Diagnostic markers for neonatal sepsis: comparing C-reactive protein, interleukin-6 and immunoglobulin M

Enhancing sepsis biomarker development: key considerations from public and private perspectives

Implementation of biomarkers in sepsis and septic shock in emergency situations, remains highly challenging. This viewpoint arose from a public-private 3-day workshop aiming to facilitate the transition of sepsis biomarkers into clinical practice. The authors consist of international academic researchers and clinician-scientists and industry experts who gathered (i) to identify current obstacles impeding biomarker research in sepsis, (ii) to outline the important milestones of the critical path of biomarker development and (iii) to discuss novel avenues in biomarker discovery and implementation. To define more appropriately the potential place of biomarkers in sepsis, a better understanding of sepsis pathophysiology is mandatory, in particular the sepsis patient's trajectory from the early inflammatory onset to the late persisting immunosuppression phase. This time-varying host response urges to develop time-resolved test to characterize persistence of immunological dysfunctions. Furthermore, age-related difference has to be considered between adult and paediatric septic patients. In this context, numerous barriers to biomarker adoption in practice, such as lack of consensus about diagnostic performances, the absence of strict recommendations for sepsis biomarker development, cost and resources implications, methodological validation challenges or limited awareness and education have been identified. Biomarker-guided interventions for sepsis to identify patients that would benefit more from therapy, such as sTREM-1-guided Nangibotide treatment or Adrenomedullin-guided Enibarcimab treatment, appear promising but require further evaluation. Artificial intelligence also has great potential in the sepsis biomarker discovery field through capability to analyse high volume complex data and identify complex multiparametric patient endotypes or trajectories. To conclude, biomarker development in sepsis requires (i) a comprehensive and multidisciplinary approach employing the most advanced analytical tools, (ii) the creation of a platform that collaboratively merges scientific and commercial needs and (iii) the support of an expedited regulatory approval process.

Role of Hematological Parameters in the Early Diagnosis of Neonatal Sepsis

The major cause of neonatal mortality and morbidity is bacterial sepsis. Blood culture is the most reliable method in neonatal sepsis. This study was conducted to study the usefulness of hematological parameters in the early diagnosis of neonatal sepsis and to assess the most sensitive and specific variables in diagnosing neonatal sepsis. This prospective study was conducted in a tertiary care hospital from January 2017 to January 2018. Peripheral blood smears were prepared from patients with clinical suspicion of sepsis or predisposing perinatal factors for sepsis and stained with Field's stain and examined. The hematological findings were analyzed according to the hematologic scoring system of Rodwell. It was found that immature PMN count, I: M ratio, and I: T ratio had the highest sensitivity (92.06%, 87.30%, and 74.60%, respectively) while I: M ratio, I: T ratio, and degenerative changes in PMN had the highest specificity (97.50%, 96.50%, and 94.0%, respectively) in the prediction of sepsis.

Diagnostic accuracy of complete blood cell count and neutrophil-to-lymphocyte, lymphocyte-to-monocyte, and platelet-to-lymphocyte ratios for neonatal infection

Background

Complete blood cell (CBC) counts and neutrophil-to-lymphocyte (NLR), lymphocyte-to-monocyte (LMR), and platelet-to-lymphocyte ratios (PLR) are simple measurements that are conducted as part of routine diagnostic procedures.

Objective

To determine the diagnostic importance, specificity, and sensitivity of these measurements for the diagnosis of neonatal infections and in discriminating between neonatal sepsis and various other infections.

Methods

We conducted a retrospective study of data from a consecutive series of 232 neonatal patients admitted to Yildirim Beyazit University Yenimahalle Training and Research Hospital in Ankara for 2 years from 2016 to 2018. We included patients with a diagnosis of or clinically suspected infection, and healthy neonates were included as controls. Data included CBC counts, and bacterial culture results, considered the criterion standard for the diagnosis of neonatal sepsis. NLR, LMR, and PLR were calculated. We compared data using independent Student t and Mann-Whitney U tests and determined the sensitivity, specificity, and likelihood ratio (LHOR) of the characteristics for neonatal sepsis using receiver operating characteristic curve analyses.

Results

We included data from 155 neonatal patients with a diagnosis or suspicion of infection and 77 healthy neonates. NLR was significantly higher in neonates with sepsis or fever due to dehydration (P < 0.001) than in neonates with other infections or healthy neonates. LMR was significantly higher in neonates with sepsis or viral infection than in those with other infections or healthy controls (P = 0.003). In neonates with early-onset sepsis (EOS), we found cut-off values of ≥4.79 [area under curve (AUC) 0.845, 95% confidence interval (CI) 0.76-0.93, LHOR 11.6, specificity 98.7%, sensitivity 15%] for NLR, ≥1.24 (AUC 0.295; CI 0.18-0.41, LHOR 1.02, specificity 2.6%, sensitivity 100%) for LMR, and ≥37.72 (AUC 0.268; CI 0.15-0.39, LHOR 0.86, specificity 7.8%, sensitivity 80%) for PLR. We found cut-off values of ≥4.94 (AUC 0.667; CI 0.56-0.77, LHOR 4.16, specificity 98.7%, sensitivity 5.4%) for NLR and ≥10.92 (AUC 0.384; CI 0.26-0.51, LHOR 6.24, specificity 98.7%, sensitivity 8.1%) for LMR in those with late-onset sepsis (LOS).

