Diagnosis of infection in sepsis: An evidence-based review

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.

Comparison of the clinical characteristics and clinical outcomes of culture-positive septic shock and culture-negative septic shock among pediatric patients

OBJECTIVES

Among pediatric patients with septic shock, culture-negative septic shock (CNSS) is common but there have been limited data on its clinical characteristics and prognosis. We compared the clinical characteristics and clinical outcomes between culture-positive septic shock (CPSS) and CNSS in pediatric patients.

DESIGN

Retrospective single-center study.

SETTING

Pediatric intensive care unit (PICU) of a tertiary referral hospital.

PATIENTS

All pediatric patients who were admitted to the PICU due to septic shock between January 2010 and November 2021, except for those with fungal or viral infections and those who expired on the day of admittance to the PICU. The primary outcome was 30-day mortality and in-hospital mortality.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 294 patients (CPSS group, n = 185 [62.9%]; CNSS group, n = 109 [37.1%]) were included. The rates of 30-day mortality and in-hospital mortality (30-day mortality 22.7% vs 22%, in-hospital mortality 29.7% vs 25.7%) were not significantly different between the CPSS group and the CNSS group. The two groups showed comparable results in clinical outcomes such as the requirement for mechanical ventilator and renal replacement therapy, PICU stay duration, and the duration of MV and vasopressor/inotrope support. Among the CPSS group, 98 (53%) patients who were infected with multi-drug resistance (MDR) bacteria had significantly higher rates of 30-day mortality and in-hospital mortality than those infected with non-MDR bacteria.

CONCLUSIONS

Among pediatric patients, the CPSS group and CNSS group did not show significant differences in clinical features and mortality. Among the CPSS group, those with MDR bacteria had poorer prognosis.

Evaluation of Sepsis-1 and Sepsis-3 Diagnostic Criteria in Patients with Sepsis in Intensive Care Unit

Background

The use of SIRS and SOFA criteria in diagnosing sepsis among patients has been characterized by increasingly growing criticism. Indeed, the definition of sepsis has attracted significant controversy in history across medical and academic realms.

Methods

The study used the Medical Information Mart for Intensive Care-III (MIMIC-III) database in assessing the effectiveness of the SIRS and SOFA diagnostic criteria. It ascertained the severity and specificity of sepsis infection in ICU patients. The Medical Information Mart for Intensive Care-III (MIMIC-III) database was established by the Beth Israel Deaconess Medical Center (BIDMC) and MIT's Computational Physiology Laboratory. The database is a voluminous single-center database containing information pertaining to 38,000 adults who were admitted to the BIDMC in the 11 years leading up to 2012. The identification of patients with sepsis was conducted using the International Classification of Diseases (ICD-10-CM) diagnosis codes.

Results

The analysis of data for this study was based on the chi-square test, which is significant in comparing the specificity, mortality, and sensitivity of the data. The process of screening the MIMIC-III database resulted in the identification of 21,368 patients with infections from the hospital admissions in the database. The results also indicate a significantly higher mortality rate within 28 days of admission in sepsis-3 patients compared with sepsis-1. In this experiment, we limited the study period to 28 days to restrict the potential of mortality caused by other factors. Additionally, we evaluated the clinical factors associated with the sepsis-1 or sepsis-3 and found out similar results in the analysis for sepsis-1 and sepsis-3.

Conclusions

The study results also portray numerous challenges in using the sepsis-3 criteria as a diagnostic tool. In particular, the ICD-10-CM diagnosis approach was limiting because it inhibited the measure of uncertainty of infection present at the beginning of the two diagnostic criteria of sepsis-1 and sepsis-3.

Diagnostic Challenges in Sepsis

Purpose of Review

Sepsis is a leading cause of death worldwide. Groundbreaking international collaborative efforts have culminated in the widely accepted surviving sepsis guidelines, with iterative improvements in management strategies and definitions providing important advances in care for patients. Key to the diagnosis of sepsis is identification of infection, and whilst the diagnostic criteria for sepsis is now clear, the diagnosis of infection remains a challenge and there is often discordance between clinician assessments for infection.

Recent Findings

We review the utility of common biochemical, microbiological and radiological tools employed by clinicians to diagnose infection and explore the difficulty of making a diagnosis of infection in severe inflammatory states through illustrative case reports. Finally, we discuss some of the novel and emerging approaches in diagnosis of infection and sepsis.

Summary

While prompt diagnosis and treatment of sepsis is essential to improve outcomes in sepsis, there remains no single tool to reliably identify or exclude infection. This contributes to unnecessary antimicrobial use that is harmful to individuals and populations. There is therefore a pressing need for novel solutions. Machine learning approaches using multiple diagnostic and clinical inputs may offer a potential solution but as yet these approaches remain experimental.

Comparison of Clinical Characteristics and Outcomes Between Positive and Negative Blood Culture Septic Patients: A Retrospective Cohort Study

Background

Few studies have studied the relationship between blood culture and mortality in sepsis patients. The aim of this study was to compare the characteristics and outcomes of positive and negative blood culture sepsis.

Methods

We performed a study on 640 patients suffering from sepsis in Beijing Chao-Yang Hospital from October 2017 to December 2019. The primary findings revolved around length and expenditure of hospital stay, the possibility of suffering from acute respiratory distress syndrome (ARDS), and any requirements for mechanical ventilation. The secondary findings revolved around whether the patient died early (28-day) or late (28-to-90-day).

Results

A total of 592 of the 640 patients met the inclusion criteria for sepsis, with 274 of them having culture-positive results. The culture-positive patients were mostly elderly suffering from diabetes and at risk of cancer, with a higher white blood cell count, and higher procalcitonin. Additionally, they scored higher in their acute physiology and chronic health evaluation II score (15 vs.11, P=0.010), as well as in their predisposition, infection, response, and organ dysfunction (17 vs 11, P<0.001) than the individuals in the culture-negative group. Culture-positive patients had a longer duration of hospital stay (14 vs 6, P<0.001) and higher in-hospital mortality (14.6% vs 8.5%, P=0.019) than culture-negative ones. No significant difference in intensive care unit (ICU) mortality (45.7% vs.36.4%, P=0.254) or early mortality (9.5% vs 7.2%, P=0.321) was noted between the two groups. However, the culture-positive patients had increased late mortality (15.7% vs.6.9%, P=0.001), when compared with those with culture-negative results in the cohort. Furthermore, the culture-positive patients who received the appropriate antibiotics early had a lower mortality rate than the culture-negative patients (7.3% vs.14.2%, P=0.008).

Conclusion

Culture-positive patients had higher in-hospital mortality, comparable early mortality, and worse late mortality than the culture-negative patients. Early appropriate use of antibiotics might reduce mortality and improve clinical prognosis.

