Predictive gene expression signature diagnoses neonatal sepsis before clinical presentation

BACKGROUND

Neonatal sepsis is a deadly disease with non-specific clinical signs, delaying diagnosis and treatment. There remains a need for early biomarkers to facilitate timely intervention. Our objective was to identify neonatal sepsis gene expression biomarkers that could predict sepsis at birth, prior to clinical presentation.

METHODS

Among 720 initially healthy full-term neonates in two hospitals (The Gambia, West Africa), we identified 21 newborns who were later hospitalized for sepsis in the first 28 days of life, split into early-onset sepsis (EOS, onset ≤7 days of life) and late-onset sepsis (LOS, onset 8-28 days of life), 12 neonates later hospitalized for localized infection without evidence of systemic involvement, and 33 matched control neonates who remained healthy. RNA-seq was performed on peripheral blood collected at birth when all neonates were healthy and also within the first week of life to identify differentially expressed genes (DEGs). Machine learning methods (sPLS-DA, LASSO) identified genes expressed at birth that predicted onset of neonatal sepsis at a later time.

FINDINGS

Neonates who later developed EOS already had ∼1000 DEGs at birth when compared to control neonates or those who later developed a localized infection or LOS. Based on these DEGs, a 4-gene signature (HSPH1, BORA, NCAPG2, PRIM1) for predicting EOS at birth was developed (training AUC = 0.94, sensitivity = 0.93, specificity = 0.92) and validated in an external cohort (validation AUC = 0.72, sensitivity = 0.83, and specificity = 0.83). Additionally, during the first week of life, EOS disrupted expression of >1800 genes including those influencing immune and metabolic transitions observed in healthy controls.

INTERPRETATION

Despite appearing healthy at birth, neonates who later developed EOS already had distinct whole blood gene expression changes at birth, which enabled the development of a 4-gene predictive signature for EOS. This could facilitate early recognition and treatment of neonatal sepsis, potentially mitigating its long-term sequelae.

FUNDING

CIHR and NIH/NIAID.

Delivery-Associated Changes in the Levels of Inflammatory Molecules in Newborns

Inflammation is considered a fundamental process accompanying physiological human birth, also playing a role in perinatal pathologies. The goal of the study was to assess the concentrations of inflammatory molecules with respect to the mode of delivery and dynamics of inflammatory molecules in neonatal samples in the first 48-72 hours of life. The concentrations of inflammatory cytokines were measured using the Luminex®xMAP multi-analyte profiling platform in cord blood and peripheral neonatal blood. Study groups included newborns delivered spontaneously (spontaneous group) and via elective caesarean section (elective group). Cord blood concentrations of interleukin 6 (IL-6) and procalcitonin were significantly higher (P < 0.0001) in the spontaneous group compared to the elective group. Neonatal blood concentrations of tumour necrosis factor (TNF) from the elective group were significantly higher com-pared to the spontaneous group (P = 0.0077). The concentrations of procalcitonin and TNF significantly increased within the first 48 to 72 hours following either mode of delivery. IL-6 and IL-18 were significantly higher in neonatal compared to umbilical cord blood in the elective group only, while the increase in the spontaneous group did not reach statistical significance. The concentrations of IL-1α, IL-1β, IL-17A and IL-22 did not show significant differen-ces between the spontaneous and elective groups as well as between umbilical cord and neonatal blood. Our findings show physiological differences in the levels of inflammatory molecules following spontaneous vaginal delivery and elective caesarean section. The results can be used as baseline values for the research of various pathologies in newborns.

Case Report of a Massive Life-threatening Neonatal Thrombosis Treated With a Targeted, Goal-oriented Scheme of Urokinase

BACKGROUND

Thrombotic events are severe, often under-diagnosed, complications occurring in newborn infants during their hospital stay. Currently, there is no consensus regarding the optimal treatment scheme for thrombolysis in neonates.

OBSERVATIONS

We present the case of a newborn suffering from a life-threatening thrombosis. Diagnosis was suggested by a gradual increase of C-reactive protein, with repeatedly normal procalcitonin. Thrombosis was successfully and safely treated with a long scheme of 21 days of urokinase, supported by vascular ultrasound and d-dimer trend.

CONCLUSIONS

Laboratory and ultrasound results may help in adjusting the duration of the thrombolytic treatment, allowing for longer therapeutic schemes that could optimize treatment success. In addition, our case may suggest a possible combined role of C-reactive protein and procalcitonin as an early diagnostic aid in neonatal thrombosis.

Presepsin for the Diagnosis of Neonatal Early-Onset Sepsis: A Systematic Review and Meta-analysis

Importance

Neonatal early-onset sepsis (EOS) is a severe disease, particularly in preterm infants. Timely diagnosis can be challenging owing to unspecific presentation and questionable performance of the common markers of infection. Presepsin was recently proven to be a promising biomarker for the diagnosis of EOS.

Objective

To assess presepsin accuracy for the diagnosis of EOS.

Data Sources

PubMed Medline, EMBASE, Web of Science, and Google Scholar. No publication date restrictions were applied. The literature search was limited to the English language. Articles were checked for duplication.

Study Selection

Inclusion criteria were studies that (1) included term or preterm newborns (defined as newborns with gestational age ≥37 weeks or <37 weeks, respectively); (2) included a diagnosis of EOS, defined as culture-proven sepsis for primary analysis and as either clinical or culture-proven sepsis for secondary analysis; and (3) assessed presepsin values during the initial workup for suspected EOS. Exclusion criteria were studies that (1) did not include EOS cases; (2) lacked data on presepsin sensitivity and/or specificity; and (3) were case reports, commentaries, or reviews. Two independent reviewers performed the study selection.

Data Extraction and Synthesis

Two independent reviewers performed data extraction and quality assessment. Quality assessment was performed using the Quality Assessment for Studies of Diagnostic Accuracy 2 tool, and data were reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Data were pooled using a random-effects model.

Main Outcomes and Measures

The outcomes of interest for both the primary and secondary analyses were presepsin sensitivity, specificity, and diagnostic odds ratio for the diagnosis of EOS.

Results

A total of 12 studies of 245 (4.9%) met inclusion criteria for the primary analysis. Twenty-three studies of 245 (9.4%) met the inclusion criteria for the secondary analysis. In the primary analysis, among 12 studies and 828 newborns of any gestational age, pooled sensitivity and specificity were 0.93 (95% CI, 0.86-0.95) and 0.91 (95% CI, 0.85-0.95), respectively; pooled diagnostic odds ratio was 131.69 (95% CI, 54.93-310.94). Subgroup analysis showed that presepsin specificity was associated with the inclusion of only EOS or all neonatal sepsis. Presepsin accuracy was not associated with gestational age, measurement with chemiluminescence enzyme immunoassay or enzyme-linked immunosorbent assay testing, country where the study was performed, or risk of bias judgment. In the secondary analysis, among 23 studies and 1866 newborns, accuracy was significantly associated with only test type.

