Biomarkers for the diagnosis of neonatal sepsis and necrotizing enterocolitis: Clinical practice guidelines

Reliability of IL-6 Alone and in Combination for Diagnosis of Late Onset Sepsis: A Systematic Review

Diagnosis of neonatal sepsis is difficult due to nonspecific signs and symptoms. Interleukin-6 (IL-6) is a promising marker for neonatal sepsis. We aimed to test the accuracy of IL-6 in neonates after 72 h of life in case of late onset sepsis (LOS). We searched for studies regarding IL-6 accuracy for the diagnosis of LOS between 1990 and 2020 using the PubMed database. Following study selection, the reported IL-6 sensitivities and specificities ranged between 68% and 100% and 28% and 100%, with median values of 85.7% and 82% and pooled values of 88% and 78% (respectively) in the 15 studies including 1306 infants. Subgroup analysis revealed a better sensitivity (87% vs. 82%), but not specificity (both 86%), in preterm infants compared to term infants or mixed populations. Early sample collection revealed the highest sensitivity (84%), but had the lowest specificity (86%). To assess quality, we used a STARD checklist adapted for septic neonates and the QUADAS criteria. Limitations of this review include the heterogeneous group of studies on the one side and the small number of studies on the other side that analyzed different combinations of biomarkers. We concluded that IL-6 demonstrated good performance especially in the preterm infant population and the best results were achieved by measurements at the time of LOS suspicion.

Simple, miniaturized biosensors for wireless mapping of thermoregulatory responses

Temperature is the most commonly collected vital sign in all of clinical medicine; it plays a critical role in care decisions related to topics ranging from infection to inflammation, sleep, and fertility. Most assessments of body temperature occur at isolated anatomical locations (e.g. axilla, rectum, temporal artery, or oral cavity). Even this relatively primitive mode for monitoring can be challenging with vulnerable patient populations due to physical encumbrances and artifacts associated with the sizes, weights, shapes and mechanical properties of the sensors and, for continuous monitoring, their hard-wired interfaces to data collection units. Here, we introduce a simple, miniaturized, lightweight sensor as a wireless alternative, designed to address demanding applications such as those related to the care of neonates in high ambient humidity environments with radiant heating found in incubators in intensive care units. Such devices can be deployed onto specific anatomical locations of premature infants for homeostatic assessments. The estimated core body temperature aligns, to within 0.05 °C, with clinical grade, wired sensors, consistent with regulatory medical device requirements. Time-synchronized, multi-device operation across multiple body locations supports continuous, full-body measurements of spatio-temporal variations in temperature and additional modes of determining tissue health status in the context of sepsis detection and various environmental exposures. In addition to thermal sensing, these same devices support measurements of a range of other essential vital signs derived from thermo-mechanical coupling to the skin, for applications ranging from neonatal and infant care to sleep medicine and even pulmonary medicine.

Blood Biomarkers of Neonatal Sepsis with Special Emphasis on the Monocyte Distribution Width Value as an Early Sepsis Index

Background and Objectives: Early detection of neonatal sepsis is critical because it is potentially fatal. Therefore, sepsis biomarkers of sufficient sensitivity and specificity are needed. This study aimed to evaluate the utility of peripheral blood parameters as neonatal sepsis biomarkers and the diagnostic performance of the monocyte distribution width (MDW) in sepsis in a neonatal intensive care unit. Materials and Methods: A cross-sectional study was conducted from September 2019 to August 2020 at the King Saud University Medical City in Riyadh, Saudi Arabia. Samples were collected and organised as follows: 77 study cases were subdivided into two subgroups (other health complication (49) and sepsis (28)), and there were 70 controls. The causative microorganisms of neonatal sepsis were isolated. Peripheral blood samples were collected from each neonate in an ethylenediaminetetraacetic acid tube for a complete blood count and a leukocyte differential count. Moreover, the receiver operating characteristic (ROC) curve analysis was used to measure the diagnostic performance of the MDW. Results: The haematological parameters and neonatal sepsis cases had a considerable correlation. The MDW was the most significant haematological parameter. The ROC analysis of the MDW demonstrated that the area under the curve was 0.89 (95% confidence interval: 0.867 to 0.998) with a sensitivity of 89.3%, a specificity of 88.2%, and a negative predictive value of 97.2% at the cut-off point of 23. Conclusions: The use of haematological parameters is feasible and can be performed rapidly. Neonatal sepsis showed a strong correlation with leukopenia, anaemia, thrombocytopenia, and an elevated MDW value. Moreover, the ROC curve analysis confirmed the high diagnostic ability of the MDW in neonatal sepsis prediction.

Bioinformatic Analysis and Machine Learning Methods in Neonatal Sepsis: Identification of Biomarkers and Immune Infiltration

The disease neonatal sepsis (NS) poses a serious threat to life, and its pathogenesis remains unclear. Using the Gene Expression Omnibus (GEO) database, differentially expressed genes (DEGs) were identified and functional enrichment analyses were conducted. Three machine learning algorithms containing the least absolute shrinkage and selection operator (LASSO), support vector machine recursive feature elimination (SVM-RFE), and random forest (RF) were applied to identify the optimal feature genes (OFGs). This study conducted CIBERSORT to present the abundance of immune infiltrates between septic and control neonates and assessed the relationship between OFGs and immune cells. In total, 44 DEGs were discovered between the septic and control newborns. Throughout the enrichment analysis, DEGs were primarily related to inflammatory signaling pathways and immune responses. The OFGs derived from machine learning algorithms were intersected to yield four biomarkers, namely Hexokinase 3 (HK3), Cystatin 7 (CST7), Resistin (RETN), and Glycogenin 1 (GYG1). The potential biomarkers were validated in other datasets and LPS-stimulated HEUVCs. Septic infants showed a higher proportion of neutrophils (p < 0.001), M0 macrophages (p < 0.001), and regulatory T cells (p = 0.004). HK3, CST7, RETN, and GYG1 showed significant correlations with immune cells. Overall, the biomarkers offered promising insights into the molecular mechanisms of immune regulation for the prediction and treatment of NS.

A Retrospective Case Control Study Examining Procalcitonin as a Biomarker for Necrotizing Enterocolitis

Abstract Background: Procalcitonin (PCT) is a biomarker for sepsis, but its utility has not been investigated in necrotizing enterocolitis (NEC). Necrotizing enterocolitis is a devastating multisystem disease of infants that in severe cases requires surgical intervention. We hypothesize that an elevated PCT will be associated with surgical NEC. Patients and Methods: After obtaining Institutional Review Board (IRB) approval (#12655), we performed a single institution retrospective case control study between 2010 and 2021 of infants up to three months of age. Inclusion criteria was PCT drawn within 72 hours of NEC or sepsis diagnosis. Control infants had a PCT drawn in the absence of infectious symptoms. Recursive partitioning (RP) identified PCT cutoffs. Categorical variable associations were tested using Fisher exact or χ² tests. Continuous variables were tested using Wilcoxon rank sum test, Student t-test, and Kruskal-Wallis test. Adjusted associations of PCT and other covariables with NEC or sepsis versus controls were obtained via multinomial logistic regression analysis. Results: We identified 49 patients with NEC, 71 with sepsis, and 523 control patients. Based on RP, we selected two PCT cutoffs: 1.4 ng/mL and 3.19 ng/ml. A PCT of ≥1.4 ng/mL was associated with surgical (n = 16) compared with medical (n = 33) NEC (87.5% vs. 39.4%; p = 0.0015). A PCT of ≥1.4 ng/mL was associated with NEC versus control (p < 0.0001) even when adjusting for prematurity and excluding stage IA/IB NEC (odds ratio [OR], 28.46; 95% confidence interval [CI], 11.27-71.88). A PCT of 1.4-3.19 ng/mL was associated with both NEC (adjusted odds ratio [aOR], 11.43; 95% CI, 2.57-50.78) and sepsis (aOR, 6.63; 95% CI, 2.66-16.55) compared with controls. Conclusions: A PCT of ≥1.4 ng/mL is associated with surgical NEC and may be a potential indicator for risk of disease progression.