Toward Rapid Detection of Viable Bacteria in Whole Blood for Early Sepsis Diagnostics and Susceptibility Testing

Sepsis is a serious bloodstream infection where the immunity of the host body is compromised, leading to organ failure and death of the patient. In early sepsis, the concentration of bacteria is very low and the time of diagnosis is very critical since mortality increases exponentially with every hour after infection. Common culture-based methods fail in fast bacteria determination, while recent rapid diagnostic methods are expensive and prone to false positives. In this work, we present a sepsis kit for fast detection of bacteria in whole blood, here achieved by combining selective cell lysis and a sensitive colorimetric approach detecting as low as 10³ CFU/mL bacteria in less than 5 h. Homemade selective cell lysis buffer (combination of saponin and sodium cholate) allows fast processing of whole blood in 5 min while maintaining bacteria alive (100% viability). After filtration, retained bacteria on filter paper are incubated under constant illumination with the electrochromic precursors, i.e., ferricyanide and ferric ammonium citrate. Viable bacteria metabolically reduce iron(III) complexes, initiating a photocatalytic cascade toward Prussian blue formation. As a proof of concept, we combine this method with antibiotic susceptibility testing to determine the minimum inhibitory concentration (MIC) using two antibiotics (ampicillin and gentamicin). Although this kit is used to demonstrate its applicability to sepsis, this approach is expected to impact other key sectors such as hygiene evaluation, microbial contaminated food/beverage, or UTI, among others.

Comparison of culture-negative and culture-positive sepsis or septic shock: a systematic review and meta-analysis

Background

Mortality and other clinical outcomes between culture-negative and culture-positive septic patients have been documented inconsistently and are very controversial. A systematic review and meta-analysis was performed to compare the clinical outcomes of culture-negative and culture-positive sepsis or septic shock.

Methods

We searched the PubMed, Cochrane and Embase databases for studies from inception to the 1st of January 2021. We included studies involving patients with sepsis or septic shock. All authors reported our primary outcome of all-cause mortality and clearly compared culture-negative versus culture-positive patients with clinically relevant secondary outcomes (ICU length of stay, hospital length of stay, mechanical ventilation requirements, mechanical ventilation duration and renal replacement requirements). Results were expressed as odds ratio (OR) and mean difference (MD) with accompanying 95% confidence interval (CI).

Results

Seven studies including 22,655 patients were included. The primary outcome of this meta-analysis showed that there was no statistically significant difference in the all-cause mortality between two groups (OR = 0.95; 95% CI, 0.88 to 1.01; P = 0.12; Chi-² = 30.71; I² = 80%). Secondary outcomes demonstrated that there was no statistically significant difference in the ICU length of stay (MD = − 0.19;95% CI, − 0.42 to 0.04; P = 0.10;Chi-² = 5.73; I² = 48%), mechanical ventilation requirements (OR = 1.02; 95% CI, 0.94 to 1.11; P = 0.61; Chi² = 6.32; I² = 53%) and renal replacement requirements (OR = 0.82; 95% CI, 0.67 to 1.01; P = 0.06; Chi-² = 1.21; I² = 0%) between two groups. The hospital length of stay of culture-positive group was longer than that of the culture-negative group (MD = − 3.48;95% CI, − 4.34 to − 2.63; P < 0.00001;Chi-² = 1.03; I² = 0%). The mechanical ventilation duration of culture-positive group was longer than that of the culture-negative group (MD = − 0.64;95% CI, − 0.88 to − 0.4; P < 0.00001;Chi-² = 4.86; I² = 38%).

Conclusions

Culture positivity or negativity was not associated with mortality of sepsis or septic shock patients. Furthermore, culture-positive septic patients had similar ICU length of stay, mechanical ventilation requirements and renal replacement requirements as those culture-negative patients. The hospital length of stay and mechanical ventilation duration of culture-positive septic patients were both longer than that of the culture-negative patients. Further large-scale studies are still required to confirm these results.

Diagnostic Accuracy of Immunologic Biomarkers for Accurate Diagnosis of Bloodstream Infection in Patients with Malignancy: Procalcitonin in Comparison with C-Reactive Protein

Purpose

To calculate the diagnostic value of C-reactive protein (CRP) and serum procalcitonin (PCT) levels for the pathologic presence of microbes in the bloodstream of patients with malignancy, in comparison with blood culture. Methodology. Blood culture (by reference method) and assay results of PCT and CRP of febrile patients, with clinical suspicion to blood infections, were collected. Statistical aspects of PCT  and CRP tests were evaluated.

Results

Data from 255 cases were gathered. The area under the curve for differentiating bacteremia from nonbacteremia for PCT (0.741) was superior to that of CRP (0.612). Amongst the different cutoffs of PCT and CRP, the cutoff of ≥1.17 ng/ml and >47 mg/l had the sensitivity of 75 and 58.3%, the best NPV of 91.5% and 81.3%, and the best specificity of 79.9% and 72.8%, respectively. Discussion. Despite statistically nonsignificant results, PCT seems to be a superior indicator to CRP for rejecting the presence of microorganism in bloodstream. For PCT, the cutoff value of 1.17 ng/ml (bacteremia from nonbacteremia) had the highest NPV value of 91.5% in malignant patients, suspicion of sepsis.

Associations between serum L-arginine and ficolins in the early phase of acute ischemic stroke - A pilot study

INTRODUCTION

Activation of both the L-arginine and the lectin pathway contributes to the pathophysiology and the outcome of acute ischemic stroke (AIS). However, the interplay between the two systems has not yet been examined.

METHODS

A total of 44 patients with AIS were recruited into this study. Serial measurement of serum L-arginine, asymmetric and symmetric dimethylarginine (ADMA, SDMA), and hsCRP, ficolin-2, ficolin-3, MAP-1, MASP-3 and mannose-binding lectin (MBL) were analyzed within 6 h after onset of stroke and 72 h later. Outcomes were assessed as National Institutes of Health Stroke Scale (NIHSS) worsening by 24 h, poststroke infection, and death by 1 month.

RESULTS

In the hyperacute stage of AIS, ficolin-3, MAP-1 and MBL were positively correlated with L-arginine within 6 h after onset of symptoms (p<0.05 respectively). Significantly lower ficolin-3 and MASP-3 levels were found at 72 h in patients, who developed post-stroke infection after day 4, when compared to patients without post-stroke infections (p=0.03 and p=0.009). At 72 hours, ficolin-3 levels negatively correlated with S100B (p=0.01). Ficolin-3 at 72 post-stroke hours remained an independent predictor of post-stroke infection, while only hsCRP was an independent predictor of 30-day mortality.

CONCLUSION

Early consumption of ficolin-3 is associated with complications such as post-stroke infections. In the hyperacute phase of AIS, the positive correlation between ficolins and the NO donor L-arginine may reflect the protective role of L-arginine presumably by improving the cerebral microcirculation in a prothrombotic environment induced by complement activation.

Marker Of Sepsis Severity Is Associated With The Variation In Cardio-Ankle Vascular Index (CAVI) During Sepsis Treatment

Introduction

The main pathophysiology of sepsis is considered to be circulation crisis with an imbalance of vasodilation and vasoconstriction mechanisms, which contributes to multiple organ failure. However, sepsis-induced hemodynamic changes have not been fully validated by novel arterial stiffness parameter. The aim of this study was to clarify the acute vascular alteration and hemodynamic change in sepsis using cardio-ankle-vascular index (CAVI).

Methods

Twenty-one Japanese patients (14 males and 7 females, age 62.8 ± 19.0 years) with sepsis were recruited. CAVI was measured before and 1-week after sepsis treatment.

