Serum amyloid A: an early and accurate marker of neonatal early-onset sepsis

Point-of-Care Serum Amyloid A as a Diagnostic Marker for Neonatal Sepsis

OBJECTIVES

To evaluate diagnostic accuracy of point-of-care Serum Amyloid A (POC-SAA) and its comparison with procalcitonin for diagnosis of neonatal sepsis.

METHODS

The present diagnostic accuracy study consecutively recruited neonates with suspected sepsis. Blood samples for sepsis screen, culture, high sensitivity C-reactive protein (CRP) (hs-CRP, as a part of sepsis screen), procalcitonin and POC-SAA were collected before starting antibiotics. The optimum cut-off level of biomarkers (POC-SAA and procalcitonin) was determined by receiver-operating-characteristics curve (ROC) analysis. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of POC-SAA and procalcitonin were derived for 'clinical sepsis (neonates with suspected sepsis and either positive sepsis screen and/or blood culture)' and 'culture positive sepsis' (neonates with suspected sepsis and positive blood culture).

RESULTS

Seventy-four neonates with mean±SD gestational age of 32.8±3.7 wk were evaluated for suspected sepsis, of which the proportion of 'clinical sepsis' and 'culture positive sepsis' was 37.8% had 16.2%, respectively. At a cut-off of 25.4 mg/L, POC-SAA had sensitivity, specificity, PPV and NPV of 53.6%, 80.4%, 62.5% and 74.0%, respectively for diagnosis of clinical sepsis. The sensitivity, specificity, PPV and NPV of POC-SAA for detection of culture positive sepsis were 83.3%, 61.3%, 29.4% and 95.0%, respectively at a cut-off of 10.3 mg/L. There was no significant difference in the diagnostic accuracy of biomarkers for detection of culture positive sepsis (area under the curve, AUC of POC-SAA vs. procalcitonin vs. hs-CRP: 0.72 vs. 0.85 vs. 0.85; p = 0.21).

CONCLUSIONS

POC-SAA is comparable to procalcitonin and hs-CRP for diagnosis of neonatal sepsis.

Deficiency of Acute-Phase Serum Amyloid A Exacerbates Sepsis-Induced Mortality and Lung Injury in Mice

Serum amyloid A (SAA) is a family of proteins, the plasma levels of which may increase >1000-fold in acute inflammatory states. We investigated the role of SAA in sepsis using mice deficient in all three acute-phase SAA isoforms (SAA-TKO). SAA deficiency significantly increased mortality rates in the three experimental sepsis mouse models: cecal ligation and puncture (CLP), cecal slurry (CS) injection, and lipopolysaccharide (LPS) treatments. SAA-TKO mice had exacerbated lung pathology compared to wild-type (WT) mice after CLP. A bulk RNA sequencing performed on lung tissues excised 24 h after CLP indicated significant enrichment in the expression of genes associated with chemokine production, chemokine and cytokine-mediated signaling, neutrophil chemotaxis, and neutrophil migration in SAA-TKO compared to WT mice. Consistently, myeloperoxidase activity and neutrophil counts were significantly increased in the lungs of septic SAA-TKO mice compared to WT mice. The in vitro treatment of HL-60, neutrophil-like cells, with SAA or SAA bound to a high-density lipoprotein (SAA-HDL), significantly decreased cellular transmigration through laminin-coated membranes compared to untreated cells. Thus, SAA potentially prevents neutrophil transmigration into injured lungs, thus reducing exacerbated tissue injury and mortality. In conclusion, we demonstrate for the first time that endogenous SAA plays a protective role in sepsis, including ameliorating lung injury.

Biomarkers of Neonatal Sepsis: Where We Are and Where We Are Going

Neonatal sepsis is a bacterial bloodstream infection leading to severe clinical manifestations frequently associated with death or irreversible long-term deficits. Antibiotics are the drug of choice to treat sepsis, regardless of age. In neonates, the lack of reliable criteria for a definite diagnosis and the supposition that an early antibiotic administration could reduce sepsis development in children at risk have led to a relevant antibiotic overuse for both prevention and therapy. The availability of biomarkers of neonatal sepsis that could alert the physician to an early diagnosis of neonatal sepsis could improve the short and long-term outcomes of true sepsis cases and reduce the indiscriminate and deleterious use of preventive antibiotics. The main aim of this narrative review is to summarize the main results in this regard and to detail the accuracy of currently used biomarkers for the early diagnosis of neonatal sepsis. Literature analysis showed that, despite intense research, the diagnosis of neonatal sepsis and the conduct of antibiotic therapy cannot be at present decided on the basis of a single biomarker. Given the importance of the problem and the need to reduce the abuse of antibiotics, further studies are urgently required. However, instead of looking for new biomarkers, it seems easier and more productive to test combinations of two or more of the presently available biomarkers. Moreover, studies based on omics technologies should be strongly boosted. However, while waiting for new information, the use of the clinical scores prepared by some scientific institutions could be suggested. Based on maternal risk factors and infant clinical indicators, sepsis risk can be calculated, and a significant reduction in antibiotic consumption can be obtained.

Serum amyloid A and metabolic disease: evidence for a critical role in chronic inflammatory conditions

Serum amyloid A (SAA) subtypes 1-3 are well-described acute phase reactants that are elevated in acute inflammatory conditions such as infection, tissue injury, and trauma, while SAA4 is constitutively expressed. SAA subtypes also have been implicated as playing roles in chronic metabolic diseases including obesity, diabetes, and cardiovascular disease, and possibly in autoimmune diseases such as systemic lupus erythematosis, rheumatoid arthritis, and inflammatory bowel disease. Distinctions between the expression kinetics of SAA in acute inflammatory responses and chronic disease states suggest the potential for differentiating SAA functions. Although circulating SAA levels can rise up to 1,000-fold during an acute inflammatory event, elevations are more modest (∼5-fold) in chronic metabolic conditions. The majority of acute-phase SAA derives from the liver, while in chronic inflammatory conditions SAA also derives from adipose tissue, the intestine, and elsewhere. In this review, roles for SAA subtypes in chronic metabolic disease states are contrasted to current knowledge about acute phase SAA. Investigations show distinct differences between SAA expression and function in human and animal models of metabolic disease, as well as sexual dimorphism of SAA subtype responses.

Maternal Serum Amyloid A as a Marker of Preterm Birth/PROM: A Systematic Review and Meta-Analysis

Background and Objectives: Preterm birth, one of the leading causes of neonatal mortality, occurs in between 5 and 18% of births. Premature birth can be induced by a variety of triggers, including infection or inflammation. Serum amyloid A, a family of apolipoproteins, increases significantly and rapidly at the onset of inflammation. This study aims to systematically review the results of studies in the literature that have examined the correlation between SAA and PTB/PROM. Materials and Methods: To examine the correlation between serum amyloid A levels in women who gave birth prematurely, a systematic analysis was performed according to PRISMA guidelines. Studies were retrieved by searching the electronic databases PubMed and Google Scholar. The primary outcome measure was the standardized mean difference in serum amyloid A level comparing the preterm birth or premature rupture of membranes groups and the term birth group. Results: Based on the inclusion criteria, a total of 5 manuscripts adequately addressed the desired outcome and were thus included in the analysis. All included studies showed a statistically significant difference in serum SAA levels between the preterm birth or preterm rupture of membranes groups and the term birth group. The pooled effect, according to the random effects model, is SMD = 2.70. However, the effect is not significant (p = 0.097). In addition, the analysis reveals an increased heterogeneity with an I² = 96%. Further, the analysis of the influence on heterogeneity found a study that has a significant influence on heterogeneity. However, even after outline exclusion, heterogeneity remained high I² = 90.7%. Conclusions: There is an association between increased levels of SAA and preterm birth/PROM, but studies have shown great heterogeneity.