Conclusions and Relevance

Results of this systematic review and meta-analysis suggest that presepsin was an accurate biomarker of EOS. Clinical trials are warranted to assess its usefulness and safety to reduce early antibiotic exposure, particularly in preterm newborns.

Noninfectious influencers of early-onset sepsis biomarkers

Diagnostic tests for sepsis aim to either detect the infectious agent (such as microbiological cultures) or detect host markers that commonly change in response to an infection (such as C-reactive protein). The latter category of tests has advantages compared to culture-based methods, including a quick turnaround time and in some cases lower requirements for blood samples. They also provide information on the immune response of the host, a critical determinant of clinical outcome. However, they do not always differentiate nonspecific host inflammation from true infection and can inadvertently lead to antibiotic overuse. Multiple noninfectious conditions unique to neonates in the first days after birth can lead to inflammatory marker profiles that mimic those seen among infected infants. Our goal was to review noninfectious conditions and patient characteristics that alter host inflammatory markers commonly used for the diagnosis of early-onset sepsis. Recognizing these conditions can focus the use of biomarkers on patients most likely to benefit while avoiding scenarios that promote false positives. We highlight approaches that may improve biomarker performance and emphasize the need to use patient outcomes, in addition to conventional diagnostic performance analysis, to establish clinical utility.

Physiological and metabolic adaptations in pregnancy: importance of trimester-specific reference intervals to investigate maternal health and complications

Diagnosis, prognostication, and monitoring of maternal health throughout pregnancy relies on laboratory testing, including but not limited to key markers of thyroid, hepatic, cardiac, hematology, and renal function. Dynamic physiological processes during gestation significantly influence the maternal biochemistry that supports both the mother and fetus. Resultant changes in blood biochemistry alter the expected values of common laboratory tests. However, the importance of pregnancy-specific reference intervals for laboratory test result interpretation and appropriate monitoring of maternal health and complications is underappreciated. Most clinical laboratories continue to use non-pregnant adult reference intervals for laboratory test interpretation in pregnancy. The current review summarizes and critically evaluates the available literature regarding physiological and metabolic adaptations in pregnancy and their influence on common biomarkers of health and disease. The main laboratory parameters discussed include thyroid, hepatic, metabolic, renal, hematology, inflammatory, and cardiac markers. Considering the available data, further studies are urgently needed to establish trimester-specific reference intervals in healthy pregnant women on updated analytical platforms. Without such data, the standard of clinical laboratory service in pregnancy remains compromised and affects the quality of maternal-fetal healthcare.

Procalcitonin for individualizing antibiotic treatment: an update with a focus on COVID-19

Procalcitonin (PCT) is useful for differentiating between viral and bacterial infections and for reducing the unnecessary use of antibiotics. As the rise of antimicrobial resistance reaches “alarming” levels according to the World Health Organization, the importance of using biomarkers, such as PCT to limit unnecessary antibiotic exposure has further increased. Randomized trials in patients with respiratory tract infections have shown that PCT has prognostic implications and its use, embedded in stewardship protocols, leads to reductions in the use of antibiotics in different clinical settings without compromising clinical outcomes. However, available data are heterogeneous and recent trials found no significant benefit. Still, from these trials, we have learned several key considerations for the optimal use of PCT, which depend on the clinical setting, severity of presentation, and pretest probability for bacterial infection. For patients with respiratory infections and sepsis, PCT can be used to determine whether to initiate antimicrobial therapy in low-risk settings and, together with clinical data, whether to discontinue antimicrobial therapy in certain high-risk settings. There is also increasing evidence regarding PCT-guided therapy in patients with coronavirus disease 2019 (COVID-19). This review provides an up-to-date overview of the use of PCT in different clinical settings and diseases, including a discussion about its potential to improve the care of patients with COVID-19.

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.

Evaluation of leucine-rich alpha-2 glycoprotein as a biomarker of fetal infection

This study aimed to determine the association between umbilical cord leucine-rich alpha-2 glycoprotein (LRG) and fetal infection and investigate the underlying mechanism of LRG elevation in fetuses. We retrospectively reviewed the medical records of patients who delivered at Osaka University Hospital between 2012 and 2017 and selected those with histologically confirmed chorioamnionitis (CAM), which is a common pregnancy complication that may cause neonatal infection. The participants were divided into two groups: CAM with fetal infection (CAM-f[+] group, n = 14) and CAM without fetal infection (CAM-f[−] group, n = 31). Fetal infection was defined by the histological evidence of funisitis. We also selected 50 cases without clinical signs of CAM to serve as the control. LRG concentrations in sera obtained from the umbilical cord were unaffected by gestational age at delivery, neonatal birth weight, nor the presence of noninfectious obstetric complications (all, p > 0.05). Meanwhile, the LRG levels (median, Interquartile range [IQR]) were significantly higher in the CAM-f(+) group (10.37 [5.21–13.7] μg/ml) than in the CAM-f(−) (3.61 [2.71–4.65] μg/ml) or control group (3.39 [2.81–3.93] μg/ml; p < 0.01). The area under the receiver operating characteristic (ROC) curve of LRG for recognizing fetal infection was 0.92 (optimal cutoff, 5.08 μg/ml; sensitivity, 86%; specificity, 88%). In a mouse CAM model established by lipopolysaccharide administration, the fetal LRG protein in sera and LRG mRNA in the liver were significantly higher than those in phosphate-buffered saline (PBS)-administered control mice (p < 0.01). In vitro experiments using a fetal liver-derived cell line (WRL68) showed that the expression of LRG mRNA was significantly increased after interleukin (IL)-6, IL-1β, and tumor necrosis factor- alpha (TNF-α) stimulation (p < 0.01); the induction was considerably stronger following IL-6 and TNF-α stimulation (p < 0.01). In conclusion, LRG is an effective biomarker of fetal infection, and fetal hepatocytes stimulated with inflammatory cytokines may be the primary source of LRG production in utero.

Procalcitonin Level at 24 Hours of Age May be Predictive for Transient Tachypnea of the Newborn

Objective It is an important problem to differentiate transient tachypnea of the newborn (TTN) from bacterial pneumonia or other conditions in patients admitted to Neonatal Intensive Care Unit. The aim of this study was to evaluate the predictive value of procalcitonin (PCT) for TTN.

Methods A total of 52 infants were contained in the study. The patients were divided into three groups. Group 1 consisted of patients with pronounced grunting at more than 2 hours postnatal age (n = 16). Group 2 consisted of patients whose grunt was reduced or gone at 2 hours postnatal age but in whom tachypnea persisted until 24 hours postnatal age (n = 18). Group 3 consisted of patients with minimal or no respiratory distress at 24 hours postnatal age (n = 18). In all groups, PCT concentrations were determined at birth and 24 hours postnatal age.