Results

The leading underlying cause of sepsis was pyelonephritis, followed by pneumonia, lung abscess, hepatic abscess and cholecystitis. All subjects recovered from sepsis. Analysis of all subjects showed a significant increase in CAVI after 1-week treatment (7.9 ± 2.4 to 9.6 ± 1.8, P < 0.001), but no significant change in blood pressure (BP) was observed. Significant correlations were observed for all combinations among the change in CAVI, systolic BP and ln[procalcitonin (PCT)], respectively. Additionally, in subjects with PCT at presentation ≥2.0 ng/mL, the increase in CAVI after treatment was significantly greater compared to those with PCT < 2.0 ng/mL (2.4 ± 1.6 vs 1.1 ± 0.9, P = 0.037).

Discussion

CAVI may reflect sepsis-induced vascular alteration which is not indicated by BP change, and is associated with sepsis severity. These findings suggest the usefulness of CAVI in the management of circulatory failure in sepsis patients.

Determination of Melatonin Deprivation Impact on Sepsis With Acute Phase Reactants

BACKGROUND

The aim of the present study is to determine the association of melatonin hormone level on CRP, Total Antioxidant Status, Leukocyte, Procalcitonin, and Malondialdehyde, all acute phase reactants in the dark and light cycle of rats with sepsis model.

MATERIALS AND METHODS

In this study, 54 rats were divided into three groups. Whereas the first and third groups had a 12 h dark-light cycle, the second group was exposed to light for 24 h at 21°C-22°C for 10 d without any water and food restrictions. In the second and third groups, sepsis model was formed by cecal ligation and puncture (CLP) method at the end of 10th day, and blood samples were taken at the end of the 10th day. C-reactive protein, Malondialdehyde, Procalcitonin in the blood samples were analyzed by ELISA, and the levels of Total Antioxidant Status and leukocyte were determined by colorimetric method in the subsequent 12 and 24 h.

RESULTS

CRP values increased in the second group rats, which were kept continuously under light and had undergone CLP, from 288.8 mg/L to 584.0 mg/L at the end of the 12 h and the end of the 24 h, approximately, two times. In rats, which were kept under 12 h of light, 12 h of darkness, and applied CLP (group 3), these values increased from 416.9 to 619.1; an increase of 1.5 times. When assessed for MDA, it was determined that the differences between Group 2 and Group 3 were more prominent between 0 h and 12 h. While the MDA values in group 2 increased from 16.53 nmol/mL at the 12 h to 17.66 nmol/mL at the 24 h. However, MDA values did not yield statistically significant changes in the third group. Changes in the in PCT values were similar to the MDA values obtained. Increase coefficient of the PCT values between 0 h and 12 h in the second group 2 was 1.26; however, in the third group, it was negligible.

CONCLUSIONS

An increase in the oxidative stress was observed in the rats that underwent CLP and melatonin deprivation via continuous 24 h light exposure for 10 d. Accordingly, deprivation of light is considered to be effective in sepsis treatment due to the increase in melatonin levels in intensive care unit patients.

MALDI-TOF MS monitoring of PBMC activation status in sepsis

Background

MALDI-TOF mass spectrometry (MS) on whole cells enables the detection of different cell types and cell activation. Here, we wondered whether this approach would be useful to investigate the host response in sepsis.

Methods

Peripheral blood mononuclear cells (PBMCs) from patients with severe sepsis and healthy donors were analyzed with MALDI-TOF MS. PBMCs from healthy donors were also stimulated with lipopolysaccharide, peptidoglycan, CpG oligonucleotides, polyinosinic polycytidylic acid, and with heat-inactivated bacteria. Averaged spectra of PBMCs stimulated in vitro by different agonists were generated from the database using the Biotyper software and matching scores between each spectrum from patients and averaged spectra from the database were calculated.

Results

We show that the MALDI-TOF MS signature of PBMCs from septic patients was specific, compared with healthy controls. As the fingerprints observed in patients may be related to PBMC activation, PBMCs from healthy controls were stimulated with cytokines, soluble Pathogen-Associated Molecular Patterns (PAMPs) and heat-killed bacteria, and we created a database of reference spectra. The MALDI-TOF MS profiles of PBMCs from septic patients were then compared with the database. No differences were found between patients with documented infection (n = 6) and those without bacteriological documentation (n = 6). The spectra of PBMCs from septic patients matched with those of interferon-γ- and interleukin-10-stimulated PBMCs, confirming that sepsis is characterized by both inflammatory and immunoregulatory features. Interestingly, the spectra of PBMCs from septic patients without documented infection matched with the reference spectrum of PBMCs stimulated by CpG oligonucleotides, suggesting a bacterial etiology in these patients.

Conclusions

Despite the limits of this preliminary study, these results indicate that the monitoring of functional status of PBMCs in peripheral blood by whole cell MALDI-TOF MS could provide unique opportunities to assess disease progression or resolution in clinical settings.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3266-7) contains supplementary material, which is available to authorized users.

Determinants of Outcome in Burn ICU Patients with Septic Shock

Infectious complications remain one of the most challenging concerns for the burn team. The goal of this study was to evaluate the diagnostic and therapeutic approaches and prognosis in burn patients with septic shock. This retrospective study included patients with severe burn injury who were admitted to a burn intensive care unit (ICU). Demographic and clinical data were recorded for each patient. The diagnostic and prognostic value of a number of clinical and laboratory parameters and various treatment options were evaluated. Sixty-four of the 378 patients (16.9%) were identified as having experienced a septic shock during ICU stay. The mortality rate of patients with septic shock was 46.9%. The main bacterial strains responsible for infection were Gram-negative bacteria (78.1%). Factors associated with outcome of septic shock on logistic regression analysis were presence of stage III of acute kidney injury (odds ratio [95% confidence interval] 2.03 [1.06-3.84]; P = 0.019), and lactate levels > 4 mmol/L during the first 48 hours of shock (odds ratio 1.92; 95% confidence interval: 1.02-3.62; P = 0.043). Prognosis of septic shock remains poor in burn patients with septic shock. The main causative pathogens of septic shock identified in our burn ICU were Gram-negative species. The main prognostic factors identified in this study were the presence of AKI, stage III, and high lactate levels early after the onset of septic shock.

Septic predictor index: A novel platform to identify thermally injured patients susceptible to sepsis

BACKGROUND

During the past decades' sepsis has become the major cause of death in severely burned patients. Despite the importance of burn sepsis, its diagnosis, let alone its prediction, is difficult if not impossible. Recently, we have demonstrated burn patients have increased NLRP3 inflammasome activation in white adipose tissue. We aimed to delineate a unique immune profile that can be used to identify septic outcomes in severely burned patients.

METHODS

Adult burn patients (n = 37) admitted to our burn center between June 2013-2015 were enrolled in this study. White adipose tissue from the site of injury and plasma were collected from severely burned patients (>20% total body surface area) within 96 hours after thermal injury, indiscriminate of sex or age.

RESULTS

We found that patients exhibiting aberrantly high levels of proinflammatory interleukin-1β and decreased macrophages at the site of injury are highly susceptible to development of sepsis. Septic patients also had increased anti-inflammatory (interleukin-10, interleukin-1RA) cytokines in plasma. The Septic Predictor Index was generated as a quotient for the site of injury macrophage proportion and interleukin-1β production. All patients who eventually develop sepsis had septic predictor index values >0.5. Septic patients with Septic Predictor Index values >1 all had sepsis onset within 12 days post-injury, whereas patients with Septic Predictor Index values between 0.5-1 all had later onset (>12 days).