Diagnostic Performance and Patient Outcomes With C-Reactive Protein Use in Early-Onset Sepsis Evaluations

OBJECTIVES

To determine performance of C-reactive protein (CRP) in the diagnosis of early-onset sepsis, and to assess patient outcomes with and without routine use of CRP.

STUDY DESIGN

This was a retrospective cohort study of infants admitted to 2 neonatal intensive care units. CRP was used routinely in early-onset sepsis evaluations during 2009-2014; this period was used to determine CRP performance at a cut-off of ≥10 mg/L in diagnosis of culture-confirmed early-onset sepsis. Routine CRP use was discontinued during 2018-2020; outcomes among infants admitted during this period were compared with those in 2012-2014.

RESULTS

From 2009 to 2014, 10 134 infants were admitted; 9103 (89.8%) had CRP and 7549 (74.5%) had blood culture obtained within 3 days of birth. CRP obtained ±4 hours from blood culture had a sensitivity of 41.7%, specificity 89.9%, and positive likelihood ratio 4.12 in diagnosis of early-onset sepsis. When obtained 24-72 hours after blood culture, sensitivity of CRP increased (89.5%), but specificity (55.7%) and positive likelihood ratio (2.02) decreased. Comparing the periods with (n = 4977) and without (n = 5135) routine use of CRP, we observed lower rates of early-onset sepsis evaluation (74.5% vs 50.5%), antibiotic initiation (65.0% vs 50.8%), and antibiotic prolongation in the absence of early-onset sepsis (17.3% vs 7.2%) in the later period. Rate and timing of early-onset sepsis detection, transfer to a greater level of care, and in-hospital mortality were not different between periods.

CONCLUSIONS

CRP diagnostic performance was not sufficient to guide decision-making in early-onset sepsis. Discontinuation of routine CRP use was not associated with differences in patient outcomes despite lower rates of antibiotic administration.

Serum amyloid A as a marker to detect sepsis and predict outcome in hospitalized neonatal foals

BACKGROUND

Serum amyloid A (SAA) has been reported to hold promise as diagnostic and prognostic marker in foals. This has not been investigated thoroughly.

OBJECTIVES

Evaluate admission SAA concentrations as predictor of sepsis and outcome.

ANIMALS

Five hundred and ninety hospitalized foals <14 days old.

METHODS

Retrospective multicenter study. Foals were scored with sepsis and survival scores, grouped according to health category (septic, sick but nonseptic, uncertain sepsis status) and outcome; septic foals were further categorized according to severity (normal sepsis, severe sepsis, and septic shock). SAA was compared between groups using Mann-Whitney test and Kruskal-Wallis test. Receiver operating characteristic curves identified optimal SAA cut off values for detecting sepsis and predicting outcome.

RESULTS

Admission SAA concentrations differed significantly between sick nonseptic foals (312.1 ± 685.4 mg/L) and septic foals (1079.7 ± 1254.5 mg/L) and increased with increasing sepsis score. SAA did not differ between sepsis severity groups. The optimal cut off for sepsis detection was 1050 mg/L (sensitivity 30.2%, specificity 90.7%). Admission SAA concentrations were lower in surviving (435.0 ± 723.6 mg/L) compared to nonsurviving foals (1062.7 ± 1440.1 mg/L) and decreased with increasing survival score. The optimal cut off for nonsurvival prediction was 1250 mg/L (sensitivity 22.1%, specificity 90.8%).

CONCLUSIONS AND CLINICAL IMPORTANCE

SAA concentration was higher in septic foals and nonsurviving foals. Even though optimal cut offs for SAA to detect sepsis and predict outcome had low sensitivity, they had good specificity. SAA can therefore be used as a marker to rule out sepsis and nonsurvival.

Triple quantitative detection of three inflammatory biomarkers with a biotin-streptavidin-phycoerythrin based lateral flow immunoassay

Quantified inflammatory biomarkers are effective clinical strategy for correct and reasonable drug treatment. In the study, a triple lateral flow immunoassay (triple LFIA) had firstly been developed for specific and simultaneous detection of three pivotal inflammatory biomarkers (PCT, CRP and SAA) via biotin-streptavidin-phycoerythrin signal amplification system in one strip. The developed triple LFIA adopted phycoerythrin (PE) as chromophore to eliminate auto-fluorescence interference from plasma biomolecules and anti-PE mAb as single control line to reduce the nonspecific adsorption, which featured particular advantages in high sensitivity and specificity in a large range of analyte concentrations with the LODs of 0.106 ng/mL for PCT, 0.345 μg/mL for CRP and 3.112 μg/mL SAA, respectively. And the linear quantitative detection ranges were from 0.106 to 100 ng/mL, from 0.345 to 200 μg/mL, and from 3.112 to 200 μg/mL, respectively. Compared to commercial chemiluminescence immunoassay method, the correlations for tested PCT, CRP and SAA in 108 clinical samples were 0.989, 0.987 and 0.988, respectively. In summary, we had proposed a rapid and accurate plasma detection to measure inflammation factors, which facilitated the clinical value to achieve precise treatment.

A Three-Protein Panel to Support the Diagnosis of Sepsis in Children

Sepsis is a syndrome without a standard validated diagnostic test. Early recognition is crucial. Serum proteome analysis in children with sepsis may identify new biomarkers. This study aimed to find suitable blood biomarkers for an early diagnosis of sepsis. An analytical observational case-control study was carried out in a single center. Children admitted to a Pediatric Intensive Care Unit with clinical diagnosed sepsis were eligible for study. A proteomic analysis conducted by mass spectrometry was performed. Forty patients with sepsis and 24 healthy donors were recruited. Proteomics results revealed 44 proteins differentially expressed between patients and healthy controls. Six proteins were selected to be validated: lactoferrin, serum amyloid-A1 (SAA-1), complement factor B, leucine-rich alpha-2 glycoprotein (LRG1), soluble interleukin-2 alpha chain receptor (sCD25) and soluble haptoglobin−hemoglobin receptor. Our results showed that sCD25, SAA-1, and LRG1 had high levels of specificity and sensitivity, as well as an excellent area under the ROC curve (>0.9). Our study provides a serum proteomic analysis that identifies new diagnostic biomarkers in sepsis. SAA-1, sCD25 and LRG1 were able to separate septic from healthy donor, so they could be used together with other clinical and analytical features to improve sepsis diagnosis in children.

Evaluation of the diagnostic and prognostic values of serum HSP90α in sepsis patients: a retrospective study

Background

Sepsis is a serious syndrome that is caused by immune responses dysfunction and leads to high mortality. The abilities of heat shock protein 90α (HSP90α) in assessing the diagnosis and prognosis in patients with sepsis remain ill-defined to date. We conducted a study to reveal the possible clinical applications of HSP90α as biomarker for the diagnosis and prognosis in patients with sepsis.

Methods

In total, 150 patients of sepsis, 110 patients without sepsis admitted to ICU and 110 healthy subjects were involved in this study. The serum HSP90α contents, sequential organ failure assessment (SOFA) scores, procalcitonin (PCT), and short-term survival status of the participants were measured and compared. Logistic and linear regression models adjusting for potential confounders were used to examine the association of HSP90α with sepsis survival. Moreover, serum IL-1β, IL-18, MIP-3α, and ENA-78 were also determined. Finally, Spearman correlation analysis was employed to reveal a possible mechanism that HSP90α contributed to the short-term deaths.

