Treatment of sepsis and septic shock: a review

Antibacterial Fusion Protein BPI21/LL-37 Modification Enhances the Therapeutic Efficacy of hUC-MSCs in Sepsis

Sepsis, which is characterized by multiple organ dysfunctions as a result of an unbalanced host-inflammatory response to pathogens, is potentially a life-threatening condition and a major cause of death in the intensive care units (ICUs). However, effective treatment or intervention to prevent sepsis-associated lethality is still lacking. Human umbilical cord mesenchymal stem cell (hUC-MSC) transplantation has been shown to have potent immunomodulatory properties and improve tissue repair yet lacks direct antibacterial and endotoxin clearance activities. In this study, we engineered hUC-MSCs to express a broad-spectrum antibacterial fusion peptide containing BPI21 and LL-37 (named BPI21/LL-37) and confirmed that the BPI21/LL-37 modification did not affect the stemness and immunoregulatory capacities of hUC-MSCs but remarkably, enhanced its antibacterial and toxin-neutralizing activities in vitro. Furthermore, we showed that administration of BPI21/LL-37-engineered hUC-MSCs significantly reduces serum levels of tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and IL-6, whereas increases that of IL-10 in cecal ligation and puncture (CLP)-induced sepsis mouse model. Administration of BPI21/LL-37-engineered hUC-MSCs significantly reduced systemic endotoxin (lipopolysaccharide [LPS]) levels and organ bacterial load, ameliorated damage to multiple organs, and improved survival. Taken together, our study demonstrates that BPI21/LL-37-engineered hUC-MSCs might offer a novel therapeutic strategy to prevent or treat sepsis via enhanced antimicrobial and anti-inflammatory properties to preserve organ functions better.

Evaluation of the Hyplex BloodScreen Multiplex PCR-Enzyme-linked immunosorbent assay system for direct identification of gram-positive cocci and gram-negative bacilli from positive blood cultures

We evaluated the Hyplex BloodScreen PCR-enzyme-linked immunosorbent assay (ELISA) system (BAG, Lich, Germany), a new diagnostic test for the direct identification of gram-negative bacilli and gram-positive cocci from positive blood cultures, with 482 positive BACTEC 9240 blood culture bottles. The test involves amplification of the bacterial DNA by multiplex PCR and subsequent hybridization of the PCR product to specific oligonucleotide probes in an ELISA-based format. The available probes allow the separate detection of Escherichia coli, Pseudomonas aeruginosa, Enterobacter aerogenes, Klebsiella spp., Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis/Enterococcus faecium, Streptococcus pyogenes, and Streptococcus pneumoniae and the staphylococcal mecA gene. The Hyplex BloodScreen test showed an overall sensitivity of 100% for the identification of gram-negative bacilli and 96.6 to 100% for the identification of gram-positive cocci (S. aureus, 100%; S. epidermidis, 97.2%; Enterococcus faecalis/Enterococcus faecium, 96.6%; and Streptococcus pneumoniae, 100%). The specificities of the test modules ranged from 92.5 to 100% for gram-negative bacilli and 97.7 to 100% for gram-positive cocci (Escherichia coli, 92.5%; Pseudomonas aeruginosa, 98.5%; Klebsiella spp., 100%; Enterobacter aerogenes, 100%; S. aureus, 100%, S. epidermidis, 97.7%; Enterococcus faecalis/Enterococcus faecium, 99.6%; Streptococcus pyogenes, 100%; and Streptococcus pneumoniae, 99.3%). The result of the mecA gene detection module correlated with the result of the phenotypic oxacillin resistance testing in all 38 isolates of Staphylococcus aureus investigated. In conclusion, the Hyplex BloodScreen PCR-ELISA system is well suited for the direct and specific identification of the most common pathogenic bacteria and the direct detection of the mecA gene of Staphylococcus aureus in positive blood cultures.