CONCLUSION

The Septic Predictor Index can determine sepsis onset accurately in thermally injured patients a priori and further enables surgeons to develop clinical studies and focused therapies specifically designed for septic cohorts.

Bloodstream Infections

Bacteremia and sepsis are conditions associated with high mortality and are of great impact to health care operations. Among the top causes of mortality in the United States, these conditions cause over 600 fatalities each day. Empiric, broad-spectrum treatment is a common but often a costly approach that may fail to effectively target the correct microbe, may inadvertently harm patients via antimicrobial toxicity or downstream antimicrobial resistance. To meet the diagnostic challenges of bacteremia and sepsis, laboratories must understand the complexity of diagnosing and treating septic patients, in order to focus on creating algorithms that can help direct a more targeted approach to antimicrobial therapy and synergize with existing clinical practices defined in new Surviving Sepsis Guidelines. Significant advances have been made in improving blood culture media; as yet no molecular or antigen-based method has proven superior for the detection of bacteremia in terms of limit of detection. Several methods for rapid molecular identification of pathogens from blood cultures bottles are available and many more are on the diagnostic horizon. Ultimately, early intervention by molecular detection of bacteria and fungi directly from whole blood could provide the most patient benefit and contribute to tailored antibiotic coverage of the patient early on in the course of the disease. Although blood cultures remain as the best means of diagnosing bacteremia and candidemia, complementary testing with antigen tests, microbiologic investigations from other body sites, and histopathology can often aid in the diagnosis of disseminated disease, and application of emerging nucleic acid test methods and other new technology may greatly impact our ability to bacteremic and septic patients, particularly those who are immunocompromised.

An electrochemical biosensor for detection of the sepsis-related biomarker procalcitonin

An electrochemical peptide sensor employing a sensitive synthetic peptide was designed for the diagnosis of sepsis.

Septic shock with no diagnosis at 24 hours: a pragmatic multicenter prospective cohort study

Background

The lack of a patent source of infection after 24 hours of management of shock considered septic is a common and disturbing scenario. We aimed to determine the prevalence and the causes of shock with no diagnosis 24 hours after its onset, and to compare the outcomes of patients with early-confirmed septic shock to those of others.

Methods

We conducted a pragmatic, prospective, multicenter observational cohort study in ten intensive care units (ICU) in France. We included all consecutive patients admitted to the ICU with suspected septic shock defined by clinical suspicion of infection leading to antibiotic prescription plus acute circulatory failure requiring vasopressor support.

Results

A total of 508 patients were admitted with suspected septic shock. Among them, 374 (74 %) had early-confirmed septic shock, while the 134 others (26 %) had no source of infection identified nor microbiological documentation retrieved 24 hours after shock onset. Among these, 37/134 (28 %) had late-confirmed septic shock diagnosed after 24 hours, 59/134 (44 %) had a condition mimicking septic (septic shock mimicker, mainly related to adverse drug reactions, acute mesenteric ischemia and malignancies) and 38/134 (28 %) had shock of unknown origin by the end of the ICU stay. There were no differences between patients with early-confirmed septic shock and the remainder in ICU mortality and the median duration of ICU stay, of tracheal intubation and of vasopressor support. The multivariable Cox model showed that the risk of day-60 mortality did not differ between patients with or without early-confirmed septic shock. A sensitivity analysis was performed in the subgroup (n = 369/508) of patients meeting the Sepsis-3 definition criteria and displayed consistent results.

Conclusions

One quarter of the patients admitted in the ICU with suspected septic shock had no infection identified 24 hours after its onset and almost half of them were eventually diagnosed with a septic shock mimicker. Outcome did not differ between patients with early-confirmed septic shock and other patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-016-1537-5) contains supplementary material, which is available to authorized users.

Correlation of the L-Arginine Pathway with Thrombo-Inflammation May Contribute to the Outcome of Acute Ischemic Stroke

BACKGROUND

Immune responses contribute to secondary injury after acute ischemic stroke (AIS), and metabolites of the L-arginine pathway are associated with stroke outcome. Here, we analyzed the relationship of the L-arginine pathway with thrombo-inflammatory biomarkers in AIS and their additive and independent associations to outcome.

METHODS

Serial changes in P-selectin, tPA, MCP-1, sCD40L, IL-6, IL-8, L-arginine, and asymmetric and symmetric dimethylarginine (ADMA, SDMA) were investigated in 55 patients with AIS and without infection within 6 and 72 hours after stroke onset. Outcomes were assessed as National Institutes of Health Stroke Scale (NIHSS) worsening by 24 hours, poststroke infection, and death by 1 month.

RESULTS

Serum levels of L-arginine showed negative correlation, whereas ADMA and SDMA showed positive correlation with thrombo-inflammatory biomarkers in the hyperacute phase. Most of these correlations disappeared by 72 poststroke hours. Correlation of MCP-1 with both ADMA and SDMA levels at 6 hours was associated with both NIHSS worsening and poststroke infections, respectively; sCD40L and SDMA correlation at 6 hours was also associated with NIHSS worsening. Negative correlation between P-selectin and L-arginine concentrations in the hyperacute phase was associated with NIHSS worsening. Strong negative correlation was found between IL-6 and L-arginine levels in the hyperacute phase in patients with poststroke infection. Only L-arginine and SDMA at 72 hours were independently associated with poststroke infection respectively.

CONCLUSIONS

Concentration of L-arginine and ADMA/SDMA differentially correlates with thrombo-inflammation in the hyperacute phase of ischemic stroke. Such correlations are independently associated with poststroke infection but not with other outcomes.

Early Dynamics of P-selectin and Interleukin 6 Predicts Outcomes in Ischemic Stroke

BACKGROUND

Thromboinflammatory molecules connect the prothrombotic state, endothelial dysfunction, and systemic/local inflammation in the acute phase of ischemic stroke.

METHODS

We prospectively investigated (1) serial changes in the levels of thromboinflammatory biomarkers in 76 patients with acute ischemic stroke (6, 24, and 72 hours after onset); (2) compared with 44 patients with asymptomatic severe (≥70%) carotid stenosis and 66 patients with Parkinson disease; and (3) we applied multiple regression methods, relating biological biomarkers combined with demographic data and comorbidities to poststroke infection, death, and functional outcome, and assessed the ability of the models to predict each outcome.

RESULTS

Interleukin 6 (IL-6) levels and change of IL-6 concentrations by 72 hours correlated with the size of tissue damage indicated by S100B titers. Levels of IL-6 and P-selectin at 72 hours were higher in patients with large-artery versus lacunar stroke. High concentration of IL-6, monocyte chemotactic protein 1, and S100B at 6 hours were associated with poststroke infections; high concentration of IL-6, S100B, and high-sensitivity C-reactive protein (hsCRP) correlated with death. Change of P-selectin from 6 to 72 hours by 1 unit increased the incidence of poststroke infections with an odds ratio of 22.7; each 100 units of IL-6 at baseline increased the odds of death by 9‰, and at 72 hours, the odds of poststroke infections by 4‰. Each unit of baseline hsCRP elevated the odds of death by 7%.