Results PCT concentrations at birth were significantly higher in Group 1 than other groups, but there was no difference between Groups 2 and 3. PCT concentrations at 24 hours postnatal age were significantly higher in Groups 1 and 2 than Group 3. No difference was found between Group 1 and Group 2 at 24 hours postnatal age. All PCT concentrations in Group 3 were significantly lower than other groups. PCT thresholds for the diagnosis of TTN were 0.44 ng/mL at birth (sensitivity 58%, specificity 50%) and 5.11 ng/mL at 24 hours postnatal age (sensitivity 79.4%, specificity 89.1%).

Conclusion Serial PCT measurements at birth and postnatal 24 hours may be helpful in differentiating between pneumonia and TTN. Further researches are needed to confirm this initial study.

Diagnostic Accuracy of Biomarkers for Early-Onset Neonatal Bacterial Infections: Evaluation of Serum Procalcitonin Reference Curves

To date, no clinical studies have compared the accuracy of serum procalcitonin (PCT) reference curves. We aimed to validate the diagnostic accuracy of previously reported serum PCT reference curves and to determine which biomarkers among a cut-off value over the 95th percentile in the serum PCT reference curve, white blood cell (WBC) count, and C-reactive protein (CRP) and immunoglobulin M (IgM) levels, have the highest diagnostic accuracy for early-onset neonatal bacterial infections. This retrospective cohort study assessed 16 preterm and 23 term infants with suspected bacterial infections within 72 h after birth. Each infant group was divided into two subgroups: confirmed- and non-infection. The diagnostic accuracy was determined using the Youden index. The reference curves by Fukuzumi et al. in preterm and term infants had the highest Youden indexes: 1.000 and 0.324, respectively. Among preterm infants, the Youden index for PCT was 1.000. Among term infants, the Youden index for a combination of PCT, CRP, and WBC and/or IgM was 1.000. In conclusion, a serum PCT level over the 95th percentile on the reference curve for preterm infants and a combination of PCT and CRP levels with WBC count and/or IgM levels for term infants provided sufficient diagnostic accuracy.

Serum Biomarkers for the Early Detection of the Early-Onset Neonatal Sepsis: A Single-Center Prospective Study

BACKGROUND

Reducing the hazards of the early-onset neonatal sepsis (EONS) is a priority justifying the further investigation for potential biomarkers for its early diagnosis.

PURPOSE

We aimed to investigate the diagnostic value of presepsin, procalcitonin, lactoferrin, interleukin (IL)-6, and IL-8 for the early diagnosis of EONS.

METHODS

A prospective comparative study, including 30 cases with highly suspected EONS and 30 matched controls, was conducted. Besides the complete blood count and blood culture, C-reactive protein, procalcitonin, presepsin, IL-6, IL-8, and lactoferrin were measured at the admission and after 72 hours.

RESULTS

At the time of the admission, presepsin, procalcitonin, C-reactive protein, and IL-8 were significantly higher in the sepsis group. The levels of presepsin, procalcitonin, and IL-8 significantly decreased after 72 hours of the admission. Presepsin, procalcitonin, IL-8, and IL-6 showed a high diagnostic ability for sepsis at admission with area under the curve of 0.934, 0.798, 0.775, and 0.751, respectively. The cutoff values of presepsin, procalcitonin, IL-8, and IL-6 were 821 pg/mL, 2.3 ng/mL, 54 pg/mL, and 24 pg/mL, with a sensitivity of 88.9%, 72.2%, 83.3%, and 94.4% and specificity of 85.7%, 80.9%, 71.4%, and 52.4%, respectively. Lactoferrin had the lowest diagnostic ability with area under the curve of 0.558.

IMPLICATIONS FOR PRACTICE

Presepsin was the most accurate biomarker followed by procalcitonin, IL-8, and IL-6 regarding the early diagnosis and management of EONS. The combination between these biomarkers is highly recommended.

IMPLICATIONS FOR RESEARCH

Further studies are needed to investigate the diagnostic ability of the combination of these biomarkers.

Establishment of reference intervals for maternal blood and umbilical cord blood procalcitonin in healthy Chinese women in late pregnancy

AIM

To establish reference intervals (RIs) for maternal blood and umbilical cord blood procalcitonin (PCT) in healthy Chinese women in late pregnancy.

METHODS

One hundred and twenty-seven healthy Chinese women in late pregnancy, including 70 vaginal deliveries and 57 cesarean section deliveries, were retrospectively analyzed. These pregnant women gave birth to 58 male infants and 69 female infants. Another 127 age-matched healthy women who were not pregnant were enrolled as the control group. PCT levels in maternal blood, umbilical cord blood and control blood were determined using electrochemiluminescence immunoassay. The RIs of PCT were defined using an intermediate 95% interval.

RESULTS

The RIs for maternal blood and umbilical cord blood PCT were 0.020-0.075 ng/mL and 0.020-0.159 ng/mL, respectively. The cord blood PCT level was not significantly different between different delivery methods (P > 0.05). In contrast, the umbilical cord blood PCT in female newborns was higher than that in male newborns (0.088 ± 0.046 ng/mL vs 0.072 ± 0.030 ng/mL, P < 0.05).

CONCLUSION

Maternal blood and umbilical cord blood PCT of Chinese women in late pregnancy have different RIs, and umbilical cord blood PCT level is affected by the gender of newborns.

Predictive value of procalcitonin, C-reactive protein, and white blood cells for chorioamnionitis among women with preterm premature rupture of membranes

OBJECTIVE

To determine the predictive value of procalcitonin, C-reactive protein (CRP), and white blood cells (WBC) for chorioamnionitis among women with preterm premature rupture of membranes (PPROM).

METHODS

A prospective cross-sectional study of all women with singleton pregnancy and PPROM admitted to a referral hospital in Shiraz, Iran, from 2016 to 2018. All women were hospitalized until delivery. The incidence of chorioamnionitis was recorded. Maternal serum CRP, procalcitonin, and WBC were measured on the day of admission and the day before termination of pregnancy. The diagnostic accuracy of each test was evaluated by receiver operator characteristic (ROC) curve analysis.

RESULTS

Overall, 75 women with PPROM were included in the study. After termination of pregnancy, 34 (45.3%) were diagnosed with clinical chorioamnionitis. Those with chorioamnionitis had significantly higher serum levels of CRP both on admission (P=0.004) and before termination of pregnancy (P<0.001). The area under the curve for last CRP was 0.78 (95% confidence interval, 0.57-0.84), indicating moderate accuracy. Procalcitonin and WBC had low accuracy to predict chorioamnionitis.

CONCLUSION

Among CRP, procalcitonin, and WBC, maternal serum CRP was found to be the most accurate predictor of chorioamnionitis among women with PPROM.