Algorithm for the identification of bacterial pathogens in positive blood cultures by real-time LightCycler polymerase chain reaction (PCR) with sequence-specific probes

We developed real-time polymerase chain reaction (PCR) assays for rapid detection of the most common and clinically relevant bacteria in positive blood culture bottles, including Staphylococcus spp., S. epidermidis, S. aureus, Enterococcus spp. (including differentiation of E. faecalis and E. faecium), Streptococcus spp., Streptococcus agalactiae, Enterobacteriaceae, E. coli, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Acinetobacter spp., Bacteroides spp., Haemophilus influenzae, and Neisseria meningitidis. A total of 507 positive blood cultures were investigated according to a specific PCR algorithm based on the microscopic result of the blood culture, and the PCR results were compared to the culture results. Apart from-cross reactions between E. coli and Chryseomonas luteola and Enterococcus faecium and E. durans, the PCR assay correctly identified all bacteria in the blood cultures and did not show any false-positive results. Regarding blood cultures positive with a single species of bacteria (n = 474), 98.3% of all bacteria were correctly detected by the PCR algorithm within a few hours. However, in mixed infections, the sensitivity was lower. The PCR algorithm is well suited for rapid identification of the most common bacteria in positive blood cultures.

Case review: septic shock in the pregnant patient

This case study involves a 36-year-old female at 15 weeks gestation who presented with severe lower abdominal pain post amniocentesis and subsequently deteriorated into a state of septic shock whilst in the ED. The circumstances surrounding this patient's presentation and subsequent clinical course are presented. The assessment and management of septic shock is also described with specific consideration to this patient's pregnant state.

Advances in the Understanding of Clinical Manifestations and Therapy of Severe Sepsis: An Update for Critical Care Nurses

Severe sepsis is a major public health concern and a burden on the healthcare system. Despite improvements in efforts to control the source of infection and increased recognition by healthcare providers of patients with the disease, the mortality rate remains unacceptably high, from 30% to 50%. The systemic inflammatory response syndrome criteria are used as diagnostic indicators of sepsis when they occur in patients with known or suspected infection. The outcome of a patient with severe sepsis is often related to the occurrence of sepsis-induced multiple organ dysfunction syndrome. Multiple organ dysfunction syndrome appears to result from a cascade of organism-related factors, inflammatory mediators, endothelial injury, disturbed hemostasis, and microcirculatory abnormalities. In patients with severe sepsis, derangements of inflammation and coagulation are tightly linked. Although numerous clinical trials focused on interventions in one or the other of the inflammatory and coagulation systems failed to show reduced mortality due to sepsis, a member of a new class of drugs called “cogins” was effective. In its active form, protein C has anti-inflammatory, antithrombotic, and profibrinolytic properties that can reduce organ injury associated with severe sepsis. A recombinant form of activated protein C, drotrecogin alfa (activated), significantly reduces 28-day mortality due to all causes in patients with severe sepsis and has an acceptable safety profile. This review provides an overview of severe sepsis, highlighting recent advances in treatment of the disease and the role of critical care nurses.

The role of the critical care nurse in the assessment and management of the patient with severe sepsis

Sepsis with acute organ dysfunction is common, frequently fatal, and expensive. The critical care nurse is involved in the continuous bedside care of the critically ill patient; consequently, he or she has the opportunity to prevent sepsis through infection control practices and general nursing care, to identify patients at risk for the disease, to monitor these patients for the clinical signs of sepsis, and to detect developing organ dysfunction as a manifestation of severe sepsis. In addition, the nurse is responsible for monitoring the patient's response to organ support measures and specific antisepsis interventions. The role of the critical care nurse in the assessment and management of severe sepsis is significant and can greatly improve outcomes for the patient with this disease. Drotrecogin alfa (activated) is a promising new therapy in the treatment of severe sepsis. Nurses caring for patients with this disease need to understand the issues related to the administration of drotrecogin alfa (activated) and the monitoring of patients receiving this drug to promote optimal and appropriate use of this innovative therapy.

An audit of the use of granulocyte colony-stimulating factor in septic shock

BACKGROUND

Granulocyte colony-stimulating factor (G-CSF) stimulates the production of neutrophils and modulates the function and activity of developing and mature neutrophils. In septic shock, the immune system can be considered one of the failing organ systems. G-CSF improves immune function and may be a useful adjunctive therapy in patients with septic shock.

AIM

To evaluate the introduction of G-CSF as an adjunct to our standard treatment for community-acquired septic shock.