Results

Serum HSP90α levels in sepsis patients were higher than those in ICU controls and healthy controls (P < 0.001), and even increased in patients who died within 28 days (P < 0.001). Logistic and linear regression models identified HSP90α was an independent risk factors for sepsis mortality. Receiver operating characteristic (ROC) analysis displayed that HSP90α had a considerable predictive performance for sepsis outcome, with an area under curve (AUC) value up to 0.79. Survival analysis demonstrated that the mortality of sepsis individuals at 28 days was positively associated with HSP90α levels, especially the levels of HSP90α were greater than 120 ng/mL (P < 0.001). Moreover, among sepsis patients, those who died had notably elevated cytokines, IL-1β, IL-18, and chemokines, MIP-3α, ENA-78, relative to survivors. Further correlation analysis demonstrated that there was a nominally positive correlation between HSP90α and IL-1β, IL-18, and MIP-3α.

Conclusion

HSP90α is of favorable clinical significance in sepsis diagnosis and prognosis, laying a foundation for future clinical applications.

Diagnosis of Neonatal Sepsis: The Role of Inflammatory Markers

This is a narrative review on the role of biomarkers in the diagnosis of neonatal sepsis. We describe the difficulties to obtain standardized definitions in neonatal sepsis and discuss the limitations of published evidence of cut-off values and their sensitivities and specificities. Maternal risk factors influence the results of inflammatory markers as do gestational age, the time of sampling, the use of either cord blood or neonatal peripheral blood, and some non-infectious causes. Current evidence suggests that the use of promising diagnostic markers such as CD11b, CD64, IL-6, IL-8, PCT, and CRP, either alone or in combination, might enable clinicians discontinuing antibiotics confidently within 24-48 h. However, none of the current diagnostic markers is sensitive and specific enough to support the decision of withholding antibiotic treatment without considering clinical findings. It therefore seems to be justified that antibiotics are often initiated in ill term and especially preterm infants. Early markers like IL-6 and later markers like CRP are helpful in the diagnosis of neonatal sepsis considering the clinical aspect of the neonate, the gestational age, maternal risk factors and the time (age of the neonate regarding early-onset sepsis) of blood sampling.

Molecular imprinting based electrochemical biosensor for identification of serum amyloid A (SAA), a neonatal sepsis biomarker

Neonatal septicemia is a bacterial infection in newborns. It is caused by bacteria including Escherichia coli and Group B Streptococcus (GBS). Neonatal septicemia is divided into early-onset and late-onset sepsis. The diagnosis of neonatal septicemia is a challenging task because of the presence of nonspecific symptoms. Biomarkers such as C-reactive protein (CRP), procalcitonin (PCT), and serum amyloid A (SAA) can help in the detection of sepsis at early stages. The level of biomarkers is elevated once sepsis occurs in the body. This study presents the development of an electrochemical biosensor based on nanomaterials integrated molecularly imprinted polymer technique. To obtain the synergistic effect and high conductivity, multi-walled carbon nanotubes (MWCNTs), manganese oxide nanospheres (MnO₂NSs), and cobalt oxide nanoparticles (Co₃O₄NPs) were coated over the screen-printed electrode (SPE). A further modification was done by polymerizing molecularly imprinted polymer (MIP) specifically synthesized for SAA onto modified SPE. The performance of the designed platform was evaluated through electrochemical techniques. The operating range of the developed sensor was found to be 0.01 pM to 1 μM and 0.01 pM as the lower detection limit.

Knowledge gaps in late-onset neonatal sepsis in preterm neonates: a roadmap for future research

Late-onset neonatal sepsis (LONS) remains an important threat to the health of preterm neonates in the neonatal intensive care unit. Strategies to optimize care for preterm neonates with LONS are likely to improve survival and long-term neurocognitive outcomes. However, many important questions on how to improve the prevention, early detection, and therapy for LONS in preterm neonates remain unanswered. This review identifies important knowledge gaps in the management of LONS and describe possible methods and technologies that can be used to resolve these knowledge gaps. The availability of computational medicine and hypothesis-free-omics approaches give way to building bedside feedback tools to guide clinicians in personalized management of LONS. Despite advances in technology, implementation in clinical practice is largely lacking although such tools would help clinicians to optimize many aspects of the management of LONS. We outline which steps are needed to get possible research findings implemented on the neonatal intensive care unit and provide a roadmap for future research initiatives. IMPACT: This review identifies knowledge gaps in prevention, early detection, antibiotic, and additional therapy of late-onset neonatal sepsis in preterm neonates and provides a roadmap for future research efforts. Research opportunities are addressed, which could provide the means to fill knowledge gaps and the steps that need to be made before possible clinical use. Methods to personalize medicine and technologies feasible for bedside clinical use are described.

Profiling Tryptophan Catabolites of Human Gut Microbiota and Acute-Phase Protein Levels in Neonatal Dried Blood Specimens

National screening programs use dried blood specimens to detect metabolic disorders or aberrant protein functions that are not clinically evident in the neonatal period. Similarly, gut microbiota metabolites and immunological acute-phase proteins may reveal latent immune aberrations. Microbial metabolites interact with xenobiotic receptors (i.e., aryl hydrocarbon and pregnane-X) to maintain gastrointestinal tissue health, supported by acute-phase proteins, functioning as sensors of microbial immunomodulation and homeostasis. The delivery (vaginal or cesarean section) shapes the microbial colonization, which substantially modulates both the immune system’s response and mucosal homeostasis. This study profiled microbial metabolites of the kynurenine and tryptophan pathway and acute-phase proteins in 134 neonatal dried blood specimens. We newly established neonatal blood levels of microbial xenobiotic receptors ligands (i.e., indole-3-aldehyde, indole-3-butyric acid, and indole-3-acetamide) on the second day of life. Furthermore, we observed diverse microbial metabolic profiles in neonates born vaginally and via cesarean section, potentially due to microbial immunomodulatory influence. In summary, these findings suggest the supportive role of human gut microbiota in developing and maintaining immune system homeostasis.

Neonatal sepsis at point of care

Sepsis, which includes infection followed by inflammation, is one of the leading causes of death among neonates worldwide. The major attribute of this disease process is dysregulated host response to infection leading to organ dysfunction and potentially death. A comprehensive understanding of the host response as well as the pathogen itself are important factors contributing to outcome. Early diagnosis is paramount, as it leads to accurate assessment and improved clinical management. Accordingly, a number of diagnostic platforms have been introduced to assess the presence of blood stream pathogens in septic neonates. Unfortunately, current point-of-care (POC) methods rely on a single parameter/biomarker and thus lack a comprehensive evaluation. The emerging field of biosensing has, however, resulted in the development of a wide range of analytical devices that may be useful at POC. This review discusses currently available methods to screen the inflammatory process in neonatal sepsis. We describe POC sensor-based methods for single platform multi-analyte detection and highlight the latest advances in this evolving technology. Finally, we critically evaluate the applicability of these POC devices clinically for early diagnosis of sepsis in neonates.

Infection-Mediated Clinical Biomarkers for a COVID-19 Electrical Biosensing Platform

The race towards the development of user-friendly, portable, fast-detection, and low-cost devices for healthcare systems has become the focus of effective screening efforts since the pandemic attack in December 2019, which is known as the coronavirus disease 2019 (COVID-19) pandemic. Currently existing techniques such as RT-PCR, antigen-antibody-based detection, and CT scans are prompt solutions for diagnosing infected patients. However, the limitations of currently available indicators have enticed researchers to search for adjunct or additional solutions for COVID-19 diagnosis. Meanwhile, identifying biomarkers or indicators is necessary for understanding the severity of the disease and aids in developing efficient drugs and vaccines. Therefore, clinical studies on infected patients revealed that infection-mediated clinical biomarkers, especially pro-inflammatory cytokines and acute phase proteins, are highly associated with COVID-19. These biomarkers are undermined or overlooked in the context of diagnosis and prognosis evaluation of infected patients. Hence, this review discusses the potential implementation of these biomarkers for COVID-19 electrical biosensing platforms. The secretion range for each biomarker is reviewed based on clinical studies. Currently available electrical biosensors comprising electrochemical and electronic biosensors associated with these biomarkers are discussed, and insights into the use of infection-mediated clinical biomarkers as prognostic and adjunct diagnostic indicators in developing an electrical-based COVID-19 biosensor are provided.