The Role of Coagulase-Negative Staphylococci Biofilms on Late-Onset Sepsis: Current Challenges and Emerging Diagnostics and Therapies

Infections are one of the most significant complications of neonates, especially those born preterm, with sepsis as one of the principal causes of mortality. Coagulase-negative staphylococci (CoNS), a group of staphylococcal species that naturally inhabit healthy human skin and mucosa, are the most common cause of late-onset sepsis, especially in preterms. One of the risk factors for the development of CoNS infections is the presence of implanted biomedical devices, which are frequently used for medications and/or nutrient delivery, as they serve as a scaffold for biofilm formation. The major concerns related to CoNS infections have to do with the increasing resistance to multiple antibiotics observed among this bacterial group and biofilm cells’ increased tolerance to antibiotics. As such, the treatment of CoNS biofilm-associated infections with antibiotics is increasingly challenging and considering that antibiotics remain the primary form of treatment, this issue will likely persist in upcoming years. For that reason, the development of innovative and efficient therapeutic measures is of utmost importance. This narrative review assesses the current challenges and emerging diagnostic tools and therapies for the treatment of CoNS biofilm-associated infections, with a special focus on late-onset sepsis.

Feasibility of phagocytes functional testing in neonatal sepsis diagnostics

Neonatal sepsis is a problem still relevant for healthcare in Russia and worldwide due to high mortality and resistance to treatment. Generalization of infection in newborns occurs because of innate immunity deficiency that particularly leads to neutrophil and monocyte malfunction. Nowadays clinical practice of neonatal sepsis diagnostics does not include phagocytes functional testing. Purpose. The study aims at evaluating the ability of sepsis biomarkers (CRP, PCT, lactate, CD64, CD16, HLA-DR) to differentiate the pathogenesis of organ dysfunction in newborns in the ICU setting.Material and methods. We assessed the surface expression of neutrophil CD64 and CD16, as well as monocytic HLA-DR in newborn ICU patients with different genesis of multiple organ failure — sepsis, asphyxia and combined; as well as different outcomes of hospitalization in the ICU — survivors and deaths.Results. We have shown a significant increase in the neutrophil CD64 expression and a decrease in the monocytic HLA-DR in infectious and combined genesis of multiple organ failure compared with severe asphyxia; deaths were associated with reduced expression of neutrophil CD16.Conclusion. Our data could substantiate combined use of the phagocytes functional testing indicators together with conventional sepsis biomarkers in order to increase their prognostic and predictive value.

Special Issue "Recent Advances in Neonatal Sepsis"

Perinatal medicine and neonatology have seen significant advancements in recent decades [...].

Growth and differentiation factor 15 (GDF15) levels predict adverse respiratory outcomes in premature neonates

Growth and differentiation factor 15 (GDF15) is a stress-responsive cytokine, and its expression increases during inflammation, hyperoxia, and senescence. Significantly, GDF15 is secreted by the placenta, and maternal levels increase throughout pregnancy. Serum GDF15 level is a promising biomarker for many lung diseases like pulmonary hypertension and pulmonary fibrosis. However, circulating GDF15 levels in preterm infants and their role as a predictor of respiratory outcomes have not been studied. We hypothesized that GDF15 levels would increase with gestational age at birth, and that postnatal GDF15 will be correlated with adverse respiratory outcomes in preterm infants. Scavenged blood samples were retrieved from 57 preterm infants at five time points, from birth until 36-weeks postmenstrual age (PMA). GDF15 levels were measured using ELISA in 114 samples. We performed two-sample t-test, correlation and linear regression, logistic regression, and mixed-effects linear models for statistical analysis, and significance was identified when p < 0.05. Contrary to our hypothesis, for every 1-week increase in gestational age at birth, the predicted GDF15 level decreased by 475.0 pg/ml (p < 0.001). Greater PMA was significantly associated with lower serum GDF15 levels (p < 0.001). Interestingly, higher GDF15 levels were associated with a longer need for mechanical ventilation (p = 0.034), prolonged respiratory support need (p < 0.001), and length of hospital stay (p = 0.006). In conclusion, in preterm infants, GDF15 levels show an inverse correlation with gestational age at birth, with higher levels in more preterm babies, and levels trend down postnatally. Furthermore, longitudinal GDF15 levels through 36 weeks PMA predict adverse respiratory outcomes in preterm infants.

Association of neutropenia at disease onset with severe surgical necrotizing enterocolitis and higher mortality: A retrospective study

Background

Neutrophils are among the earliest immune cells recruited to the site of an intestinal injury, but their predictive role in the progression of necrotizing enterocolitis (NEC) has not been fully elucidated. This study aimed to evaluate if a reduction in neutrophils at the onset of NEC is associated with severe surgical NEC and/or NEC-associated deaths.

Methods

This is a retrospective cohort study in which neonates underwent surgery due to NEC during 2015-2020. The data on absolute neutrophil count (ANC), before and at the onset of NEC, were collected from the complete blood count results. The primary exposure was the difference in absolute neutrophil count (ΔANC) at NEC onset. The primary outcome was severe surgical NEC, defined as the residual small bowel length after intestinal resection of <30 cm.

Results

A total of 157 neonates were included in this study, of which 53 were diagnosed with severe surgical NEC. A decrease in ANC at the onset of NEC was associated with an increased probability of severe surgical NEC (crude odds ratio [OR] 1.248, 95% CI 1.107-1.407; P = 0.000). ΔANC (area under the curve [AUC] 0.729, 95% CI 0.653-0.797; P < 0.001] was a good predictor for severe surgical NEC. The addition of platelets to ΔANC at NEC onset (AUC 0.738, 95% CI 0.662-0.808; P < 0.001) resulted in a higher AUC and specificity for severe surgical NEC prediction than ΔANC alone. A reduction in the neutrophil count at NEC onset (ΔANC > 0) was associated with adverse outcomes (hazard ratio [HR] 3.48, 95% CI 1.64-7.36) and a lower survival probability (χ² 10.63; P < 0.001).

Conclusion

A reduction in the ANC at the onset of NEC was associated with severe surgical NEC and higher mortality. The addition of platelets to ΔANC at NEC onset resulted in a higher predictive value of severe surgical NEC. This study may provide a new insight into the bedside evaluation of NEC by analyzing data from the day of NEC onset.

Proteomics Profiling of Stool Samples from Preterm Neonates with SWATH/DIA Mass Spectrometry for Predicting Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is a life-threatening condition for premature infants in neonatal intensive care units. Finding indicators that can predict NEC development before symptoms appear would provide more time to apply targeted interventions. In this study, stools from 132 very-low-birth-weight (VLBW) infants were collected daily in the context of a multi-center prospective study aimed at investigating the potential of fecal biomarkers for NEC prediction using proteomics technology. Eight of the VLBW infants received a stage-3 NEC diagnosis. Stools collected from the NEC infants up to 10 days before their diagnosis were available for seven of them. Their samples were matched with those from seven pairs of non-NEC controls. The samples were processed for liquid chromatography-tandem mass spectrometry analysis using SWATH/DIA acquisition and cross-compatible proteomic software to perform label-free quantification. ROC curve and principal component analyses were used to explore discriminating information and to evaluate candidate protein markers. A series of 36 proteins showed the most efficient capacity with a signature that predicted all seven NEC infants at least a week in advance. Overall, our study demonstrates that multiplexed proteomic signature detection constitutes a promising approach for the early detection of NEC development in premature infants.

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.

Correlation of systemic immune-inflammation Index with surgical necrotizing enterocolitis

BACKGROUND

Systemic Immune-Inflammation Index (SII), known as an easy, economical and useful marker, correlates with the severity of inflammatory response. However, the usefulness of SII in necrotizing enterocolitis (NEC) remains unclear. Therefore, we evaluated the correlation of SII at NEC diagnosis and subsequent surgery.