Conclusions

CBCs, NLR, LMR, and PLR may be useful for the differential diagnosis of EOS and LOS, and neonates with sepsis from those with other infection. NLR may be a useful diagnostic test to identify neonatal patients with septicemia more quickly than other commonly used diagnostic tests such as blood cultures. NLR has high specificity and LHOR, but low sensitivity.

Diagnostic predictability of miR-4535 and miR-1915-5p expression in amniotic fluid for foetal morbidity of infection

INTRODUCTION

Clinical prediction of foetal inflammatory response syndrome (FIRS) is highly necessary. We have previously reported that miR-4535 and miR-1915-5p are potential biomarkers for severe chorioamnionitis based on the results of microRNA array analysis. Therefore, we evaluated the relationship between foetal morbidity of infection and miR-4535, miR-1915-5p, interleukin (IL)-6, or 16S rDNA copy number levels in amniotic fluid from pregnant women with chorioamnionitis.

METHODS

Amniotic fluid from 57 pregnant women with preterm premature membrane rupture or threatened premature labour were collected. Infants with WBC counts <5000/μL or >20,000/μL, CRP >0.5 mg/mL, or IgM >20 mg/mL at birth received a diagnosis of suspicious foetal infection, and those requiring antibiotic administration for >5 days were considered infected newborns. miR-4535, miR-1915-5p, and IL-6 levels and 16S rDNA copy number were evaluated. Mann-Whitney U test and Dunn's test were used for comparison. The area under the curve (AUC) and Youden index were calculated to examine the diagnostic accuracy of foetal morbidity of infection.

RESULTS

miR-4535, miR-1915-5p, 16S rDNA, and IL-6 were significantly higher in patients with severe chorioamnionitis than in patients with chorionitis or sub-chorionitis (P < 0.05). miR-4535 and miR-1915-5p levels were significantly associated with WBC counts <5000/μL or >20,000/μL, CRP >0.5 mg/mL, or IgM >20 mg/mL (P < 0.05). AUC values of miR-4535 and miR-1915-5p indicated moderate or low accuracy for foetal morbidity of infection, while those of IL-6 and 16S rDNA seemed unreliable.

DISCUSSION

MiR-4535 and miR-1915-5p levels in amniotic fluid may be considered clinically predictive for foetal morbidity of infection.

The Diagnostic Performance of Interleukin-6 and C-Reactive Protein for Early Identification of Neonatal Sepsis

Interleukin-6 (IL-6) and C-reactive protein (CRP) are being used for diagnosis of sepsis. However, studies have reported varying cut-off levels and diagnostic performance. This study aims to investigate the optimal cut-off levels and performance of IL-6 and CRP for the diagnosis of neonatal sepsis. The study was conducted at the University Hospital of Leipzig, Germany from November 2012 to June 2020. A total of 899 neonates: 104 culture proven sepsis, 160 clinical sepsis, and 625 controls were included. Blood culture was performed using BacT/ALERT 3D system. IL-6 and CRP were analyzed by electrochemiluminescent immunoassay and immunoturbidimetric assay, respectively. Data were analyzed using SPSS 20 statistical software. Among neonates with proven sepsis, the optimal cut-off value of IL-6 was 313.5 pg/mL. The optimal cut-off values for CRP in 5 days serial measurements (CRP1, CRP2, CRP3, CRP4, and CRP5) were 2.15 mg/L, 8.01 mg/L, 6.80 mg/L, 5.25 mg/L, and 3.72 mg/L, respectively. IL-6 showed 73.1% sensitivity, 80.2% specificity, 37.6% PPV, and 94.8% NPV. The highest performance of CRP was observed in the second day with 89.4% sensitivity, 97.3% specificity, 94.5% PPV, and 98.3% NPV. The combination of IL-6 and CRP showed increase in sensitivity with decrease in specificity. In conclusion, this study defines the optimal cut-off values for IL-6 and CRP. The combination of IL-6 and CRP demonstrated increased sensitivity. The CRP 2 at cut-off 8.01 mg/L showed the highest diagnostic performance for identification of culture negative clinical sepsis cases. We recommend the combination of IL-6 (≥313.5 pg/mL) and CRP1 (≥2.15 mg/L) or IL-6 (≥313.5 pg/mL) and CRP2 (≥8.01 mg/L) for early and accurate diagnosis of neonatal sepsis. The recommendation is based on increased sensitivity, that is, to minimize the risk of any missing cases of sepsis. The CRP2 alone at cut-off 8.01 mg/L might be used to identify clinical sepsis cases among culture negative sepsis suspected neonates in hospital settings.

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.

Effects of immunotherapy on mortality in neonates with suspected or proven sepsis: a systematic review and network meta-analysis

Background

To investigate the efficacies of different immunotherapies in neonates with suspected or proven sepsis.

Methods

We searched the Cochrane Library, EMBASE, MEDLINE, EBSCOhost, and Web of Science for studies published before May 2019 that investigated different immunotherapies in neonates with suspected or proven sepsis. Comparisons were among immunotherapies and between immunotherapy and placebo. The review was registered in the PROSPERO CRD database.