Relevance of Biomarkers Currently in Use or Research for Practical Diagnosis Approach of Neonatal Early-Onset Sepsis

Neonatal early-onset sepsis (EOS) is defined as an invasive infection that occurs in the first 72 h of life. The incidence of EOS varies from 0.5–2% live births in developed countries, up to 9.8% live births in low resource settings, generating a high mortality rate, especially in extremely low birth weight neonates. Clinical signs are nonspecific, leading to a late diagnosis and high mortality. Currently, there are several markers used for sepsis evaluation, such as hematological indices, acute phase reactants, cytokines, which by themselves do not show acceptable sensitivity and specificity for the diagnosis of EOS in neonates. Newer and more selective markers have surfaced recently, such as presepsin and endocan, but they are currently only in the experimental research stages. This comprehensive review article is based on the role of biomarkers currently in use or in the research phase from a basic, translational, and clinical viewpoint that helps us to improve the quality of neonatal early-onset sepsis diagnosis and management.

Prognostic value of serum amyloid A in patients with COVID-19

OBJECTIVE

To investigate the prognostic value of serum amyloid A (SAA) in the patients with Corona Virus Disease 2019 (COVID-19).

METHODS

The medical data of 89 COVID-19 patients admitted to Renmin Hospital of Wuhan University from January 3, 2020 to February 26, 2020 were collected. Eighty-nine cases were divided into survival group (53 cases) and non-survival group (36 cases) according to the results of 28-day follow-up. The SAA levels of all patients were recorded and compared on 1 day after admission (before treatment) and 3 days, 5 days, and 7 days after treatment. The ROC curve was drawn to analyze the prognosis of patients with COVID-19 by SAA.

RESULTS

The difference of comparison of SAA between survival group and non-survival group before treatment was not statistically significant, Z1 = - 1.426, P = 0.154. The Z1 values (Z1 is the Z value of the rank sum test) of the two groups of patients at 3 days, 5 days, and 7 days after treatment were - 5.569, - 6.967, and - 7.542, respectively. The P values were all less than 0.001, and the difference was statistically significant. The ROC curve results showed that SAA has higher sensitivity to the prognostic value of 1 day (before treatment), 3 days, 5 days, and 7 days after treatment, with values of 0.806, 0.972, 0.861, and 0.961, respectively. Compared with SAA on the 7th day and C-reactive protein, leukocyte count, neutrophil count, lymphocyte count, and hemoglobin on the 7th day, the sensitivities were: 96.1%, 83.3%, 88.3%, 83.3%, 67.9%, and 83.0%, respectively, of which SAA has the highest sensitivity.

CONCLUSION

SAA can be used as a predictor of the prognosis in patients with COVID-19.

Recent advances in developing biosensing based platforms for neonatal sepsis

Neonatal sepsis is a bloodstream infection primarily caused by Escherichia coli (E. coli), Group B Streptococcus (GBS), Listeria monocytogenes, Haemophilus influenzae, S. aureus, Klebsiella spp. and non-typhoidal Salmonella bacteria. Neonatal Sepsis is referred as a critical response to the infection in the neonatal period that can lead to the failure of body organs and thereby causing damage to the tissues resulting in death of the neonates. Nearly 4 million deaths across the world are occurred due to neonatal sepsis infections. In order to prevent the bloodstream infections in the neonates, it is indispensable to diagnose the disease properly for appropriate treatment during the point of care. Numerous studies have been reported to identify major biomarkers associated with neonatal sepsis including Serum Amyloid A (SAA), C - reactive protein (CRP), Procalcitonin (PCT) and Lipopolysaccharide-binding protein (LBP). Distinct diagnostic platforms have also been developed detecting the presence of bloodstream infections including electrochemical, potentiometric, and impedimetric sensors. Recently, electrochemical biosensors with the integration of nanomaterials have emerged as a better platform for neonatal sepsis biomarkers detection. This review article summarizes the diverse screening platforms, evaluation parameters, and new advances based on implications of nanomaterials for the development of biosensors detecting neonatal sepsis infections. The review further elucidates the significance and future scope of distinctive platforms which are predominantly associated with detection of neonatal sepsis.

Clinical Value of Serum Amyloid-A Protein, High-density Lipoprotein Cholesterol and Apolipoprotein-A1 in the Diagnosis and Follow-up of Neonatal Sepsis

BACKGROUND

To evaluate the performance of serum amyloid-A (SAA), high-density lipoprotein cholesterol (HDL-C) and apolipoprotein-A1 (Apo-A1) levels in the identification and monitoring of neonatal sepsis.

METHODS

This prospective study included 113 full-term septic neonates (postnatal age 4-28 days) admitted to the Special Care Neonatal Unit of a University Hospital from January 1, 2016, to April 30, 2019, and 68 healthy neonates (controls). Blood samples were drawn serially in septic neonates at enrollment and on days 1, 3 and 7, and once in controls, for SAA, HDL-C and Apo-A1 determination.

RESULTS

At enrollment, SAA levels were significantly higher in septic neonates in comparison with controls (median 50.7 vs. 3.5 mg/L; P < 0.0001); HDL-C and Apo-A1 levels were significantly lower in patients than in controls (P < 0.001 and P < 0.006, respectively). SAA levels were higher in culture-positive compared with culture-negative sepsis (median 202.0 vs. 14.2 mg/L; P < 0.0001). HDL-C and Apo-A1 levels did not differ significantly between culture-positive and culture-negative sepsis. Receiver operating characteristic curve analysis of SAA levels at enrollment resulted in significant areas under the curve (AUC) for detecting sepsis {AUC = 0.929 [95% confidence interval: 0.885-0.973]; P < 0.0001} and also for discriminating between culture-positive and culture-negative sepsis [AUC = 0.933 (95% confidence interval: 0.882-0.984); P < 0.0001]. The combination of HDL-C and Apo-A1 with SAA increased its diagnostic performance. Furthermore, serial SAA levels following enrollment could indicate clinical response in septic neonates.

CONCLUSIONS

SAA seems to be a useful biomarker for identification and monitoring of neonatal sepsis, and also for discriminating between culture-positive and culture-negative sepsis. HDL-C and Apo-A1 could be used as complementary markers.

Neonatal Sepsis

Neonatal sepsis is associated with severe morbidity and mortality in the neonatal period. Clinical manifestations range from subclinical infection to severe local or systemic infection. Neonatal sepsis is divided into three groups as early-onset neonatal sepsis, late-onset neonatal sepsis and very late-onset neonatal sepsis according to the time of the onset. It was observed that the incidence of early-onset neonatal sepsis decreased with intrapartum antibiotic treatment. However, the incidence of late-onset neonatal sepsis has increased with the increase in the survival rate of preterm and very low weight babies. The source of the causative pathogen may be acquisition from the intrauterine origin but may also acquisition from maternal flora, hospital or community. Prematurity, low birth weight, chorioamnionitis, premature prolonged rupture of membranes, resuscitation, low APGAR score, inability to breastfeed, prolonged hospital stay and invasive procedures are among the risk factors. This article reviews current information on the definition, classification, epidemiology, risk factors, pathogenesis, clinical symptoms, diagnostic methods and treatment of neonatal sepsis.