METHODS

Retrospective review of 131 neonates with NEC in a tertiary-level pediatric referral hospital was conducted with assessments of demographic data, general blood examination results at NEC diagnosis, treatment strategies and clinical outcomes. The receiver operating characteristic (ROC) curve determined the optimal cut-off values of SII, platelet-to-lymphocyte ratio (PLR), and neutrophil-to-lymphocyte ratio. Univariate/multivariate logistic regression analysis and ROC curve were conducted to evaluate the predictive significance of SII in identifying the patients who eventually received surgery. Additionally, NEC-related deaths were assessed.

RESULTS

Overall, 49 (37.4%) cases received surgical intervention and mortality was 12.3% (14/131). The area under ROC curve of SII at NEC diagnosis to predict subsequent surgery was 0.833 (optimal cut-off value: 235.85). The SII value in surgical intervention group was significantly higher than that in medical treatment group (332.92 ± 158.52 vs. 158.84 ± 106.82, P < 0.001). Independent influencing factors for surgical NEC were SII (95% confidence interval [CI]: 4.568∼36.449, odds ratio [OR]:12.904, P < 0.001) and PLR (95% CI: 1.071∼7.356, OR:2.807, P = 0.036). SII ≤ 235.85 could identify patients at high risk for surgery, with 87.76% sensitivity, 73.17% specificity, outperformed PLR. Furthermore, mortality was significantly higher in patients with SII ≤ 235.85 than those with SII > 235.85 (20.0% vs. 1.5%, P < 0.001).

CONCLUSION

SII and PLR at NEC diagnosis were independent influencing factors for subsequent surgery. SII ≤ 235.85 may be a useful predictive marker for the identification of surgical NEC and mortality.

Lipocalin-2 and calprotectin as stool biomarkers for predicting necrotizing enterocolitis in premature neonates

BACKGROUND

Necrotizing enterocolitis (NEC) is a major challenge for premature infants in neonatal intensive care units and efforts toward the search for indicators that could be used to predict the development of the disease have given limited results until now.

METHODS

In this study, stools from 132 very low birth weight infants were collected daily in the context of a multi-center prospective study aimed at investigating the potential of fecal biomarkers for NEC prediction. Eight infants (~6%) received a stage 3 NEC diagnosis. Their stools collected up to 10 days before diagnosis were included and matched with 14 non-NEC controls and tested by ELISA for the quantitation of eight biomarkers.

RESULTS

Biomarkers were evaluated in all available stool samples leading to the identification of lipocalin-2 and calprotectin as the two most reliable predicting markers over the 10-day period prior to NEC development. Pooling the data for each infant confirmed the significance of lipocalin-2 and calprotectin, individually and in combination 1 week in advance of the NEC clinical diagnosis.

CONCLUSIONS

The lipocalin-2 and calprotectin tandem represents a significant biomarker signature for predicting NEC development. Although not yet fulfilling the "perfect biomarker" criteria, it represents a first step toward it.

IMPACT

Stool biomarkers can be used to predict NEC development in very low birth weight infants more than a week before the diagnosis. LCN2 was identified as a new robust biomarker for predicting NEC development, which used in conjunction with CALPRO, allows the identification of more than half of the cases that will develop NEC in very low birth weight infants. Combining more stool markers with the LCN2/CALPRO tandem such as PGE2 can further improve the algorithm for the prediction of NEC development.

Diagnosis of neonatal sepsis: the past, present and future

Sepsis remains a significant cause of neonatal mortality and morbidity, especially in low- and middle-income countries. Neonatal sepsis presents with nonspecific signs and symptoms that necessitate tests to confirm the diagnosis. Early and accurate diagnosis of infection will improve clinical outcomes and decrease the overuse of antibiotics. Current diagnostic methods rely on conventional culture methods, which is time-consuming, and may delay critical therapeutic decisions. Nonculture-based techniques including molecular methods and mass spectrometry may overcome some of the limitations seen with culture-based techniques. Biomarkers including hematological indices, cell adhesion molecules, interleukins, and acute-phase reactants have been used for the diagnosis of neonatal sepsis. In this review, we examine past and current microbiological techniques, hematological indices, and inflammatory biomarkers that may aid sepsis diagnosis. The search for an ideal biomarker that has adequate diagnostic accuracy early in sepsis is still ongoing. We discuss promising strategies for the future that are being developed and tested that may help us diagnose sepsis early and improve clinical outcomes. IMPACT: Reviews the clinical relevance of currently available diagnostic tests for sepsis. Summarizes the diagnostic accuracy of novel biomarkers for neonatal sepsis. Outlines future strategies including the use of omics technology, personalized medicine, and point of care tests.

Reliability of Interleukin-6 Alone and in Combination for Diagnosis of Early Onset Neonatal Sepsis: Systematic Review

Neonatal sepsis is a major cause of morbidity and mortality in both preterm and term infants. Early-onset neonatal sepsis (EONS) presents within the first 72 h of life. Diagnosis is difficult as signs and symptoms are non-specific, and inflammatory markers are widely used to confirm or rule out neonatal sepsis. Interleukin-6 (IL-6) is part of the fetal inflammatory response syndrome (FIRS) and therefore an interesting early marker for neonatal sepsis. The main objective for this review was to assess the diagnostic potential of IL-6, alone and in combination, for diagnosis of early neonatal sepsis (EONS) in term and preterm infants, in cord and peripheral blood, and in dependence of timing of sample collection. IL-6 diagnostic accuracy studies for diagnosing EONS published between 1990 and 2020 were retrieved using the PubMed database. We included 31 out of 204 articles evaluating the potential of IL-6 for the diagnosis of EONS in a study population of newborns with culture-proven and/or clinically suspected sepsis. We excluded articles dealing with neonatal bacterial infections other than sepsis and biomarkers other than inflammatory markers, those written in languages other than English or German, studies that did not distinguish between EONS and late-onset sepsis, and animal and in vitro studies. Full-text articles were checked for other relevant studies according to the PRISMA criteria. We identified 31 studies on IL-6 diagnostic accuracy for EONS diagnosis between 1990 and 2020 including a total of 3,276 infants. Sensitivity and specificity were reported, and subgroup analysis was performed. A STARD checklist adapted for neonates with neonatal sepsis was used for quality assessment. The range of IL-6 sensitivity and specificity in neonatal samples was 42.1-100% and 43-100%; the median values were 83 and 83.3%, respectively. IL-6 accuracy was better in preterm infants than in mixed-study populations. Early sample collection at the time of sepsis suspicion had the highest sensitivity when compared to other time points. Cord blood IL-6 had higher diagnostic value compared to peripheral blood. The biomarker combination of IL-6 and CRP was found to be highly sensitive, but poorly specific. Limitations of this review include use of only one database and inclusion of a heterogeneous group of studies and a small number of studies looking at biomarker combinations; a strength of this review is its focus on early-onset sepsis, since type of sepsis was identified as a significant source of heterogeneity in IL-6 diagnostic accuracy studies. We concluded that IL-6 has a good performance as an early diagnostic marker of EONS within a study population of preterm infants, with best results for cord blood IL-6 using cutoff values above 30 pg/ml.

The role and mechanisms of miRNA in neonatal necrotizing enterocolitis

Neonatal necrotizing enterocolitis (NEC), the most significant causes of neonatal mortality, is a disease of acute intestinal inflammation. At present, it is not clear exactly how the disease is caused, but it has been suggested that this disorder is a result of a complex interaction among prematurity, enteral feeding and inappropriate pro-inflammation response and bacterial infection of the intestine. A microRNA (miRNA) is a class of endogenous non-coding single-stranded RNA that is about 23 nucleotides long engaging in the regulation of the gene expression. Recently, numerous studies have determined that abnormal miRNA expression plays important roles in various diseases, including NEC. Here, we summarized the role of miRNAs in NEC. We introduce the biosynthetic and function of miRNAs and then describe the possible mechanisms of miRNAs in the initiation and development of NEC, including their influence on the intestinal epithelial barrier's function and regulation of the inflammatory process. Finally, this review aids in a comprehensive understanding of the current miRNA to accurately predict the diagnosis of NEC and provide ideas to find potential therapeutic targets of miRNA for NEC. In conclusion, our aims are to highlight the close relationship between miRNAs and NEC and to summarize the practical value of developing diagnostic biomarkers and potential therapeutic targets of NEC.