Procalcitonin versus C-reactive protein: review of kinetics and performance for diagnosis of neonatal sepsis

Procalcitonin (PCT) and C-reactive protein (CRP) are commonly used biomarkers, but their diagnostic advantage for neonatal early-onset (EOS) or late-onset (LOS) sepsis is controversial. In a comprehensive literature review we found significant heterogeneity between studies in sample timing, cut-off values, consideration of blood culture results for sepsis classification, and definition of EOS versus LOS. We identified 39 studies directly comparing PCT with CRP, but only four in very low birth weight (VLBW) neonates. The mean sensitivity for EOS, LOS, and EOS + LOS was 73.6%, 88.9%, and 76.5% for PCT, compared to 65.6%, 77.4%, and 66.4% for CRP, respectively. Mean specificity of PCT and CRP was 82.8% versus 82.7% for EOS, 75.6% versus 81.7% for LOS, and 80.4% versus 91.3% for EOS + LOS. More studies directly comparing both biomarkers for EOS and LOS, especially in extremely and very-low-birth-weight infants, are needed to determine their clinical value for guidance of antibiotic therapy in neonatal sepsis.

Procalcitonin-guided decision making for duration of antibiotic therapy in neonates with suspected early-onset sepsis: a multicentre, randomised controlled trial (NeoPIns)

BACKGROUND

Up to 7% of term and late-preterm neonates in high-income countries receive antibiotics during the first 3 days of life because of suspected early-onset sepsis. The prevalence of culture-proven early-onset sepsis is 0·1% or less in high-income countries, suggesting substantial overtreatment. We assess whether procalcitonin-guided decision making for suspected early-onset sepsis can safely reduce the duration of antibiotic treatment.

METHODS

We did this randomised controlled intervention trial in Dutch (n=11), Swiss (n=4), Canadian (n=2), and Czech (n=1) hospitals. Neonates of gestational age 34 weeks or older, with suspected early-onset sepsis requiring antibiotic treatment were stratified into four risk categories by their treating physicians and randomly assigned [1:1] using a computer-generated list stratified per centre to procalcitonin-guided decision making or standard care-based antibiotic treatment. Neonates who underwent surgery within the first week of life or had major congenital malformations that would have required hospital admission were excluded. Only principal investigators were masked for group assignment. Co-primary outcomes were non-inferiority for re-infection or death in the first month of life (margin 2·0%) and superiority for duration of antibiotic therapy. Intention-to-treat and per-protocol analyses were done. This trial was registered with ClinicalTrials.gov, number NCT00854932.

FINDINGS

Between May 21, 2009, and Feb 14, 2015, we screened 2440 neonates with suspected early-onset sepsis. 622 infants were excluded due to lack of parental consent, 93 were ineligible for reasons unknown (68), congenital malformation (22), or surgery in the first week of life (3). 14 neonates were excluded as 100% data monitoring or retrieval was not feasible, and one neonate was excluded because their procalcitonin measurements could not be taken. 1710 neonates were enrolled and randomly assigned to either procalcitonin-guided therapy (n=866) or standard therapy (n=844). 1408 neonates underwent per-protocol analysis (745 in the procalcitonin group and 663 standard group). For the procalcitonin group, the duration of antibiotic therapy was reduced (intention to treat: 55·1 vs 65·0 h, p<0·0001; per protocol: 51·8 vs 64·0 h; p<0·0001). No sepsis-related deaths occurred, and 9 (<1%) of 1710 neonates had possible re-infection. The risk difference for non-inferiority was 0·1% (95% CI -4·6 to 4·8) in the intention-to-treat analysis (5 [0·6%] of 866 neonates in the procalcitonin group vs 4 [0·5%] of 844 neonates in the standard group) and 0·1% (-5·2 to 5·3) in the per-protocol analysis (5 [0·7%] of 745 neonates in the procalcitonin group vs 4 [0·6%] of 663 neonates in the standard group).

INTERPRETATION

Procalcitonin-guided decision making was superior to standard care in reducing antibiotic therapy in neonates with suspected early-onset sepsis. Non-inferiority for re-infection or death could not be shown due to the low occurrence of re-infections and absence of study-related death.

FUNDING

The Thrasher Foundation, the NutsOhra Foundation, the Sophia Foundation for Scientific research.

Biomarkers for diagnosis of neonatal sepsis: a literature review

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

The influencing factors on procalcitonin values in newborns with noninfectious conditions during the first week of life

Purpose

Although procalcitonin (PCT) level is useful for the diagnosis of neonatal sepsis, PCT reliability is inconsistent because of the varied conditions encountered in neonatal intensive care units. This study aimed to investigate PCT levels and factors influencing increased PCT levelin newborns without bacterial infection during the first week of life.

Methods

In newborns hospitalized between March 2013 and October 2015, PCT levels were measured on the first, third, and seventh days after birth. Newborns with proven bacterial (blood culture positive for bacteria) or suspicious infection (presence of C-reactive protein expression or leukocytosis/leukopenia) were excluded. Various neonatal conditions were analyzed to identify the factors influencing increased PCT level.

Results

Among 292 newborns with a gestational age of 35.2±3.0 weeks and a birth weight of 2,428±643 g, preterm newborns (n=212) had higher PCT levels than term newborns (n=80). Of the newborns, 7.9% had increased PCT level (23 of 292) on the firstday; 28.3% (81 of 286), on the third day; and 3.3% (7 of 121), on the seventh day after birth. The increased PCT level was significantly associated with prenatal disuse of antibiotics (P=0.004) and surfactant administration (P<0.001) on the first day after birth, postnatal use of antibiotics (P=0.001) and ventilator application (P=0.001) on the third day after birth, and very low birth weight (P=0.042) on the seventh day after birth.

Conclusion

In newborns without bacterial infection, increased PCT level was significantly associated with lower gestational age and respiratory difficulty during the first week of life. Further studies are needed for clinical applications.

Procalcitonin in the Early Course Post Pediatric Cardiac Surgery

OBJECTIVE

Procalcitonin has emerged as a promising infection marker, but previous reports from small-sized studies suggest nonspecific elevation of procalcitonin after pediatric heart surgery. As procalcitonin is increasingly used as a marker for infection in the PICU, the aim of this study was to identify factors associated with postoperative procalcitonin elevation and to investigate the role of procalcitonin as an early marker of outcome after cardiac surgery.

DESIGN

Prospective observational study.

SETTING

Single, tertiary referral PICU.

PATIENTS

Patients aged 0-16 years following cardiac surgery with or without cardiopulmonary bypass.

INTERVENTIONS

Procalcitonin was measured in all patients at admission to PICU, and on postoperative day 1 and 2. Outcome variables included major adverse event, length of stay in PICU, postoperative renal failure requiring temporary dialysis, duration of mechanical ventilation and duration of inotropic support. A major adverse event was defined as cardiac arrest, need for postoperative extracorporeal life support or death within 3 months of cardiac surgery.

MEASUREMENTS AND MAIN RESULTS

In 221 included patients who underwent 232 operations, procalcitonin at admission to PICU was significantly associated with mechanical ventilation prior to surgery (p = 0.001), preoperative myocardial dysfunction (p = 0.002), duration of cardiopulmonary bypass (p < 0.001), intraoperative cross-clamp time (p = 0.015), and serum lactate at admission (p < 0.001). Patients suffering a major adverse event and patients with postoperative renal failure had significantly higher procalcitonin levels at admission to PICU (p = 0.04 and 0.01, respectively). Furthermore, procalcitonin levels at admission correlated significantly with the length of stay in the PICU (p = 0.005), time on mechanical ventilation (p = 0.03), and duration of inotropic support (p = 0.02).