Biomarkers of sepsis: time for a reappraisal

INTRODUCTION

Sepsis biomarkers can have important diagnostic, therapeutic, and prognostic functions. In a previous review, we identified 3370 references reporting on 178 different biomarkers related to sepsis. In the present review, we evaluate the progress in the research of sepsis biomarkers.

METHODS

Using the same methodology as in our previous review, we searched the PubMed database from 2009 until September 2019 using the terms "Biomarker" AND "Sepsis." There were no restrictions by age or language, and all studies, clinical and experimental, were included.

RESULTS

We retrieved a total of 5367 new references since our previous review. We identified 258 biomarkers, 80 of which were new compared to our previous list. The majority of biomarkers have been evaluated in fewer than 5 studies, with 81 (31%) being assessed in just a single study. Apart from studies of C-reactive protein (CRP) or procalcitonin (PCT), only 26 biomarkers have been assessed in clinical studies with more than 300 participants. Forty biomarkers have been compared to PCT and/or CRP for their diagnostic value; 9 were shown to have a better diagnostic value for sepsis than either or both of these biomarkers. Forty-four biomarkers have been evaluated for a role in answering a specific clinical question rather than for their general diagnostic or prognostic properties in sepsis.

CONCLUSIONS

The number of biomarkers being identified is still increasing although at a slower rate than in the past. Most of the biomarkers have not been well-studied; in particular, the clinical role of these biomarkers needs to be better evaluated.

Urinary I-FABP, L-FABP, TFF-3, and SAA Can Diagnose and Predict the Disease Course in Necrotizing Enterocolitis at the Early Stage of Disease

Necrotizing enterocolitis (NEC) is a severe gastrointestinal disease affecting mainly preterm newborns. It is characterized by unexpected onset and rapid progression with specific diagnostic signs as pneumatosis intestinalis or gas in the portal vein appearing later in the course of the disease. Therefore, we analyzed diagnostic and prognostic potential of the markers of early NEC pathogenesis, such as excessive inflammatory response (serum amyloid A (SAA)) and gut epithelium damage (intestinal and liver fatty acid-binding protein (I-FABP and L-FABP, respectively) and trefoil factor-3 (TFF-3)). We used ELISA to analyze these biomarkers in the urine of patients with suspected NEC, either spontaneous or surgery-related, or in infants without gut surgery (controls). Next, we compared their levels with the type of the disease (NEC or sepsis) and its severity. Already at the time of NEC suspicion, infants who developed NEC had significantly higher levels of all tested biomarkers than controls and higher levels of I-FABP and L-FABP than those who will later develop sepsis. Infants who will develop surgery-related NEC had higher levels of I-FABP and L-FABP than those who will develop sepsis already during the first 6 hours after the abdominal surgery. I-FABP was able to discriminate between infants who will develop NEC or sepsis and the SAA was able to discriminate between medical and surgical NEC. Moreover, the combination of TFF-3 with I-FABP and SAA could predict pneumatosis intestinalis, and the combination of I-FABP, L-FABP, and SAA could predict gas in the portal vein or long-term hospitalization and low SAA predicts early full enteral feeding. Thus, these biomarkers may be useful not only in the early, noninvasive diagnostics but also in the subsequent NEC management.

Necrotizing enterocolitis: It's not all in the gut

Necrotizing enterocolitis is the leading cause of death due to gastrointestinal disease in preterm neonates, affecting 5–12% of neonates born at a very-low birth weight. Necrotizing enterocolitis can present with a slow and insidious onset, with some neonates displaying early symptoms such as feeding intolerance. Treatment during the early stages includes bowel rest and careful use of antibiotics, but surgery is required if pneumoperitoneum and intestinal perforation occur. Mortality rates among neonates requiring surgery are estimated to be 20–30%, mandating the development of non-invasive and reliable biomarkers to predict necrotizing enterocolitis before the onset of clinical signs. Such biomarkers would allow at-risk neonates to receive maximal preventative therapies such as careful nutritional consideration, probiotics, and increased skin-to-skin care.

Impact statement

Necrotizing enterocolitis (NEC) is a devastating gastrointestinal disease; its high mortality rate mandates the development of non-invasive biomarkers to predict NEC before its onset. This review summarizes the pathogenesis, prevention, unresolved issues, and long-term outcomes of NEC.

Acute phase reactant serum amyloid A in inflammation and other diseases

Acute-phase reactant serum amyloid A (A-SAA) plays an important role in acute and chronic inflammation and is used in clinical laboratories as an indicator of inflammation. Although both A-SAA and C-reactive protein (CRP) are acute-phase proteins, the detection of A-SAA is more conclusive than the detection of CRP in patients with viral infections, severe acute pancreatitis, and rejection reactions to kidney transplants. A-SAA has greater clinical diagnostic value in patients who are immunosuppressed, patients with cystic fibrosis who are treated with corticoids, and preterm infants with late-onset sepsis. Nevertheless, for the assessment of the inflammation status and identification of viral infection in other pathologies, such as bacterial infections, the combinatorial use of A-SAA and other acute-phase proteins (APPs), such as CRP and procalcitonin (PCT), can provide more information and sensitivity than the use of any of these proteins alone, and the information generated is important in guiding antibiotic therapy. In addition, A-SAA-associated diseases and the diagnostic value of A-SAA are discussed. However, the relationship between different A-SAA isotypes and their human diseases are mostly derived from research laboratories with limited clinical samples. Thus, further clinical evaluations are necessary to confirm the clinical significance of each A-SAA isotype. Furthermore, the currently available A-SAA assays are based on polyclonal antibodies, which lack isotype specificity and are associated with many inflammatory diseases. Therefore, these assays are usually used in combination with other biomarkers in the clinic.

C-reactive protein for diagnosing late-onset infection in newborn infants

BACKGROUND

Late-onset infection is the most common serious complication associated with hospital care for newborn infants. Because confirming the diagnosis by microbiological culture typically takes 24 to 48 hours, the serum level of the inflammatory marker C-reactive protein (CRP) measured as part of the initial investigation is used as an adjunctive rapid test to guide management in infants with suspected late-onset infection.

OBJECTIVES

To determine the diagnostic accuracy of serum CRP measurement in detecting late-onset infection in newborn infants.

SEARCH METHODS

We searched electronic databases (MEDLINE, Embase, and Science Citation Index to September 2017), conference proceedings, previous reviews, and the reference lists of retrieved articles.

SELECTION CRITERIA

We included cohort and cross-sectional studies evaluating the diagnostic accuracy of serum CRP levels for the detection of late-onset infection (occurring more than 72 hours after birth) in newborn infants.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility for inclusion, evaluated the methodological quality of included studies, and extracted data to estimate diagnostic accuracy using hierarchical summary receiver operating characteristic (SROC) models. We assessed heterogeneity by examining variability of study estimates and overlap of the 95% confidence interval (CI) in forest plots of sensitivity and specificity.

MAIN RESULTS

The search identified 20 studies (1615 infants). Most were small, single-centre, prospective cohort studies conducted in neonatal units in high- or middle-income countries since the late 1990s. Risk of bias in the included studies was generally low with independent assessment of index and reference tests. Most studies used a prespecified serum CRP threshold level as the definition of a 'positive' index test (typical cut-off level between 5 mg/L and 10 mg/L) and the culture of a pathogenic micro-organism from blood as the reference standard.At median specificity (0.74), sensitivity was 0.62 (95% CI 0.50 to 0.73). Heterogeneity was evident in the forest plots but it was not possible to conduct subgroup or meta-regression analyses by gestational ages, types of infection, or types of infecting micro-organism. Covariates for whether studies used a predefined threshold or not, and whether studies used a standard threshold of between 5 mg/L and 10 mg/L, were not statistically significant.