Vagal Tone and Proinflammatory Cytokines Predict Feeding Intolerance and Necrotizing Enterocolitis Risk

BACKGROUND

Necrotizing enterocolitis (NEC) is the leading cause of death due to gastrointestinal disease in preterm neonates; yet, clinicians lack reliable and noninvasive predictive tools.

PURPOSE

We aimed to test that diminished high-frequency heart rate variability (HF-HRV) and elevated levels of proinflammatory cytokines would have utility in NEC prediction.

METHODS

In this multisite prospective study, we enrolled 250 preterm (26-34 weeks' postmenstrual age [PMA]) neonates with physiological stability at 72 hours of life. HRV was measured noninvasively using electrocardiograhic data from standardized cardiorespiratory monitors at postnatal week 1 of life and weekly thereafter until 35 weeks' PMA or discharge; blood was collected for cytokines at postnatal weeks 1 and 3. NEC was diagnosed via Modified Bell's Staging Criteria.

RESULTS

HF-HRV was decreased at weeks 1 and 2 in neonates (47% females) who developed feeding intolerance or stage 2+ NEC. In addition, these neonates displayed elevated levels of IL-8 at week 1 and increased levels of IL-1β, IL-6, TNF-α, and IL-8 at week 3 of life. Low HF-HRV was associated with elevated IL-6 or IL-8 levels at weeks 1 and 3 of life. Logistic regression indicated that only HF-HRV was a significant predictor of feeding intolerance or NEC development.

IMPLICATIONS FOR PRACTICE AND RESEARCH

HRV is a promising noninvasive modality for NEC risk detection. The association of low HF-HRV with elevated proinflammatory cytokines provides evidence for a putative role of the vagal cholinergic pathway in NEC pathogenesis. Future studies should focus on application of these techniques to test clinical therapeutics.Video Abstract available at https://journals.lww.com/advancesinneonatalcare/Pages/videogallery.aspx?autoPlay=false&videoId=54.

Urine-derived extracellular vesicle miRNAs as possible biomarkers for and mediators of necrotizing enterocolitis: A proof of concept study

BACKGROUND

Early-stage symptomology of necrotizing enterocolitis (NEC) is similar in presentation to non-NEC sepsis, though the treatment plans differ based on antibiotic administration and withholding of feeds. Improved diagnostics for NEC differentiation would allow clinicians to more rapidly set individual patients on a targeted treatment path. Extracellular vesicle-derived miRNAs, have previously demonstrated efficacy as disease biomarkers. To determine if these miRNAs are differentially-expressed in NEC infants, we performed transcriptomic analysis of urine-derived extracellular vesicle-derived miRNAs.

METHODS

Urine was non-invasively obtained from infants in one of four groups (n ≥ 8) (Medical NEC, Surgical NEC, non-NEC sepsis, and healthy age-matched controls). EV-derived miRNAs were isolated and transcriptomic analysis was performed.

RESULTS

Multiple miRNAs, including miR-376a, miR-518a-3p and miR-604, were significantly altered when comparing NEC to non-NEC sepsis and healthy controls, and could potentially be used as specific NEC biomarkers. Additionally, Ingenuity Pathway Analysis demonstrated that miRs differentially-expressed in NEC were associated with inflammatory disease and intestinal disease. Signal transduction molecules associated with NEC including TP53 and RPS15, which were also reduced transcriptionally in a rat model of NEC.

CONCLUSION

These data indicate that there is a pool of potential urine EV-derived miRNAs that may be validated as NEC biomarkers in the differentiation of NEC from non-NEC sepsis and from age-matched controls. Additionally, signal transduction molecules associated with miRNAs differentially-expressed in human NEC are altered in a murine model of NEC, suggesting potential crossover between murine models of the disease and actual human presentation.

LEVEL OF EVIDENCE

Level III Study of Diagnostic Test.

The Role and Validity of Diagnostic Biomarkers in Late-Onset Neonatal Sepsis

Sepsis remains a leading cause of mortality in the neonatal population, and currently, there is still no consensus on an accurate biomarker that can aid prompt diagnosis. This review focuses on studies investigating biomarkers for late-onset neonatal sepsis specifically. We discuss the current evidence for traditionally used biomarkers and present recent developments on more novel markers.  Suitable articles were selected from PubMed, Embase, Medline, Cochrane Handbook of Systematic Reviews, and ScienceDirect. Inclusion criteria were studies published from 2010 to 2020. Exclusion criteria were animal model-based studies. Keywords in search strategy were late-onset neonatal sepsis + biomarkers + diagnosis.  Evidence is growing increasingly weak for commonly studied biomarkers such as C-reactive protein (CRP) and procalcitonin (PCT). Levels of markers such as Serum Amyloid A and Neutrophil CD64 increase more rapidly post-onset of infection compared to CRP. Moreover, this review found that the more novel biomarkers discussed such as presepsin and endocan may show superior and more promising potential as diagnostic markers. However, larger studies over multicenters are deemed essential to ascertain the ideal biomarker.

Serum HMGB1 level is correlated with serum I-FABP level in neonatal patients with necrotizing enterocolitis

Background

This study aims to investigate clinical significance of HMGB1 in neonatal patients with necrotizing enterocolitis (NEC).

Methods

This observational study enrolled a total of 106 stage II-III NEC neonatal patients, who were admitted in our hospital from March 2014 to March 2019. In addition, 99 suspected NEC patients and 200 healthy controls were included. The serum levels of HMGB1, I-FABP, and inflammatory factors CRP, IL-1β, IL-6 and TNF-α were determined by enzyme-linked immunosorbent assay (ELISA). Then, the demographic data and clinical characteristics of all patients were collected. Statistical analysis was conducted to determine the correlation between HMGB1 and the clinical characteristics.

Results

No significant difference was found in the basic characteristics of NEC patients and healthy controls, except for birth weight and gestational age. The expression levels of HMGB1, I-FABP, and inflammatory factors IL-1β, IL-6 and TNF-α were significantly higher in NEC patients, when compared to healthy controls. The serum levels of HMGB1, I-FABP, IL-1β and IL-6 markedly increased in stage II-III NEC patients, when compared to stage I NEC patients. The Pearson’s analysis revealed a positive correlation between HMGB1 and I-FABP, HMGB1 and IL-1β, and HMGB1 and IL-6. The ROC curve revealed that both HMGB1 and I-FABP can potentially be used as diagnostic factors for NEC. The logistic multivariate regression revealed that I-FABP, IL-1β and IL-6 are independent risk factors for mortality in neonatal NEC patients.

Conclusions

Serum HMGB1 levels are upregulated in neonatal NEC patients, and these are correlated with the patient’s prognosis.

Interleukin-6 as a Biomarker of Early-Onset Neonatal Sepsis

OBJECTIVE

The aim of this study is to determine the utility of C reactive protein (CRP) and interleukin (IL)-6 in the diagnosis of neonatal sepsis (NS) in a neonatal intensive care unit (NICU) in the south of Colombia.

STUDY DESIGN

A nonmatched case-control study was conducted. Convenience sampling was performed. Data were obtained from clinical records. IL-6 levels were determined using enzyme-linked immunosorbent assay. Receiver operator characteristic (ROC) curve analysis and Youden's index were used to determine the optimal cutoffs for CRP and IL-6 levels in diagnosing NS, early-onset NS (EONS), and late-onset NS (LONS).