METHODS

We performed a prospective data collection and analysis to determine whether the addition of G-CSF to our standard treatment for community-acquired septic shock was associated with improved hospital outcome, compared with an historical cohort of similar patients. We included all patients admitted to the Intensive Care Unit (ICU) with community-acquired septic shock between December 1998 and March 2000. Patients received 300 microg G-CSF intravenously daily for 10 days in addition to our standard treatment for community-acquired septic shock. G-CSF was discontinued early if the patient was discharged from ICU before 10 days or if the absolute neutrophil count exceeded 75 x 10(6)/mL.

RESULTS

A total of 36 patients with community-acquired septic shock, an average Apache 2 score of 26.7, and a predicted mortality of 0.79, were treated with G-CSF from December 1998 to March 2000. Hospital mortality was 31% compared with an historical cohort of 11 similar patients with a hospital mortality of 73% (P = 0.018). In the subgroup of patients with melioidosis septic shock, the hospital survival improved from 5% to 100% (P < 0.0001). No significant adverse events occurred as a result of the administration of G-CSF.

CONCLUSION

G-CSF is a safe adjunctive therapy in community-acquired septic shock and may be associated with improved outcome. The use of G-CSF in septic shock should undergo further investigation to define subgroups of patients who may benefit from G-CSF. The use of G-CSF in patients with septic shock due to Burkholderia pseudomallei is recommended.

Pathogenesis and treatment of disseminated intravascular coagulation in the septic patient

The incidence of sepsis and complications stemming from septicemia has remained constant in recent years despite improved levels of monitoring and care. Disseminated intravascular coagulation (DIC), a syndrome that occurs frequently in septic patients, is associated with increased mortality. Organ dysfunction is also a common sequela that is strongly correlated with DIC. Cytokines released early in the course of sepsis stimulate a procoagulant state that causes development of intravascular fibrin deposition. In a later stage of DIC, bleeding may occur in parallel because of consumption of clotting factors and inhibitors. Therapeutic strategies to attenuate or reverse these conditions have focused on multiple stages of the molecular cascade of events, including preventing cytokine induction, inhibiting coagulation processes, and promoting fibrinolysis. Recent clinical trials have supported the use of antithrombin and activated protein C supplementation in DIC associated with severe sepsis. Studies of other novel therapeutic avenues are still ongoing. Future efforts may be directed at combining 2 or more agents to achieve prompt and successful reversal of DIC.

Systemic inflammatory response syndrome

Despite advances in perinatal care in the past decade, sepsis and its complications continue to present problems for the neonate, remaining a major cause of neonatal morbidity and mortality. Sepsis research is focusing on how the neonate (host) responds to bacteria. The newborn may develop a systemic reaction to bacteria that induces the release of substances known as inflammatory mediators. Termed the systemic inflammatory response syndrome (SIRS), this reaction is believed to be responsible for the signs and symptoms of sepsis. This article introduces the neonatal nurse to SIRS, providing an overview of various inflammatory mediators and cytokines, their clinical consequences, and potential new therapies in the management of SIRS.

Traumatic Shock Alias Posttrauma Critical Illness

Trauma is the most common cause of death under the age of 45. Many trauma patients die of multiple organ failure, especially acute respiratory distress syndrome. The basic cause of traumatic shock has only partially been elucidated. Data resources include research papers on the subject of trauma and shock from 1875 to the present. These papers numbered more than 40,000. Almost all of the papers proposed that traumatic shock was due to hypovolemia. The concept of a shock toxin as promulgated during World War I is correct. This toxin is a thrombogenic aminophospholipid that occurs only on the inner layer of all cell membranes and is liberated by cell destruction. It causes disseminated intravascular coagulation, which may obstruct the microcirculation of any and all organs producing multiple organ failure by microclots. These microclots may be lysed by plasminogen activator and circulation to the organs restored.