AUTHORS' CONCLUSIONS

The serum CRP level at initial evaluation of an infant with suspected late-onset infection is unlikely to be considered sufficiently accurate to aid early diagnosis or select infants to undergo further investigation or treatment with antimicrobial therapy or other interventions.

Anti-microbial stewardship: antibiotic use in well-appearing term neonates born to mothers with chorioamnionitis

OBJECTIVE

To determine if implementation of a protocol based on a neonatal early-onset sepsis (EOS) calculator developed by Kaiser Permanente would safely reduce antibiotic use in well-appearing term infants born to mothers with chorioamnionitis in the unique setting of an Observation Nursery.

STUDY DESIGN

Data obtained from a retrospective chart review of well-appearing term infants born between 2009 and 2016 were entered into the EOS calculator to obtain management recommendations.

RESULTS

Three hundred and sixty-two infants met the study criteria. Management according to the EOS calculator would reduce antibiotic use from 99% to 2.5% (P<0.0001) of patients. Average length of therapy would also decrease from 2.08 to 0.05 days (P<0.0001). One infant, who remained asymptomatic, had Enterococcus bacteremia and received a 7-day course of broad-spectrum antibiotics.

CONCLUSIONS

Culture-positive sepsis in asymptomatic neonates born to mothers with chorioamnionitis is rare. Management according to the EOS calculator would markedly reduce the potential complications of antibiotic use. These data should initiate re-examination of existing protocols for management of this cohort of patients.

Serum Markers of Necrotizing Enterocolitis: A Systematic Review

OBJECTIVE

The aim of the study was to systematically review the diagnostic utility of serum biomarkers for the diagnosis of necrotizing enterocolitis (NEC).

METHODS

We conducted an electronic and manual search of the available evidence. We included studies reporting data on the diagnostic accuracy of "serum" biomarkers for the diagnosis of NEC, available until January 2016.

RESULTS

We selected 22 studies from the 1296 articles retrieved. Only S100 A8/A9 protein and apolipoprotein-CII showed high sensitivity (100% and 96.4%, respectively) and specificity (90% and 95%, respectively) in the studies using Bell stage II NEC as target condition. High sensitivity and specificity were reported for interleukin-10 (100% and 90%), interleukin1-receptor antagonist (100% and 91.7%), intestinal fatty acid-binding protein (100% and 91%) and ischemia-modified albumin (94.7% and 92%), when tested to predict the evolution from definite to advanced NEC. Given the amount of uncertainty, the limited availability of data and heterogeneity among the populations in the different studies, we were unable to perform a meta-analysis. Major concerns about the applicability stemmed from the spectrum of patients enrolled and the inclusion of diseases different from Bell stage ≥2 NEC as target conditions.

CONCLUSIONS

We identified only few markers with good diagnostic accuracy and found an overall low quality of the studies on serum NEC biomarkers. In conclusion, data supporting their use are insufficient.

Biomarkers for diagnosis of neonatal sepsis: a literature review

Sepsis is an important cause of mortality and morbidity in neonatal populations. There has been constant search of an ideal sepsis biomarker that have high sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), so that both the diagnosis and exclusion of neonatal sepsis can be made at the earliest possible and appropriate antibiotics can be started to neonate. Ideal sepsis biomarker will help in guiding us when not to start antibiotics in case of suspect sepsis and total duration of antibiotics course in case of proven sepsis. There are numerous sepsis biomarkers that have been evaluated for early detection of neonatal sepsis but till date there is no single ideal biomarker that fulfills all essential criteria's for being an ideal biomarker. The most commonly used biomarkers are C-reactive protein (CRP) and procalcitonin (PCT), but both have shown varied sensitivity, specificity, PPV and NPV in different studies. We conducted literature search for various neonatal sepsis biomarkers and this review article will cover briefly all the markers with current available evidence.

Cord Blood Acute Phase Reactants Predict Early Onset Neonatal Sepsis in Preterm Infants

BACKGROUND

Early onset sepsis (EOS) is a major cause of morbidity and mortality in preterm infants, yet diagnosis remains inadequate resulting in missed cases or prolonged empiric antibiotics with adverse consequences. Evaluation of acute phase reactant (APR) biomarkers in umbilical cord blood at birth may improve EOS detection in preterm infants with intrauterine infection.

METHODS

In this nested case-control study, infants (29.7 weeks gestation, IQR: 27.7-32.2) were identified from a longitudinal cohort with archived cord blood and placental histopathology. Patients were categorized using culture, laboratory, clinical, and antibiotic treatment data into sepsis groups: confirmed sepsis (cEOS, n = 12); presumed sepsis (PS, n = 30); and no sepsis (controls, n = 30). Nine APRs were measured in duplicate from cord blood using commercially available multiplex immunoassays (Bio-Plex Pro™). In addition, placental histopathologic data were linked to biomarker results.

RESULTS

cEOS organisms were Escherichia coli, Streptococcus agalactiae, Proteus mirabilis, Haemophilus influenzae and Listeria monocytogenes. C-reactive protein (CRP), serum amyloid A (SAA), haptoglobin (Hp), serum amyloid P and ferritin were significantly elevated in cEOS compared to controls (p<0.01). SAA, CRP, and Hp were elevated in cEOS but not in PS (p<0.01) and had AUCs of 99%, 96%, and 95% respectively in predicting cEOS. Regression analysis revealed robust associations of SAA, CRP, and Hp with EOS after adjustment for covariates. Procalcitonin, fibrinogen, α-2-macroglobulin and tissue plasminogen activator were not significantly different across groups. Placental acute inflammation was associated with APR elevation and was present in all cEOS, 9 PS, and 17 control infants.

CONCLUSION

This study shows that certain APRs are elevated in cord blood of premature infants with EOS of intrauterine origin. SAA, CRP, and Hp at birth have potential diagnostic utility for risk stratification and identification of infants with EOS.

Diagnostic value of C-reactive protein in neonatal sepsis: A meta-analysis

The aim of this study was to determine the value of C-reactive protein (CRP) in the diagnosis of patients with neonatal sepsis by a meta-analysis. Potential relevant studies were searched through the PubMed, Embase, and Cochrane Library databases before February 2016. We combined estimates of sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) with their 95% confidence intervals (CIs) of CRP for neonatal sepsis diagnosis. Summary receiver operating characteristic (SROC) curve was applied to evaluate the diagnostic value of CRP. The meta-regression and subgroup analysis were performed when heterogeneity was significant. In total, 31 studies were included in our meta-analysis with 5698 participants. The overall estimates for CRP in the diagnosis of neonatal sepsis were: sensitivity 0.69 (95% CI, 0.66–0.71), specificity 0.77 (95% CI, 0.76–0.78), PLR 3.83 (95% CI, 3.03–4.84), NLR 0.38 (95% CI, 0.31–0.45), and DOR 12.65 (95% CI, 8.91–17.94). The area under the curve (AUC) and Q* index were 0.8458 and 0.7773. Meta-regression analysis showed that heterogeneity was irrelevant to test time, cutoff value, assay method of CRP, neonates, and sepsis type. Heterogeneity still existed but decreased after subgroup analysis. CRP might be a valuable approach for the diagnosis of neonatal sepsis.

