Biomarkers as point of care tests (POCT) in neonatal sepsis: A state of science review

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.

Micromotor-based dual aptassay for early cost-effective diagnosis of neonatal sepsis

Given the long-life expectancy of the newborn, research aimed at improving sepsis diagnosis and management in this population has been recognized as cost-effective, which at early stages continues to be a tremendous challenge. Despite there is not an ideal-specific biomarker, the simultaneous detection of biomarkers with different behavior during an infection such as procalcitonin (PCT) as high specificity biomarker with one of the earliest biomarkers in sepsis as interleukin-6 (IL-6) increases diagnostic performance. This is not only due to their high positive predictive value but also, since it can also help the clinician to rule out infection and thus avoid the use of antibiotics, due to their high negative predictive value. To this end, we explore a cutting-edge micromotor (MM)-based OFF-ON dual aptassay for simultaneous determination of both biomarkers in 15 min using just 2 μL of sample from low-birth-weight neonates with gestational age less than 32 weeks and birthweight below 1000 g with clinical suspicion of late-onset sepsis. The approach reached the high sensitivities demanded in the clinical scenario (LODPCT = 0.003 ng/mL, LODIL6 = 0.15 pg/mL) with excellent correlation performance (r > 0.9990, p < 0.05) of the MM-based approach with the Hospital method for both biomarkers during the analysis of diagnosed samples and reliability (Er < 6% for PCT, and Er < 4% for IL-6). The proposed approach also encompasses distinctive technical attributes in a clinical scenario since its minimal sample volume requirements and expeditious results compatible with few easy-to-obtain drops of heel stick blood samples from newborns admitted to the neonatal intensive care unit. This would enable the monitoring of both sepsis biomarkers within the initial hours after the manifestation of symptoms in high-risk neonates as a valuable tool in facilitating prompt and well-informed decisions about the initiation of antibiotic therapy.These results revealed the asset behind micromotor technology for multiplexing analysis in diagnosing neonatal sepsis, opening new avenues in low sample volume-based diagnostics.

Identifying Effective Biomarkers for Accurate Pancreatic Cancer Prognosis Using Statistical Machine Learning

Pancreatic cancer (PC) has one of the lowest survival rates among all major types of cancer. Consequently, it is one of the leading causes of mortality worldwide. Serum biomarkers historically correlate well with the early prognosis of post-surgical complications of PC. However, attempts to identify an effective biomarker panel for the successful prognosis of PC were almost non-existent in the current literature. The current study investigated the roles of various serum biomarkers including carbohydrate antigen 19-9 (CA19-9), chemokine (C-X-C motif) ligand 8 (CXCL-8), procalcitonin (PCT), and other relevant clinical data for identifying PC progression, classified into sepsis, recurrence, and other post-surgical complications, among PC patients. The most relevant biochemical and clinical markers for PC prognosis were identified using a random-forest-powered feature elimination method. Using this informative biomarker panel, the selected machine-learning (ML) classification models demonstrated highly accurate results for classifying PC patients into three complication groups on independent test data. The superiority of the combined biomarker panel (Max AUC-ROC = 100%) was further established over using CA19-9 features exclusively (Max AUC-ROC = 75%) for the task of classifying PC progression. This novel study demonstrates the effectiveness of the combined biomarker panel in successfully diagnosing PC progression and other relevant complications among Egyptian PC survivors.

Performance of 11 Host Biomarkers Alone or in Combination in the Diagnosis of Late-Onset Sepsis in Hospitalized Neonates: The Prospective EMERAUDE Study

Despite the high prevalence of late-onset sepsis (LOS) in neonatal intensive care units, a reliable diagnosis remains difficult. This prospective, multicenter cohort study aimed to identify biomarkers early to rule out the diagnosis of LOS in 230 neonates ≥7 days of life with signs of suspected LOS. Blood levels of eleven protein biomarkers (PCT, IL-10, IL-6, NGAL, IP-10, PTX3, CD14, LBP, IL-27, gelsolin, and calprotectin) were measured. Patients received standard of care blinded to biomarker results, and an independent adjudication committee blinded to biomarker results assigned each patient to either infected, not infected, or unclassified groups. Performances of biomarkers were assessed considering a sensitivity of at least 0.898. The adjudication committee classified 22% of patients as infected and all of these received antibiotics. A total of 27% of the not infected group also received antibiotics. The best biomarkers alone were IL-6, IL-10, and NGAL with an area under the curve (95% confidence interval) of 0.864 (0.798-0.929), 0.845 (0.777-0.914), and 0.829 (0.760-0.898), respectively. The best combinations of up to four biomarkers were PCT/IL-10, PTX3/NGAL, and PTX3/NGAL/gelsolin. The best models of biomarkers could have identified not infected patients early on and avoided up to 64% of unjustified antibiotics. At the onset of clinical suspicion of LOS, additional biomarkers could help the clinician in identifying non-infected patients.