A Review of Septic Shock

The mortality of septic shock, both in percentage of septic shock cases and total number of septic shock cases, has been increasing over the past several decades. This is despite major advances in diagnosis and treatment. The basic cause of traumatic and septic shock has only partially been elucidated. This review presents information about the basic cause and mechanism of septic shock as well as a new treatment based on this information. Data sources include research papers on the subject of septic shock from 1875 until the present. These papers numbered more than 10,000, most of which are not included in the reference list because many are duplicative. The main result of the review of literature is that all of a wide variety of treatments of septic shock have not resulted in a lowering of mortality, but in fact have increased it. Another toxin (in addition to endotoxin and its secondarily induced host mediators) is proposed. This toxin causes disseminated intravascular coagulation, which may obstruct the microcirculation of any and all organs, producing multiple organ failure by microclots. These microclots may be lysed by plasminogen activator and circulation to the organs restored.

The three-dimensional structure of human bactericidal/permeability-increasing protein: implications for understanding protein-lipopolysaccharide interactions

Gram-negative bacterial infections are often complicated by the inflammatory properties of lipopolysaccharides (LPS) on or released from the bacterial outer membrane. When present in the mammalian bloodstream, LPS can trigger a series of pathological changes, sometimes resulting in septic shock. Two related mammalian proteins, bactericidal/permeability-increasing protein (BPI) and lipopolysaccharide-binding protein (LBP), are known to affect the LPS-induced inflammatory response and are, therefore, of clinical interest. The recently determined three-dimensional structure of human BPI provides information on the overall protein fold, domain organization, and conserved regions of these two proteins. In addition, the discovery of two apolar lipid binding pockets in BPI indicates a possible site of interaction with LPS. The BPI structure is a powerful tool for the design of site-directed mutants, peptide mimetics/inhibitors, and BPI/LBP chimeras. These studies should help further define the functions of BPI and LBP, and their mechanism of interaction with LPS.

Traumatic and septic shock alias post-trauma critical illness

BACKGROUND

The mortality associated with septic shock, both in percentage of septic shock cases and total number of septic shock cases, has been increasing over the past several decades. This is despite major advances in diagnosis and treatment. The basic cause of traumatic and septic shock has been only partially elucidated.

METHODS

Data sources include research papers on the subject of traumatic and septic shock from 1875 to the present. These papers numbered over 10 000, few of which are included in the reference list because many are duplicative or negative. Over 1000 articles were reviewed which documented the unsuccessful search for a treatment for septic shock based on the theory that septic shock is due to endotoxin and its secondarily induced host mediators. These references are available from the author.

RESULTS

and conclusion The concept of a shock toxin in trauma and sepsis as promulgated during World War I is correct. This toxin is a thrombogenic aminophospholipid which occurs only on the inner layer of all cell membranes and is liberated by cell destruction. It causes disseminated intravascular coagulation which may obstruct the microcirculation of any or all organs, producing multiple organ failure by microclots. These microclots may be lysed by plasminogen activator and circulation to the organs restored.

Heat shock protein (HSP70) expression in septic patients

PURPOSE

This study investigates heat shock protein 70 (HSP70) expression by peripheral blood mononuclear cells (PBMCs) of septic patients admitted to an intensive care unit and examines the possibility of a correlation between HSP70 levels and plasma tumor necrosis factor alpha (TNF-alpha) concentrations. Additionally, we evaluated whether the HSP70 production could be regarded as a prognostic factor for the development of septic shock as well as for patient survival.

MATERIALS AND METHODS

Blood samples of 29 patients were taken 24 hours after the diagnosis of sepsis. HSP70 expression and TNF-alpha level were measured using indirect immunofluorescent analysis and a commercially available enzyme-linked immunosorbent assay method, respectively.

RESULTS

PBMCs expressed significantly high levels of HSP70 (11.9 +/- 5.6 [sd]) compared with those of the healthy control group (3.2 +/- 2.1% positive cells). Such enhanced levels were correlated to plasma TNF-alpha concentrations (r = .99, P < .01). This study failed to demonstrate a relationship between HSP70 production and clinical outcome.

CONCLUSION

These findings give further evidence that also in humans, heat shock response is activated during sepsis. The correlation observed between HSP70 overproduction and TNF-alpha plasma concentrations suggests that HSP70 exerts a possible protective effect against TNF-alpha cytotoxicity. Such hypothesis has not been confirmed by our clinical data.