RESULTS

Data from 31 cases and 62 controls were included. History of chorioamnionitis (infinite odds ratio [OR] [3.07-infinity]), and the presence of meconium-stained amniotic fluid during birth (OR: 9.04 [1.35-112]) were identified as risk factors for NS. Differences in CRP (p < 0.0001) and IL-6 (p < 0.0485) levels were also found, more significantly for LONS and EONS patients, respectively. In the diagnosis of LONS using CRP levels, the area under the ROC curve (AUC) was 0.8371 (p < 0.0001). The optimal cutoff was 0.53 mg/dL. For EONS diagnosis using IL-6, the AUC was 0.6869 (p = 0.0315) and the optimal cutoff was 17.75 pg/mL.

CONCLUSION

Differences between CRP and IL-6 levels were found between control and NS groups. Furthermore, CRP showed greater potential diagnostic utility in the LONS group, whereas IL-6 showed greater potential utility in the EONS group.

KEY POINTS

· NS is a major morbimortality cause worldwide. · CRP and IL-6 levels may be useful NS biomarkers. · No biomarker alone is enough for the diagnosis of NS.

Blockage of NLRP3 inflammasome activation ameliorates acute inflammatory injury and long-term cognitive impairment induced by necrotizing enterocolitis in mice

Background

Necrotizing enterocolitis (NEC) is an inflammatory gastrointestinal disease in premature neonates with high mortality and morbidity, while the underlining mechanism of intestinal injury and profound neurological dysfunction remains unclear. Here, we aimed to investigate the involvement of NLPR3 inflammasome activation in NEC-related enterocolitis and neuroinflammation, especially long-term cognitive impairment, meanwhile, explore the protective effect of NLRP3 inhibitor MCC950 on NEC in mice.

Methods

NLRP3 inflammasome activation in the intestine and brain was assessed in the NEC mouse model, and NLRP3 inhibitor MCC950 was administrated during the development of NEC. Survival rate, histopathological injury of the intestine and brain, and expression of mature IL-1β and other pro-inflammatory cytokines were analyzed. Long-term cognitive impairment was evaluated by behavioral test.

Results

The expression of NLRP3 and mature IL-1β in the intestine and brain was greatly upregulated in NEC mice compared to the controls. MCC950 treatment efficiently improved NEC survival rate, reduced intestinal and brain inflammation, and ameliorated the severity of pathological damage in both organs. Additionally, in vivo blockage of NLRP3 inflammasome with MCC950 in early life of NEC pups potently protected against NEC-associated long-term cognitive impairment.

Conclusions

Our findings suggest that NLRP3 inflammasome activation participates in NEC-induced intestinal and brain injury, and early intervention with NLRP3 inhibitor may provide beneficial therapeutic effect on NEC infants.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-021-02111-4.

Delta Neutrophil Index as a Diagnostic Marker of Neonatal Sepsis

Objective Sepsis diagnosis is challenging due to nonspecific symptomatology in newborns. Timely diagnosis is essential for reducing sepsis-related morbidity and mortality. This study was performed to determine the diagnostic value of the delta neutrophil index (DNI) for detection of neonatal sepsis and to compare its efficacy with other conventional markers.

Methods This study was conducted at a tertiary hospital in newborns with confirmed sepsis (n = 59), suspected sepsis (n = 46), and in age- and weight-matched controls (n = 49). DNI, white blood cell count, C-reactive protein (CRP) level, and platelet measurements were determined, and blood cultures were performed at the onset of symptoms.

Results The mean DNI was significantly higher in confirmed and clinical sepsis groups compared with the control group. (6.9 ± 9.3, 1.9 ± 2.1, and 0.4 ± 0.5, respectively, p < 0.001). ROC curve analysis also showed that the combination of DNI and CRP had the highest sensitivity (86%), specificity (100%), and positive predictive value (100%) for predicting neonatal sepsis. DNI values were significantly higher in nonsurvivors (p < 0.05).

Conclusion DNI could be used as a reliable diagnostic marker for neonatal sepsis, and high DNI could predict sepsis development and unfavorable outcomes. The diagnostic capability of DNI may be increased by assessing CRP measurements simultaneously.

Time of Onset of Necrotizing Enterocolitis and Focal Perforation in Preterm Infants: Impact on Clinical, Surgical, and Histological Features

Objective: There is no gold standard test for diagnosis of necrotizing enterocolitis (NEC). Timing of onset is used in some definitions and studies in an attempt to separate NEC from focal intestinal perforation (FIP) with 14 days used as a cutoff. In a large, detailed data set we aimed to compare NEC and FIP in preterm infants born <32 weeks gestation, presenting before 14 days of life in comparison to cases presenting later. Design: Infants with NEC or FIP when parents had consented to enrollment in an observational and sample collection study were included from 2009 to 2019. Clinical, surgical, histological, and outcome data were extracted and reviewed by each author independently. Patients/Episodes: In 785 infants, 174 episodes of NEC or FIP were identified of which 73 (42%) occurred before 14 days, including 54 laparotomies and 19 episodes of medically managed NEC ("early"). There were 56 laparotomies and 45 episodes of medically managed NEC presenting on or after 14 days age ("late"). Results: In early cases, 41% of laparotomies were for NEC (22 cases) and 59% for FIP (32 cases), and in late cases, 91% of laparotomies (51 cases) were for NEC and 9% (five cases) were for FIP. NEC presenting early was more likely to present with an initial septic presentation rather than discrete abdominal pathology and less likely to have clear pneumatosis. Early cases did not otherwise differ clinically, surgically, or histologically or in outcomes compared with later cases. FIP features did not differ by age at presentation. Conclusions: Although most FIP occurred early, 14% occurred later, whereas almost one third (29%) of NEC cases (surgical and medical) presented early. Infant demographics and surgical and histological findings of early- and late-presenting disease did not differ, suggesting that early and late cases are not necessarily different subtypes of the same disease although a common pathway of different pathogenesis cannot be excluded. Timing of onset does not accurately distinguish NEC from FIP, and caution should be exercised in including timing of onset in diagnostic criteria.

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.

Can Procalcitonin Improve Antibiotic Stewardship for Late-Onset Sepsis Evaluations in Neonates?

BACKGROUND

Procalcitonin (PCT) use is not widespread in the neonatal population during late-onset sepsis evaluations. Minimal data exist on appropriate PCT cutoff levels to treat with antibiotics for neonatal sepsis. New guidelines were implemented in select central Texas neonatal intensive care units for late-onset sepsis (infants older than 72 hours) with recommended PCT cutoff levels for antibiotic administration.

PURPOSE

To evaluate antibiotic usage in a local neonatal population following late-onset sepsis workups pre-/postimplementation of a PCT guideline.

METHODS

A retrospective pre-/post-quality improvement project using chart review data was performed over 11 months in 2018. Inclusion criteria were infants older than 72 hours of life having a late-onset sepsis workup. The outcome measure is appropriate antibiotic administration, based on laboratory test results or cultures, for infants pre-/post-PCT guidelines.

RESULTS

The χ test indicated that the proportion of infants receiving appropriate antibiotics pre-/postinitiation of PCT guidelines did not significantly differ. There is, however, clinical significance with an improvement in the proportion of appropriate antibiotic administration and a decrease in variability.

IMPLICATIONS FOR PRACTICE

Using PCT may help the practitioner identify sepsis earlier and more effectively, thereby reducing morbidity and mortality among neonates while improving antibiotic stewardship.

IMPLICATIONS FOR RESEARCH

The small sample size in this study and the limited number of neonatal intensive care units limit any inferences. Future research should evaluate the use of PCT in a larger sample across multiple settings.