CONCLUSIONS

In regression models, in which biological, demographic, and comorbid factors were combined, those biological biomarkers predicted poor outcome with high accuracy, which were characterized by an increasing concentration by 72 hours. Two particular biomarkers emerged to predict outcomes besides hsCRP: early dynamic changes in the systemic levels of P-selectin and IL-6.

Deficient leucocyte antisedimentation is related to post-stroke infections and outcome

BACKGROUND

Patients with stroke are more susceptible to infections, suggesting possible deficiencies of early immune responses, particularly of leucocytes.

AIMS

To serially examine leucocyte antisedimentation rate (LAR), a simple test to detect activation of leucocytes, and correlate it with S100beta, procalcitonin and outcome in patients with acute ischaemic events.

METHODS

Venous blood samples were taken from 61 healthy volunteers and 49 patients with acute ischaemic events (acute ischaemic stroke (AIS), n = 38; transient ischaemic attack (TIA), n = 11) within 6 hours, at 24 and 72 hours after onset of symptoms.

RESULTS

LAR was significantly higher in acute ischaemic events compared to controls within 6 hours after onset of stroke regardless of post-stroke infections. In addition, the increase of LAR was delayed and attenuated in TIA in contrast to AIS. A deficiency in early increase of LAR was associated with post-stroke infections and a poor outcome, measured by the Glasgow Outcome Scale in AIS. There was a positive correlation between LAR and S100beta at 72 hours after the onset of ischaemic stroke. Increased levels of S100beta at 24 and 72 hours after stroke were associated with poor outcome.

CONCLUSIONS

An early activation of leucocytes indicated by an increase of LAR is characteristic of acute ischaemic cerebrovascular events. A delayed and ameliorated leucocyte activation represented by LAR is characteristic of TIA in contrast to stroke. Deficient early activation predisposes to post-stroke infections related to poor outcome. In addition, the extent of tissue injury correlates with the magnitude of innate immune responses.

Evaluation of the BD BACTEC FX blood volume monitoring system as a continuous quality improvement measure

The yield of blood cultures is proportional to the volume of blood cultured. We evaluated an automatic blood volume monitoring system, recently developed by Becton Dickinson within its BACTEC EpiCenter module, that calculates mean volumes of negative aerobic bottles and generates boxplots and histograms. First, we evaluated the filling degree of 339 aerobic glass blood cultures by calculating the weight-based volume for each bottle. A substantial amount of the bottles (48.3%) were inadequately filled. Evaluation of the accuracy of the monitoring system showed a mean bias of -1.4 mL (-15.4%). Additional evaluation, using the amended software on 287 aerobic blood culture bottles, resulted in an acceptable mean deviation of -0.3 mL (-3.3%). The new software version was also tested on 200 of the recently introduced plastic bottles, which will replace the glass bottles in the near future, showing a mean deviation of +2.8 mL (+26.7%). In conclusion, the mean calculated volumes can be used for the training of a single phlebotomist. However, filling problems appear to be masked when using them for phlebotomist groups or on wards. Here, visual interpretation of boxplots and histograms can serve as a useful tool to observe the spread of the filling degrees and to develop a continuous improvement program. Re-adjustment of the software has proven to be necessary for use with plastic bottles. Due to our findings, BD has developed further adjustments to the software for validated use with plastic bottles, which will be released soon.

Procalcitonin and C-reactive protein in differantiating to contamination from bacteremia

Procalcitonin (PCT) and C-reactive protein (CRP) are important biological markers used in the diagnosis of severe infections. The aim of this study was to evaluate the consistency of blood culture with PCT and CRP in differentiating contamination and non-bacteremia from true bacteremia. In this study blood samples were obtained from 809 febrile patients and analyzed using BACTEC 9120 system. All of positive blood cultures were performed Gram staining. The microorganisms were identified with conventional methods and automated systems. Antibiotic susceptibility tests were made by disc diffusion. PCT levels were analyzed by mini VIDAS device and PCT kit. PCT and CRP levels were analyzed with blood cultures in same times. Kruskal Wallis test, Mann-Whitney U test, Spearman’s rho test and ROC curve were used for statistical analyses. The bacteremia group was found to be significantly different from non-bacteremia group and contamination group in terms of both PCT and CRP (p<0.0001). The p values of PCT and CRP in differentiating bacteremia from non-bacteremia were p<0.001 for PCT, p=0.002 for CRP and in differentiating bacteremia from contamination were p<0.001 for PCT, p<0.001 for CRP. PCT is a more useful marker than CRP in the differentiating of true bacteremia from contamination according to the results of this study.

Evolutionary identification of affinity peptides for the detection of sepsis biomarker procalcitonin

We demonstrate for the first time the use of phage display for the discovery of unique peptide motifs which are capable of binding to procalcitonin. The best peptide specific for procalcitonin was found to be 1.9 ± 0.001 nanomolar affinity.

The L-arginine pathway in acute ischemic stroke and severe carotid stenosis: temporal profiles and association with biomarkers and outcome

BACKGROUND

Endothelial dysfunction is associated with increased levels of asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) resulting in a decreased production of nitric oxide, which regulates the vascular tone.

METHODS

Patients with acute ischemic stroke (AIS, n = 55) and asymptomatic significant carotid stenosis (AsCS, n = 44) were prospectively investigated. L-arginine, ADMA, SDMA, S100 B, and high-sensitivity C-reactive protein (hsCRP) were serially measured within 6 hours after the onset of stroke, at 24 and 72 poststroke hours. All markers were compared with healthy subjects (n = 45). The severity of AIS was daily assessed by National Institute of Health Stroke Scale scoring.

RESULTS

Even within 6 hours after the onset of stroke, L-arginine, ADMA, and SDMA were significantly higher in patients with AIS compared with both AsCS and healthy subjects. S100 B reflecting infarct size, positively correlated with the level of SDMA at 72 poststroke hours; changes in concentration of S100 B positively correlated with changes in the concentration of ADMA by 72 hours. Change in concentration of both ADMA and SDMA correlated with the change in concentration of hsCRP. Concentrations of L-arginine and hsCRP at 72 poststroke hours, respectively, were independent predictors of poststroke infection. S100 B level measured within 6 hours after the onset of AIS and hsCRP at 72 poststroke hours were independent predictors of death.

CONCLUSIONS

Metabolites of the L-arginine pathway were elevated in the very acute phase of ischemic stroke indicating a more pronounced endothelial dysfunction compared with AsCS. An increased basal L-arginine level in patients with AIS might be an adaptive mechanism; such transient elevation of the L-arginine/ADMA ratio at 24 poststroke hours may suggest that a temporary increase of L-arginine along with decrease of ADMA might be related to the protective role of L-arginine. Changes in the L-arginine pathway are predictive of poststroke infections.

Clinical outcomes after utilizing surviving sepsis campaign in children with septic shock and prognostic value of initial plasma NT-proBNP

BACKGROUND AND OBJECTIVE

The surviving sepsis campaign treatment guideline (SSC) implementation is associated with improved outcome in adults with severe sepsis. The effect on outcome of pediatric sepsis is less clear.