Results

All-cause mortality was not significantly different between patients who received the immunoglobulin (IgG), IgM-enriched immunoglobulin (IgGAM), granulocyte-colony stimulating factor (G-CSF) or granulocyte-macrophage colony stimulating factor (GM-CSF) immunotherapies and those who received placebo. The RRs of the immunotherapies were 0.80 (95% CI: 0.57 to 1.1), 0.45 (95% CI: 0.17 to 1.0), 0.93 (95% CI: 0.64 to 1.2) and 0.67 (95% CI: 0.39 to 1.1), respectively. Compared with placebo, none of the interventions showed statistically significant differences in the duration of hospital stay. The MDs of the immunotherapies were − 2.7 (95% CI: − 8.4 to 3.5), − 0.18 (95% CI: − 7.3 to 7.7), − 1.7 (95% CI: − 7.3 to 3.9) and − 7.2 (95% CI: − 28 to 13), respectively.

Conclusions

No significant differences in all-cause mortality or the duration of hospital stay were found in neonates with suspected or proven sepsis treated with the four types of immunotherapies and those treated with placebo.

Electronic supplementary material

The online version of this article (10.1186/s12887-019-1609-1) contains supplementary material, which is available to authorized users.

Validity of biomarkers in screening for neonatal sepsis - A single center -hospital based study

BACKGROUND

The diagnosis of neonatal sepsis still considered to be a challenge for both clinicians and the laboratory due to the non-specific clinical presentations. The present study aimed to compare and assess the diagnostic & prognostic values of C-reactive protein (CRP), high sensitivity CRP (hsCRP), presepsin, interleukin-6 (IL-6) and procalcitonin (PCT) in neonatal sepsis separately and in combination.

METHODS

This hospital-based cross-sectional study has been conducted on 168 neonates recruited from the neonatal intensive care unit (NICU) of Qena University Hospitals, Upper Egypt. Measurements of CRP using latex agglutination test, hsCRP, presepsin, IL6 and PCT assays using commercially available ELISA assay kits were done to all included neonates.

RESULTS

There were significantly higher serum levels of CRP among late onset versus early onset sepsis group with significantly higher serum levels of hsCRP and presepsin among early onset compared with the late onset sepsis group (p < 0.05 for all). There were significantly higher hsCRP, presepsin and PCT serum levels in proven versus probable sepsis group (p < 0.05 for all). Significantly higher serum levels of presepsin and PCT were noted among survivors versus non survivors sepsis group (p < 0.05 for all). The cutoff value of the serum level of CRP >6 mg/dl showed lower sensitivity and specificity than that of hsCRP at cutoff >140 ng/ml in diagnosing neonatal sepsis. The cutoff value of presepsin >200 ng/ml showed equal sensitivity and specificity to IL-6 at cutoff >22 pg/ml. The cutoff value of PCT at > 389 pg/ml showed sensitivity and specificity approximate to that of hsCRP.

CONCLUSIONS

CRP could be a helpful prognostic marker in late onset neonatal sepsis. hsCRP and PCT have higher diagnostic accuracy in neonatal sepsis in comparison to other studied markers. Both IL-6 and presepsin have equal diagnostic utility in neonatal sepsis, but presepsin could be helpful diagnostic marker in early onset neonatal sepsis.

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.

Global DNA methylation in neonatal sepsis

OBJECTIVE

To find out whether gDNA methylation can be used as a diagnostic/prognostic method for neonatal sepsis.

METHODS

The study was conducted in the neonatal division of a tertiary care referral hospital. Fifty one newborns as cases and thirty seven newborns as controls were enrolled in the study. Using 5-mC DNA ELISA method, the percentage of genomic DNA methylated in these newborns was established.

RESULTS

Highly significant difference in percentage of gDNA methylated was found between the cases and controls (Cases: 2.4 ± 0.39;

CONTROLS

2.07 ± 0.35; P < 0.0001). Culture proven and possible cases were also significantly distinguishable (P < 0.05). No significant differences in methylation were observed in terms of gestational age, birth weight and outcomes such shock, thrombocytopenia, except for renal failure.

CONCLUSIONS

The index results showed that genomic DNA methylation varies significantly among newborns with sepsis (clinical, probable and culture positive) and without sepsis. Although the global DNA methylation was not a highly sensitive diagnostic method, this study reveals that DNA methylation might play a vital role in neonatal sepsis susceptibility. Identification of the specific differentially methylated genes might serve as a promising future diagnostic/prognostic marker for neonatal sepsis.

Utility of qualitative C- reactive protein assay and white blood cells counts in the diagnosis of neonatal septicaemia at Bugando Medical Centre, Tanzania

Background

Neonatal septicaemia diagnosis based on clinical features alone is non-specific leading to the initiation of unnecessary antibiotic treatment posing a danger of increased antibiotic resistance. In the present study the utility of serial qualitative C-reactive protein (CRP) assay and white blood cells count (WBC) in the diagnosis of neonatal septicaemia was investigated using blood culture as gold standard.

Methods

A total of 305 neonates admitted at Bugando Medical Centre (BMC) neonatal units between September 2013 and April 2014 were enrolled. Demographic and clinical data were collected using standardized data collection tool. Blood specimens were collected for blood culture, WBC count and qualitative CRP assay.