Role of microbiological tests and biomarkers in antibiotic stewardship

Laboratory tests are critical in the detection and timely treatment of infection. Two categories of tests are commonly used in neonatal sepsis management: those that identify the pathogen and those that detect host response to a potential pathogen. Decision-making around antibiotic choice is related to the performance of tests that directly identify pathogens. Advances in these tests hold the key to progress in antibiotic stewardship. Tests measuring host response, on the other hand, are an indirect marker of potential infection. While an important measure of the patient's clinical state, in the absence of pathogen detection these tests cannot confirm the appropriateness of antibiotic selection. The overall impact these tests then have on antibiotic utilization depends the test's specificity for bacterial infection, clinical scenario where it is being used and the decision-rule it is being integrated into for use. In this review we discuss common and emerging laboratory tests available for assisting management of neonatal infection and specifically focus on the role they play in optimizing antibiotic utilization.

The Utility of Neutrophil CD64 and Presepsin as Diagnostic, Prognostic, and Monitoring Biomarkers in Neonatal Sepsis

Background

Neonatal septicemia is a critical medical situation; current conventional laboratory methods still have many limitations and diagnostic obstacles. For this purpose, last decades have witnessed a challenge between the battery of sepsis biomarkers including many leukocyte surface antigens, not only for early diagnostic purposes but also for better follow-up and good management of sepsis patients.

Aim

To evaluate the diagnostic, prognostic, and monitoring performance of both neutrophil CD64 (nCD64) and presepsin as sepsis biomarkers compared to each other and to the conventional laboratory sepsis parameters aiming to decide which is the best fitting for routine daily use in neonatal intensive care units (NICUs).

Methods

235 neonates were enrolled from three Egyptian neonatal ICUs, during the period from November 2015 till March 2018; they were classified into two main groups: the control group (n = 102) and the sepsis group (n = 133). Laboratory sepsis evaluation included highly sensitive CRP (hs-CRP), CBC, in addition to nCD64 (flow cytometry technique), and presepsin measurement (CLEIA technique combined with Magtration® technology); the diagnosis was confirmed thereafter by positive blood culture results (BacT/Alert system). Sixty-two of the enrolled sepsis neonates were subjected to follow-up assessment; they were reclassified according to their clinical improvement at the second time assessment into (group 1: sepsis group without improvement) (n = 20) and (group 2: improved sepsis group) (n = 42).

Results

Significant increase in nCD64 and presepsin values was found in sepsis groups compared to the controls. At cutoff 41.6%, nCD64% could discriminate the presence of septicemia with sensitivity 94.7%, specificity 93.6 %, and AUC 0.925, while presepsin at cutoff 686 pg/ml achieves sensitivity 82.7%, specificity 95.5%, and AUC 0.887, respectively. Significant increase in nCD64 (P < 0.001) and hs-CRP (P=0.018) values was observed in severe sepsis/septic shock patients compared to nonsevere sepsis patients. Delta change percentage (dC%) between initial and follow-up evaluations for both improved and nonimproved sepsis patients was dC Z value −5.904 for nCD64% followed by dC Z value −4.494 for presepsin.

Conclusion

nCD64 and presepsin are valuable early diagnostic and monitoring sepsis biomarkers; the highest sensitivity could be achieved by a univariant sepsis marker in this study was recorded by the nCD64% biomarker, while the highest specificity was documented by presepsin. Combined measurement of both achieves the highest diagnostic performance in sepsis neonates. Either of CD64 or presepsin combined with hs-CRP associated with better performance than any of them alone. nCD64 carries an additional promising role in reflecting sepsis prognosis.

Valuable Role of Neutrophil CD64 and Highly Sensitive CRP Biomarkers for Diagnostic, Monitoring, and Prognostic Evaluations of Sepsis Patients in Neonatal ICUs

Background

Neonatal sepsis (NS) is a very critical medical situation associated with high morbidities and mortalities. There is an utmost need for a new tool helping in early diagnosis and proper management of sepsis neonates. Neutrophil CD64 (nCD64) shows a very promising value in this concerning issue.

Aim

Evaluate the diagnostic, monitoring, and prognostic performances of nCD64 and highly sensitive CRP (hs-CRP) in NS as well as the possible best panel of biomarkers that can achieve the most desirable results.

Methods

Patients were enrolled from three neonatal intensive care units (NICUs) (n = 121 patients) and classified according to their initial sepsis evaluation into three groups: disease control group (n = 30), proven sepsis group (n = 17), and clinical sepsis group (n = 74). Laboratory evaluation included hs-CRP, complete blood count (CBC), and blood culture in addition to nCD64 (done by flow cytometry technique). Besides the diagnostic evaluations, follow-up evaluations were done for 40 patients after five days from the first time; patients were reclassified according to their outcome into the improved sepsis neonates' group (n = 26) and sepsis neonates without improvement (n = 14).

Results

Significant increase in nCD64 and hs-CRP results were present in sepsis groups compared to the disease controls (P < 0.001); nCD64 at 43% cutoff value could detect the presence of sepsis with 85.6% sensitivity and 93% specificity. Additionally, delta change percentage (dC%) between improved sepsis neonates and sepsis neonates without improvement showed a significant difference in the levels of both nCD64 (P < 0.001) and hs-CRP (P = 0.001).

Conclusion

Besides the promising diagnostic performance documented by nCD64 which is higher than the other laboratory sepsis biomarkers used routinely in NICUs, nCD64 has a valuable role in sepsis patients' monitoring and prognostic evaluation. hs-CRP was moderate in its diagnostic and monitoring results being less than that achieved by nCD64. Combined measurement of nCD64% and hs-CRP gives better diagnostic and monitoring performance than that achieved by any of them alone.

Reducing Vancomycin Use in a Level IV NICU

BACKGROUND AND OBJECTIVES

Vancomycin remains one of the most commonly prescribed antibiotics in NICUs despite recommendations to limit its use for known resistant infections. Baseline data revealing substantially higher vancomycin use in our NICU compared to peer institutions informed our quality improvement initiative. Our aim was to reduce the vancomycin prescribing rate in neonates hospitalized in our NICU by 50% within 1 year and sustain for 1 year.

METHODS

In the 60-bed level IV NICU of an academic referral center, we used a quality improvement framework to develop key drivers and interventions including (1) physician education with benchmarking antibiotic prescribing rates; (2) pharmacy-initiated 48-hour antibiotic time-outs on rounds; (3) development of clinical pathways to standardize empirical antibiotic choices for early-onset sepsis, late-onset sepsis, and necrotizing enterocolitis; coupled with (4) daily prospective audit with feedback from the antimicrobial stewardship program.

RESULTS

We used statistical process u-charts to show vancomycin use declined from 112 to 38 days of therapy per 1000 patient-days. After education, pharmacy-initiated 48-hour time-outs, and development of clinical pathways, vancomycin use declined by 29%, and by an additional 52% after implementation of prospective audit with feedback. Vancomycin-associated acute kidney injury also declined from 1.4 to 0.1 events per 1000 patient-days.

CONCLUSIONS

Through a sequential implementation approach of education, standardization of care with clinical pathways, pharmacist-initiated 48-hour time-outs, and prospective audit with feedback, vancomycin days of therapy declined by 66% over a 1-year period and has been sustained for 1 year.

Assessment of C-Reactive Protein Diagnostic Test Accuracy for Late-Onset Infection in Newborn Infants: A Systematic Review and Meta-analysis

IMPORTANCE

Rapid and accurate diagnosis of late-onset infection in newborn infants could inform treatment decisions and avoid unnecessary administration of antibiotics.

OBJECTIVE

To compare the accuracy of serum C-reactive protein (CRP) with that of microbiological blood culture for diagnosing late-onset infection in newborns.

DATA SOURCES

MEDLINE (1946-2019), Embase (1946-2019), and Science Citation Index (1900-2019) databases were searched for references (any language). The MeSH search terms included were "exp infant, newborn/" or "premature birth/" plus free text synonyms; and "C-reactive protein/" plus free text synonyms; and "exp sepsis/" or "exp bacterial infections/" plus free text synonyms. The proceedings from relevant conferences and references of identified papers were scrutinized. Authors were contacted to request missing data.

