Multinational, observational study of procalcitonin in ICU patients with pneumonia requiring mechanical ventilation: a multicenter observational study

Serum procalcitonin as a diagnostic biomarker in dogs with bacterial respiratory diseases

BACKGROUND

Procalcitonin (PCT) is a useful biomarker in humans in the identification of bacterial respiratory infections.

OBJECTIVES

The aim of this study was to investigate the utility of serum PCT measurements as a diagnostic biomarker in canine bacterial lower respiratory tract diseases.

METHODS

PCT concentrations were measured in serum samples with an ELISA method previously validated for dogs. All dogs underwent thorough clinical examinations, and the diagnosis of respiratory disease was based on clinical and laboratory findings, diagnostic imaging, as well as cytology and bacterial culture of respiratory samples. PCT concentrations between different cohorts of dogs were compared with an ANOVA-model.

RESULTS

Sixty-two privately owned dogs with respiratory diseases, 25 with bacterial pneumonia (BP), 17 with bacterial bronchitis caused by Bordetella bronchiseptica (BB), and 20 with chronic bronchitis (CB) as well as 44 healthy controls were included in the study. Serum PCT concentrations in dogs with bacterial respiratory diseases (BP mean 51.8 ng/L ± standard deviation [SD] 40.6 ng/L and BB mean 61.4 ng/L ± SD 35.3 ng/L) were not significantly different when compared with dogs with a non-bacterial respiratory disease (CB mean 89.7 ± SD 73.5 ng/L) or healthy dogs (mean 51.0 ng/L ± SD 37.5 ng/L, p > .05 in all comparisons).

CONCLUSIONS

These results indicate that despite being a valuable diagnostic, prognostic, and follow-up marker in humans with pneumonia, serum PCT concentrations are not elevated in dogs with bacterial respiratory diseases and, therefore, cannot be used as a diagnostic biomarker in dogs.

An inflammation-based model for identifying severe acute pancreatitis: a single-center retrospective study

BACKGROUND AND AIMS

Severe acute pancreatitis (SAP) is potentially lethal. Considering the role of inflammation in the progression of acute pancreatitis (AP), this study aims to develop a model based on inflammatory indexes for identifying the presence of SAP.

METHODS

Overall, 253 patients with AP who were consecutively admitted between July 2018 and November 2020 were screened, of whom 60 had SAP. Systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR), neutrophil-to-platelet ratio (NPR), systemic inflammation response index (SIRI), platelet-to-albumin ratio (PAR), C-reactive protein-to-albumin ratio (CAR), C-reactive protein-to-lymphocyte ratio (CLR), and triglyceride glucose (TyG) index were calculated. Multivariate logistic regression analyses were performed to identify independent risk factors of SAP. Then, inflammation-based models were established. Receiver operating characteristics (ROC) curve analyses were performed. Area under ROC curve (AUROC) was calculated.

RESULTS

Diabetes mellitus, fatty liver, high white blood cell count (WBC), C-reactive protein (CRP), red blood cell distribution width (RDW), procalcitonin (PCT), SII, NLR, NPR, CAR, CLR, and TyG index, and a low LMR were significantly associated with SAP. Considering the collinearity among these variables, 10 multivariate logistic regression analyses were separately performed. Finally, four independent inflammation-based models were established. Of them, the best one, which was calculated as follows: 1.204*fatty liver (yes = 1; no = 0) + 0.419*PCT + 0.005*CLR - 2.629, had an AUROC of 0.795 with a specificity of 73.4% and a sensitivity of 71.7%.

CONCLUSION

The inflammation-based model consisting of fatty liver, PCT, and CLR has a good diagnostic performance for SAP.

Guidelines for the Use of Procalcitonin for Rational Use of Antibiotics

How to cite this article: Khilnani GC, Tiwari P, Zirpe KG, Chaudhary D, Govil D, Dixit S, et al. Guidelines for the Use of Procalcitonin for Rational Use of Antibiotics. Indian J Crit Care Med 2022;26(S2):S77-S94.

A 29-MRNA HOST RESPONSE WHOLE-BLOOD SIGNATURE IMPROVES PREDICTION OF 28-DAY MORTALITY AND 7-DAY INTENSIVE CARE UNIT CARE IN ADULTS PRESENTING TO THE EMERGENCY DEPARTMENT WITH SUSPECTED ACUTE INFECTION AND/OR SEPSIS

ABSTRACT

Background: Risk stratification of emergency department patients with suspected acute infections and/or suspected sepsis remains challenging. We prospectively validated a 29-messenger RNA host response classifier for predicting severity in these patients. Methods: We enrolled adults presenting with suspected acute infections and at least one vital sign abnormality to six emergency departments in Greece. Twenty-nine target host RNAs were quantified on NanoString nCounter and analyzed with the Inflammatix Severity 2 (IMX-SEV-2) classifier to determine risk scores as low, moderate, and high severity. Performance of IMX-SEV-2 for prediction of 28-day mortality was compared with that of lactate, procalcitonin, and quick sequential organ failure assessment (qSOFA). Results: A total of 397 individuals were enrolled; 38 individuals (9.6%) died within 28 days. Inflammatix Severity 2 classifier predicted 28-day mortality with an area under the receiver operator characteristics curve of 0.82 (95% confidence interval [CI], 0.74-0.90) compared with lactate, 0.66 (95% CI, 0.54-0.77); procalcitonin, 0.67 (95% CI, 0.57-0.78); and qSOFA, 0.81 (95% CI, 0.72-0.89). Combining qSOFA with IMX-SEV-2 improved prognostic accuracy from 0.81 to 0.89 (95% CI, 0.82-0.96). The high-severity (rule-in) interpretation band of IMX-SEV-2 demonstrated 96.9% specificity for predicting 28-day mortality, whereas the low-severity (rule-out) band had a sensitivity of 78.9%. Similarly, IMX-SEV-2 alone accurately predicted the need for day-7 intensive care unit care and further boosted overall accuracy when combined with qSOFA. Conclusions: Inflammatix Severity 2 classifier predicted 28-day mortality and 7-day intensive care unit care with high accuracy and boosted the accuracy of clinical scores when used in combination.

Clinico-bacterial and prognostic factors in patients with suspected blood stream infection and elevated serum procalcitonin levels

This study determined prognostic factors by comparing clinico-bacterial factors based on significant elevated serum procalcitonin levels in patients with suspected bloodstream infection (BSI). We retrospectively analyzed the medical records of 1,052 patients (age ≥16 years) with fever (temperature ≥38°C) and serum procalcitonin levels of ≥2.0 ng/mL, and blood culture results. The optimal cutoff value of the significant elevation of procalcitonin was determined using the minimum P-value approach. Clinico-bacterial factors were analyzed per the procalcitonin levels, and significant independent factors for short-term survival were investigated in 445 patients with BSI. Patients with suspected BSI were aged, on average, 72.3 ± 15.1 years, and the incidence of positive blood culture was 42.3%; and the 14-day survival was 83.4%. Procalcitonin ≥100 ng/mL was the most significant predictor for survival. Multivariate analysis in patients with suspected BSI showed that estimated glomerular filtration rate (eGFR) <30 mL/min/1.73 m² and procalcitonin ≥100 ng/mL were significant independent unfavorable prognostic factors. Microorganisms were similar between patients with procalcitonin level 2-99 ng/mL (n=359) and those with ≥100 ng/mL (n=86). Multivariate analysis in patients with BSI showed that eGFR <30 mL/min/1.73 m², procalcitonin ≥100 ng/mL, and primary infectious foci were significant independent prognostic factors. Patients with foci in the gastrointestinal tract and respiratory system had unfavorable 14-day survival. In conclusions, eGFR <30 mL/min/1.73 m² and procalcitonin ≥100 ng/mL were significant independent unfavorable prognostic factors for suspected BSI. Primary infectious foci (gastrointestinal tract and respiratory system) were associated with unfavorable short-term survival in patients with positive blood culture.

Assessment of mechanisms of infectious pneumonia based on expression of fibrinogen, procalcitonin, high-sensitivity C-reactive protein expression, T helper 17 cells, regulatory T cells interleukin-10, and interleukin-17

BACKGROUND

Infectious pneumonia is one of the important causes of neonatal death that can lead to the imbalance of T helper 17 cells (Th17) and T regulatory T cells (Treg) cells. The correlation between plasma fibrinogen (FIB), procalcitonin (PCT), C-reactive protein (CRP) and Th17/Treg-IL-10/IL-17 axis balance and their specific role in the occurrence and development of infectious pneumonia are not completely clear.

