition.

Risk factors for sepsis after percutaneous renal stone surgery

Since its introduction into the endourologist's armamentarium almost 40 years ago, percutaneous nephrolithotomy (PCNL) has become the standard of care for patients with large-volume nephrolithiasis. Postoperative infection is one of the most common complications of the procedure, and postoperative sepsis is one of the most detrimental. A number of factors have been found to increase the risk of postoperative sepsis. These include patient characteristics that are known preoperatively, such as urine culture obtained from the bladder or from the renal pelvis if percutaneous access to the renal pelvis is obtained in advance to the procedure. Neurogenic bladder dysfunction secondary to spinal cord injury and anatomical renal abnormalities, such as pelvicalyceal dilatation, have also been associated with increased incidence of fever and sepsis after the procedure. Several intraoperative factors, such as the average renal pressure sustained during PCNL and the operative time, also seem to increase the risk of sepsis. Finally, the contribution of postoperative factors, such as presence of a nephrostomy tube or a urethral catheter, has also been investigated. A short preoperative course of antibiotics has been found to significantly decrease the rate of postoperative fever and sepsis. Novel agents targeted at sepsis prevention and treatment, such as anti-endotoxin antibodies and cholesterol-lowering drugs statins, are currently under investigation.

Developing new antibacterials through natural product research

INTRODUCTION

Natural products have long been instrumental for discovering antibiotics, but many pharmaceutical companies abandoned this field and new antibiotics declined. In contrast, microbial resistance to current antibiotics has approached critical levels.

AREAS COVERED

This article gives historical perspectives by providing background about present-day economic realities and medical needs for antibiotic research, whose pipeline is mostly focused toward older known agents and newer semi-synthetic derivatives. Future research trends and projected technological developments open many innovative opportunities to discover novel antibacterials and find ways to control pathogenic bacteria without conventional antibiotics that provoke resistance.

EXPERT OPINION

The successful registration of daptomycin, retapamulin and fidaxomicin indicate the re-emergence of natural products has already begun. Semi-synthetic derivatives from other under-explored classes are progressing. More effort is being put into approaches such as total synthesis, discovery of new structural scaffolds for synthesis, alterations of biosynthetic pathways, combinatorial biosynthesis, new screening targets and new resources from which to isolate natural products. A return to successful screening of actinomycetes depends on solving the rate-limiting dereplication obstacle. Long-term solutions need to come from greater exploration of the massive numbers of uncultured microbes. An ultimate solution to the antibiotic-promoted microbial resistance cycle may lie in finding ways to control bacteria by non-lethal means.

Preclinical investigations reveal the broad-spectrum neutralizing activity of peptide Pep19-2.5 on bacterial pathogenicity factors

Bacterial infections are known to cause severe health-threatening conditions, including sepsis. All attempts to get this disease under control failed in the past, and especially in times of increasing antibiotic resistance, this leads to one of the most urgent medical challenges of our times. We designed a peptide to bind with high affinity to endotoxins, one of the most potent pathogenicity factors involved in triggering sepsis. The peptide Pep19-2.5 reveals high endotoxin neutralization efficiency in vitro, and here, we demonstrate its antiseptic/anti-inflammatory effects in vivo in the mouse models of endotoxemia, bacteremia, and cecal ligation and puncture, as well as in an ex vivo model of human tissue. Furthermore, we show that Pep19-2.5 can bind and neutralize not only endotoxins but also other bacterial pathogenicity factors, such as those from the Gram-positive bacterium Staphylococcus aureus. This broad neutralization efficiency and the additive action of the peptide with common antibiotics makes it an exceptionally appropriate drug candidate against bacterial sepsis and also offers multiple other medication opportunities.