STUDY SELECTION

Cohort and cross-sectional studies were included that compared the accuracy of serum CRP levels with microbiological culture results to diagnose late-onset (>72 hours after birth) infection in newborns (any gestational age) hospitalized after birth. Two reviewers assessed study eligibility. Among 10 394 records, 148 studies were assessed as full texts.

DATA EXTRACTION AND SYNTHESIS

The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guideline extension for Diagnostic Test Accuracy (DTA) reviews was followed. Two reviewers assessed the method quality of each study using guidance from the Cochrane Screening and Diagnostic Test Methods Group (adapted from the Quality Assessment of Diagnostic Accuracy Studies 2).

MAIN OUTCOMES AND MEASURES

The primary meta-analysis outcome was diagnostic test accuracy of serum CRP level taken at initial investigation of an infant with suspected late-onset infection. The median specificity (proportion of true-negative results) and calculated pooled sensitivity (proportion of true-positive results) were determined by generating hierarchical summary receiver characteristic operating curves.

RESULTS

In total, 22 studies with 2255 infants were included (sample size range, 11-590 infants). Participants in most studies were preterm (<37 weeks) or very low-birth weight (<1500 g) infants. Two studies additionally enrolled infants born at term. Most studies (16) used a prespecified CRP level cutoff for a "positive" index test (5-10 mg/L), and most studies (17) used the culture of a pathogenic microorganism from blood as the reference standard. Risk of bias was low with independent assessment of index and reference tests. At median specificity (0.74), pooled sensitivity was 0.62 (95% CI, 0.50-0.72). Adding serum CRP level to the assessment of an infant with a 40% pretest probability of late-onset infection (the median for the included studies) generated posttest probabilities of 26% for a negative test result and 61% for a positive test result.

CONCLUSIONS AND RELEVANCE

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

Neonatal sepsis in low-income countries: epidemiology, diagnosis and prevention

Introduction: Sepsis accounts for up to one-third of neonatal deaths in the world each year. The World Health Organization acknowledges neonatal sepsis as a major global health concern, and that the highest burden occurs in low- and middle-income countries (LMICs). Despite major research and clinical progress in this area, we still lack accurate diagnostic tools for neonatal sepsis, complicating the management of this condition.Areas covered: The purpose here is to review the latest data on the incidence, diagnosis, prevention, and management of neonatal sepsis in LMIC. We discuss the limitations of current diagnostic tests - including their lack of availability - and how this may influence global estimates of cases. We review the benefits of antenatal, intrapartum, and post-natal preventive measures. We briefly discuss the management, highlighting the emergence of antimicrobial resistance. Finally, we expose some high priority areas.Expert opinion: Neonatal sepsis is a challenging condition requiring a multifaceted approach to address the major diagnostic issues, but also the underlying socio-economic causes that nourish epidemic cases in LMIC. Focusing on antibiotics as a main pillar of intervention is likely to engender antimicrobial resistance, eventually hindering the appreciable gains LMICs have achieved in neonatal health outcomes.

Emerging Biomarkers for Prediction and Early Diagnosis of Necrotizing Enterocolitis in the Era of Metabolomics and Proteomics

Necrotizing Enterocolitis (NEC) is a catastrophic disease affecting predominantly premature infants and is characterized by high mortality and serious long-term consequences. Traditionally, diagnosis of NEC is based on clinical and radiological findings, which, however, are non-specific for NEC, thus confusing differential diagnosis of other conditions such as neonatal sepsis and spontaneous intestinal perforation. In addition, by the time clinical and radiological findings become apparent, NEC has already progressed to an advanced stage. During the last three decades, a lot of research has focused on the discovery of biomarkers, which could accurately predict and make an early diagnosis of NEC. Biomarkers used thus far in clinical practice include acute phase proteins, inflammation mediators, and molecules involved in the immune response. However, none has been proven accurate enough to predict and make an early diagnosis of NEC or discriminate clinical from surgical NEC or other non-NEC gastrointestinal diseases. Complexity of mechanisms involved in NEC pathogenesis, which remains largely poorly elucidated, could partly explain the unsatisfactory diagnostic performance of the existing NEC biomarkers. More recently applied technics can provide important insight into the pathophysiological mechanisms underlying NEC but can also aid the detection of potentially predictive, early diagnostic, and prognostic biomarkers. Progress in omics technology has allowed for the simultaneous measurement of a large number of proteins, metabolic products, lipids, and genes, using serum/plasma, urine, feces, tissues, and other biological specimens. This review is an update of current data on emerging NEC biomarkers detected using proteomics and metabolomics, further discussing limitations and future perspectives in prediction and early diagnosis of NEC.

Adjunctive therapy to treat neonatal sepsis

Introduction: Neonatal sepsis (NS) is a very severe condition that causes significant morbidity and mortality.Areas covered: To overcome the limits of antibiotic therapy and improve NS outcomes, measures chosen among those theoretically able to improve host defenses or positively interfere with deleterious immune responses could be suggested. This paper discusses the mechanisms of action of these measures, whether their efficacy in prophylaxis justifies use in NS therapy and their impact.Expert opinion: NS remains a relevant problem despite the availability of antibiotics effective against the most common agents and the introduction of effective preventive measures such as group B Streptococcus prenatal screening and intrapartum antibiotic prophylaxis. This explains why attempts to introduce new prophylactic and therapeutic measures have been made. Unfortunately, none of the measures suggested and tested to date can be considered a definitive advance. It is highly likely that in the future, new measures will be proposed according to the increase in the knowledge of the characteristics of immune system function in preterm infants and the methods to modulate unproper immune responses.

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.

Soluble CD14 subtype (sCD14-ST) as biomarker in neonatal early-onset sepsis and late-onset sepsis: a systematic review and meta-analysis

Background

Early diagnosis of bacterial sepsis in neonates is hampered by non-specific symptoms and the lack of rapid responding laboratory measures. The biomarker soluble CD14 subtype (sCD14-ST) seems promising in the diagnostic process of neonatal sepsis. In order to evaluate the differences in diagnostic accuracy of sCD14-ST between early onset sepsis (EOS) and late onset sepsis (LOS) we assessed this systematic review and meta-analysis.

Results

Twelve articles were included in the systematic review and 10 in the meta-analysis. There was a high risk of bias on patient selection, index test and/or flow and timing. The overall quality of the included studies was moderate.

At sepsis onset a consequently higher level of sCD14-ST was found in septic neonates compared to healthy controls with significant higher levels in LOS compared to EOS. In the first 24 h after sepsis onset a significant increase in pooled means of plasma sCD14-ST levels was seen in EOS (t(71.6) = 7.3, p < .0001) while this was not seen in LOS or healthy controls. Optimal cut-off values ranged from 305 to 672 ng/l for EOS cases versus healthy controls. The pooled sensitivity was 81% (95%CI: 0.76–0.85), the pooled specificity was 86% (0.81–0.89) with an AUC of 0.9412 (SE 0.1178). In LOS optimal cut-off values ranged from 801 to 885 ng/l with a pooled sensitivity of 81% (0.74–0.86) and a pooled specificity of 100% (0.98–1.00). An AUC and SROC was not estimable in LOS because of the low number of studies.

Conclusions

sCD14-ST is a promising and rapid-responding diagnostic biomarker for EOS and LOS. The difference in pooled means between EOS and LOS underlines the importance to consider EOS and LOS as two different disease entities, requiring separate analysis in original articles and systematic reviews.

Electronic supplementary material

The online version of this article (10.1186/s12865-019-0298-8) contains supplementary material, which is available to authorized users.

Neonates are not just little children and need more finesse in dosing of antibiotics

OBJECTIVES

Neonates are not just little children. They need more finesse in decisions on when to treat, which antibiotics to use and how to dose these antibiotics.

METHODS

Representative compounds of three major classes of antibiotics (beta-lactams, aminoglycosides, glycopeptides) are discussed in a narrative review to illustrate the recent progress in the knowledge on PK and its covariates (how to dose).