PURPOSE

To determine the clinical outcomes of SSC implementation and to investigate the prognostic value of initial plasma NT-proBNP and procalcitonin in children.

MATERIALS AND METHODS

Infants and children (aged 1month/0-15 years with severe sepsis or septic shock) were prospectively enrolled and treated according to the guidelines. Initial blood drawn was saved for NT-pro-BNP, procalcitonin measurements and clinical data were also recorded.

RESULTS

A total of 47 subjects were recruited. Since the application of the SSC, our mortality rate had significantly decreased from 42-19% (P = 0.003) as compared to the data in the previous 3 years. Clinical factors that significantly increased the mortality rate were: Initial central venous oxygen saturation < 7 0% after fluid resuscitation [odds ratio (OR) = 23.3; 95% confidence interval (CI) 3.7-143; P = 0.001], and initial albumin level (≤ 3 g/dl, OR = 6.7; 95% CI 1.2-37.5, P = 0.03). There was asignificant difference between the initial NT-proBNP levels between survivors and non survivors, (6280.3 ± 9597 ng/L, P < 0.001), but not for procalcitonin (12.7 ± 24.8, 29.3 ± 46 μg/L, P = 0.1), respectively. An initial NT-proBNP level of more than 11,200 pg/ml predicted Pediatric Intensive Care Unit (PICU) mortality with a sensitivity of 85.7% and a specificity of 90%.

CONCLUSIONS

A modified SSC for severe sepsis and septic shock significantly reduced the mortality rate in our PICU. High initial NT-ProBNP level was associated with mortality.

[Validation of APACHE II and SOFA scores in 2 cohorts of patients with suspected infection and sepsis, not admitted to critical care units]

OBJECTIVE

To validate the APACHE II and SOFA scores in patients with suspected infection in clinical settings other than intensive care units.

MATERIALS AND METHODS

A secondary analysis was performed on 2,530 adult patients participating in 2 cohort studies, with suspected infection as admission diagnosis within the first 24 h of hospitalization. The performance of both scoring systems was studied in order to set calibration and discrimination, respectively, on the outcomes such as mortality, admission to Intensive Care Unit, development of septic shock, or multiple organ dysfunctions.

RESULTS

The AUC-ROC values for mortality at discharge and on day 28 in the first cohort were around 0.50 for the SOFA and APACHE II scores; whereas for the second cohort the discrimination value was around 0.70. Calibration of both scoring systems for primary outcomes, according to Hosmer-Lemeshow test, showed p>.05 in the first cohort; while in the second cohort calibration it only showed a p>.05 in the case of the SOFA for mortality at hospital discharge.

CONCLUSION

This validation study of SOFA and APACHE II scores in patients with suspected infection in-hospital units other than the Intensive Care Unit, showed no consistent performance for calibration and discrimination. Its application in emergency and in-hospital patients is limited.

Unrevealing culture-negative severe sepsis

Sepsis involves a wide array of sources and microorganisms, only a fraction of which are microbiologically documented. Culture-negative sepsis poses special diagnostic challenges to both clinicians and microbiologists and further questions the validity of sepsis definitions.

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 preanalytical optimization of blood cultures: a review and the clinical importance of benchmarking in 5 Belgian hospitals

Bloodstream infections remain a major challenge in medicine. Optimal detection of pathogens is only possible if the quality of preanalytical factors is thoroughly controlled. Since the laboratory is responsible for this preanalytical phase, the quality control of critical factors should be integrated in its quality control program. The numerous recommendations regarding blood culture collection contain controversies. Only an unambiguous guideline permits standardization and interlaboratory quality control. We present an evidence-based concise guideline of critical preanalytical determinants for blood culture collection and summarize key performance indicators with their concomitant target values. In an attempt to benchmark, we compared the true-positive rate, contamination rate, and collected blood volume of blood culture bottles in 5 Belgian hospital laboratories. The true-positive blood culture rate fell within previously defined acceptation criteria by Baron et al. (2005) in all 5 hospitals, whereas the contamination rate exceeded the target value in 4 locations. Most unexpected, in each of the 5 laboratories, more than one third of the blood culture bottles were incorrectly filled, irrespective of the manufacturer of the blood culture vials. As a consequence of this shortcoming, one manufacturer recently developed an automatic blood volume monitoring system. In conclusion, clear recommendations for standardized blood culture collection combined with quality control of critical factors of the preanalytical phase are essential for diagnostic blood culture improvement.

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.

The sensitivity of neutrophil CD64 expression as a biomarker of bacterial infection is low in critically ill patients

PURPOSE

CD64 expression on the surface of neutrophils has recently been proposed as an early marker of bacterial infection. The goal of this study was to determine whether the CD64 index allows differentiation of bacterial sepsis from viral and fungal sepsis and other inflammatory states in a critical-care setting.

METHODS

This was an observational prospective study conducted in a medical ICU of a university hospital. All patients admitted between September 2009 and March 2010 with at least two criteria for systemic inflammatory response syndrome (SIRS) were eligible for inclusion. Upon admission, hematological exams were conducted by flow cytometry, allowing quantification of CD64 expression (Leuko64™ kit, Trillium Diagnostics LLC, USA). ROC curve analysis was performed to evaluate the utility of the CD64 index in the diagnosis of bacterial infection. Patients with suspected infection were excluded when infection could not be microbiologically confirmed.

RESULTS

Our study included 293 patients with a SAPS II score of 45 (31-59). Bacterial infection was found in 148 patients and SIRS or non-bacterial infection was documented in 145 patients. A CD64 index greater than 2.2 predicted bacterial infection with a sensitivity and specificity of 63% (55-71%) and 89% (83-94%), respectively. The area under the ROC curve was 0.8 (0.75-0.84). Positive and negative likelihood ratios were 5.7 (5.0-6.5) and 0.4 (0.3-0.7), respectively.

CONCLUSIONS

The CD64 index is specific for bacterial infection among ICU patients. As a result of its weak sensitivity, the CD64 index may not be practically recommended, but it may be useful in combination with a more sensitive biological marker.

Low ficolin-3 levels in early follow-up serum samples are associated with the severity and unfavorable outcome of acute ischemic stroke

Background

A number of data indicate that the lectin pathway of complement activation contributes to the pathophysiology of ischemic stroke. The lectin pathway may be triggered by the binding of mannose-binding lectin (MBL), ficolin-2 or ficolin-3 to different ligands. Although several papers demonstrated the significance of MBL in ischemic stroke, the role of ficolins has not been examined.

Methods

Sera were obtained within 12 hours after the onset of ischemic stroke (admission samples) and 3-4 days later (follow-up samples) from 65 patients. The control group comprised 100 healthy individuals and 135 patients with significant carotid stenosis (patient controls). The concentrations of ficolin-2 and ficolin-3, initiator molecules of the lectin complement pathway, were measured by ELISA methods. Concentration of C-reactive protein (CRP) was also determined by a particle-enhanced immunturbidimetric assay.