METHODS

Thirty specific-pathogen free Sprague Dawley (SD) rats were randomly divided into a control group for comparison and IPN model group. After the establishment of infectious pneumonia model, levels of FIB, PCT, hs-CRP, IL-10, and IL-17 in the serum of the two groups were measured using enzyme linked immunosorbent assay (ELISA), the pathological changes of lung tissue were observed using hematoxylin and eosin (HE) staining, the number of Treg and Th17 cells and the ratio of Th17/Treg in serum were detected using flow cytometry, and the levels of retinoic acid-related orphan receptor γt and forkhead box P3 (FOXP3) in lung tissue were detected using reverse transcription polymerase chain reaction (RT-PCR) and western blot.

RESULTS

The results showed that the serum levels of FIB, PCT, hs-CRP, Th17 cell number, Th17/Treg ratio, left lung dry and wet weight, lung tissue wet/dry ratio, lung pathology score and IL-17 level in the model group were significantly higher than those in the control group, while the number of Treg cells and the level of IL-10 in the model group were significantly lower than those in the control group. In addition, the expression of Foxp3mRNA and protein in lung tissue of model group decreased significantly, while the expression level of ROR- γ t mRNA and protein increased.

CONCLUSIONS

In infectious pneumonia, the expression levels of FIB, PCT and hs-CRP are up-regulated, and Th17 cells are activated, Treg cells are inhibited, proinflammatory cytokine IL-17 expression is up-regulated, anti-inflammatory cytokine IL-10 expression is down-regulated, resulting in increased inflammatory response, thus promoting the occurrence and development of infectious pneumonia.

[Which biomarkers for diagnosis and guidance of anti-infection treatment in sepsis?]

To date no biomarker has been identified bringing together perfect sensitivity and specificity to discriminate between inflammation and infections. Since the 1930s new markers of tissue damage and endothelial damage have been identified but which are incapable of identifying infections in every clinical setting to enable initiation of early antibiotic treatment. In this review the most important classical biomarkers and upcoming new PCR-based approaches are addressed. These markers are highlighted with respect to special clinical settings and to control the success of antibiotic treatment. The issue of discrimination between inflammation and infection is not yet solved. Based on one single biomarker it is impossible to decide whether infection is the reason for the patient's worsening condition but the combination of biomarkers or the integration of new biomarkers may be a meaningful supplement. The measurement of different biomarkers of infection or inflammation is part of the routine in critical care and will be essential in the future.

A literature review of severity scores for adults with influenza or community-acquired pneumonia - implications for influenza vaccines and therapeutics

Influenza vaccination and antiviral therapeutics may attenuate disease, decreasing severity of illness in vaccinated and treated persons. Standardized assessment tools, definitions of disease severity, and clinical endpoints would support characterizing the attenuating effects of influenza vaccines and antivirals. We review potential clinical parameters and endpoints that may be useful for ordinal scales evaluating attenuating effects of influenza vaccines and antivirals in hospital-based studies. In studies of influenza and community-acquired pneumonia, common physiologic parameters that predicted outcomes such as mortality, ICU admission, complications, and duration of stay included vital signs (hypotension, tachypnea, fever, hypoxia), laboratory results (blood urea nitrogen, platelets, serum sodium), and radiographic findings of infiltrates or effusions. Ordinal scales based on these parameters may be useful endpoints for evaluating attenuating effects of influenza vaccines and therapeutics. Factors such as clinical and policy relevance, reproducibility, and specificity of measurements should be considered when creating a standardized ordinal scale for assessment.

Recommendations for antibiotic selection for severe nosocomial infections

Severe infection and its evolution to sepsis are becoming more prevalent every day and are among the leading causes of critical illness and mortality. Proper management is crucial to improve prognosis. This document addresses three essential points that have a significant impact on this objective: a) early recognition of patients with sepsis criteria, b) identification of those patients who suffer from an infection and have a high risk of progressing to sepsis, and c) adequate selection and optimization of the initial antimicrobial treatment.

A comparison of diagnostic algorithms and clinical parameters to diagnose ventilator-associated pneumonia: a prospective observational study

Background

Suspicion and clinical criteria continue to serve as the foundation for ventilator-associated pneumonia (VAP) diagnosis, however the criteria used to diagnose VAP vary widely. Data from head-to-head comparisons of clinical diagnostic algorithms is lacking, thus a prospective observational study was performed to determine the performance characteristics of the Johanson criteria, Clinical Pulmonary Infection Score (CPIS), and Centers for Disease Control and Prevention’s National Healthcare Safety Network (CDC/NHSN) criteria as compared to Hospital in Europe Link for Infection Control through Surveillance (HELICS) reference standard.

Methods

A prospective observational cohort study was performed in three mixed medical-surgical ICUs from one academic medical center from 1 October 2016 to 30 April 2018. VAP diagnostic criteria were applied to each patient including CDC/NHSN, CPIS, HELICS and Johanson criteria. Tracheal aspirate cultures (TAC) and serum procalcitonin values were obtained for each patient.

Results

Eighty-five patients were enrolled (VAP 45, controls 40). Using HELICS as the reference standard, the sensitivity and specificity for each of the assessed diagnostic algorithms were: CDC/NHSN (Sensitivity 54.2%; Specificity 100%), CPIS (Sensitivity 68.75%; Specificity 95.23%), Johanson (Sensitivity 67.69%; Specificity 95%). The positive TAC rate was 81.2%. The sensitivity for positive TAC with the serum procalcitonin level > 0.5 ng/ml was 51.8%.

Conclusion

VAP remains a considerable source of morbidity and mortality in modern intensive care units. The optimal diagnostic method remains unclear. Using HELICS criteria as the reference standard, CPIS had the greatest comparative diagnostic accuracy, whereas the sensitivity of the CDC/NHSN was only marginally better than a positive TAC plus serum procalcitonin > 0.5 ng/ml. Algorithm accuracy was improved by adding serum procalcitonin > 0.5 ng/ml, but not positive quantitative TAC.

Trial Registration: Not indicated for this study type.

Klebsiella pneumoniae pneumonia in patients with rheumatic autoimmune diseases: clinical characteristics, antimicrobial resistance and factors associated with extended-spectrum β-lactamase production

Background

Over the past decades, Klebsiella pneumoniae (K. pneumoniae) infections have been increasing and affected immunocompromised patients nosocomially and communally, with extended-spectrum β-lactamase (ESBL) production becoming a major concern. Patients with rheumatic autoimmune diseases, mostly receiving immunosuppressive therapy, are vulnerable to various infections, including K. pneumoniae. However, few have investigated K. pneumoniae infections in this specific population. This study aimed to identify factors associated with ESBL production and mortality of K. pneumoniae pneumonia among patients with rheumatic autoimmune diseases in the Emergency Department.

Methods

We retrospectively investigated patients with rheumatic diseases who were diagnosed with K. pneumoniae pneumonia. The diagnosis of K. pneumoniae pneumonia was based on clinical manifestations, radiological findings and microbiological testing results. Prognostic factors and risk factors for ESBL production were determined with univariate and multivariate logistic regression analysis. Empirical therapy and antimicrobial susceptibility data were also collected.

Results

Of 477 K. pneumoniae pneumonia patients, 60 were enrolled into this study. The in-hospital mortality was 28.3%. Septic shock, ICU admission, the need for mechanical ventilation and change of antibiotics due to clinical deterioration, all related to mortality, were included as unfavorable clinical outcomes. Multivariate analysis suggested that ESBL production (OR, 6.793; p = 0.012), initial PCT ≥ 0.5 ng/ml (OR, 5.024; p = 0.033) and respiratory failure at admission (OR, 4.401; p = 0.046) predicted increased mortality. ESBL production was significantly associated with dose of corticosteroids (OR, 1.033; p = 0.008) and CMV viremia (OR, 4.836; p = 0.032) in patients with rheumatic autoimmune diseases. Abnormal leukocyte count (OR, 0.192; p = 0.036) was identified as a protective factor of ESBL-producing K. pneumoniae pneumonia. The most commonly used empirical antibiotic was ceftazidime, while most isolates showed less resistance to carbapenems and amikacin in susceptibility testing.