Cord blood presepsin as a predictor of early-onset neonatal sepsis in term and preterm newborns

BACKGROUND

To date, no studies on presepsin values in cord blood of term infants with risk factors for early-onset sepsis (EOS) are available, whereas only one study reported presepsin values in cord blood of preterm infants at risk. In this study, we investigated the presepsin values in cord blood of term and preterm infants with documented risk factors for EOS.

METHODS

In this single-center prospective pilot study, we enrolled neonates presenting with documented risk factors for EOS. P-SEP levels were assessed in a blood sample collected from the clamped umbilical cord after the delivery in 93 neonates, using a point-of-care device. The primary outcome of our study was to evaluate the role of cord blood P-SEP in predicting clinical EOS in term and preterm infants.

RESULTS

During the study period, we enrolled 93 neonates with risk factors for EOS with a gestational age ranging between 24.6 and 41.6 weeks (median 38.0). The median P-SEP value in all infants was 491 pg/ml (IQR 377 - 729). Median cord P-SEP values were significantly higher in infants with clinical sepsis (909 pg/ml, IQR 586 - 1307) rather than in infants without (467 pg/ml, IQR 369 - 635) (p = 0.010). We found a statistically significant correlation between cord P-SEP value at birth and the later diagnosis of clinical sepsis (Kendall's τ coefficient 0.222, p = 0.002). We identified the maximum Youden's Index (best cut-off point) at 579 pg/ml, corresponding to a sensitivity of 87.5% and a specificity of 71.8% in predicting clinical sepsis.

CONCLUSIONS

Maximum Youden's index was 579 pg/ml for clinical EOS using cord P-SEP values. This could be the starting point to realize multicenter studies, confirming the feasibility of dosing P-SEP in cord blood of infants with risk factors of EOS to discriminate those who could develop clinical sepsis and spare the inappropriate use of antibiotics.

Clinical predictors of bacteraemia in neonates with suspected early-onset sepsis in Malawi: a prospective cohort study

OBJECTIVES

We studied neonates with suspected early-onset sepsis (EOS, sepsis developing in the first 72 hours after delivery) in Malawi to (1) describe clinical characteristics and microbiological findings, (2) identify which patient characteristics may be associated with pathogen positivity on blood culture, and (3) describe mortality and its potential determinants.

DESIGN

Prospective observational study (May 2018-June 2019).

SETTING

Neonatal ward in Queen Elizabeth Central Hospital, the largest government hospital in Malawi.

PATIENTS

All neonates with suspected EOS in whom a blood culture was obtained.

RESULTS

Out of 4308 neonatal admissions, 1244 (28.9%) had suspected EOS. We included 1149 neonates, of which 109 blood cultures had significant growth (9.5%). The most commonly isolated pathogens were Staphylococcus aureus, Klebsiella pneumoniae, Enterobacter cloacae, Escherichia coli and Acinetobacter baumanii. Many of the Gram negatives were extended-spectrum beta lactamase-producing Enterobacteriaceae, and these were 40-100% resistant to first-line and second-line antimicrobials. Gestational age (GA) of <32 weeks was associated with pathogen-positive blood cultures (<28 weeks: adjusted OR (AOR) 2.72, 95% CI 1.04 to 7.13; 28-32 weeks: AOR 2.26, 95% CI 1.21 to 4.21; p=0.005). Mortality was 17.6% (202/1149) and associated with low birth weight (<1000 g: AOR 47.57, 95% CI 12.59 to 179.81; 1000-1500 g: AOR 11.31, 95% CI 6.97 to 18.36; 1500-2500 g: AOR 2.20, 95% CI 1.42 to 3.39; p<0.001), low Apgar scores at 5 min (0-3: AOR 18.60, 95% CI 8.81 to 39.27; 4-6: AOR 4.41, 95% CI 2.81 to 6.93; p<0.001), positive maternal venereal disease research laboratory status (AOR 2.53, 95% CI 1.25 to 5.12; p=0.001) and congenital anomalies (AOR 7.37, 95% CI 3.61 to 15.05; p<0.001). Prolonged rupture of membranes was inversely associated with mortality (AOR 0.43, 95% CI 0.19 to 0.98; p 0.007).