A Dormant Microbial Component in the Development of Preeclampsia

Preeclampsia (PE) is a complex, multisystem disorder that remains a leading cause of morbidity and mortality in pregnancy. Four main classes of dysregulation accompany PE and are widely considered to contribute to its severity. These are abnormal trophoblast invasion of the placenta, anti-angiogenic responses, oxidative stress, and inflammation. What is lacking, however, is an explanation of how these themselves are caused. We here develop the unifying idea, and the considerable evidence for it, that the originating cause of PE (and of the four classes of dysregulation) is, in fact, microbial infection, that most such microbes are dormant and hence resist detection by conventional (replication-dependent) microbiology, and that by occasional resuscitation and growth it is they that are responsible for all the observable sequelae, including the continuing, chronic inflammation. In particular, bacterial products such as lipopolysaccharide (LPS), also known as endotoxin, are well known as highly inflammagenic and stimulate an innate (and possibly trained) immune response that exacerbates the inflammation further. The known need of microbes for free iron can explain the iron dysregulation that accompanies PE. We describe the main routes of infection (gut, oral, and urinary tract infection) and the regularly observed presence of microbes in placental and other tissues in PE. Every known proteomic biomarker of "preeclampsia" that we assessed has, in fact, also been shown to be raised in response to infection. An infectious component to PE fulfills the Bradford Hill criteria for ascribing a disease to an environmental cause and suggests a number of treatments, some of which have, in fact, been shown to be successful. PE was classically referred to as endotoxemia or toxemia of pregnancy, and it is ironic that it seems that LPS and other microbial endotoxins really are involved. Overall, the recognition of an infectious component in the etiology of PE mirrors that for ulcers and other diseases that were previously considered to lack one.

Concentrations of serum amyloid A and plasma fibrinogen in horses undergoing emergency abdominal surgery

OBJECTIVE

To compare the perioperative response of serum amyloid A (SAA) to fibrinogen in horses requiring exploratory celiotomy for colic and to determine if SAA could be used to predict complications and outcome.

DESIGN

Prospective observational clinical study.

SETTING

University teaching hospital.

ANIMALS

Eighteen horses undergoing exploratory celiotomy for colic. Inclusion criteria for the study included survival and anesthetic recovery from exploratory celiotomy, no history of surgery within the past year.

INTERVENTIONS

Blood was obtained via jugular venipuncture before surgery (time 0) and at 24, 48, 72, and 96 hours after recovery from anesthesia.

MEASUREMENTS AND MAIN RESULTS

Quantitative and semiquantitative fibrinogen, SAA, total nucleated cell counts, and total protein were evaluated at each time point. Multivariable linear regression was used to assess differences at each time point and after grouping horses according to duration of colic prior to surgery, strangulating surgical lesion or not, presence of systemic inflammatory response syndrome (SIRS) on admission, and postsurgical complications. Significant (P < 0.05) increases in SAA concentrations occurred in all cases after surgery compared to fibrinogen concentration, which only demonstrated a mild, clinically insignificant increase postsurgery. SAA concentrations were also significantly increased (P < 0.05) in cases identified with SIRS prior to surgery and postoperatively at 48 (P = 0.05) and 72 hours (P = 0.02) in horses that developed complications.

CONCLUSIONS

Measurement of SAA is a more sensitive indicator of inflammation than fibrinogen in the perioperative period of horses requiring exploratory celiotomy for colic. Serial measurement of SAA at 48, 72, and 96 hours after surgery may be helpful to determine risk of complications and guide postoperative management. Measurement of SAA on admission also allows for quantification of SIRS when it is detected clinically.

Admission levels of serum amyloid a and procalcitonin are more predictive of the diagnosis of acute appendicitis compared with C-reactive protein

BACKGROUND

Acute appendicitis is the commonest surgical emergency, but its diagnosis can be elusive with a negative appendicectomy rate of 20%. The aims of this study were to investigate the potential value of the markers of acute inflammation, serum amyloid A (SAA), and serum procalcitonin (ProCT), in the diagnosis of acute appendicitis in adults and to compare that with the commonly used serum C-reactive protein (CRP).

METHODS

Adult patients presenting with acute right lower abdominal pain and a clinical suspicion of acute appendicitis were included. Blood samples were obtained within 6 hours of admission for rapid serum CRP assay and for end-of-recruitment batch analysis of SAA and serum ProCT concentrations.

RESULTS

A total of 147 patients (81 males) with a mean (±SD) age of 36 (±17) years were recruited. Appendicitis was confirmed histologically in 61 of 72 patients (84.7%) who underwent appendicectomy. A post hoc analysis revealed a diagnostic sensitivity and specificity for SAA of 92% and 72%, ProCT of 85% and 74%, and CRP of 75% and 72%, respectively. The receiver operator characteristics for the area under the curves showed that SAA (P=0.011) and ProCT (P=0.037) significantly exceeded CRP in the prediction of acute appendicitis on admission.

CONCLUSIONS

The measurement of SAA and serum ProCT on admission in patients with clinically suspected acute appendicitis seems to outperform serum CRP in aiding that diagnosis.

Host response biomarkers in the diagnosis of sepsis: a general overview

Critically ill patients who display a systemic inflammatory response syndrome (SIRS) are prone to develop nosocomial infections. The challenge remains to distinguish as early as possible among SIRS patients those who are developing sepsis. Following a sterile insult, damage-associated molecular patterns (DAMPs) released by damaged tissues and necrotic cells initiate an inflammatory response close to that observed during sepsis. During sepsis, pathogen-associated molecular patterns (PAMPs) trigger the release of host mediators involved in innate immunity and inflammation through identical receptors as DAMPs. In both clinical settings, a compensatory anti-inflammatory response syndrome (CARS) is concomitantly initiated. The exacerbated production of pro- or anti-inflammatory mediators allows their detection in biological fluids and particularly within the bloodstream. Some of these mediators can be used as biomarkers to decipher among the patients those who developed sepsis, and eventually they can be used as prognosis markers. In addition to plasma biomarkers, the analysis of some surface markers on circulating leukocytes or the study of mRNA and miRNA can be helpful. While there is no magic marker, a combination of few biomarkers might offer a high accuracy for diagnosis.

Use of early biomarkers in neonatal brain damage and sepsis: state of the art and future perspectives

The identification of early noninvasive biochemical markers of disease is a crucial issue of the current scientific research, particularly during the first period of life, since it could provide useful and precocious diagnostic information when clinical and radiological signs are still silent. The ideal biomarker should be practical and sensitive in the precocious identification of at risk patients. An earlier diagnosis may lead to a larger therapeutic window and improve neonatal outcome. Brain damage and sepsis are common causes of severe morbidity with poor outcome and mortality during the perinatal period. A large number of potential biomarkers, including neuroproteins, calcium binding proteins, enzymes, oxidative stress markers, vasoactive agents, and inflammatory mediators, have been so far investigated. The aim of the present review was to provide a brief overview of some of the more commonly investigated biomarkers used in case of neonatal brain damage and sepsis.

Diagnostic utility of biomarkers for neonatal sepsis--a systematic review

Neonatal sepsis is a major cause of morbidity and mortality. Early diagnosis and treatment of the neonate with suspected sepsis are essential to prevent life-threatening complications. Diagnosis of neonatal sepsis is a challenge due to non-specific clinical signs and the fact that infection markers are difficult to interpret in the first and critical phase of neonatal sepsis. The objective of the present study was to systematically evaluate existing evidence of the diagnostic utility of biomarkers for prediction of sepsis in neonates. We conducted a systematic literature search performed in PubMed and Embase. The study population was neonates with gestation age > 24 weeks in their first 28 days of life with suspected sepsis. The included manuscripts were rated due to criteria from a modified rating scale developed by Douglas Altman. Of 292 potentially relevant manuscripts, 77 fulfilled the inclusion and exclusion criteria; 16 (21%) were rated as high-quality studies. C-reactive protein (CRP) was the most extensively studied biomarker evaluated. The high-quality studies indicated that the acute phase protein serum amyloid A had high sensitivity, both at onset of symptoms and 2 days after. The studies evaluating serum amyloid A presented a variable positive predictive value (PPV, 0.67 and 0.92) with a high negative predictive value (NPV, 0.97 and 1.00). The existing evidence of the diagnostic value of serum amyloid A for neonatal sepsis showed promising results, and should be further investigated in clinical settings.