Conclusions

K. pneumoniae pneumonia could be life-threatening in patients with rheumatic autoimmune diseases. Our findings suggested that ESBL production, initial PCT ≥ 0.5 ng/ml and respiratory failure at admission were independent factors associated with poor prognosis. Dose of corticosteroids and CMV viremia, predicting ESBL production in K. pneumoniae pneumonia, may help make individualized antibiotic decisions in clinical practice.

Procalcitonin Correlates With but Is Not Superior to Other Diagnostic Markers of Bacterial Pneumonia

OBJECTIVES

Despite extensive research on procalcitonin (PCT)-guided therapy in lower respiratory tract infections, the association between PCT and bacterial pneumonia remains unclear.

METHODS

We evaluated retrospectively the performance of PCT in patients presenting with lower respiratory tract infection symptoms and grouped by seven diagnoses. All patients had microbial testing, chest imaging, and CBC counts within 1 day of PCT testing.

RESULTS

Median PCT level in patients diagnosed with bacterial pneumonia was significantly higher than in patients diagnosed with other sources of infections or those not diagnosed with infections. Median PCT levels were not different among patients grouped by type or quantity of pathogen detected. They were significantly higher in patients with higher pathogenicity scores for isolated bacteria, those with abnormal WBC count, and those with chest imaging consistent with bacterial pneumonia. A diagnostic workup that included imaging, WBC count, and Gram stain had an area under the receiver operating characteristic curve of 0.748, and the addition of PCT increased it to 0.778.

CONCLUSIONS

PCT was higher in patients diagnosed with bacterial pneumonia. Less clear is its diagnostic ability to detect bacterial pneumonia over and above imaging and laboratory data routinely available to clinicians.

A novel procalcitonin-based score for detecting sepsis among critically ill patients

Background

Procalcitonin (PCT) has been widely investigated as an infection biomarker. The study aimed to prove that serum PCT, combining with other relevant variables, has an even better sepsis-detecting ability in critically ill patients.

Methods

We conducted a retrospective cohort study in a regional teaching hospital enrolling eligible patients admitted to intensive care units (ICU) between July 1, 2016, and December 31, 2016, and followed them until March 31, 2017. The primary outcome measurement was the occurrence of sepsis. We used multivariate logistic regression analysis to determine the independent factors for sepsis and constructed a novel PCT-based score containing these factors. The area under the receiver operating characteristics curve (AUROC) was applied to evaluate sepsis-detecting abilities. Finally, we validated the score using a validation cohort.

Results

A total of 258 critically ill patients (70.9±16.3 years; 55.4% man) were enrolled in the derivation cohort and further subgrouped into the sepsis group (n = 115) and the non-sepsis group (n = 143). By using the multivariate logistic regression analysis, we disclosed five independent factors for detecting sepsis, namely, “serum PCT level,” “albumin level” and “neutrophil-lymphocyte ratio” at ICU admission, along with “diabetes mellitus,” and “with vasopressor.” We subsequently constructed a PCT-based score containing the five weighted factors. The PCT-based score performed well in detecting sepsis with the cut-points of 8 points (AUROC 0.80; 95% confidence interval (CI) 0.74–0.85; sensitivity 0.70; specificity 0.76), which was better than PCT alone, C-reactive protein and infection probability score. The findings were confirmed using an independent validation cohort (n = 72, 69.2±16.7 years, 62.5% men) (cut-point: 8 points; AUROC, 0.79; 95% CI 0.69–0.90; sensitivity 0.64; specificity 0.87).

Conclusions

We proposed a novel PCT-based score that performs better in detecting sepsis than serum PCT levels alone, C-reactive protein, and infection probability score.

Diagnostic Accuracy of Procalcitonin for Early Aspiration Pneumonia in Critically Ill Patients with Coma: A Prospective Study

BACKGROUND

Early diagnostic orientation for differentiating pneumonia from pneumonitis at the early stage after aspiration would be valuable to avoid unnecessary antibiotic therapy. We assessed the accuracy of procalcitonin (PCT) in diagnosing aspiration pneumonia (AP) in intensive care unit (ICU) patients requiring mechanical ventilation after out-of-hospital coma.

METHODS

Prospective observational 2-year cohort study in a medical-surgical ICU. PCT, C-reactive protein (CRP) and white blood cell count (WBC) were measured at admission (H0) and 6 h (H), H12, H24, H48, H96, and H120 after inclusion. Lower respiratory tract microbiological investigations performed routinely in patients with aspiration syndrome were the reference standard for diagnosing AP. Performance of PCT, CRP, and WBC up to H48 in diagnosing AP was compared based on the areas under the ROC curves (AUC) and likelihood ratios (LR+ and LR-) computed for the best cutoff values.

RESULTS

Of 103 patients with coma, 45 (44%) had AP. Repeated PCT assays demonstrated a significant increase in patients with AP versus without AP from H0 to H120. Among the three biomarkers, PCT showed the earliest change. ROC-AUC values were poor for all three biomarkers. Best ROC-AUC values for diagnosing AP were for CRP at H24 [0.73 (95%CI 0.61-0.84)] and PCT at H48 [0.73 (95%CI 0.61-0.84)]. LR+ was best for PCT at H24 (3.5) and LR- for CRP and WBC at H24 (0.4 and 0.4, respectively).

CONCLUSIONS

Early and repeated assays of PCT, CRP, and WBC demonstrated significant increases in all three biomarkers in patients with versus without AP. All three biomarkers had poor diagnostic performance for ruling out AP. Whereas PCT had the fastest kinetics, PCT assays within 48 h after ICU admission do not help to diagnose AP in ICU patients with coma.

Lactate dehydrogenase as a prognostic marker of renal transplant recipients with severe community-acquired pneumonia: a 10-year retrospective study

BACKGROUND

Lactate dehydrogenase (LDH) is an easily accessible biological marker that has been associated with several pulmonary disorders. The aim of this study was to investigate the prognostic value of serum LDH in renal transplant recipients with severe community-acquired pneumonia (CAP).

METHODS

A total of 77 renal transplant recipients with severe CAP admitted to the intensive care unit (ICU) were screened for eligibility in this retrospective study. Patient characteristics and laboratory tests, such as LDH on day 1 (LDH_{day 1}) and day 3 (LDH_{day 3}) were recorded. Cox regression models were used to assess the performance of LDH to predict 90-day mortality.

RESULTS

Median LDH level was higher on day 1 in 90-day nonsurvivors (440 U/L, IQR, 362-1,055 U/L) than in survivors (334 U/L, IQR, 265-432 U/L; P<0.001); median LDH level on day 3 in nonsurvivors was 522.5 U/L (IQR, 457.5-1,058.5 U/L) and in survivors 290 U/L (IQR, 223-387.5 U/L; P<0.001). Analysis of LDH kinetics from day 1 to day 3 showed an increase in nonsurvivors and a decrease in survivors. Moreover, Multivariate Cox analysis showed that LDH_{day 1} (increase per 100 U/L), LDH_{day 3} (increase per 100 U/L) and LDH kinetics (increase per 10%) were independently associated with 90-day mortality.

CONCLUSIONS

Serum LDH levels and LDH kinetics early were independently associated with 90-day mortality in renal transplant recipients with severe CAP. In future, the prognostic role of LDH needs to be warranted.

Procalcitonin: Where Are We Now?

Procalcitonin is a biomarker that is generally elevated in bacterial infections. This review describes a conceptual framework for biomarkers using lessons from the history of troponin, applies this framework to procalcitonin with a review of observational studies and randomized trials in and out of the intensive care unit, and concludes with clinical recommendations and thoughts on how to test a test.