Expression and subcellular targeting of human complement factor C5a in Nicotiana species

We evaluated transgenic tobacco plants as an alternative to Escherichia coli for the production of recombinant human complement factor 5a (C5a). C5a has not been expressed in plants before and is highly unstable in vivo in its native form, so it was necessary to establish the most suitable subcellular targeting strategy. We used the strong and constitutive CaMV 35S promoter to drive transgene expression and compared three different subcellular compartments. The yields of C5a in the T(0) transgenic plants were low in terms of the proportion of total soluble protein (TSP) when targeted to the apoplast (0.0002% TSP) or endoplasmic reticulum (0.0003% TSP) but was one order of magnitude higher when targeted to the vacuole (0.001% TSP). The yields could be increased by conventional breeding (up to 0.014% TSP in the T₂ generation). C5a accumulated to the same level in seeds and leaves when targeted to the apoplast but was up to 1.7-fold more abundant in the seeds when targeted to the ER or vacuole, although this difference was less striking in the better-performing lines. When yields were calculated as an amount per gram fresh weight of transgenic plant tissue, the vacuole targeting strategy was clearly more efficient in seeds, reaching 35.8 µg C5a per gram of fresh seed weight compared to 10.62 µg C5a per gram fresh weight of leaves. Transient expression of C5aER and C5aVac in N. benthamiana, using MagnICON vectors, reached up to 0.2% and 0.7% of TSP, respectively, but was accompanied by cytotoxic effects and induced leaf senescence. Western blot of the plant extracts revealed a band matching the corresponding glycosylated native protein and the bioassay demonstrated that recombinant C5a was biologically active.

Human recombinant protein C for severe sepsis and septic shock in adult and paediatric patients

BACKGROUND

Sepsis is a common and frequently fatal condition. Human recombinant activated protein C (APC) has been introduced to reduce the high risk of death associated with severe sepsis or septic shock. This systematic review is an update of a Cochrane review originally published in 2007.

OBJECTIVES

We assessed the benefits and harms of APC for patients with severe sepsis or septic shock.

SEARCH METHODS

We searched CENTRAL (The Cochrane Library 2012, Issue 6); MEDLINE (2010 to June 2012); EMBASE (2010 to June 2012); BIOSIS (1965 to June 2012); CINAHL (1982 to June 2012) and LILACS (1982 to June 2012). There was no language restriction.

SELECTION CRITERIA

We included randomized clinical trials assessing the effects of APC for severe sepsis or septic shock in adults and children. We excluded studies on neonates. We considered all-cause mortality at day 28 and at the end of study follow up, and hospital mortality as the primary outcomes.

DATA COLLECTION AND ANALYSIS

We independently performed trial selection, risk of bias assessment, and data extraction in duplicate. We estimated relative risks (RR) for dichotomous outcomes. We measured statistical heterogeneity using the I(2) statistic. We used a random-effects model.

MAIN RESULTS

We identified one new randomized clinical trial in this update which includes six randomized clinical trials involving 6781 participants in total, five randomized clinical trials in adult (N = 6307) and one randomized clinical trial in paediatric (N = 474) participants. All trials had high risk of bias and were sponsored by the pharmaceutical industry. APC compared with placebo did not significantly affect all-cause mortality at day 28 compared with placebo (780/3435 (22.7%) versus 767/3346 (22.9%); RR 1.00, 95% confidence interval (CI) 0.86 to 1.16; I(2) = 56%). APC did not significantly affect in-hospital mortality (393/1767 (22.2%) versus 379/1710 (22.1%); RR 1.01, 95% CI 0.87 to 1.16; I(2) = 20%). APC was associated with an increased risk of serious bleeding (113/3424 (3.3%) versus 74/3343 (2.2%); RR 1.45, 95% CI 1.08 to 1.94; I(2) = 0%). APC did not significantly affect serious adverse events (463/3334 (13.9%) versus 439/3302 (13.2%); RR 1.04, 95% CI 0.92 to 1.18; I(2) = 0%). Trial sequential analyses showed that more trials do not seem to be needed for reliable conclusions regarding these outcomes.

AUTHORS' CONCLUSIONS

This updated review found no evidence suggesting that APC should be used for treating patients with severe sepsis or septic shock. APC seems to be associated with a higher risk of bleeding. The drug company behind APC, Eli Lilly, has announced the discontinuation of all ongoing clinical trials using this drug for treating patients with severe sepsis or septic shock. APC should not be used for sepsis or septic shock outside randomized clinical trials.