Results

Of 305 neonates; 224 (73.4%) were ≤ 72 hrs of age and 91(29.8%) had low birth weight. The positive CRP assay was observed in 67 (22.0%), 80 (26.2%) and 88 (28.9%) of neonates on day 1, 2 and 3 respectively; with any CRP positive occurred in 104 (34.1%) of neonates. The sensitivities of CRP assay in the diagnosis of septicaemia using culture as gold standard on day 1, 2, 3 and any positive were 40.4%, 53.2%, 54.8% and 62.9% respectively. While specificities were 82.7%, 80.7%, 77.8% and 73.3% respectively. Higher sensitivity of 75% was observed when CRP was used to diagnose gram negative septicaemia compared to 50% that was observed in the diagnosis of gram positive septicaemia. WBC count of ≥13 × 10⁹ /L had sensitivity and specificity of 64.5% and 66.7% respectively with area under the curve of 0.694. When the any positive CRP and WBC of ≥13 × 10⁹ /L were used the sensitivity increased to 90.3% with specificity of 50%. Neonates with septicaemia due to gram negative bacteria were significantly found to have higher rates of positive CRP than neonates with gram positive septicaemia and with negative culture (p < 0.001, OR 8.2, 95 CI; 2.9-26).

Conclusion

In place where blood culture is limited neonates having clinical features of neonatal sepsis with positive qualitative CRP assay and increased WBC should urgently be initiated on appropriate sepsis management in order to reduce morbidity and mortality associated with neonatal sepsis.

Effective Biomarkers for Diagnosis of Neonatal Sepsis

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

Normal Ranges for Acute Phase Reactants (Interleukin-6, Tumour Necrosis Factor-alpha and C-reactive Protein) in Umbilical Cord Blood of Healthy Term Neonates at the Mount Hope Women's Hospital, Trinidad

OBJECTIVE

To determine normal ranges for interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-α) and C-reactive protein (CRP) in umbilical cord blood from healthy term neonates at the Mount Hope Women's Hospital (MHWH), Trinidad.

METHODS

A prospective cohort study was conducted on healthy pregnant women admitted to the MHWH during the period October 1 to December 31, 2010. Women who were term with no signs of or risk factors for sepsis were recruited into the study after informed consent was obtained. Data were collected including maternal age, antenatal and perinatal history. Umbilical cord blood samples were collected and analysed for IL-6, TNF-α and CRP. Ethical approval was obtained from the Ethics Committee, Faculty of Medical Sciences, The University of the West Indies, Trinidad and Tobago.

RESULTS

One hundred and sixty-two samples from healthy term neonates were analysed for IL-6 and TNF-α. One hundred and thirty-one samples were analysed for CRP due to one faulty kit. There were almost equal numbers of males (55%) and females (45%). Ninety per cent were > 2500 g at birth and 10% had low birthweight. Reference ranges of 0-16.4 pg/ml, 0-29.4 pg/ml and 0-12.4 mg/L were found for IL-6, TNF-α and CRP, respectively with 95% confidence intervals (11.6, 21.5 pg/ml; 24.0, 33.1 and 8.4, 15.1, respectively).

CONCLUSION

The normal ranges for IL-6, TNF-α and CRP in umbilical cord blood for healthy term Trinidadian neonates were 0-16.4 pg/ml, 0-29.4 pg/ml and 0-12.4 mg/L, respectively.

Rapid diagnosis of sepsis

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

Proadrenomedullin as a prognostic marker in neonatal sepsis

BACKGROUND

Proadrenomedullin (pro-ADM) for the diagnosis of proven and clinical sepsis in a newborn cohort including preterm newborns has not been investigated. We aimed to investigate the value of pro-ADM as a new marker by comparing it with conventional markers in neonatal sepsis (NS).

METHODS

Participants were stratified into three groups; proven sepsis (Group 1a), clinical sepsis (Group 1b), and the control group (Group 2), which consisted of newborns of matched gestational age and birth weight. Sequential measurements of white blood cell count, C-reactive protein (CRP), interleukin-6 (IL-6), and pro-ADM were compared.

RESULTS

A total of 76 patients with NS (31 with proven sepsis and 45 with clinical sepsis) and 52 healthy controls were enrolled. Mean baseline serum levels of CRP, IL-6, and pro-ADM were significantly higher in both Group 1a and Group 1b as compared with healthy controls (P < 0.001 for both). Although mean baseline CRP and IL-6 levels were similar between groups, mean baseline pro-ADM level was higher in the proven sepsis group than in the clinical sepsis group (P < 0.001).

CONCLUSION

The use of pro-ADM in combination with other acute-phase reactants such as CRP and IL-6 for the diagnosis and follow-up of patients with NS has high sensitivity and specificity.

Thymic involution as a predictor of early-onset neonatal sepsis

BACKGROUND

Diagnosis of early-onset neonatal sepsis (EONS) is often difficult because of vague clinical signs and non-specific laboratory parameters.

OBJECTIVE

To assess the statistical validity of thymic size estimation as a diagnostic marker of EONS compared with cord blood interleukin-6 (IL-6) concentrations.