Results

Concentrations of both ficolin-2 and ficolin-3 were significantly (p < 0.001) decreased in both the admission and in the follow-up samples of patients with definite ischemic stroke as compared to healthy subjects. Concentrations of ficolin-2 and ficolin-3 were even higher in patient controls than in healthy subjects, indicating that the decreased levels in sera during the acute phase of stroke are related to the acute ischemic event. Ficolin-3 levels in the follow-up samples inversely correlated with the severity of stroke indicated by NIH scale on admission. In follow-up samples an inverse correlation was observed between ficolin-3 levels and concentration of S100β, an indicator of the size of cerebral infarct. Patients with low ficolin-3 levels and high CRP levels in the follow up samples had a significantly worse outcome (adjusted ORs 5.6 and 3.9, respectively) as measured by the modified Rankin scale compared to patients with higher ficolin-3 and lower CRP concentrations. High CRP concentrations were similarly predictive for worse outcome, and the effects of low ficolin-3 and high CRP were independent.

Conclusions

Our findings indicate that ficolin-mediated lectin pathways of complement activation contribute to the pathogenesis of ischemic stroke and may be additive to complement-independent inflammatory processes.

[Prognostic value of procalcitonin, C-reactive protein and leukocytes in septic shock]

OBJECTIVES

This study evaluates the potential prognostic value of serial measurements of different biomarkers (procalcitonin [PCT], C-reactive protein and leukocytes [CRP]) in septic shock patients.

DESIGN

Prospective observational study.

SETTING

Intensive care unit of a third-level University Hospital.

PATIENTS

The study comprised a total of 88 septic shock patients defined using the 2001 Consensus Conference SCCM/ESICM/ACCP/ATS/SIS criteria. The PCT, CRP and leukocytes were recorded on admission to the ICU and again 72 hours after admission.

INTERVENTIONS

None.

RESULTS

Those patients with increasing procalcitonin levels showed higher hospital mortality than those with a decreasing levels (58.8% vs. 15.4%, P<0.01). No such effect was observed in relation to C-reactive protein or leukocytes. The best area under the curve for prognosis was for procalcitonin clearance (0.79). A procalcitonin clearance of 70% or higher offered a sensitivity and specificity of 94.7% and 53%, respectively.

CONCLUSIONS

Serial procalcitonin measurements are more predictive of the prognosis of septic shock patients than single measurements of this parameter. The prognostic reliability of the latter is also better than in the case of C-reactive protein and leukocytes. The application of serial procalcitonin measurements may allow the identification of those septic patients at increased mortality risk, and help improve their treatment.

Early-onset ventilator-associated pneumonia incidence in intensive care units: a surveillance-based study

Background

The incidence of ventilator-associated pneumonia (VAP) within the first 48 hours of intensive care unit (ICU) stay has been poorly investigated. The objective was to estimate early-onset VAP occurrence in ICUs within 48 hours after admission.

Methods

We analyzed data from prospective surveillance between 01/01/2001 and 31/12/2009 in 11 ICUs of Lyon hospitals (France). The inclusion criteria were: first ICU admission, not hospitalized before admission, invasive mechanical ventilation during first ICU day, free of antibiotics at admission, and ICU stay ≥ 48 hours. VAP was defined according to a national protocol. Its incidence was the number of events per 1,000 invasive mechanical ventilation-days. The Poisson regression model was fitted from day 2 (D2) to D8 to incident VAP to estimate the expected VAP incidence from D0 to D1 of ICU stay.

Results

Totally, 367 (10.8%) of 3,387 patients in 45,760 patient-days developed VAP within the first 9 days. The predicted cumulative VAP incidence at D0 and D1 was 5.3 (2.6-9.8) and 8.3 (6.1-11.1), respectively. The predicted cumulative VAP incidence was 23.0 (20.8-25.3) at D8. The proportion of missed VAP within 48 hours from admission was 11% (9%-17%).

Conclusions

Our study indicates underestimation of early-onset VAP incidence in ICUs, if only VAP occurring ≥ 48 hours are considered to be hospital-acquired. Clinicians should be encouraged to develop a strategy for early detection after ICU admission.

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.

Incidence and bacteriology of burn infections at a military burn center

Considerable advancements in shock resuscitation and wound management have extended the survival of burned patients, increasing the risk of serious infection. We performed a 6-year review of bacteria identification and antibiotic susceptibility records at the US Army Institute of Surgical Research Burn Center between January 2003 and December 2008. The primary goal was to identify the bacteria recovered from patients with severe burns and determine how the bacteriology changes during extended hospitalization as influenced by population and burn severity. A total of 460 patients were admitted to the burn ICU with 3507 bacteria recovered from 13,727 bacteriology cultures performed. The most prevalent organisms recovered were Acinetobacter baumannii (780), Pseudomonas aeruginosa (703), Klebsiella pneumoniae (695) and Staphylococcus aureus (469). A. baumannii was most often recovered from combat-injured (58%) and S. aureus the most frequent isolate from local (46%) burn patients. Culture recovery rate of A. baumannii and S. aureus was highest during the first 15 hospital days (73% and 71%); while a majority of P. aeruginosa and K. pneumoniae were recovered after day 15 (63% and 53%). All 4 pathogens were recovered throughout the course of hospitalization. A. baumannii was the most prevalent pathogen recovered from patients with total body surface area (TBSA) burns less than 30% (203) and 30-60% (338) while P. aeruginosa was most prevalent in patients with burns greater than 60% TBSA (292). Shifting epidemiology of bacteria recovered during extended hospitalization, bacteriology differences between combat-injured and local burn patients, and impact of % TBSA may affect patient management decisions during the course of therapy.

Suspected infections in children treated for ALL

AIM

The aim of our study was to get epidemiological information on bacterial infections in children treated for ALL and to analyse which patients have an enhanced infection risk.

METHODS

Episodes of suspected or confirmed infections were evaluated during the first 12 months of treatment for childhood acute lymphoblastic leukaemia (ALL).

RESULTS

The number of patients was 73 (43 boys). The median age was 4.6 years. A total of 179 episodes occurred, varying from none in six patients to eight in one. Bacteria were cultured in 57 episodes (31.8%), the most common being coagulase-negative staphylococci. The number of episodes fell significantly with increasing age for suspected and confirmed infections (p < 0.001 and p = 0.03). The proportion of confirmed infections was significantly higher (p < 0.001) in the first episodes. The average number of suspected infections was higher in girls than in boys (p = 0.03), but confirmed infections were not.

CONCLUSION

Most of the serious infections occur early in the treatment and the number of suspected and confirmed infections falls with age. Suspicion of infection is more likely in girls, but the number of confirmed infections is equal in both sexes. Coagulase-negative staphylococcus was most commonly isolated, highlighting the importance of careful handling of central venous devices.

Diagnosis of bloodstream infections in immunocompromised patients by real-time PCR

OBJECTIVES

The diagnosis of bloodstream infections (BSIs) in immunocompromised patients, such as patients with cancer, is challenging. Although blood culture (BC) is considered the standard diagnostic tool for BSIs, it takes several days to yield results and has low sensitivity in these patients. Here, we tested a novel method for diagnosing BSIs in a large cohort of immunodepressed patients.

METHODS

Real-time PCR (LightCycler SeptiFast Test M(GRADE), Roche Diagnostics) was compared with BC for its ability to detect bacteria and fungi in blood samples from 100 immunocompromised patients (98 with cancer) in whom sepsis was suspected.