RESULTS

This knowledge can subsequently be converted to targeted exposure dosing regimens. This is because it is reasonable to postulate that pharmacodynamics (PD) of antibiotics are similar in neonates to that in other populations if a similar concentration-time profile and targeted exposure are attained. However, this approach has its limitations, since the clinical response may be different in neonates because of maturational differences in innate immunity or toxicity. These dosing regimens should at least be validated.

CONCLUSION

Relevant information on the PK of antibiotics and its covariates have been generated, but the next steps are to validate the dosing regimens suggested, and consider more sophisticated dosing regimens. This approach should subsequently pave the way to conduct comparative studies to assess the efficacy and safety of these commonly used drugs in neonates.

Screening and Serial Neutrophil Counts Do Not Contribute to the Recognition or Diagnosis of Late-Onset Neonatal Sepsis

OBJECTIVE

To determine the validity of screening and serial neutrophil counts in predicting the absence/presence of late-onset sepsis (LOS) in infants with central venous catheters.

STUDY DESIGN

Retrospective study of infants admitted to the neonatal intensive care unit (2009-2013) at Parkland Hospital with a central venous catheter and ≥1 LOS evaluations. Infants were categorized as proven or suspect LOS or uninfected based on results of blood cultures, clinical illness, and duration of antibiotics. Receiver operating curves (ROCs) were constructed to predict the absence or presence of LOS using Manroe reference ranges for total and immature neutrophils and the immature to total neutrophil ratio at 0, 12, and 24 hours after blood culture and the neutrophil value score, which assesses serial values.

RESULTS

Of the 497 infants with a central venous catheter, 179 underwent ≥1 LOS evaluations, and 140 of 179 (78%) had ≥1 complete evaluations (2 blood cultures and neutrophil values at 0, 12, and 24 hours), resulting in 188 complete LOS evaluations. The gestational age was 28 ± 4 weeks and LOS evaluation occurred at 29 ± 34 days (SD; 4-197 days). Sixty-one (35%) infants had proven LOS, 48 (23%) were suspect, and 71 (38%) were noninfected. ROC comparing proven vs noninfected was ≤0.56 for total neutrophils, immature neutrophils, and immature to total neutrophil ratio at 0, 12, and 24 hours and similar for proven + suspect vs noninfected. ROC for neutrophil value scores and absence of LOS was 0.56.

CONCLUSIONS

Screening neutrophil values are poor predictors of LOS in neonates with a central venous catheter, as are serial neutrophils and the neutrophil value score. Alternative biomarkers are needed.

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.

Turkish Neonatal Society guideline on neonatal infections-diagnosis and treatment

Neonatal infections are a major cause of morbidity and mortality in the first month of life, especially in developing countries. Despite advances in neonatology, neonatal infections still haves clinical importance because of nonspecific signs and symptoms, no perfect diagnostic marker, and interference with non-infectious diseases of newborns. Diagnosis is typically made by clinical and laboratory findings. Empiric antibiotic therapy should be started in a newborn with signs and symptoms of infection after cultures are taken according to the time of the signs and symptoms, risk factors, admission from community or hospital, focus of infection, and antibiotic susceptibility estimation. Treatment should be continued according to clinical findings and culture results. Intrapartum antibiotic prophylaxis, proper hand washing, aseptic techniques for invasive procedures, appropriate neonatal intensive care unit design, isolation procedures, and especially breast milk use are needed to prevent infections. The use of diagnosis and treatment protocols increases clinical success.

Immunomodulation to Prevent or Treat Neonatal Sepsis: Past, Present, and Future

Despite continued advances in neonatal medicine, sepsis remains a leading cause of death worldwide in neonatal intensive care units. The clinical presentation of sepsis in neonates varies markedly from that in older children and adults, and distinct acute inflammatory responses results in age-specific inflammatory and protective immune response to infection. This review first provides an overview of the neonatal immune system, then covers current mainstream, and experimental preventive and adjuvant therapies in neonatal sepsis. We also discuss how the distinct physiology of the perinatal period shapes early life immune responses and review strategies to reduce neonatal sepsis-related morbidity and mortality. A summary of studies that characterize immune ontogeny and neonatal sepsis is presented, followed by discussion of clinical trials assessing interventions such as breast milk, lactoferrin, probiotics, and pentoxifylline. Finally, we critically appraise future treatment options such as stem cell therapy, other antimicrobial protein and peptides, and targeting of pattern recognition receptors in an effort to prevent and/or treat sepsis in this highly vulnerable neonatal population.

The role of nCD64 in the diagnosis of neonatal sepsis in preterm newborns

BACKGROUND

Diagnosing neonatal sepsis is difficult, particularly in preterm newborns. A promising method appears to be evaluation of cell surface markers by flow cytometry.

METHODS

This prospective study investigated 217 newborns suspected of having early- or late-onset neonatal sepsis. In all, flow cytometry was used to determine the proportion of CD64-positive neutrophils (nCD64). Based on the clinical course and laboratory test results, newborns were categorized as having proven, possible, clinical or no neonatal sepsis. Subsequently, associations between the categories and nCD64 values were analyzed.

RESULTS

There were significant associations between nCD64 values and the development of sepsis in newborns with both early- or late-onset sepsis.

CONCLUSION

nCD64expression is significantly elevated in preterm newborn with early and late onset sepsis. The results show that nCD64 is a reliable marker for diagnosing neonatal sepsis.

NMR-Based Plasma Metabolomics at Set Intervals in Newborn Dairy Calves with Severe Sepsis

The aim of this first study was to reveal the new potential biomarkers by a metabolomics approach in severe septic calves. Sepsis is a common cause of morbidity and mortality in newborn dairy calves. The main challenges with the use of biomarkers of sepsis in domestic animals are their availability, cost, and time required to obtain a result. Metabolomics may offer the potential to identify biomarkers that define calf sepsis in terms of combined clinical, physiological, and pathobiological abnormalities. To our knowledge, this is the first study presenting an NMR- (nuclear magnetic resonance-) based plasma metabolomics at set intervals in neonatal septic calves. Twenty neonatal dairy calves with severe sepsis and ten healthy calves were used. Hematological and biochemical health profiles were gathered in plasma samples at set intervals. Similarly, NMR spectra were acquired. All diseased animals (except one) died after 72 hours. Clinical and laboratory results were in accordance with those of severe septic animals. Multivariate analysis on NMR plasma spectra proved to be an excellent tool for faster identification of calves with severe sepsis from healthy animals. The NMR-based metabolomic profile may contribute to the better understanding of severe sepsis in newborn calves.

Efficacy of zinc supplementation for neonatal sepsis: a systematic review and meta-analysis

Background: Zinc supplementation has some potential in treating neonatal sepsis. We conduct a systematic review and meta-analysis to explore the efficacy of zinc supplementation for neonatal sepsis. Methods: PubMed, Embase, Web of science, EBSCO, and Cochrane Library databases are systematically searched. Randomized controlled trials (RCTs) assessing the efficacy of zinc supplementation in neonatal sepsis are included. Two investigators independently search articles, extract the data, and assessed the quality of included studies. Meta-analysis is performed using the random-effect model. Results: Four RCTs involving 986 patients are included in the meta-analysis. Overall, compared with control intervention in neonatal sepsis, zinc supplementation is able to significantly reduce mortality rate (risk ratio (RR) = 0.48; 95% confidence intervals (CIs) = 0.25-0.94; p = .03) and improve serum zinc (mean difference (MD) = 81.97; 95% CI = 34.57-129.37; p = .0007), but has no remarkable influence on hospital stay (MD = -4.51; 95% CI = -15.08 to 6.05; p = .40) and the number of expired patients (RR = 0.63; 95% CI = 0.24-1.65; p = .35). Conclusions: Zinc supplementation may significantly reduce mortality rate and improve serum zinc in neonatal sepsis, but has no substantial influence on hospital stay and the number of expired patients.