SUBJECTS AND METHODS

Thirty-two neonates delivered in hospital and admitted to the neonatal unit with EONS comprised the study group. EONS was diagnosed on the basis of development of clinical signs and symptoms of sepsis within 72 hours of birth in the presence of antenatal risk factors for chorio-amnionitis and a positive blood culture. Thirty-two gestational age- and gender-matched healthy neonates served as controls. Cord blood IL-6 concentrations were estimated by ELISA. Thymic size was assessed by sonological measurement of thymic dimensions (longitudinal and transverse diameters, thymic volume and thymic index) within 24 hours of birth in the study infants and the controls. Data were analyzed by SPSS 16.0.

RESULTS

Thymic size was significantly smaller whereas cord blood IL-6 concentrations were significantly higher (P<0.001) in the sepsis group than in the controls. Sensitivity and specificity of thymic dimensions were comparable to IL-6 concentrations for diagnosing EONS. Significant correlation was noted between reduction in thymic size and a rise in IL-6 concentrations.

CONCLUSION

Thymic involution can be used as a reliable diagnostic marker for EONS.

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Neonatal sepsis: Role of a battery of immunohematological tests in early diagnosis

BACKGROUND AND OBJECTIVE

Worldwide, many neonates with sepsis die due to lack of early diagnosis. In this study we attempt to analyze the value of various immunological and hematological parameters, singly and in combination, for the diagnosis of neonatal sepsis, with the aim being to formulate guidelines for the early diagnosis of the condition.

MATERIALS AND METHODS

In this prospective study, 62 patients having clinical suspicion of neonatal sepsis were evaluated with a battery of investigations. Neonates admitted for other causes and without clinical suspicion of sepsis were selected as controls (n=40). The tests included blood culture, hemoglobin level, total and differential blood count, absolute neutrophil count, ratio of immature to total neutrophil count (I/T ratio), micro-erythrocyte sedimentation rate (m-ESR), C-reactive protein (CRP), platelet count, serum IgM level, and plasma fibrinogen level. Patients were divided into proven cases (positive blood culture) and probable cases (negative blood culture).

RESULTS

Positive blood culture was seen in 38 cases (61.3%). Raised m-ESR (>8 mm in the first hour) was seen in 63.2% of proven and 66.7% of probable cases. I/T ratio of ≥0.2 was seen in 63.2% and 58.3% of proven and probable cases, respectively. Morphological changes in neutrophils were detected in 68.4% of proven cases and 91.7% of probable cases. Positive CRP test (≥6 mg/l) was found in 84.2% of proven cases and 100% of probable cases. Raised serum IgM, leucopenia, and neutropenia were seen in a small number of patients (11%-37%). Raised fibrinogen level (>400 mg/l) was seen in patients as well as in controls.

CONCLUSIONS

The four useful tests that we identified were m-ESR, I/T ratio, morphological changes in neutrophils, and CRP; and role of these tests in early diagnosis of neonatal sepis were statistically significant (P<.05). The most sensitive test was CRP (84%) and the most specific test was m-ESR (94%). A combination of three or all of these four tests was highly specific (95%-100%).

Automated determination of neutrophil VCS parameters in diagnosis and treatment efficacy of neonatal sepsis

INTRODUCTION

The Coulter LH780 hematology analyzer can evaluate mean neutrophil volume (MNV), conductivity (MNC), scatter (MNS), and distribution width (DW). We sought to investigate the value of volume, conductivity, and scatter (VCS) parameters in diagnosis and treatment efficacy of neonatal sepsis.

RESULTS

We observed significant increases in MNV, volume distribution width (VDW), conductivity distribution width (CDW), and significant decreases in MNC and MNS in septic newborns. There were significant decreases in MNV, VDW, and CDW, whereas MNC and MNS increased at the end of the treatment. Gram-negative sepsis caused higher MNV and VDW than Gram-positive sepsis.

DISCUSSION

This is the largest reported study seeking to determine cutoff levels of neutrophil VCS parameters in diagnosis of sepsis, and the first study in the evaluation of treatment efficacy and the effects of sepsis onset time and birth weight. We suggest that neutrophil VCS parameters and their DWs are useful both for early diagnosis and evaluation of treatment efficacy in neonatal sepsis without requirement for any extra blood collection.

METHODS

Peripheral blood samples from 304 newborns, 206 in group I (76 proven and 130 clinical sepsis) and 98 in group II (control group), were studied on diagnosis, 3rd day, and at the end of the treatment.

Emerging biomarkers for the diagnosis of severe neonatal infections applicable to low resource settings

More than 500 000 children die each year in low resource settings due to serious neonatal infections. Better diagnostics that can be utilized in these settings to identify infected infants have the potential to significantly reduce neonatal deaths and the associated morbidity. A systematic review was performed and identified more than 250 potential new biomarkers for the diagnosis of serious neonatal infections. Eight of these biomarkers were both high-performance and high-abundance (antithrombin, inter-α inhibitor proteins, interferon-γ inducible protein-10, interleukin-1 receptor antagonist, LPS binding protein, mannose binding lectin, serum amyloid A, resistin, visfatin), and are promising for the diagnosis of serious neonatal infections in low resource settings. Future clinical trials comparing these biomarkers with more traditional biomarkers seem warranted.