Non-faradaic electrochemical impedimetric profiling of procalcitonin and C-reactive protein as a dual marker biosensor for early sepsis detection

In this work, we demonstrate a robust, dual marker, biosensing strategy for specific and sensitive electrochemical response of Procalcitonin and C-reactive protein in complex body fluids such as human serum and whole blood for the detection of sepsis. Enhanced sensitivity is achieved by leveraging the physicochemical properties of zinc oxide at the electrode-solution interface. Characterization techniques such as SEM, EDAX, AFM, FTIR and fluorescence microscopy were performed to ensure a suitable biosensing surface. The characteristic biomolecular interactions between the target analyte and specific capture probe is quantified through unique frequency signatures using non-faradaic electrochemical impedance spectroscopy (EIS). The developed biosensor demonstrated a detection limit of 0.10 ng mL⁻¹ for PCT in human serum and whole blood with an R² of 0.99 and 0.98 respectively. CRP demonstrated a detection limit of 0.10 μg mL⁻¹ in human serum and whole blood with an R² of 0.90 and 0.98 respectively. Cross-reactivity analysis demonstrated robust selectivity to PCT and CRP with negligible interaction to non-specific biomolecules. The novel aspect of this technology is the ability to fine-tune individual biomarkers response owing to the optimal frequency tuning capability. The developed biosensor requires an ultra-low sample volume of 10 μL without the need for sample dilution for rapid analysis. We envision the developed dual marker biosensor to be useful as a sepsis-screening device for prognostic monitoring.

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Ultra-sensitive, specific, low volume biosensor developed for rapid screening of host response biomarkers to detect sepsis.

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EIS captures the interfacial changes within the electrical double layer due to the binding interaction of PCT & CRP.

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Enhanced sensor response with a LOD of 0.10 ng mL⁻¹ for PCT and 0.10 μg mL⁻¹ for CRP and an R² of 0.99 in human serum & blood.

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Biomolecular frequency tuning using electrochemical impedance spectroscopy enables multi-marker detection.

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Developed dual marker biosensor demonstrates specific response towards target biomolecules.

Outcome prediction using the Mortality in Emergency Department Sepsis score combined with procalcitonin for influenza patients

BACKGROUND

Severe influenza is often associated with bacterial coinfection and can trigger sepsis, which increases the severity, complexity and mortality of the disease. To determine an effective method for predicting 28-day mortality of emergency department (ED) patients with influenza, we investigated the Mortality in Emergency Department Sepsis (MEDS) score, procalcitonin (PCT) and other relevant biomarkers.

METHODS

We conducted a retrospective, observational, monocentric study, and the endpoint was 28-day mortality. Independent predictors were identified and a new combination predictive model was created both by logistic regression, and the model was evaluated by a receiver operating characteristic (ROC) curve.

RESULTS

A total of 364 consecutive ED admitted patients with influenza were enrolled and 45 patients died within 28 days. For predicting 28-day mortality, the MEDS score and PCT were independent predictors with adjusted odds ratio of 1.318 (95% CI 1.206-1.439) and 1.038 (95% CI 1.010-1.065), and with AUCs of 0.817 (95% CI 0.756-0.878) and 0.793 (95% CI 0.725-0.861), respectively. The new combination of the MEDS score with PCT significantly improved the efficacy for predicting 28-day mortality with an AUC of 0.857 (95% CI 0.809-0.905), and was superior to the SOFA score with an AUC of 0.837 (95% CI 0.779-0.894).

CONCLUSION

The MEDS score and PCT, especially when combined, perform well for predicting mortality of ED admitted patients with influenza.

Point of care technologies for sepsis diagnosis and treatment

Sepsis is a rapidly progressing, life threatening immune response triggered by infection that affects millions worldwide each year. Current clinical diagnosis relies on broad physiological parameters and time consuming lab-based cell culture. If proper treatment is not provided, cases of sepsis can drastically increase in severity over the course of a few hours. Development of new point of care tools for sepsis has the potential to improve diagnostic speed and accuracy, leading to prompt administration of appropriate therapeutics, thereby reducing healthcare costs and improving patient outcomes. In this review we examine developing and commercially available technologies to assess the feasibility of rapid, accurate sepsis diagnosis, with emphasis on point of care.

Procalcitonin Value Is an Early Prognostic Factor Related to Mortality in Admission to Pediatric Intensive Care Unit

Introduction

Procalcitonin (PCT) and C-reactive protein (CRP) are already known predictive markers in serious bacterial infections, and it is emphasized that these biomarkers can be used as a marker of increased mortality in critically ill patients. Herein, we aimed to evaluate the initial serum PCT and CRP levels on the outcome of patients in pediatric intensive care units (PICUs) and find out if these biomarkers can be used to predict mortality.

Materials and Methods

The relationship between the initial serum PCT and CRP levels and invasive mechanical ventilation (IMV) and noninvasive mechanical ventilation (NIV) support, inotropic drug need, acute renal kidney injury (AKI), continuous renal replacement therapy (CRRT), mortality, and hospitalization period was investigated retrospectively.

Results

In total, 418 suitable patients (226 males and 192 females) were included in the study. Age distributions of patients ranged from 1 month to 17 years. There was a statistically significant relationship between PCT levels in the first biochemical analysis performed during admission and MV support, inotropic drug use, mortality, ARF, hospitalization in the intensive care unit, CRRT and blood component transfusion. There was a statistically significant relationship between CRP levels and MV support, NIV, inotropic drug use, mortality, AKI, hospitalization in the intensive care unit, CRRT, and blood component transfusion.

Conclusion

We suggest that the initial PCT and CRP levels during admission can be used to predict the outcome of patients in PICU.

The use of procalcitonin in the determination of severity of sepsis, patient outcomes and infection characteristics

Objective

The primary objective of this study was to determine the correlation between procalcitonin values and illness severity by evaluating the degree of end organ dysfunction using the Sequential Organ Failure Assessment score, length of stay and the severity of sepsis (sepsis alone vs. septic shock), The hypothesis that procalcitonin values would be higher in sicker patients was formulated before data collection began. Secondary outcomes studied in relation to procalcitonin levels included infection characteristics such as the site of infection, microbial agent and dialysis dependent CKD.

Design

Unblinded retrospective cohort study. September 2014-December 2016.

Setting

364 patients with a diagnosis of sepsis or severe sepsis who were admitted to the general medical ward and ICU at Methodist Medical Center and Proctor Hospital in Peoria, Illinois, USA.

Results

This study demonstrates the following: Weak positive correlation between procalcitonin and SOFA score. Negligible correlation with length of stay. Higher values in patients who died than in patients who survived to discharge (p = 0.058). Sensitivity and specificity of procalcitonin for septic shock was 63 and 65% respectively. Sites typically infected by gram negative bacteria have higher procalcitonin values than sites infected by gram positive bacteria (p = 0.03). Higher procalcitonin in bacteremia than non-bacteremic infections (p = 0.004). Higher procalcitonin in dialysis-dependent CKD patients (p = 0.020).

Conclusions

Procalcitonin has a higher specificity for bacterial infections than other acute phase reactants. Although initial procalcitonin value may be helpful in the determination of illness severity, it is not always a reliable prognostic indicator and carries little significance as a standalone value. Procalcitonin values may be influenced by preexisting comorbid conditions such as chronic kidney disease, which are associated with higher procalcitonin values at baseline. Procalcitonin can provide invaluable information when viewed as one piece of a clinical puzzle, and is most powerful when the interpreting physician is aware of how values are influenced by the different clinical scenarios presented in this article.

Efficacy and safety of trimodulin, a novel polyclonal antibody preparation, in patients with severe community-acquired pneumonia: a randomized, placebo-controlled, double-blind, multicenter, phase II trial (CIGMA study)

Purpose

The CIGMA study investigated a novel human polyclonal antibody preparation (trimodulin) containing ~ 23% immunoglobulin (Ig) M, ~ 21% IgA, and ~ 56% IgG as add-on therapy for patients with severe community-acquired pneumonia (sCAP).

Methods

In this double-blind, phase II study (NCT01420744), 160 patients with sCAP requiring invasive mechanical ventilation were randomized (1:1) to trimodulin (42 mg IgM/kg/day) or placebo for five consecutive days. Primary endpoint was ventilator-free days (VFDs). Secondary endpoints included 28-day all-cause and pneumonia-related mortality. Safety and tolerability were monitored. Exploratory post hoc analyses were performed in subsets stratified by baseline C-reactive protein (CRP; ≥ 70 mg/L) and/or IgM (≤ 0.8 g/L).