The meningococcal adhesin NhhA provokes proinflammatory responses in macrophages via toll-like receptor 4-dependent and -independent pathways

Activation of macrophages by Toll-like receptors (TLRs) and functionally related proteins is essential for host defense and innate immunity. TLRs recognize a wide variety of pathogen-associated molecules. Here, we demonstrate that the meningococcal outer membrane protein NhhA has immunostimulatory functions and triggers release of proinflammatory cytokines from macrophages. NhhA-induced cytokine release was found to proceed via two distinct pathways in RAW 264.7 macrophages. Interleukin-6 (IL-6) secretion was dependent on activation of TLR4 and required the TLR signaling adaptor protein MyD88. In contrast, release of tumor necrosis factor (TNF) was TLR4 and MyD88 independent. Both pathways involved NF-κB-dependent gene regulation. Using a PCR-based screen, we could identify additional targets of NhhA-dependent gene activation such as the cytokines and growth factors IL-1α, IL-1β, granulocyte colony-stimulating factor (G-CSF), and granulocyte-macrophage colony-stimulating factor (GM-CSF). In human monocyte-derived macrophages, G-CSF, GM-CSF, and IL-6 were found to be major targets of NhhA-dependent gene regulation. NhhA induced transcription of IL-6 and G-CSF mRNA via TLR4-dependent pathways, whereas GM-CSF transcription was induced via TLR4-independent pathways. These data provide new insights into the role of NhhA in host-pathogen interaction.

Human recombinant activated protein C for severe sepsis

BACKGROUND

Sepsis is a common and frequently fatal condition. Human recombinant activated protein C (APC) has been used to reduce the high rate of death by severe sepsis or septic shock. This is an update of a Cochrane review (originally published in 2007 and updated in 2008).

OBJECTIVES

We assessed the clinical effectiveness and safety of APC for the treatment of patients with severe sepsis or septic shock.

SEARCH METHODS

For this updated review we searched CENTRAL (The Cochrane Library 2010, Issue 6); MEDLINE (1966 to June 2010); EMBASE (1980 to July 1, 2010); BIOSIS (1965 to July 1, 2010); CINAHL (1982 to 16 June 2010) and LILACS (1982 to 16 June 2010). There was no language restriction.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) assessing the effects of APC for severe sepsis in adults and children. We excluded studies on neonates. We considered all-cause mortality at day 28, at the end of study follow up, and hospital mortality as the primary outcomes.

DATA COLLECTION AND ANALYSIS

We independently performed study selection, risk of bias assessment and data extraction. We estimated relative risks (RR) for dichotomous outcomes. We measured statistical heterogeneity using the I(2) statistic. We used a random-effects model.

MAIN RESULTS

We identified one new RCT in this update. We included a total of five RCTs involving 5101 participants. For 28-day mortality, APC did not reduce the risk of death in adult participants with severe sepsis (pooled RR 0.97, 95% confidence interval (CI) 0.78 to 1.22; P = 0.82, I(2) = 68%). APC use was associated with an increased risk of bleeding (RR 1.47, 95% CI 1.09 to 2.00; P = 0.01, I(2) = 0%). In paediatric patients, APC did not reduce the risk of death (RR 0.98, 95% CI 0.66 to 1.46; P = 0.93). Although the included trials had no major limitations most of them modified their original completion or recruitment protocols.

AUTHORS' CONCLUSIONS

This updated review found no evidence suggesting that APC should be used for treating patients with severe sepsis or septic shock. Additionally, APC is associated with a higher risk of bleeding. Unless additional RCTs provide evidence of a treatment effect, policy-makers, clinicians and academics should not promote the use of APC.Warning: On October 25th 2011, the European Medicines Agency issued a press release on the worldwide withdrawal of Xigris (activated protein C / drotrecogin alfa) from the market by Eli Lilly due to lack of beneficial effect on 28-day mortality in the PROWESS-SHOCK study. Furthermore, Eli Lily has announced the discontinuation of all other ongoing clinical trials. The final results of the PROWESS-SHOCK study are expected to be published in 2012. This systematic review will be updated when results of the PROWESS-SHOCK or other trials are published.