CONCLUSION

In Malawi, EOS was suspected in nearly a third of neonatal admissions and had a high mortality. Ten per cent were culture-confirmed and predicted by low GA. To reduce the impact of suspected neonatal sepsis in least developed countries, improved maternal and antenatal care and development of rapid point of care methods to more accurately guide antimicrobial use could simultaneously improve outcome and reduce antimicrobial resistance.

Predictors of Death in Patients with Neonatal Sepsis in a Peruvian Hospital

Reducing neonatal mortality is a global challenge. This study’s objective was to determine the predictors of mortality in patients with neonatal sepsis. The study was a retrospective cohort study in a Peruvian hospital from January 2014 to April 2022. Neonates diagnosed with sepsis were included. To find predictors of mortality, we used Cox proportional regression models. We evaluated 288 neonates with sepsis; the median birth weight and hospitalization time were 3270 g and seven days, respectively. During follow-up, 18.4% did not survive, and the most common complications were jaundice (35.42%), respiratory distress syndrome (29.51%), and septic shock (12.5%). The most isolated bacteria were Klebsiella pneumoniae. The risk factors associated with higher mortality were prematurity (aHR = 13.92; 95% CI: 1.71−113.51), platelets <150,000 (aHR = 3.64; 1.22−10.88), creatinine greater than 1.10 (aHR = 3.03; 1.09−8.45), septic shock (aHR = 4.41; 2.23−8.74), and admission to IMV (aHR = 5.61; 1.86−16.88), On the other hand, breastfeeding was associated with a lower risk of death (aHR = 0.25; 0.13−0.48). In conclusion, we report a high incidence of death and identify clinical (prematurity, septic shock, admission to IMV) and laboratory characteristics (elevated creatinine and thrombocytopenia) associated with higher mortality in patients with neonatal sepsis. Breastfeeding was a factor associated with survival in these patients.

Re-visiting micro ESR as a screening tool for neonatal sepsis

Our study evaluated the role of micro-erythrocte sedimentation rate (micro-ESR) in the early detection of neonatal sepsis.

Neonates with >34 completed weeks of gestation, appropriate for gestational age, admitted in our Neonatal Intensive Care Unit with clinical suspicion of early onset sepsis were enrolled in the study. A sepsis screen and blood culture was performed on all the babies within 4 h of admission. The sensitivity of micro-ESR for detecting positive blood culture was calculated and the best cut-off was determined using the Area Under Curve.

Component 1 Inhibitor Missense (Val480Met) Variant Is Associated With Gene Expression and Sepsis Development in Neonatal Lung Disease

BACKGROUND

Neonatal lung disease has a multifaceted etiopathology, including an explosive inflammatory sequence in the immature lung. Complement component 1 Esterase INHibitor (C1INH) is implicated in controlling inflammation in response to infection/injury.

AIM

To explore for the first time the association of the C1INH rs4926 (Val480Met) variant and circulatory transcript expression levels in the neonates that had evidence of lung disease and the clinic-laboratory data.

METHODS

A total of 139 unrelated neonates were enrolled in this case-control study. C1INH genotyping and expression analyses were done using TaqMan Genotyping and Real-Time qPCR, respectively.

RESULTS

A/A genotype carriers were two times more likely to develop in newborns with lung disease under homozygote (A/A vs. G/G: OR = 2.66, 95%CI = 1.03-6.87, p = 0.039) and recessive (A/A vs. G/G-A/G: OR = 2.42, 95%CI = 1.07-6.06, p = 0.047) models. Also, a higher frequency of A/A genotype was observed in the patient's cohort complicated with sepsis (44.2 vs. 14.3%, p = 0.002). Neonates with lung disease with A variant had more risk for developing sepsis under homozygote (A/A vs. G/G: OR = 5.19, 95%CI = 1.73-15.6, p = 0.002), dominant (A/G-A/A vs. G/G: OR = 2.39, 95%CI = 1.02-5.58, p = 0.041), and recessive (A/A vs. G/G-A/G: OR = 5.38, 95%CI = 1.86-15.5, p < 0.001) models. Regression analysis revealed rs4926^*A/A genotype as an independent predictor risk factor for sepsis development in cohorts with lung disease (adjusted OR = 4.26, 95%CI = 1.38-13.1, p = 0.012). The circulatory transcript was significantly downregulated in neonates with lung disease in whom rs4926^*A/A carriers had the least expression levels (median: -2.86, IQR: -3.55 to -1.71; p < 0.001). ROC curve analysis revealed C1INH expression could differentiate between cohorts with/without subsequent development of sepsis, and the discrimination ability was enhanced when combined with circulatory IL-6 and CRP levels (AUC = 0.926, 95%CI = 0.87-0.97).