CONCLUSIONS

Elevated levels of procalcitonin in the early phase after pediatric cardiac surgery are a marker for increased risk for major adverse events and postoperative renal failure and increased postoperative morbidity.

Recognising early onset neonatal sepsis: an essential step in appropriate antimicrobial use

Early diagnosis and timely treatment of early onset neonatal sepsis (EOS) are essential to prevent life threatening complications. Subtle, nonspecific clinical presentation and low predictive values of biomarkers complicate early diagnosis. This uncertainty commonly results in unnecessary and prolonged empiric antibiotic treatment. Annually, approximately 395,000 neonates (7.9% of live term births) are treated for suspected EOS in the European Union, while the incidence of proven EOS varies between 0.01 and 0.53 per 1000 live births. Adherence to guidelines for the management of suspicion of EOS is poor. Pragmatic approaches to minimise overtreatment in neonates with suspected EOS, using combined stratified risk algorithms, based on maternal and perinatal risk factors, clinical characteristics of the neonate and sequential biomarkers are promising.

Age-specific percentile-based reference curve of serum procalcitonin concentrations in Japanese preterm infants

Procalcitonin (PCT) levels are elevated early after birth in newborn infants; however, the physiological features and reference of serum PCT concentrations have not been fully studied in preterm infants. The aims of the current study were to establish an age-specific percentile-based reference curve of serum PCT concentrations in preterm infants and determine the features. The PCT concentration peaked in infants at 1 day old and decreased thereafter. At 1 day old, serum PCT concentrations in preterm infants <34 weeks’ gestational age were higher than those in late preterm infants between 34 and 36 weeks’ gestational age or term infants ≥37 weeks’ gestational age. Although the 50-percentile value in late preterm and term infants reached the adult normal level (0.1 ng/mL) at 5 days old, it did not in preterm infants. It took 9 weeks for preterm infants to reach it. Serum PCT concentrations at onset in late-onset infected preterm infants were over the 95-percentile value. We showed that the physiological feature in preterm infants was significantly different from that in late preterm infants, even in those <37 weeks’ gestational age. To detect late-onset bacterial infection and sepsis, an age-specific percentile-based reference curve may be useful in preterm infants.

Did antepartum hypoxic insult caused by fetal vessel thrombosis influence the procalcitonin level in umbilical blood? A case report

We report a case of marked elevation of the procalcitonin level in umbilical blood and neonatal blood at birth. The mother did not perceive fetal motion. Antepartum fetal heart rate monitoring showed a loss of variability and absence of acceleration. No fetal breathing movement, fetal movement, or fetal tone were observed by ultrasonography. The female neonate was delivered by cesarean section at 25 weeks of gestation, with birthweight 774 g. The umbilical arterial pH value at birth was 7.29. Mild elevation in interleukin-6 and tumor necrosis factor-α in umbilical blood were observed. Cytochrome c showed a high level in umbilical and neonatal blood at birth. Placental histopathology revealed multiple fetal vessel thrombosis in the large stem villi and chorionic vessels. The neonate showed no infectious signs throughout the neonatal period. Computed tomography at 3 months of age revealed atrophy in the cerebrum and cerebellum. At 1 year after birth, the infant showed spastic quadriplegia. In this case, antepartum asphyxia due to fetal vessel thrombosis may have influenced the elevation of procalcitonin level in umbilical blood and neonatal blood at birth.

Procalcitonin as a marker of respiratory disorder in neonates

BACKGROUND

Serum procalcitonin (PCT) increases in various respiratory disorders such as acute respiratory distress syndrome. Elevated PCT is also observed in healthy neonates. In this study, we investigated whether PCT is a good marker of respiratory disorder in neonates.

METHODS

A total of 155 neonates with or without respiratory disorder, were eligible for the study. PCT was measured on electrochemiluminescence immunoassay. Each neonate was allocated to the non-respiratory disorder (control) group (n = 95), or a respiratory disorder group (n = 60). PCT was compared between the groups, and association with other markers, including C-reactive protein (CRP) and white blood cell (WBC) count, was analyzed.

RESULTS

Of the 60 neonates in the respiratory disorder group, 39, 10, five, one, two, two, and one neonates had transient tachypnea of the newborn, respiratory distress syndrome, air leak syndrome, meconium aspiration syndrome, 18-trisomy, neonatal asphyxia, and congenital diaphragmatic hernia, respectively. Mean PCT, CRP and WBC count in the respiratory disorder group were 9.01 ng/mL, 0.26 mg/dL, and 16,100 cells/μL, respectively. The area under the curve obtained for PCT in distinguishing between the respiratory disorder and control groups was 0.85 (sensitivity, 66.7%; specificity, 93.0%; optimum cut-off, 3.73 ng/mL), that for CRP was 0.72 (sensitivity, 75.0%; specificity, 64.6%; optimum cut-off, 0.14 mg/dL), and for WBC it was 0.44 (sensitivity, 60.0%; specificity, 29.6%; optimum cut-off, 15,000 cells/μL).

CONCLUSIONS

PCT is more susceptible, as a diagnostic parameter of infection, to the effect of respiratory disturbance than CRP and WBC.

Commentaries on 'procalcitonin to initiate or discontinue antibiotics in acute respiratory tract infections' with a response from the review authors

These are commentaries on a Cochrane review, published in this issue of EBCH, first published as: Schuetz P, Müller B, Christ-Crain M, Stolz D, Tamm M, Bouadma L, Luyt CE, Wolff M, Chastre J, Tubach F, Kristoffersen KB, Burkhardt O, Welte T, Schroeder S, Nobre V, Wei L, Bhatnagar N, Bucher HC, Briel M. Procalcitonin to initiate or discontinue antibiotics in acute respiratory tract infections. Cochrane Database of Systematic Reviews 2012, Issue 9. Art. No.: CD007498. DOI: 10.1002/14651858.CD007498.pub2.

Neonatal sepsis: an old problem with new insights

Neonatal sepsis continues to be a common and significant health care burden, especially in very-low-birth-weight infants (VLBW <1500 g). Though intrapartum antibiotic prophylaxis has decreased the incidence of early-onset group B streptococcal infection dramatically, it still remains a major cause of neonatal sepsis. Moreover, some studies among VLBW preterm infants have shown an increase in early-onset sepsis caused by Escherichia coli. As the signs and symptoms of neonatal sepsis are nonspecific, early diagnosis and prompt treatment remains a challenge. There have been a myriad of studies on various diagnostic markers like hematological indices, acute phase reactants, C-reactive protein, procalcitonin, cytokines, and cell surface markers among others. Nonetheless, further research is needed to identify a biomarker with high diagnostic accuracy and validity. Some of the newer markers like inter α inhibitor proteins have shown promising results thereby potentially aiding in early detection of neonates with sepsis. In order to decrease the widespread, prolonged use of unnecessary antibiotics and improve the outcome of the infants with sepsis, reliable identification of sepsis at an earlier stage is paramount.