Biomarkers for diagnosis of neonatal infections: A systematic analysis of their potential as a point-of-care diagnostics

BACKGROUND

Neonatal infections annually claim lives of 1.4 million neonates worldwide. Until now, there is no ideal diagnostic test for detecting sepsis and thus management of possible sepsis cases often depends on clinical algorithm leading to empirical treatment. This often results in unnecessary antibiotic use, which may lead to emergence of antibiotic resistance. Biomarkers have shown great promise in diagnosis of sepsis and guiding appropriate treatment of neonates. In this study, we conducted a literature review of existing biomarkers to analyze their status for use as a point-of-care diagnostic in developing countries.

METHODS

PubMed and EMBASE database were searched with keywords, 'infections', 'neonates', and 'biomarkers' to retrieve potentially relevant papers from the period 1980 to 2010. Leading hospitals and manufacturers were communicated to inquire about the cost, laboratory requirements and current standing of biomarkers in clinical use.

RESULTS

The search returned 6407 papers on biomarkers; 65 were selected after applying inclusion and exclusion criteria. Among the studies, C-reactive protein (CRP), procalcitonin (PCT) and interleukin 6 (IL-6) were the most widely studied biomarkers and were considered to be most promising for diagnosing neonatal infections. About 90% of the studies were from developed countries; more than 50% were from Europe.

CONCLUSIONS

Extensive work is being performed to find the diagnostic and prognostic value of biomarkers. However, the methodologies and study design are highly variable. Despite numerous research papers on biomarkers, their use in clinical setting is limited to CRP. The methods for detection of biomarkers are far too advanced to be used at the community level where most of the babies are dying. It is important that a harmonized multi-site study is initiated to find a battery of biomarkers for diagnosis of neonatal infections.

Serum calprotectin: an antimicrobial peptide as a new marker for the diagnosis of sepsis in very low birth weight newborns

To determine the diagnostic utility of serum calprotectin, a mediator of innate immune response against infections, we performed a multicenter study involving newborns with a birth weight <1500 g and a postnatal age >72 hours of life. The diagnostic accuracy of serum calprotectin was compared with that of the most commonly used markers of neonatal sepsis (white blood cell count, immature-to-total-neutrophil ratio, platelet count, and C-reactive protein). We found that the serum calprotectin concentration was significantly higher (P < .001) in 62 newborns with confirmed sepsis (3.1 ± 1.0  μg/mL) than in either 29 noninfected subjects (1.1 ± 0.3 μg/ml) or 110 healthy controls (0.91 ± 0.58 μg/ml). The diagnostic accuracy of serum calprotectin was greater (sensitivity 89%, specificity 96%) than that of the traditional markers of sepsis. In conclusion, serum calprotectin is an accurate marker of sepsis in very low birth weight newborns.

Tracking changes of lymphocyte subsets and pre-inflammatory mediators in full-term neonates with suspected or documented infection

Investigation was made of changes in immune system parameters during the course of neonatal infection. The study population consisted of 95 full-term neonates matched for chronological age and sex, divided into three groups: suspected infection (n=20), sepsis (n=25), infection-free control subjects (n=50). Serial measurements were made of the cytokines interleukin-6 (IL-6), interleukin-1b (IL-1b) and tumour necrosis factor-α (TNF-α), lymphocyte subsets [CD3+, CD4+, CD8+, natural killer (NK) cells and B cells], the immunoglobulins (Ig) (IgG, IgM and IgA), C-reactive protein (CRP), and the total blood count, before, 2 days after initiation of treatment and after stopping treatment (time periods first, second and third, respectively). IL6, TNF-α, IL1-b and CRP were higher at the first time period in the sepsis group, and IL6 and TNF-α continued to be higher in this group at the second period. IL-6 and TNF-α were precise sepsis predictors with sensitivity and specificity of 0.92, 0.98 and 0.91, 0.92, respectively. NK cells, B cells, CD3+, CD4+, CD8+ were higher in the sepsis and suspected infection groups, but the ratios CD3+/CD4+, CD3+/CD8+, CD4+/CD8+ showed no difference from the controls. IgG was lower and IgM higher in the sepsis group. In the control subjects CD3+, CD4+, CD8+ lymphocytes increased with increasing age. It is concluded that IL-6 and TNF are good diagnostic markers of sepsis in full-term neonates. Lymphocyte subsets were affected by both the clinical condition and the chronological age. NK and B cells may be elevated in suspected and documented sepsis, and further studies are needed to determine their clinical significance.

What are the cut-off levels for IL-6 and CRP in neonatal sepsis?