CONCLUSION

The C1INH rs4926 variant might play an essential role in the susceptibility to neonatal lung disease and could predict sepsis development in this cohort. Furthermore, the circulatory expression levels of this gene were downregulated in the neonatal lung disease cohort, supporting its potential role in the pathophysiology of this disorder, and highlighting its promising role in future targeted therapy.

Umbilical Cord Procalcitonin to Detect Early-Onset Sepsis in Newborns: A Promising Biomarker

Background: Up to 7% of neonates born in high-income countries receive antibiotics for suspected early-onset sepsis (EOS). Culture-proven neonatal sepsis has a prevalence of 0.2%, suggesting considerable overtreatment. We studied the diagnostic accuracy of umbilical cord blood and infant blood procalcitonin (PCT) in diagnosing EOS to improve antibiotic stewardship. Methods: Umbilical cord blood PCT was tested in newborns ≥ 32 weeks of gestation. Groups were defined as following: A) culture-proven or probable EOS (n = 25); B) Possible EOS, based on risk factors for which antibiotics were administered for <72 h (n = 49); C) Risk factor(s) for EOS without need for antibiotic treatment (n = 181); D) Healthy controls (n = 74). Additionally, venous or capillary blood PCT and C-reactive protein (CRP) were tested if blood drawing was necessary for standard care. Results: Between June 2019 and March 2021, 329 newborns were included. Umbilical cord blood PCT was significantly higher in group A than in group C and D. No difference between venous or arterial samples was found. Sensitivity and specificity for cord blood procalcitonin were 83 and 62%, respectively (cut-off 0.1 ng/mL). Antepartum maternal antibiotic administration was associated with decreased PCT levels in both cord blood and infant blood directly postpartum in all groups combined. Conclusion: Umbilical cord blood PCT levels are increased in newborns ≥32 weeks with a proven or probable EOS and low in newborns with risk factors for infection, but PCT seems not a reliable marker after maternal antibiotic treatment. PCT could be useful to distinguish infected from healthy newborns with or without EOS risk factors.

The Emerging Role of Presepsin (P-SEP) in the Diagnosis of Sepsis in the Critically Ill Infant: A Literature Review

Sepsis causes high rates of morbidity and mortality in NICUs. The estimated incidence varies between 5 and 170 per 1000 births, depending on the social context. In very low birth-weight neonates, the level of mortality increases with the duration of hospitalization, reaching 36% among infants aged 8-14 days and 52% among infants aged 15-28 days. Early diagnosis is the only tool to improve the poor prognosis of neonatal sepsis. Blood culture, the gold standard for diagnosis, is time-consuming and poorly sensitive. C-reactive protein and procalcitonin, currently used as sepsis biomarkers, are influenced by several maternal and fetal pro-inflammatory conditions in the perinatal age. Presepsin is the N-terminal fragment of soluble CD14 subtype (sCD14-ST): it is released in the bloodstream by monocytes and macrophages, in response to bacterial invasion. Presepsin seems to be a new, promising biomarker for the early diagnosis of sepsis in neonates as it is not modified by perinatal confounding inflammatory factors. The aim of the present review is to collect current knowledge about the role of presepsin in critically ill neonates.

Update Advances on C-Reactive Protein in COVID-19 and Other Viral Infections

Severe coronavirus disease 2019 (COVID-19) can manifest as a viral-induced hyperinflammation with multiorgan dysfunction. It has been documented that severe COVID-19 is associated with higher levels of inflammatory mediators than a mild disease, and tracking these markers may allow early identification or even prediction of disease progression. It is well known that C-reactive protein (CRP) is the acute-phase protein and the active regulator of host innate immunity, which is highly predictive of the need for mechanical ventilation and may guide escalation of treatment of COVID-19-related uncontrolled inflammation. There are numerous causes of an elevated CRP, including acute and chronic responses, and these can be infectious or non-infectious in etiology. CRP are normally lacking in viral infections, while adaptive immunity appears to be essential for COVID-19 virus clearance, and the macrophage activation syndrome may explain the high serum CRP contents and contribute to the disease progression. Nevertheless, for the assessment of host inflammatory status and identification of viral infection in other pathologies, such as bacterial sepsis, the acute-phase proteins, including CRP and procalcitonin, can provide more important information for guiding clinical diagnosis and antibiotic therapy. This review is aimed to highlight the current and most recent studies with regard to the clinical significance of CRP in severe COVID-19 and other viral associated illnesses, including update advances on the implication of CRP and its form specifically on the pathogenesis of these diseases. The progressive understanding in these areas may be translated into promising measures to prevent severe outcomes and mitigate appropriate treatment modalities in critical COVID-19 and other viral infections.