Results

Overall, there was no statistically significant difference in VFDs between trimodulin (mean 11.0, median 11 [n = 81]) and placebo (mean 9.6; median 8 [n = 79]; p = 0.173). Twenty-eight-day all-cause mortality was 22.2% vs. 27.8%, respectively (p = 0.465). Time to discharge from intensive care unit and mean duration of hospitalization were comparable between groups. Adverse-event incidences were comparable. Post hoc subset analyses, which included the majority of patients (58–78%), showed significant reductions in all-cause mortality (trimodulin vs. placebo) in patients with high CRP, low IgM, and high CRP/low IgM at baseline.

Conclusions

No significant differences were found in VFDs and mortality between trimodulin and placebo groups. Post hoc analyses supported improved outcome regarding mortality with trimodulin in subsets of patients with elevated CRP, reduced IgM, or both. These findings warrant further investigation.

Trial registration: NCT01420744.

Electronic supplementary material

The online version of this article (10.1007/s00134-018-5143-7) contains supplementary material, which is available to authorized users.

Risk stratification and prediction value of procalcitonin and clinical severity scores for community-acquired pneumonia in ED

OBJECTIVE

Community-acquired pneumonia (CAP) is a common presentation to the emergency department (ED) and has high mortality rates. The aim of our study is to investigate the risk stratification and prognostic prediction value of precalcitonin (PCT) and clinical severity scores on patients with CAP in ED.

METHODS

226 consecutive adult patients with CAP admitted in ED of a tertiary teaching hospital were enrolled. Demographic information and clinical parameters including PCT levels were analyzed. CURB65, PSI, SOFA and qSOFA scores were calculated and compared between the severe CAP (SCAP) and non-severe CAP (NSCAP) group or the death and survival group. Receiver-operating characteristic (ROC) curves for 28-day mortality were calculated for each predictor using cut-off values. Logistic regression models and area under the curve (AUC) analysis were performed to compare the performance of predictors.

RESULTS

Fifty-one patients were classified as SCAP and forty-nine patients died within 28days. There was significant difference between either SCAP and NSCAP group or death and survival group in PCT level and CURB65, PSI, SOFA, qSOFA scores (p < 0.001). The AUCs of the PCT and CURB65, PSI, SOFA and qSOFA in predicting SCAP were 0.875, 0.805, 0.810, 0.852 and 0.724, respectively. PCT is superior in predicting SCAP and the models combining PCT and SOFA demonstrated superior performance to those of PCT or the CAP severity score alone. The AUCs of the PCT and CURB65, PSI, SOFA and qSOFA in predicting 28-day mortality were 0.822, 0.829, 0.813, 0.913 and 0.717, respectively. SOFA achieved the highest AUC and the combination of PCT and SOFA had the highest superiority over other combinations in predicting 28-day mortality.

CONCLUSION

Serum PCT is a valuable single predictor for SCAP. SOFA is superior in prediction of 28-day mortality. Combination of PCT and SOFA could improve the performance of single predictors. More further studies with larger sample size are warranted to validate our results.

Biomarkers in Sepsis

A biomarker is a characteristic by which a (patho)physiologic process can be identified. Biomarkers can be of diagnostic value (to discriminate infection from noninfectious conditions or to determine the causative pathogen), of prognostic value (assigning risk profiles and predict outcome), and in the future may be of theranostic value (aid in selection and monitoring of therapy). Systems biology provides a promising tool for the discovery of novel biomarkers. Biomarkers can be the key to personalized targeted treatment in the future clinical management of sepsis.

Comparative Analysis of the Host Response to Community-acquired and Hospital-acquired Pneumonia in Critically Ill Patients

RATIONALE

Preclinical studies suggest that hospitalized patients are susceptible to infections caused by nosocomial respiratory pathogens at least in part because of immune suppression caused by the condition for which they were admitted.

OBJECTIVES

We aimed to characterize the systemic host response in hospital-acquired pneumonia (HAP) when compared with community-acquired pneumonia (CAP).

METHODS

We performed a prospective study in two intensive care units (ICUs) in 453 patients with HAP (n = 222) or CAP (n = 231). Immune responses were determined on ICU admission by measuring 19 plasma biomarkers reflecting organ systems implicated in infection pathogenesis (in 192 patients with HAP and 183 patients with CAP) and by applying genome-wide blood gene expression profiling (in 111 patients with HAP and 110 patients with CAP).

MEASUREMENTS AND MAIN RESULTS

Patients with HAP and CAP presented with similar disease severities and mortality rates did not differ up to 1 year after admission. Plasma proteome analysis revealed largely similar responses, including systemic inflammatory and cytokine responses, and activation of coagulation and the vascular endothelium. The blood leukocyte genomic response was greater than 75% common in patients with HAP and CAP, comprising proinflammatory, antiinflammatory, T-cell signaling, and metabolic pathway gene sets. Patients with HAP showed overexpression of genes involved in cell-cell junction remodeling, adhesion, and diapedesis, which corresponded with lower plasma levels of matrix metalloproteinase-8 and soluble E-selectin. In addition, patients with HAP demonstrated underexpression of a type-I interferon signaling gene signature.

CONCLUSIONS

Patients with HAP and CAP present with a largely similar host response at ICU admission.

Soluble membrane receptors, interleukin 6, procalcitonin and C reactive protein as prognostic markers in patients with severe sepsis and septic shock

Background

The objective of this study was to explore the diagnostic and prognostic value of soluble triggering receptor expressed on myeloid cell 1 (sTREM-1), soluble cluster of differentiation 14 (sCD14), soluble cluster of differentiation 163 (sCD163), interleukin-6 (IL-6), procalcitonin (PCT), and C-reactive protein (CRP) serum levels for patients with severe sepsis and septic shock in an intensive care unit (ICU).

Methods

Fifty patients admitted at the ICU with the diagnosis of severe sepsis or septic shock were studied. SOFA and APACHE II scores as well as serum biomarkers were measured at days 0, 2 and 5. The influence of these variables on 28-day mortality was analyzed. Twenty healthy individuals served as controls.

Results

Baseline serum concentrations of sTREM-1, sCD163, IL-6 and PCT correlated with SOFA score. Only sTREM-1 levels correlated with APACHE II score. The 28-day mortality rate for all patients was 42%. The absence of risk factors for infection, presence of septic shock, baseline values of sCD14 and decrease of PCT and IL-6 from baseline to day 5 were variables associated to mortality in the univariate analysis. The unique independent factor associated to mortality in the multivariate analysis was a decrease of PCT higher than 50% from days 0 to 5.

Conclusions

Serum levels of sTREM-1 are correlated with the severity of sepsis. A 50% decrease of PCT was the unique variable associated with survival in the multivariate analysis.

Prognostic value of procalcitonin in hospitalized patients with lower respiratory tract infections

Lower respiratory tract infections are common and potentially lethal conditions and are a major cause of inadequate antibiotic prescriptions. Characterization of disease severity and prognostic prediction in affected patients can aid disease management and can increase accuracy in determining the need for and place of hospitalization. The inclusion of biomarkers, particularly procalcitonin, in the decision taken process is a promising strategy. This study aims to present a narrative review of the potential applications and limitations of procalcitonin as a prognostic marker in hospitalized patients with lower respiratory tract infections. The studies on this topic are heterogeneous with respect to procalcitonin measurement techniques, cutoff values, clinical settings, and disease severity. The results show that procalcitonin delivers moderate performance for prognostic prediction in patients with lower respiratory tract infections; its predictive performance was not higher than that of classical methods, and knowledge of procalcitonin levels is most useful when interpreted together with other clinical and laboratory results. Overall, repeated measurement of the procalcitonin levels during the first days of treatment provides more prognostic information than a single measurement; however, information on the cost-effectiveness of this procedure in intensive care patients is lacking. The results of studies that evaluated the prognostic value of initial procalcitonin levels in patients with community-acquired pneumonia are more consistent and have greater potential for practical application; in this case, low procalcitonin levels identify those patients with a low risk of adverse outcomes.

Comparison between procalcitonin and C-reactive protein in predicting bacteremias and confounding factors: a case-control study

Background:

The detection of infectious bacteria in blood culture samples is important for diagnosis and treatment, but this requires 1–2 days at least, and is not adequate as a rapid test. Therefore, we have investigated the diagnostic ability and the optimal cutoff value of procalcitonin (PCT) and C-reactive protein (CRP) for predicting the bacteremias using receiver operating characteristic (ROC) curves and relative cumulative frequency distribution (RCD) curves.