Umbilical blood biomarkers for predicting early-onset neonatal sepsis

BACKGROUND

Since the 1990s, finding the most efficient markers or combinations as predictors of early-onset neonatal sepsis has been the hot topic of studies. But there is no review of such biomarkers detected in umbilical blood at birth. By comparing clinical values of common inflammatory markers detected in cord blood shortly after birth, in this study we tried to find the most performing one or the most efficient combination that might be potentially used in birth room, as the earliest predictor of early-onset neonatal sepsis.

DATA SOURCES

We searched PubMed and Elsevier's Web of Science for studies evaluating cord blood inflammatory markers in relation to early-onset neonatal sepsis.

RESULTS

Among C-reactive protein (CRP), procalcitonin (PCT), IL-6, IL-8, TNF-α and IL-1β, none of them could be used individually to establish or exclude the diagnosis of early-onset neonatal sepsis, but PCT, IL-6 and IL-8 have great superiority to CRP, TNF-α and IL-1β. When combined with other hematological markers and clinical observation, the clinical reliability of PCT, IL-6 and IL-8 could be improved. Prolonging the sample collection time window seems to have a positive effect on the clinical utility of IL-6 and IL-8.

CONCLUSIONS

More researches focusing on the combination of different umbilical cord biomarkers in different clinical settings are needed to achieve clearer conclusions. Multi-center, large-sized analysis, especially examining groups of cytokines, is also expected.

Procalcitonin levels during pregnancy, delivery and postpartum

AIMS

To determine the normal value ranges of procalcitonin (PCT) in women with uncomplicated pregnancies.

METHODS

This prospective cohort study was conducted between May 2009 and February 2010 among 60 women without signs of clinical infection (31 vaginal deliveries, 29 cesarean sections) attending the maternity unit of the University of Geneva Hospitals. Sequential follow-up of PCT levels was performed at 24-28 weeks (n=7), 36-40 weeks (n=60), at delivery (n=59), and at days 2-3 (n=58) and 10 (n=53) postpartum using a sensitive PCT assay with a functional sensitivity of 0.06 μg/L.

RESULTS

Median levels of PCT were: 24-28 weeks: 0.043 μg/L (range 0.010-0.080); 36-40 weeks: 0.061 μg/L (range 0.010-0.110); at delivery: 0.068 μg/L (range 0.010-0.170); days 2-3: 0.200 μg/L (range 0.030-5.00); and day 10: 0.060 μg/L (range 0.020-0.120). At days 2-3 postpartum, three women had a PCT level between 0.25 μg/L and 0.5 μg/L and two women had a level higher than 0.5 μg/L.

CONCLUSIONS

This study provides reference values for PCT during the third trimester, at delivery and at the immediate postpartum period. A cut-off PCT level of 0.25 μg/L can be used during the third trimester, at delivery, and at the immediate postpartum period to rule out infection.

Procalcitonin measurement at 24 hours of age may be helpful in the prompt diagnosis of early-onset neonatal sepsis

BACKGROUND

The clinical signs of early-onset neonatal sepsis (EONS) are nonspecific and indistinguishable from those of noninfectious disorders. The early diagnosis of EONS is difficult, but is essential to improve outcomes. The aim of this study was to determine the diagnostic value of procalcitonin (PCT) at birth and at 24h of age in the prompt diagnosis of EONS.

METHODS

The patient group consisted of neonates with a Töllner score of ≥ 10 or a Töllner score of 5-10 but with the presence of prolonged rupture of the membranes (> 18 h) or chorioamnionitis or maternal fever (n=171). The control group (n=89) comprised neonates admitted to the neonatal intensive care unit for different disease entities. Procalcitonin levels at birth (first) and at 24h of age (second) were measured for each neonate in both of the study groups.

RESULTS

There was no difference between the two groups in terms of gender, birth weight, or gestational age. The mean (min-max) first PCT level was 0.48 (0.07-3.48)ng/ml in the controls and 0.51 (0.09-28.6)ng/ml in patients. The mean (min-max) second PCT level was 1.72 (0.21-18.23)ng/ml in the controls and 16.17 (0.17-100)ng/ml in patients. There was no statistically significant difference in PCT levels between the patient and control groups at birth. However, at 24h of age, PCT levels were significantly higher in the patient group than in the control group (p<0.001). Serum PCT levels in controls at 24h of age were slightly increased compared to levels at birth, but as a normal reaction. PCT thresholds for the diagnosis of sepsis were 0.59 ng/ml at birth (sensitivity 48.7%, specificity 68.6%) and 5.38 ng/ml at 24h of life (sensitivity 83.3%, specificity 88.6%).

CONCLUSIONS

In EONS, PCT measurements at birth may initially be normal; a serial PCT measurement at 24h of age may be more helpful for an early diagnosis. During the first 24h of life PCT is a more sensitive marker of infection than C-reactive protein. Further studies are needed to confirm our findings.

Serum procalcitonin as a diagnostic marker for neonatal sepsis: a systematic review and meta-analysis

PURPOSE

To assess the value of serum procalcitonin (PCT) for the differentiation between patients with and without neonatal sepsis.

METHODS

We systematically searched PubMed, Scopus, and the Cochrane Library for studies evaluating PCT in neonatal sepsis. PCT had to be measured in neonatal blood samples, at the initial presentation of patients with suspected sepsis, before the administration of antibiotics. We performed a bivariate meta-analysis of sensitivity and specificity, and constructed a hierarchical summary receiver-operating characteristic (HSROC) curve.

RESULTS

Overall, 29 studies eligible for inclusion were identified. We analyzed the 16 studies (involving 1,959 neonates) that evaluated PCT in neonates with culture-proven or clinically diagnosed sepsis in comparison with ill neonates with other conditions. The pooled (95% confidence interval) sensitivity and specificity were 81% (74-87%) and 79% (69-87%), respectively. The area under the HSROC curve (AUC) was 0.87. The diagnostic accuracy of PCT seemed higher for neonates with late-onset sepsis (>72 h of life) than for those with early onset sepsis; the AUC for these analyses was 0.95 and 0.78, respectively. However, fewer data were available for late-onset sepsis. High statistical heterogeneity was observed for all analyses.

CONCLUSION

Our findings suggest that serum PCT at presentation has very good diagnostic accuracy (AUC = 0.87) for the diagnosis of neonatal sepsis. However, in view of the marked observed statistical heterogeneity, along with the lack of a uniform definition for neonatal sepsis, the interpretation of these findings should be done with appropriate caution.