LPS pretreatment ameliorates multiple organ injuries and improves survival in a murine model of polymicrobial sepsis

OBJECTIVE

The endotoxin tolerance phenotype is characterized with decreased inflammation and increased phagocytosis. We hypothesized that endotoxin tolerance would provide protective effects on experimental sepsis with multiple organ injuries induced by cecal ligation and puncture (CLP).

METHODS

Endotoxin tolerance was induced in male Sprague-Dawley rats with daily intraperitoneal injection of either 0.6 mg/kg of lipopolysaccharide (LPS) or vehicle for four consecutive days before subsequent CLP. Biochemical parameters, histological changes, inflammatory cytokine production, and lung tissue nuclear factor-κB (NF-κB) activation were assessed post-CLP. In a separate experiment, survival rate was monitored for 7 days after CLP.

RESULTS

In vehicle-treated animals, CLP caused multiple organ injuries confirmed by the biochemical variables and histological examination. This was accompanied by an early activation of NF-κB in the lung and a substantial increase in plasma levels of tumor necrosis factor-α, interleukin-6, and interleukin-10. In contrast, pretreatment with LPS not only alleviated the development of multiple organ injuries after CLP, but also decreased sepsis-induced activation of pulmonary NF-κB and reduced plasma cytokines production. In addition, LPS pretreatment improved the survival in rats subjected to CLP.

CONCLUSIONS

The beneficial effects of endotoxin tolerance indicate the potential of immunomodulatory strategies in the management of severe sepsis.

Human recombinant activated protein C for severe sepsis

BACKGROUND

Sepsis is a common and frequently fatal condition. Human recombinant activated protein C (APC) has been used to reduce the high rate of death by severe sepsis or septic shock. This is an update of a Cochrane review (originally published in 2007 and updated in 2008).

OBJECTIVES

We assessed the clinical effectiveness and safety of APC for the treatment of patients with severe sepsis or septic shock.

SEARCH STRATEGY

For this updated review we searched CENTRAL (The Cochrane Library 2010, Issue 6); MEDLINE (1966 to June 2010); EMBASE (1980 to July 1, 2010); BIOSIS (1965 to July 1, 2010); CINAHL (1982 to 16 June 2010) and LILACS (1982 to 16 June 2010). There was no language restriction.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) assessing the effects of APC for severe sepsis in adults and children. We excluded studies on neonates. We considered all-cause mortality at day 28, at the end of study follow up, and hospital mortality as the primary outcomes.

DATA COLLECTION AND ANALYSIS

We independently performed study selection, risk of bias assessment and data extraction. We estimated relative risks (RR) for dichotomous outcomes. We measured statistical heterogeneity using the I(2) statistic. We used a random-effects model.

MAIN RESULTS

We identified one new RCT in this update. We included a total of five RCTs involving 5101 participants. For 28-day mortality, APC did not reduce the risk of death in adult participants with severe sepsis (pooled RR 0.97, 95% confidence interval (CI) 0.78 to 1.22; P = 0.82, I(2) = 68%). APC use was associated with an increased risk of bleeding (RR 1.47, 95% CI 1.09 to 2.00; P = 0.01, I(2) = 0%). In paediatric patients, APC did not reduce the risk of death (RR 0.98, 95% CI 0.66 to 1.46; P = 0.93). Although the included trials had no major limitations most of them modified their original completion or recruitment protocols.

AUTHORS' CONCLUSIONS

This updated review found no evidence suggesting that APC should be used for treating patients with severe sepsis or septic shock. Additionally, APC is associated with a higher risk of bleeding. Unless additional RCTs provide evidence of a treatment effect, policy-makers, clinicians and academics should not promote the use of APC.

Prior statin use is not associated with improved outcome in emergency patients admitted with infection: a prospective observational study

OBJECTIVES

The objective was to determine whether prior statin use is associated with lower mortality in emergency patients admitted with infection.