Methods:

A case-control study was performed in inpatients (852 subjects: 426 positive cultures and 426 negative cultures) from January 1 to December 31, 2014. We retrospectively investigated their blood culture and blood chemistry findings recorded in this period using electronic medical records.

Results:

Area under the ROC curve of PCT and CRP were 0.79 and 0.66, respectively. The optimal cutoff values were 0.5 μg/L with a sensitivity of 70% and specificity of 70% for PCT and 50.0 mg/L with a sensitivity of 63% and specificity of 65% for CRP. When the optimal cutoff value was treated as a reference, the odds ratio (OR) was 71.11 and the hazard ratio (HR) was 6.27 for PCT >2.0 μg/L, and the risk of blood culture positivity was markedly elevated. PCT levels were significantly higher in the population with Gram-negative rod (GNR) infections than in the population with Gram-positive coccal (GPC) infections.

Conclusions:

The elevation of CRP and PCT were significantly associated with bacteremias. PCT was superior to CRP as a diagnostic indicator for predicting bacteremias, for discriminating bacterial from nonbacterial infections, and for determining bacterial species.

Prognostic value of Pneumonia Severity Index, CURB-65, CRB-65, and procalcitonin in community-acquired pneumonia in Singapore

Objective:

The purpose of this study was to evaluate the performance of three severity scoring tools and procalcitonin (PCT) in severity stratification and mortality prediction among patients with community-acquired pneumonia (CAP) in Singapore.

Methods:

The method used was a retrospective observational study of all the consecutive patients with CAP admitted through the emergency department of Singapore General Hospital between 2012–2013.

Results:

Among 1902 study subjects, the overall 30-day mortality was 15.7%. The mortality rates for Pneumonia Severity Index (PSI) class I–III were 0, 0, and 3.7%, which were comparable to the original published data. CURB-65 and CRB-65 had higher mortality rates in all severity levels. In three levels of risk stratification, the low risk group of PSI (class I–III) included 42.6% of the patients with mortality rate of 1.9%, whereas the low risk group defined by CURB-65 (score 0–1) and CRB-65 (score 0) included 52.0% and 24.4% of the patients with higher mortality rates (7.3% and 4.5% respectively). PSI was the most sensitive in mortality prediction with area under receiver operating characteristic (ROC) curve of 0.82, higher than CURB-65 (0.71), CRB-65 (0.67), and PCT (0.63) ( p<0.001). The initial level of PCT was higher in non-survivors and intensive care unit (ICU)-admitted patients compared to survivors (0.91 vs 0.36 ng/ml, p<0.001) and non-ICU patients (3.70 vs 0.38 ng/ml, p<0.001). Incorporating PCT did not improve the discriminatory power of the scoring tools for mortality prediction.

Conclusions:

PSI was a reliable tool for severity stratification and morality prediction among the patients with CAP in Singapore.

Serum Procalcitonin as a Biomarker for the Prediction of Bacterial Exacerbation and Mortality in Severe COPD Exacerbations Requiring Mechanical Ventilation

BACKGROUND

Procalcitonin (PCT) is being used as a marker of bacterial infections. Although there are several studies showing the diagnostic yield of PCT to differentiate bacterial involvement in chronic obstructive pulmonary disease exacerbations (COPDE), the prognostic yield of PCT in severe COPDE has been studied less.

OBJECTIVES

The primary aim was to determine whether the level of serum PCT at admission in severe COPDE serves as a prognostic biomarker for hospital mortality. The secondary aim was to determine the role of PCT in identifying a bacterial exacerbation.

METHODS

A total of 63 COPDE patients (median age 71 years; male 58.7%) were retrospectively analyzed from our intensive care unit database.

RESULTS

The hospital mortality rate was 23.8%. Admission PCT levels were higher in patients who died during hospitalization (0.66 vs. 0.17 ng/ml; p = 0.014). This association between hospital mortality and serum PCT level remained significant in a multivariate analysis; for every 1 ng/ml increase in PCT level, hospital mortality increased 1.85 times (odds ratio; 95% confidence interval: 1.07-3.19; p = 0.026). The optimal admission PCT threshold was 0.25 ng/ml in order to discern patients who had bacterial exacerbation with a sensitivity of 63%, a specificity of 67%, and a negative predictive value of 80%. The negative predictive value increased to 89% when both the admission and follow-up PCT levels remained <0.25 ng/ml.

CONCLUSION

This study shows that admission PCT levels have a prognostic importance in estimating hospital mortality among patients with severe COPDE. A PCT level <0.25 ng/ml at the time of admission and during follow-up is suggestive of the absence of a bacterial cause of COPDE.

Prognostic value of procalcitonin in pneumonia: A systematic review and meta-analysis

This meta-analysis was performed to determine the accuracy of procalcitonin (PCT) in predicting mortality in pneumonia patients with different pathogenic features and disease severities. A systematic search of English-language articles was performed using PubMed, Embase, Web of Knowledge and the Cochrane Library to identify studies. The diagnostic value of PCT in predicting prognosis was determined using a bivariate meta-analysis model. The Q-test and I(2) index were used to test heterogeneity. A total of 21 studies comprising 6007 patients were included. An elevated PCT level was a risk factor for death from community-acquired pneumonia (CAP) (risk ratio (RR) 4.38, 95% confidence interval (CI) 2.98-6.43), particularly in patients with a low CURB-65 score. The commonly used cut-off, 0.5 ng/mL, had low sensitivity (SEN) and was not able to identify patients at high risk of dying. Furthermore, the PCT assay with functional SEN <0.1 ng/mL was necessary to predict mortality in CAP in the clinic. For critically ill patients, an elevated PCT level was associated with an increased risk of mortality (RR 4.18, 95% CI: 3.19-5.48). The prognostic performance was nearly equal between patients with ventilator-associated pneumonia (VAP) and patients with CAP.

Comparative usefulness of inflammatory markers to indicate bacterial infection-analyzed according to blood culture results and related clinical factors

To assess relationships of inflammatory markers and 2 related clinical factors with blood culture results, we retrospectively investigated inpatients' blood culture and blood chemistry findings that were recorded from January to December 2014 using electronic medical records and analyzed the data of 852 subjects (426 culture-positive and 426 culture-negative). Results suggested that the risk of positive blood culture statistically increased as inflammatory marker levels and the number of related factors increased. Concerning the effectiveness of inflammatory markers, when the outcome definition was also changed for C-reactive protein (CRP), the odds ratio had a similar value, whereas when the outcome definition of blood culture positivity was used for procalcitonin (PCT), the greatest effectiveness of that was detected. Therefore, the current results suggest that PCT is more useful than CRP as an auxiliary indication of bacterial infection.

Tumor necrosis factor receptor 1 (TNFRI) for ventilator-associated pneumonia diagnosis by cytokine multiplex analysis

BACKGROUND

The diagnosis of ventilator-associated pneumonia (VAP) is challenging. An important aspect to improve outcome is early recognition of VAP and the initiation of the appropriate empirical treatment. We hypothesized that biological markers in plasma can rule out VAP at the moment of clinical suspicion and could rule in VAP before the diagnosis can be made clinically.

METHODS

In this prospective study, patients with VAP (n = 24, microbiology confirmed) were compared to controls (n = 19) with a similar duration of mechanical ventilation. Blood samples from the day of VAP diagnosis and 1 and 3 days before were analyzed with a multiplex array for markers of inflammation, coagulation, and apoptosis. The best biomarker combination was selected and the diagnostic accuracy was given by the area under the receiver operating characteristic curve (ROC-AUC).

RESULTS

TNF-receptor 1 (TNFRI) and granulocyte colony-stimulating factor (GCSF) were selected as optimal biomarkers at the day of VAP diagnosis, which resulted in a ROC-AUC of 0.96, with excellent sensitivity. Three days before the diagnosis TNFRI and plasminogen activator inhibitor-1 (PAI-1) levels in plasma predicted VAP with a ROC-AUC of 0.79. The slope of IL-10 and PAI-1 resulted in a ROC-AUC of 0.77. These biomarkers improved the classification of the clinical pulmonary infection score when combined.