Neonatal sepsis, characterized by systemic signs of infection in the first month of life, remains an important clinical syndrome. Despite advances in neonatology, it has high rates of mortality and morbidity. The combine or alone usage of interleukin-6 (IL-6) and C-reactive protein (CRP) has recently been proven to be useful in the early diagnosis of sepsis in newborns. The study included 282 patients; there were 232 in Group I (170 proven and 62 clinical sepsis) and 50 in Group II (control group). The optimum cut-off value in the diagnosis of neonatal sepsis was found to be 24.65 pg/ml for IL-6 and 4.82 mg/l for CRP. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of this IL-6 cut-off for neonatal sepsis were 72, 84, 95, and 42%, respectively. Sensitivity, specificity, PPV, and NPV of the CRP cut-off for neonatal sepsis were 67, 97, 99, and 39%, respectively. The combination of IL-6 (>24.65 pg/ml) and CRP (>4.82 mg/l) in the diagnosis of neonatal sepsis gave sensitivity, specificity, PPV, and NPV of 53, 100, 100, and 33%, respectively. To our knowledge, this is the largest reported study seeking to determine cut-off levels for IL-6 and CRP in the diagnosis of neonatal sepsis. In conclusion, we think that it is useful to evaluate IL-6 and CRP, in combination, for the early diagnosis of neonatal sepsis.

Evaluation of neutrophilic CD64, interleukin 10 and procalcitonin as diagnostic markers of early- and late-onset neonatal sepsis

The assay of infection markers can improve diagnostic sensitivity in neonatal sepsis. We determined the levels of neutrophilic CD64 (nCD64), procalcitonin (PCT) and interleukin 10 (IL-10) in infants with neonatal sepsis. Forty-nine newborn infants who met the criteria of sepsis were subjected to a routine sepsis evaluation as well as measurement of PCT and IL-10 levels and nCD64 expression. Of these 49 'infected' infants, 16 had a positive blood culture (culture-positive sepsis) and 33 infants were diagnosed to have clinical sepsis with negative blood cultures (culture-negative sepsis). Another 49 healthy newborn infants were included as a control group. The sensitivity, specificity, positive predictive value and negative predictive value of PCT, IL-10 and nCD64 for the diagnosis of sepsis were determined. IL-10 had the highest sensitivity of 92% and specificity of 84% using a cut-off of > or =17.3 pg/ml. For PCT, the highest sensitivity of 65% and specificity of 60% were found at a cut-off value of > or =36.4 pg/ml. nCD64 had a maximal sensitivity of 92% and specificity of 71% at a cut-off value of 2.6%. Combinations of different markers may improve the sensitivity and specificity of biomarker tests. We found that the best combination was IL-10 and nCD64, which together provided sensitivity of 95% and specificity of 83%, and a negative predictive value of 86%.

Perinatal systemic inflammatory response syndrome and retinopathy of prematurity

Fetal and neonatal inflammation is associated with several morbidities of prematurity. Its relationship to retinopathy of prematurity (ROP) has not been investigated. Our objective was to determine the relationship between cytokine levels and ROP in the first 3 postnatal wks. Data for this study were derived from the NICHD Cytokine Study. Dried blood spots (DBS) were obtained from infants <1000 g on days 0-1, 3 +/- 1, 7 +/- 2, 14 +/- 3, and 21 +/- 3. Infants were classified into three groups-no, mild, and severe ROP. Multiplex Luminex assay was used to quantify 20 cytokines. Temporal profiles of cytokines were evaluated using mixed-effects models after controlling for covariates. Of 1074 infants enrolled, 890 were examined for ROP and 877 included in the analysis. ROP was associated with several clinical characteristics on unadjusted analyses. Eight cytokines remained significantly different across ROP groups in adjusted analyses. IL-6 and IL-17 showed significant effects in early time periods (D0-3); TGF-beta, brain-derived neurotrophic factor (BDNF), and regulated on activation, normal T cell expressed and secreted (RANTES) in later time periods (D7-21) and IL-18, C-reactive protein (CRP), and neurotrophin-4 (NT-4) in both early and later time periods. We conclude that perinatal inflammation may be involved in the pathogenesis of ROP.

Clinical features of neonatal sepsis caused by resistant Gram-negative bacteria

BACKGROUND

Clinical features and outcomes of neonatal sepsis caused by resistant Gram-negative bacteria are not well described in Jordan. The aim of the present study was therefore to describe microbiology and clinical features, laboratory findings and outcomes of early- and late-onset Gram-negative neonatal sepsis.

METHODS

All patients with Gram-negative bacteremia between July 2003 and June 2005 were retrospectively included. Resistance profiles, clinical features and outcomes of early and late-onset neonatal sepsis were compared.

RESULTS

A total of 79 patients (after excluding all nine cases of Gram-positive bloodstream infection (BSI) were identified as having Gram-negative BSI (25 had early-onset and 54 had late-onset neonatal sepsis). Respiratory distress, metabolic acidosis and requirement of ventilation were found in 74.7%, 40.5%, and 58.2%, respectively. Hypotension was found in 22.9% of patients. Klebsiella pneumoniae was responsible for 43 cases (54.4.2%). Klebsiella pneumoniae resistance rates to ampicillin and ceftazidime were 100% and 50%, respectively. Mortality rate was 30.9%. Forty-eight percent of deaths occurred within 3 days of sepsis. Meningitis was diagnosed in five cases. Elevated C-reactive protein (CRP) and thrombocytopenia were seen in 28% and 24% of infants with early-onset sepsis, respectively, and in 79.6%, 59.3% of infants with late-onset sepsis respectively.

CONCLUSION

Both early- and late-onset neonatal sepsis are caused by highly resistant Gram-negative bacteria. Mortality of sepsis is high. Elevated CRP and thrombocytopenia is seen more commonly in late-onset neonatal sepsis.