METHODS

A prospective observational study was conducted at the emergency department (ED) of a tertiary adult hospital with an annual census of over 73,000 patients. Patients presenting to the ED who were subsequently hospitalized with a primary diagnosis of infection were identified within 24 hours of presentation. Data were abstracted from patients' charts and from hospital electronic databases. Patients were stratified according to reported regular statin use on presentation. The outcome measure was in-hospital mortality truncated at 30 days. An association between statin use and mortality was sought using logistic regression analysis.

RESULTS

Data were collected over a 60-week period from 2,642 admissions. Patients taking a statin on admission had a higher unadjusted mortality risk (odds ratio [OR] = 2.14, 95% confidence interval [CI] = 1.32 to 3.46) compared to those not on a statin. However, this result became nonsignificant (OR = 0.96, 95% CI = 0.55 to 1.69) after adjusting for age, severity of disease, comorbid status, and propensity score.

CONCLUSIONS

These data do not support an independent association between current preadmission statin use and lower 30-day in-hospital mortality in emergency patients admitted with infection. This result is contrary to most previously published studies.

How I manage haematology patients with septic shock

Patients with a variety of haematological conditions are at risk of infection and its most serious complication: septic shock. Mortality for septic shock remains high and especially so in patients with haematological malignancy and following bone marrow transplantation. However, advances in the treatment of severe sepsis have improved mortality rates even though evidence for the management of severe sepsis in haematology patients is limited. Wherever possible this review will concentrate on evidence directly applicable to haematology patients but inevitably will have to extrapolate evidence from other patient groups. The Surviving Sepsis Guidelines 2008 provide information on best practice in the management of patients with severe sepsis and septic shock and are broadly applicable though not specific to haematology patients. This review summarizes a practical approach to the management of severe sepsis in haematology patients and highlights areas of research which may bring new treatments in the future. The review is limited to the management and initial resuscitation of septic shock in adult haematology patients and will not address the detailed intensive care management of these patients or the management of severe sepsis in children.

Nonantibiotic therapy for multidrug-resistant Pseudomonas aeruginosa in a patient with chronic burn wounds

The authors report a special case of nonantibiotic therapy in a adolescent boy with chronically infected wounds induced by inappropriate use of antibiotics. The result of microbial cultures of the secretions on the wounds indicated that the infection of multidrug-resistant Pseudomonas aeruginosa was resistant to aminoglycoside and cephalosporin but sensitive to carbapenem and quinolones. We formulated a management strategy including daily hydrotherapy, thermal radiation therapy, balanced fluid and electrolytes and intermittent transfusion of blood products, but antibiotics were not used. Twenty-four days after his hospitalization, an autologous split-meshed skin grafting was successfully performed. He was followed up for 6 months after discharge; both lower extremities had an excellent functional recovery. The therapy introduced in this report may be beneficial for chronic infected wounds.

Interaction of antimicrobial peptide s-thanatin with lipopolysaccharide in vitro and in an experimental mouse model of septic shock caused by a multidrug-resistant clinical isolate of Escherichia coli

s-thanatin, an analogue of thanatin, was synthesised by substituting the fifteenth amino acid threonine with serine and showed broad antimicrobial activity against Gram-negative and Gram-positive bacteria. To evaluate its antimicrobial activity against a multidrug-resistant (MDR) clinical isolate as well as its anti-endotoxin activity, its lipopolysaccharide (LPS)-binding and -neutralising activity in vitro and its therapeutic efficacy in an experimental model of septic shock caused by a MDR clinical isolate of Escherichia coli were studied. The ability of s-thanatin to bind or neutralise LPS from E. coli O111:B4 was determined using a quantitative assay kit. Male ICR mice were given an intraperitoneal (i.p.) administration of 2x10(10) colony-forming units of E. coli E79466. Following bacterial challenge, all animals were randomised to receive i.p. administration of saline, 40mg/kg ceftazidime (CAZ), or 40mg/kg CAZ+s-thanatin (10, 20 or 40mg/kg). The results showed that s-thanatin not only completely bound to the LPS (median effective concentration of 17.5microg/mL) but also improved the survival and reduced the number of inoculated bacteria in a mouse model of septic shock. s-thanatin may be an attractive candidate to develop as an anti-MDR bacterial agent.