CONCLUSIONS

Concentration of TNFRI and PAI-1 and the slope of PAI-1 and IL-10 may be used to predict the development of VAP as early as 3 days before the diagnosis made clinically. TNFRI and GCSF may be used to exclude VAP at the moment of clinical suspicion. Especially TNFRI seems to be a promising marker for the prediction and diagnosis of VAP.

Clinical diagnosis of sepsis and the combined use of biomarkers and culture- and non-culture-based assays

Sepsis is among the most common causes of death in hospitalized patients, and early recognition followed by immediate initiation of therapy is an important concept to improve survival in these patients. According to the definition of sepsis, diagnosis of sepsis requires the recognition of the systemic inflammatory response syndrome (SIRS) caused by infection as well as recognition of possible infection-related organ dysfunctions for diagnosis of severe sepsis or septic shock. Both SIRS and organ dysfunctions may occur frequently in hospitalized patients for various reasons. However, the fast recognition of acute infection as a cause of SIRS and newly developed organ dysfunction may be a demanding task since culture-based results of microbiological samples will be available only days after onset of symptoms. Biomarkers and PCR-based pathogen detection may help the physician in differentiating SIRS from sepsis. Procalcitonin (PCT) is the best investigated biomarker for this purpose. Furthermore, the current data support the usage of PCT for guidance of antimicrobial therapy. C-reactive protein (CRP) may be used to monitor the course of infection but has only limited discriminative capabilities. Interleukin-6 is widely used for its fast response to the infectious stimulus, but conclusive data for the application of this biomarker are missing. None of the available biomarkers can by itself reliably differentiate SIRS from sepsis but can aid and shorten the decision process. PCR-based pathogen detection can theoretically shorten the recognition of the underlying pathogen to about 8 h. However, this technique is expensive and requires additional staff in the laboratory; controlled prospective studies are missing. Although current studies suggest that PCR-based pathogen detection may be useful to shorten time to adequate antimicrobial therapy and diagnose invasive Candida infections, no general recommendations about the application of PCR for the diagnosis of sepsis can be given.

Plasma concentrations of copeptin, C-reactive protein and procalcitonin are positively correlated with APACHE II scores in patients with sepsis

OBJECTIVE

To evaluate the correlation between Acute Physiology and Chronic Health Evaluation II (APACHE II) score and plasma concentrations of copeptin, C-reactive protein (CRP) and procalcitonin in patients with sepsis.

METHODS

Patients with sepsis were prospectively enrolled. APACHE II scores were determined during the first 24 h after admission to the intensive care unit. Plasma copeptin, CRP and procalcitonin were quantified at admission, 24 h, 48 h, and 72 h. Survival at 28 days after admission was recorded.

RESULTS

APACHE II score was significantly positively correlated with plasma copeptin, CRP and procalcitonin concentrations. Survivors (n = 15) had significantly lower APACHE II scores and copeptin, CRP and procalcitonin concentrations than nonsurvivors (n = 26). APACHE II score, copeptin at 72 h, CRP at 48 h and procalcitonin at 24 h were independent risk factors for death.

CONCLUSION

Plasma copeptin, CRP and procalcitonin concentrations were positively correlated with APACHE II score in patients with sepsis, and reflected disease severity.

Host response biomarkers in sepsis: the role of procalcitonin

Procalcitonin is the prohormone of calcitonin and present in minute quantities in health. However, during infection, its levels rise considerably and are correlated with the severity of the infection. Several assays have been developed for measurement of procalcitonin levels; in this article, we will briefly present the PCT-sensitive Kryptor(®) test (Brahms, Hennigsdorf, Germany), one of the most widely used assays for procalcitonin in recent studies. Many studies have demonstrated the value of procalcitonin levels for diagnosing sepsis and assessing disease severity. Procalcitonin levels have also been successfully used to guide antibiotic administration. However, procalcitonin is not specific for sepsis, and values need to be interpreted in the context of a full clinical examination and the presence of other signs and symptoms of sepsis.

Neonatal sepsis and inflammatory mediators

Neonatal sepsis is a major cause of morbidity and mortality and its signs and symptoms are nonspecific, which makes the diagnosis difficult. The routinely used laboratory tests are not effective methods of analysis, as they are extremely nonspecific and often cause inappropriate use of antibiotics. Sepsis is the result of an infection associated with a systemic inflammatory response with production and release of a wide range of inflammatory mediators. Cytokines are potent inflammatory mediators and their serum levels are increased during infections, so changes from other inflammatory effector molecules may occur. Although proinflammatory and anti-inflammatory cytokines have been identified as probable markers of neonatal infection, in order to characterize the inflammatory response during sepsis, it is necessary to analyze a panel of cytokines and not only the measurement of individual cytokines. Measurements of inflammatory mediators bring new options for diagnosing and following up neonatal sepsis, thus enabling early treatment and, as a result, increased neonatal survival. By taking into account the magnitude of neonatal sepsis, the aim of this review is to address the role of cytokines in the pathogenesis of neonatal sepsis and its value as a diagnostic criterion.

Alveolar pentraxin 3 as an early marker of microbiologically confirmed pneumonia: a threshold-finding prospective observational study

Introduction

Timely diagnosis of pneumonia in intubated critically ill patients is rather challenging. Pentraxin 3 (PTX3) is an acute-phase mediator produced by various cell types in the lungs. Animal studies have shown that, during pneumonia, PTX3 participates in fine-tuning of inflammation (for example, microbial clearance and recruitment of neutrophils). We previously described an association between alveolar PTX3 and lung infection in a small group of intubated patients. The aim of the present study was to determine a threshold level of alveolar PTX3 with elevated sensitivity and specificity for microbiologically confirmed pneumonia.

Methods

We recruited 82 intubated patients from two intensive care units (San Gerardo Hospital, Monza, Italy, and Massachusetts General Hospital, Boston, MA, USA) undergoing bronchoalveolar lavage (BAL) as per clinical decision. We collected BAL fluid and plasma samples, together with relevant clinical and microbiological data. We assayed PTX3 and soluble triggering receptor expressed on myeloid cells 1 (sTREM-1) in BAL fluid and PTX3, sTREM-1, C-reactive protein (CRP) and procalcitonin (PCT) in plasma. Two blinded independent physicians reviewed patient data to confirm pneumonia. We determined the PTX3 threshold in BAL fluid for pneumonia and compared it to other biomarkers.

Results

Microbiologically confirmed pneumonia of bacterial (n =12), viral (n =4) or fungal (n =8) etiology was diagnosed in 24 patients (29%). PTX3 levels in BAL fluid predicted pneumonia with an area under the receiving operator curve of 0.815 (95% CI =0.710 to 0.921, P <0.0001), whereas none of the other biomarkers were effective. In particular, PTX3 levels ≥1 ng/ml in BAL fluid predicted pneumonia in univariate analysis (β =2.784, SE =0.792, P <0.001) with elevated sensitivity (92%), specificity (60%) and negative predictive value (95%). Net reclassification index PTX3 values ≥1 ng/ml in BAL fluid for pneumonia indicated gain in sensitivity and/or specificity vs. all other mediators. These results did not change when we limited our analyses only to confirmed cases of bacterial pneumonia. Moreover, when we considered only the 70 patients who fulfilled the clinical criteria for the diagnosis of pneumonia at BAL fluid sampling, the diagnostic accuracy of PTX levels was confirmed in univariate and ROC curve analysis.

Conclusions

In this hypothesis-generating convenience sample, a PTX3 level ≥1 ng/ml in BAL fluid was discriminative of microbiologically confirmed pneumonia in mechanically ventilated patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-014-0562-5) contains supplementary material, which is available to authorized users.

Obesity and pro-inflammatory mediators are associated with acute kidney injury in patients with A/H1N1 influenza and acute respiratory distress syndrome

BACKGROUND

The obesity has been shown to increase the severity of A/H1N1 infection and the development of acute respiratory distress syndrome (ARDS) and organ involvement.

METHODS

Circulating levels of C-peptide, insulin, glucagon, leptin, acute phase reactants (procalcitonin, C-reactive protein, tissue plasminogen activator, and serum amyloids A and P), were measured in samples from 32 critically ill patients with A/H1N1 virus infection, 17 of whom had ARDS complicated by acute kidney injury (AKI) and 15 of whom had ARDS but did not develop AKI.