Effective Biomarkers for Diagnosis of Neonatal Sepsis

Infection in neonates continues to be a global problem with significant morbidity and mortality. The diagnosis of neonatal sepsis is complicated by nonspecific clinical symptomatology, a high-false negative rate, and a delay in obtaining blood culture results. An ideal biomarker needs to have a high degree of accuracy in recognizing the presence or absence of definite infection at an early stage, to guide the initiation and duration of antibiotic therapy. The diagnostic utility of the following biomarkers seems to be most practical in the early (interleukin [IL]-6, IL-8, tumor necrosis factor-alpha, neutrophil CD64), mid (procalcitonin) and late (C-reactive protein) phases of neonatal sepsis. Future research studies to assess reliability of these biomarkers should be (1) adequately powered for sample size and (2) use the gold-standard definition of blood-culture proven pathogen-specific sepsis. Significant advances in diagnostic accuracy of novel biomarkers to allow early, accurate, and cost-effective identification of pathogens responsible for neonatal sepsis is anticipated in the next 5 years.

Diagnosis value of the serum amyloid A test in neonatal sepsis: a meta-analysis

Neonatal sepsis (NS), a common disorder for humans, is recognized as a leading global public health challenge. This meta-analysis was performed to assess the accuracy of the serum amyloid A (SAA) test for diagnosing NS. The studies that evaluated the SAA test as a diagnostic marker were searched in Pubmed, EMBASE, the Cochrane Library, and Google Network between January 1996 and June 2013. A total of nine studies including 823 neonates were included in our meta-analysis. Quality of each study was evaluated by the quality assessment of diagnostic accuracy studies tool (QUADAS). The SAA test showed moderate accuracy in the diagnosis of NS both at the first suspicion of sepsis and 8-96 h after the sepsis onset, both with Q* = 0.91, which is similar to the PCT and CRP tests for the diagnosis of NS in the same period. Heterogeneity between studies was also explained by cut-off point, SAA assay, and age of included neonates. On the basis of our meta-analysis, therefore, SAA could be promising and meaningful in the diagnosis of NS.

Cord blood interleukin-6 as a predictor of early-onset neonatal sepsis

AIM

To compare diagnostic accuracy in cord blood of interleukin-6 (IL-6) with C-reactive protein (CRP) as predictors of early-onset neonatal sepsis (EOS) in newborns with prenatal risk factors for infection.

METHODS

During 12 months, cord blood IL-6 and CRP were measured immediately after birth in neonates with prenatal risk factors of infection. The odds of developing sepsis based on IL-6 and CRP values were calculated using likelihood ratios (LR), and their accuracy as predictors was compared by binary logistic regression. Multivariable logistic regression analyses were performed to identify independent risk factors for sepsis.

RESULTS

Ten of 128 neonates (7.8%) were diagnosed with EOS confirmed with positive blood culture in five cases (3.9%). Cord blood IL-6 was a greater predictor of sepsis than CRP [ROC for IL-6 (0.88) vs. CRP (0.70)]. IL-6-positive and IL-6-negative LR [7.14 vs. -0.11] were superior to those calculated for CRP [2.86 vs. -0.51]. Chorioamnionitis and Apgar at 1 min were identified as independent risk factors for EOS.

CONCLUSIONS

Cord blood IL-6 showed superior LR than CRP; therefore, it is a better predictor to initiate treatment in neonates with prenatal infectious risk factors immediately after birth.

Early diagnosis of sepsis using serum biomarkers

Sepsis, an innate immunological response of systemic inflammation to infection, is a growing problem worldwide with a relatively high mortality rate. Immediate treatment is required, necessitating quick, early and accurate diagnosis. Rapid molecular-based tests have been developed to address this need, but still suffer some disadvantages. The most commonly studied biomarkers of sepsis are reviewed for their current uses and diagnostic accuracies, including C-reactive protein, procalcitonin, serum amyloid A, mannan and IFN-γ-inducible protein 10, as well as other potentially useful biomarkers. A singular ideal biomarker has not yet been identified; an alternative approach is to shift research focus to determine the diagnostic relevancy of multiple biomarkers when used in concert. Challenges facing biomarker research, including lack of methodology standardization and assays with better detection limits, are discussed. The ongoing efforts in the development of a multiplex point-of-care testing kit, enabling quick and reliable detection of serum biomarkers, may have great potential for early diagnosis of sepsis.

Serum amyloid-A levels in neonatal necrotizing enterocolitis

We aimed to evaluate serum levels of serum amyloid-A (SAA) both in the diagnosis and monitoring the treatment response of necrotizing enterocolitis (NEC). Forty-five preterm neonates were enrolled in the study, including 15 infants with NEC, 15 with sepsis, and 15 healthy preterm infants. Pre- and posttreatment serum SAA levels were measured. Among patients with NEC, 11 had stage 1 and 4 had stage 2 disease according to the modified Bell's staging criteria. Baseline SAA levels of the infants with NEC were significantly higher than controls (P=0.013) and were significantly lower than those with sepsis (P=0.004). When infants with stage 1 and stage 2 NEC were analyzed separately, baseline SAA levels of the infants with stage 2 NEC were significantly higher than controls (P=0.027) than those with stage 1 NEC (P=0.018), but similar to those with sepsis. There was a trend that baseline SAA levels were also correlated with the Bell stage (r=0.501, P=0.057). Posttreatment SAA levels significantly decreased in infants with sepsis (P=0.002). Pre- and posttreatment SAA levels were similar in patients with stage 1 and 2 NEC. In conclusion, SAA rises in early stages of NEC and may aid in diagnosis as a serum marker.

Procalcitonin and valuable clinical symptoms in the early detection of neonatal late-onset bacterial infection

AIM

To evaluate which clinical symptoms indicate proven neonatal bacterial infection (NBI) and whether measuring procalcitonin aside from C-reactive protein and interleukin 6 improves sensitivity and specificity in diagnosis.

METHODS

In a prospective observational study, clinical symptoms and procalcitonin, C-reactive protein and interleukin 6 were simultaneously determined from the 4th day of life in 170 preterm and term neonates at the first time of suspicion of NBI. Proven NBI was defined as a positive culture of otherwise sterile body fluids or radiologically verified pneumonia in combination with elevated inflammatory markers.

RESULTS

Fifty-eight (34%) patients were diagnosed with proven late-onset NBI. In case of proven NBI, odds ratio and 95% confidence intervals were 2.64 (1.06-6.54) for arterial hypotension, 5.16 (2.55-10.43) for feeding intolerance and 9.18 (4.10-20.59) for prolonged capillary refill. Sensitivity of combined determination of C-reactive protein (>10 mg/L) and interleukin 6 (>100 pg/mL) was 91.4%, specificity 80.4%, positive predictive value 70.7% and negative predictive value 94.7%. The additional determination of procalcitonin (>0.7 ng/mL) resulted in 98.3%, 65.2%, 58.8% and 98.6%, respectively.

CONCLUSION

Arterial hypotension, feeding intolerance and especially prolonged capillary refill indicate proven neonatal late-onset bacterial infection, even at the time of first suspicion. Additional measurement of procalcitonin does indeed improve sensitivity to nearly 100%, but is linked to a decline in specificity. Nevertheless, in the high-risk neonatal population, additional procalcitonin measurement can be recommended because all infants with NBI have to be identified.