Laboratory aid to the diagnosis and therapy of infection in the neonate

Despite the advances in perinatal and neonatal care and use of newer potent antibiotics, the incidence of neonatal sepsis remains high and the outcome is still severe. For years, investigators have sought a test or panel of tests able to identify septic neonates accurately and rapidly in order to obtain an early diagnosis and develop a specific effective treatment for a successful outcome. In addition to the standard procedures (blood, CSF, and urine cultures), such panels have included a combination of haematological investigations (total, differential and immature cell counts), and levels of acute-phase reactants (principally CRP and procalcitonin), and cytokines (such as IL-6 or neutrophil CD64). Furthermore, the science of proteomics and genomics has been applied to the search for bio-markers, production of protein profiles and genetic polymorphisms that can rapidly help the prediction, early diagnosis, and treatment of human diseases, but, for now, data are as yet insufficient to confirm their validity.

Cord blood plasma reference intervals for potential sepsis markers: pro-adrenomedullin, pro-endothelin, and pro-atrial natriuretic peptide

OBJECTIVES

To establish reference values in cord blood of the following new sepsis markers: pro-adrenomedullin (MR-proADM), pro-endothelin (CT-proET-1), and pro-atrial natriuretic peptide (MR-proANP).

METHODS

MR-proADM, CT-proET-1, MR-proANP, and procalcitonin (PCT) were measured in cord blood of newborn infants by Time Resolved Amplified Cryptate Emission (TRACE) technology. The inclusion criteria in the control group (n=194) was the absence of any clinical sign or risk factor of sepsis. A group of 73 newborn infants presenting with risk factors of sepsis at delivery was also studied.

RESULTS

The median values (reference interval) of CT-proET-1, MR-pro-ADM, and MR-proANP measured in cord blood plasma were 72 pmol/L (39-115), 0.84 nmol/L (0.5-1.38), and 163 pmol/L (76-389), respectively. The PCT reference interval was not significantly different from that previously described in cord blood serum.

CONCLUSIONS

The reference intervals established will serve as a starting point for further clinical investigations aimed to elucidate the potential prognostic/diagnostic value of these markers in neonatal sepsis management.

Neonatal Procalcitonin Intervention Study (NeoPInS): Effect of Procalcitonin-guided decision making on duration of antibiotic therapy in suspected neonatal early-onset sepsis: A multi-centre randomized superiority and non-inferiority Intervention Study

BACKGROUND

Early diagnosis and treatment of the newborn infant with suspected sepsis are essential to prevent severe and life threatening complications. Diagnosis of neonatal sepsis is difficult because of the variable and nonspecific clinical presentation. Therefore, many newborns with nonspecific symptoms are started on antibiotic treatment before the presence of sepsis has been proven. With our recently published single-centre intervention study we were able to show that Procalcitonin determinations allowed to shorten the duration of antibiotic therapy in newborns with suspected early-onset sepsis.

METHODS/DESIGN

The study is designed as randomized controlled international multicenter intervention trial on the efficacy and safety of Procalcitonin guided treatment. Term and near-term infants (gestational age ≥ 34 0/7 weeks) with suspected sepsis in the first 3 days of life requiring empiric antibiotic therapy will be included. The duration of antibiotic therapy in the standard group is based on the attending physician's assessment of the likelihood of infection (infection unlikely, possible, probable or proven). In the Procalcitonin group, if infection is considered to be unlikely or possible, antibiotic therapy is discontinued when two consecutive Procalcitonin values are within the normal range. Co-primary outcome measures are the duration of antibiotic therapy (superiority aspect of the trial) and the proportion of infants with a recurrence of infection requiring additional courses of antibiotic therapy and/or death in the first month of life (safety of study intervention, non-inferiority aspect of the trial). The number of infants to be included equals 800 per arm. With these numbers the power of the study to demonstrate superiority for duration of antibiotic therapy as well as non-inferiority regarding safety, i.e. excluding a disadvantage difference larger than 2% for the experimental arm, will both be greater than 80%.

DISCUSSION

Benefit of the study is a possible limitation of unnecessary use of antibiotics. The results of our first study suggest that there is a low risk on discontinuing antibiotic treatment too early, resulting in the development of a neonatal infection with its morbidity and mortality.

TRIAL REGISTRATION

This trial is registered in the U.S. National Institutes of Health's register, located at http://www.clinicaltrials.gov. (NCT00854932).

Procalcitonin as a marker of severe bacterial infection in children in the emergency department

Procalcitonin, the prohormone of calcitonin, is a relatively new and innovative marker of bacterial infection that has multiple potential applications in the pediatric emergency department. In healthy individuals, circulating levels of procalcitonin are generally very low (<0.05 ng/mL), but in the setting of severe bacterial infection and sepsis, levels can increase by hundreds to thousands of fold within 4 to 6 hours. Although the exact physiologic function of procalcitonin has not been determined, the consistent response and rapid rise of this protein in the setting of severe bacterial infection make procalcitonin a very useful biomarker for invasive bacterial disease. In Europe, serum procalcitonin measurements are frequently used in the diagnosis and the management of patients in a variety of clinical settings. To date, the use of procalcitonin has been limited in the United States, but this valuable biomarker has many potential applications in both the pediatric emergency department and the intensive care unit. The intent of this article is to review the history of procalcitonin, describe the kinetics of the molecule in response to bacterial infection, describe the laboratory methods available for measuring procalcitonin, examine the main causes of procalcitonin elevation, and evaluate the potential applications of procalcitonin measurements in pediatric patients.

Maternal venous procalcitonin levels do not correlate with umbilical cord blood and venous blood concentrations in the neonate

BACKGROUND

To compare procalcitonin (PCT) concentrations between maternal blood and levels in umbilical cord or venous blood of neonates who were born with or without infection.

METHODS

Forty-six women with singleton pregnancies, complicated by premature rupture of membranes, preterm delivery and/or chorioamnionitis, were enrolled in this study. The study group comprised 15 patients and their infected newborns. The control group consisted of 31 women and their healthy newborns. We compared PCT concentrations between maternal, umbilical cord and neonatal serum, in both study and control groups. Additionally, PCT levels were compared between the corresponding compartments.

RESULTS

PCT concentrations in the umbilical cord and venous blood in infected newborns, but not in non-infected neonates, were significantly higher than maternal serum PCT levels. PCT concentrations of mothers who delivered infected newborns were comparable to those in the controls. However, PCT concentrations in the umbilical cord and in the venous blood of the infected newborns were higher than in healthy newborns.

CONCLUSION

Measurement of maternal PCT concentration during labor does not contribute to early prediction of infection in the neonate. However, umbilical cord PCT concentrations, as well as its neonatal venous levels on the second day of life, seem to be related to intrauterine infection, and may be a useful tool in the diagnosis of early neonatal infection.

Evaluation of procalcitonin for diagnosis of neonatal sepsis of vertical transmission

Background

The results of recent studies suggest the usefulness of PCT for early diagnosis of neonatal sepsis, with varying results. The aim of this prospective multicenter study was to determine the behavior of serum PCT concentrations in both uninfected and infected neonates, and to assess the value of this marker for diagnosis of neonatal sepsis of vertical transmission.