RESULTS

Patients with ARDS and AKI (ARDS/AKI) had higher BMI and higher levels of C-peptide, insulin, leptin, procalcitonin and serum amyloid A compared to those ARDS patient who did not develop AKI. Adjusting for confounding variables using logistic regression analysis, higher levels of C-peptide (>0.75 ng/mL) (OR=64.8, 95% CI = 2.1-1980, p = 0.0006) and BMI>30 Kg/m(2) (OR = 42.0, 95% CI = 1.2-1478, p = 0.04) were significantly associated with the development of AKI in ARDS patients.

CONCLUSION

High levels of C-peptide and BMI>30 kg/m(2) were associated with the development of AKI in ARDS patients due to A/H1N1 infection. These metabolic/obesity indicators, together with the profiles of pro-inflammatory acute phase proteins, may be important links between obesity and poor outcomes in A/H1N1 09 infection.

Role of extracellular and intracellular microRNAs in sepsis

Sepsis is the major cause of death in the intensive care unit (ICU). Numerous biomarkers have been studied to identify the cause and severity of sepsis but these factors cannot differentiate between infectious and non-infectious inflammatory response. MicroRNAs (miRNAs) are non-coding RNA transcripts that regulate the expression of genes by repressing translation or degrading mRNA. Importantly, miRNAs can be released outside cells and easily detectable in bodily fluids such as blood, sweat, urine and breast milk. Numerous studies have explored the idea of utilizing extracellular miRNAs as biomarkers for sepsis by profiling the dysregulation of miRNAs in blood samples of sepsis patients. So far, miR-223, miR-146a and miR-150 have been identified to have promising prognostic and diagnostic value to sepsis. In addition, various intracellular miRNAs have been implicated to play critical roles in regulating the TLR-NF-κB pathway, which is a well-known inflammatory signaling pathway involved in the process of sepsis. Here, we summarize the recent progress on the role of extracellular and intracellular miRNAs in sepsis. Specifically, we discuss the possible role of circulating miRNA biomarkers for the diagnosis of sepsis and how intracellular miRNAs regulate the inflammatory responses in sepsis.

Predicting treatment failure in patients with community acquired pneumonia: a case-control study

INTRODUCTION

Treatment failure in community-acquired-pneumonia (CAP) patients is associated with a high mortality rate, and therefore are a matter of great concern in clinical management. Those patients have increased mortality and are a target population for randomized clinical trials.

METHODS

A case-control study was performed in patients with CAP (non-failure cases vs. failure cases, discriminating by late and early failure). CRP, PCT, interleukin 1, 6, 8 and 10 and TNF were determined at days 1 and 3 of hospitalization.

RESULTS

A total of 253 patients were included in this study where 83 patients presented treatment failure. Of these, 40 (48.2%) had early failure. A discriminative effect was found for a higher CURB-65 score among late failure patients (p = 0.004). A significant increase on day 1 of hospitalization in CRP (p < 0.001), PCT (p = 0.004), IL-6 (p < 0.001) and IL-8 (p = 0.02), and a decrease in IL-1 (p = 0.06) in patients with failure was observed compared with patients without failure. On day 3, only the increase in CRP (p < 0.001), PCT (p = 0.007) and IL-6 (p < 0.001) remained significant. Independent predictors for early failure were higher IL-6 levels on day 1 (OR = 1.78, IC = 1.2-2.6) and pleural effusion (OR = 2.25, IC = 1.0-5.3), and for late failure, higher PCT levels on day 3 (OR = 1.60, IC = 1.0-2.5), CURB-65 score ≥ 3 (OR = 1.43, IC = 1.0-2.0), and multilobar involvement (OR = 4.50, IC = 2.1-9.9).

CONCLUSIONS

There was a good correlation of IL-6 levels and CAP failure and IL-6 & PCT with late CAP failure. Pleural effusion and multilobar involvement were simple clinical predictors of early and late failure, respectively.

TRIAL REGISTRATION

IRB Register: http://2009/5451.

Prognostic value of plasma N-terminal pro B-type natriuretic peptide levels in pneumonia patients requiring intensive care unit admission

BACKGROUND AND OBJECTIVE

Correct and early risk stratification for critically ill pneumonia patients remains an unmet medical need. This study aimed to test whether N-terminal pro B-type natriuretic peptide (NT-proBNP) can serve as a prognostic marker in this setting.

METHODS

This prospective study enrolled 216 pneumonia patients admitted to intensive care unit. Plasma NT-proBNP samples were obtained upon admission and primary outcome was all-cause mortality at 30 days. Meanwhile, Acute Physiology and Chronic Health Evaluation (APACHE) II and Infectious Diseases Society of America/American Thoracic Society (IDSA/ATS) 2007 minor criteria were assessed.

RESULTS

Overall 30-day mortality was 30%. NT-proBNP levels were significantly higher in nonsurvivors than survivors (11 938 ± 13 121 vs 5658 ± 9240 pg/mL, P = 0.001). Area under receiver operating characteristic curves of NT-proBNP, APACHE II and IDSA/ATS 2007 minor criteria were not significantly different regarding prediction of mortality (0.715, 0.754 vs 0.654, P = 0.085). Adding NT-proBNP to APACHE II significantly increased the area under receiver operating characteristic curve from 0.754 to 0.794 (P = 0.048). Receiver operating characteristic analysis revealed optimal NT-proBNP and APACHE II cut-offs of 2177.5 pg/mL and 25.5, respectively. In multivariate analysis, both NT-proBNP and APACHE II values above cut-offs had a significantly higher probability of death than those below cut-offs. A categorical approach combining NT-proBNP and APACHE II cut-offs provides additional risk stratification over a single marker approach.

CONCLUSIONS

For pneumonia patients admitted to intensive care unit, NT-proBNP strongly and independently predicts mortality, and its prognostic accuracy is comparable with APACHE II and IDSA/ATS 2007 minor criteria.

Severe pneumonia mortality in elderly patients is associated with downregulation of Toll-like receptors 2 and 4 on monocytes

BACKGROUND

Elderly patients with pneumonia have a high mortality rate. Since Toll-like receptor (TLR) signaling is involved in the inflammatory response, we conducted a prospective observational case-control study to assess the relationships of TLR2 and TLR4 mortality with elderly patients with pneumonia.

METHODS

Clinical and laboratory data were collected from these elderly patients with pneumonia (patient group; n = 40) and healthy age-matched subjects (control 1; n = 20). TLR2 and TLR4 expression levels on blood monocytes were examined, and inflammatory cytokine tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1) and interleukin-6 (IL-6) plasma concentrations were analyzed.

RESULTS

Increased TLR2 and TLR4 expression levels were detected in elderly patients with severe pneumonia compared with healthy subjects. Furthermore, we observed a positive correlation between TLR2 and TLR4 expression levels and IL-1 and IL-6 levels, and TLR2- and TLR4-positive cell percent expressions correlated with TNF-α levels. By day 28 of observation, the mortality rate of the patient group was 30%. Decreased TLR2 and TLR4 expression was observed in deceased patients compared with survivors. APACHE (Acute Physiology and Chronic Health Evaluation) II scores and CURB-65 scores (Confusion, blood Urea nitrogen, Respiratory rate and low Blood pressure scores) were lower in survivors.

CONCLUSIONS

These findings demonstrate a previously undocumented association between mortality in elderly patients with severe pneumonia and decreased TLR2 and TLR4 expression. Our results highlight that TLRs can be targeted in the development of improved immune modulation therapies for these patients.

Rapid diagnosis of sepsis

Fast and appropriate therapy is the cornerstone in the therapy of sepsis. However, the discrimination of sepsis from non-infectious causes of inflammation may be difficult. Biomarkers have been suggested to aid physicians in this decision. There is currently no biochemical technique available which alone allows a rapid and reliable discrimination between sepsis and non-infectious inflammation. Procalcitonin (PCT) is currently the most investigated biomarker for this purpose. C-reactive protein and interleukin 6 perform inferior to PCT in most studies and their value in diagnosing sepsis is not defined. All biomarkers including PCT are also released after various non-infectious inflammatory impacts. This shortcoming needs to be taken into account when biomarkers are used to aid the physician in the diagnosis of sepsis. Polymerase chain reaction (PCR) based pathogen detection may improve time to adequate therapy but cannot rule out the presence of infection when negative.