RESULTS

In concordant samples (79.2% of total cases), real-time PCR identified the presence or absence of microbes significantly faster than BC (p=3.7x10(-49), t-test). Furthermore, in 6 cases, SeptiFast distinguished contamination of BCs by coagulase-negative staphylococci. SeptiFast, however, failed to detect 5 cases of clinically relevant BSI that tested positive by BC.

CONCLUSIONS

SeptiFast rapidly diagnosed BSIs in our cohort of immunosuppressed patients. The results of this study suggest that SeptiFast can be used in conjunction with, but cannot replace, BC to better identify the etiology of fever in immunocompromised patients.

Update on the management of infection in patients with severe sepsis

Morbidity and mortality associated with the development of severe sepsis remain unacceptably high. However, with the introduction of a protocol called early goal-directed therapy, significant benefits in terms of patient's outcome have been demonstrated. In an aim to improve outcome and to increase awareness, practical evidence-based guidelines for the management of severe sepsis and septic shock were developed under the auspices of the Sepsis Surviving Campaign, easy to apply by the bedside medical and nursing staff. The treatment of severe sepsis includes 3 main essentials: (1) eradication of the inciting infection using source control measures and empiric antimicrobials, (2) hemodynamic resuscitation of tissue hypoperfusion using fluids and inotropic drugs to prevent life-threatening organ damage, and (3) sustained organ support using mechanical interventions to diminish organ injury. This review article highlights the anti-infective approach of the management of sepsis.

Inflammation and the host response to injury, a large-scale collaborative project: patient-oriented research core--standard operating procedures for clinical care VII--Guidelines for antibiotic administration in severely injured patients

When the clinical decision to treat a critically ill patient with antibiotics has been made, one must attempt to identify the site of infection based on clinical signs and symptoms, laboratory or diagnostic radiology studies. Identification of site requires, examination of patient, inspection of all wounds, chest radiograph, and calculation of clinical pulmonary infection score if ventilated, obtaining blood cultures, urinalysis, and line change if clinical suspicion of central venous catheter (CVC) source. If it is impossible to identify site, obtain cultures from all accessible suspected sites and initiate empiric, broad spectrum antibiotics. If likely site can be identified answer these questions: Is intra-abdominal site suspected? Is pulmonary source of infection suspected? Is skin, skin structure or soft tissue site suspected? If yes, does the patient have clinical signs suspicion for necrotizing soft tissue infection (NSTI)? Is a CVC infection suspected? Risk factors for more complicated infections are discussed and specific antibiotic recommendations are provided for each type and severity of clinical infection. Decision to continue, discontinue and/or alter antibiotic/antimicrobial treatment should be based on the clinical response to treatment, diagnostic or interventional findings, and culture and sensitivity data, bearing in mind that not all patients with infections will have positive cultures because of limitations of specimen handling, microbiology laboratory variations, time between specimen acquisition and culture, or presence of effective antibiotics at the time that specimens were obtained. It should also be noted that not all patients with increased temperature/WBC have an infection. Discontinuation of antibiotics is appropriate if cultures and other diagnostic studies are negative.

Severe Sepsis and Septic Shock

This chapter reviews the remarkable recent advances in the understanding of the molecular basis that underlies the pathophysiology of sepsis. This knowledge has improved diagnostic techniques and introduced new therapeutic agents into the standard management of patients with severe sepsis/septic shock. The current treatment regimens for sepsis are discussed, and the evidence to support each major treatment strategy is outlined in detail. Research priorities to further the optimal management of septic shock in the future are highlighted.

Inadequate blood volume collected for culture: a survey of health care professionals

Adequate blood culture volume is the single most important determinant for yield of organisms. We sought to determine whether health care professionals are aware of the current evidence-based recommendations for blood culture collection. An anonymous survey of employees qualified to collect blood cultures was conducted (July-October 2004) in an urban tertiary care facility. The survey asked,"What volume of blood should be collected in one bottle for a blood culture?" Of the 360 employees of the hospital surveyed, 355 returned evaluable answers for blood culture volume collected. Overall, 79% (95% confidence interval [CI], 74%-83%) answered less than 10 mL, and 44% (95% CI, 39%-49%) answered less than 5 mL of blood. When examined by occupation, 90% (95% CI, 86%-94%) of nurses, 97% (95% CI, 91%-100%) of technicians, and 55% (95% CI, 46%-64%) of physicians answered less than 10 mL; 52% (95% CI, 45%-59%) of nurses, 63% (95% CI, 46%-79%) of technicians, and 26% (95% CI, 18%-35%) of physicians answered less than 5 mL. Of all respondents, 21% (95% CI, 17%-25%) answered 1 mL or less. Our findings reveal that a high percentage of health care personnel do not know the optimal volume of blood recommended for collection. Because volume remains the most important determinant for the optimal yield of organisms, these findings raise an important quality assurance issue.

Sepsis in critical care

Sepsis is a syndrome produced by the accelerated activity of the inflammatory immune response, the clotting cascade, and endothelial damage. It is a systematic process that can progress easily into septic shock and MODS. The chemical mediators or cytokines produce a complex self-perpetuating process that impacts all body systems. It is critical for the nurse first to identify patients at risk for developing sepsis and to assess patients who have SIRS and sepsis continually for signs and symptoms of organ involvement and organ dysfunction. Once sepsis has been diagnosed, evidence-based practice indicates initiation of fluid resuscitation. Vasopressor therapy, positive inotropic support, and appropriate antibiotic therapy should be started within the first hour. Within a 6-hour timeframe the goal is stabilization of the CVP, MAP, and UOP to prevent further organ damage. The challenge for nurses caring for septic patients is to support the treatment goals, to prevent added complications including stress ulcers, DVTs, aspiration pneumonia, and the progression to MODS, and to address the patient's and the family's psychosocial needs. As complex as the pathophysiology of sepsis is, the nursing care is equally complex but also rewarding. Patients who previously might have died now recover as vigilant nursing care combines forces with new drug therapies and evidence-based practice guidelines.

An anatomy of an infection: overview of the infectious process

The immune system remains an enigmatic system in that each discovery leads to more questions and speculation. It is essential for the critical care nurse to understand the basic physiology that occurs in infections to address the issues in patients in an efficient and timely manner. Thorough patient assessment helps determine predictors and priorities. Although the protective barrier of an intact integument system often is identified as the first and best line of defense against infections, this defense can be strengthened by a critical care nurse who is equipped with the knowledge and understanding of the immune system, the latest research, and the dynamics that ensue within the patient.

Management of peritonitis in the critically ill patient

Severe secondary peritonitis carries significant mortality, despite advancements in critical care support and other therapies. Surgical management requires a multidisciplinary approach to guide the timing and the number of interventions necessary to eradicate the septic foci and create optimal healing with the fewest complications. Research is needed regarding the best surgical strategy for very severe cases. The use of deferred primary anastomosis seems safe in patients presenting with hemodynamic instability and hypoperfusion. These patients have a high risk of anastomotic failure and fistula formation. Allowing for aggressive resuscitation and judicious assessment of the progression of local inflammation are safe strategies to achieve the highest success and minimize serious and protracted complications in patients who survive the initial septic insult.