Methods

PCT was measured in 827 blood samples collected prospectively from 317 neonates admitted to 13 acute-care teaching hospitals in Spain over one year. Serum PCT concentrations were determined by a specific immunoluminometric assay. The diagnostic efficacy of PCT at birth and within 12–24 h and 36–48 h of life was evaluated calculating the sensitivity, specificity, and likelihood ratio of positive and negative results.

Results

169 asymptomatic newborns and 148 symptomatic newborns (confirmed vertical sepsis: 31, vertical clinical sepsis: 38, non-infectious diseases: 79) were studied. In asymptomatic neonates, PCT values at 12–24 h were significantly higher than at birth and at 36–48 h of life. Resuscitation at birth and chorioamnionitis were independently associated to PCT values. Neonates with confirmed vertical sepsis showed significantly higher PCT values than those with clinical sepsis. PCT thresholds for the diagnosis of sepsis were 0.55 ng/mL at birth (sensitivity 75.4%, specificity 72.3%); 4.7 ng/mL within 12–24 h of life (sensitivity 73.8%, specificity 80.8%); and 1.7 ng/mL within 36–48 h of life (sensitivity 77.6%, specificity 79.2%).

Conclusion

Serum PCT was moderately useful for the detection of sepsis of vertical transmission, and its reliability as a maker of bacterial infection requires specific cutoff values for each evaluation point over the first 48 h of life.

Procalcitonina para el diagnóstico de sepsis neonatal de transmisión vertical

OBJECTIVE

To evaluate procalcitonin (PCT) as a diagnostic marker of neonatal sepsis of vertical transmission and to compare the results of PCT with those of the most widely used laboratory tests for sepsis.

PATIENTS AND METHODS

A prospective study was conducted in 136 blood samples from 69 newborn infants admitted to a neonatal department. PCT, C-reactive protein (CRP), leukocyte count, and the immature-to-total neutrophil ratio (I/T ratio) were measured. The PCT reference range of controls from 0 to 72 hours of life was constructed, and the diagnostic efficiency of the tests was calculated, with their 95 % confidence intervals (95 % CI).

RESULTS

This study included 35 controls, 24 neonates with noninfectious disorders, and 10 neonates with sepsis (5 with culture-proven sepsis). PCT, CRP, and the I/T ratio discriminated septic from nonseptic patients. Their areas under the ROC curve were 0.696 (p = 0.009), 0.735 (p = 0.002), and 0.703 (p = 0.006), respectively, with no statistically significant differences. The accuracy of PCT, CRP, and leukocyte count improved after 24 hours of life with areas under the ROC curve of 0.813 (p = 0.007), 0.826 (p = 0.005), and 0.841 (p = 0.003), respectively. Overall, PCT detected vertically transmitted sepsis with a sensitivity of 68.4 % (95 % CI: 46.0 %-84.6 %), specificity of 82.4 % (95 % CI: 72.2 %-89.4 %), positive likelihood ratio of 3.89 (95 % CI: 2.18 %-6.96 %), and negative likelihood ratio of 0.38 (95 % CI: 0.19 %-0.76 %), similar to those of CRP.

CONCLUSIONS

PCT may be a useful marker for the diagnosis of vertically transmitted sepsis. Studies with larger sample sizes are required to establish the accuracy of PCT.

Immunologic markers in the neonatal period: diagnostic value and accuracy in infection

Diagnosis of early-onset neonatal infection has led to the development of several screening tests including C-reactive protein, a very commonly used marker, and cytokines (mainly interleukin-6 and -8), alone or in combination with C-reactive protein, based on the premise that their increases in response to infection may precede that of C-reactive protein. In recent years the search for diagnostic tests has turned to procalcitonin, a propeptide of calcitonin, which appears to be a promising marker of infection in newborn infants. Additionally, specific leukocyte cell surface antigens (mainly CD11b and CD64), detected by flow cytometry, are evaluated as markers of neonatal infection, since their expression on the cell membrane increases in substantial quantities after leukocyte activation by bacteria or their cellular products. This review aims to examine the role of these newly available immunologic indices and to assess their validity as diagnostic markers of infection during the neonatal period.

Procalcitonin as an early marker of infection in neonates and children

A child or neonate presenting with fever is a common medical problem. To differentiate between those with a severe bacterial infection and those with a localised bacterial or a viral infection can be a challenge. This review provides an overview of neonatal and paediatric studies that assess the use of procalcitonin as an early marker of bacterial infection. Procalcitonin is an excellent marker for severe, invasive bacterial infection in children. However, the use of procalcitonin in the diagnosis of neonatal bacterial infection is complicated, but if correctly used procalcitonin results in a higher specificity than C-reactive protein. In addition, procalcitonin has been shown to correlate with severity of disease (urinary tract infections and sepsis), and can therefore be used as a prognostic marker. Procalcitonin is therefore a useful additional tool for the diagnosis of bacterial disease in neonates and children.

Toward resolving the challenges of sepsis diagnosis

Sepsis in the United States has an estimated annual healthcare cost of 16.7 billion dollars and leads to 120,000 deaths. Insufficient development in both medical diagnosis and treatment of sepsis has led to continued growth in reported cases of sepsis over the past two decades with little improvement in mortality statistics. Efforts over the last decade to improve diagnosis have unsuccessfully sought to identify a "magic bullet" proteic biomarker that provides high sensitivity and specificity for infectious inflammation. More recently, genetic methods have made tracking regulation of the genes responsible for these biomarkers possible, giving current research new direction in the search to understand how host immune response combats infection. Despite the breadth of research, inadequate treatment as a result of delayed diagnosis continues to affect approximately one fourth of septic patients. In this report we review past and present diagnostic methods for sepsis and their respective limitations, and discuss the requirements for more timely diagnosis as the next step in curtailing sepsis-related mortality. We also present a proposal toward revision of the current diagnostic paradigm to include real-time immune monitoring.

Umbilical cord blood serum procalcitonin concentration in the diagnosis of early neonatal infection

OBJECTIVE

To evaluate serum procalcitonin concentration in umbilical cord blood for diagnosis of intrauterine bacterial infection.

MATERIALS AND METHODS

A prospective study was conducted between 2000 and 2001. Serum procalcitonin concentrations were evaluated in 187 umbilical cord blood samples. Five groups have been defined: controls A (n=37), full-term noninfected B1 (n=80) and infected neonates B2 (n=8), preterm noninfected C1 (n=38) and infected C2 (n=24) newborns. An immunoluminometric assay was used to determine procalcitonin concentration. The Mann-Whitney U-test and Spearman's correlation ratio were applied. The sensitivity and specificity, the positive and negative predictive values, and the area under receiver operating characteristic curves were calculated.

RESULTS

A statistically higher serum procalcitonin concentration was found in the preterm infected group (p<0.005; C2 vs A and C1).

CONCLUSION

Serum procalcitonin concentration in umbilical cord blood may be a useful parameter in the diagnosis of early neonatal infection.