Neonatal sepsis: a 6-year analysis in a neonatal care unit in Taiwan

BACKGROUND

Neonatal sepsis is the most serious problem in neonatal intensive care, resulting in significant morbidity and mortality. We evaluated the causative pathogen, drug sensitivity, hematological parameters, clinical course and mortality rate of neonatal sepsis in a Taiwanese medical center and compared our results to those of previous studies conducted in Taiwan.

METHODS

Neonates admitted to the neonatal intensive care unit (NICU) at National Taiwan University Hospital (NTUH) between January 2001 and December 2006 were included in this study. Patients were divided into early-onset sepsis and late-onset sepsis groups if their culture tested positive within the first 7 days of life or later, respectively.

RESULTS

A total of 109 episodes of sepsis were identified in 100 neonates. The incidence of sepsis was 4.06% among all NICU admissions. Most neonates with early-onset sepsis were term infants, while very low birth weight (VLBW) and preterm infants accounted for the majority of cases of late-onset sepsis. In early-onset sepsis, the most common pathogens responsible included group B streptococci (GBS) (36%) and Escherichia coli (E. coli) (26%). GBS was associated with more meningitis involvement but lower incidence of mortality compared with E. coli. The most common causative microorganisms in late-onset sepsis were coagulase-negative staphylococci (CONS) (40%) and Candida (15%). The sepsis-related mortality rates were higher in early-onset sepsis (10%) than in late-onset sepsis (7%).

CONCLUSION

Unlike previous reports from Taiwan, in the present study, GBS was found to be the leading pathogen in early-onset sepsis. GBS screening and intrapartum antibiotic prophylaxis guidelines should be used in Taiwan to prevent early neonatal sepsis. The most common causative microorganisms of late-onset sepsis were CONS and Candida species. Candida parapsilosis was associated with a high mortality rate.

Hematologic profile of sepsis in neonates: neutrophil CD64 as a diagnostic marker

OBJECTIVE

The goal was to determine the utility of neutrophil CD64 as a diagnostic marker for sepsis in neonates.

METHODS

A prospective study that enrolled consecutive infants with suspected sepsis was performed. Complete blood count with differential, blood culture, and CD64 index measurement were performed, and neutrophil CD64 indices were correlated with the diagnoses of confirmed and suspected sepsis.

RESULTS

There were 293 episodes of sepsis evaluations for 163 infants. Infants with sepsis episodes (confirmed or suspected; n = 40) were of greater gestational age (34.7 +/- 0.9 weeks), compared with those (n = 123) with no sepsis (32.6 +/- 0.5 weeks), but had similar birth weights (2325 +/- 200 vs 1969 +/- 94 g) and Apgar scores at 1 and 5 minutes. There was no difference in the duration of hospitalization for the 2 groups. As expected, the hematologic profiles of sepsis episodes (n = 128) were characterized by higher white blood cell counts, absolute neutrophil counts, absolute band counts, and immature/total neutrophil ratios but lower platelet counts. Sepsis episodes had higher neutrophil CD64 indices (5.61 +/- 0.85 vs 2.63 +/- 0.20). For all sepsis episodes, the CD64 index had an area under the curve, in receiver operating characteristic analysis, of 0.74; with a cutoff value of 2.30, the CD64 index in combination with the absolute neutrophil count had the highest negative predictive value (93%) for ruling out sepsis and 95% sensitivity for diagnosing sepsis. For culture-positive sepsis episodes, the CD64 index had the highest area under the curve (0.852) of all hematologic variables, with a sensitivity of 80% and a specificity of 79%, with a cutoff value of 4.02.

CONCLUSIONS

Neutrophil CD64 is a highly sensitive marker for neonatal sepsis. Prospective studies incorporating CD64 into a sepsis scoring system are warranted.

Nuclear factor-kappaB activation in peripheral blood mononuclear cells in children with sepsis

OBJECTIVE

To determine the activation of nuclear factor-[kappa]B in peripheral blood CD14+ monocyte/macrophages and CD3+, CD4+, and CD8+ T cells in children with sepsis.

DESIGN

Observational study.

SETTING

University hospital.

PATIENTS

Twenty-six children with sepsis (nine females and 17 males, aged between 10 days and 15 yrs; median, 4.3 yrs) on admission to our hospital between August 1999 and November 2005.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The percentages of peripheral blood CD14+ monocyte/macrophages and CD3+, CD4+, and CD8+ T cells exhibiting nuclear factor-[kappa]B activity were determined by flow cytometry. In addition, relationships among the degree to which nuclear factor-[kappa]B was activated, serum levels of cytokines (interferon-[gamma], tumor necrosis factor-[alpha], interleukin-2, interleukin-4, interleukin-6, and interleukin-10), and clinical variables were analyzed. The percentage of cells exhibiting nuclear factor-[kappa]B activity was increased among CD14+, CD3+, CD4+, and CD8+ cells in the sepsis group and was significantly higher among CD14+, CD3+, and CD4+ cells of the patients with severe sepsis (n = 9) than those of patients with nonsevere sepsis (n = 17). The percentage of cells exhibiting nuclear factor-[kappa]B activity was significantly higher among CD14+ cells than CD3+ cells in the patients with severe sepsis. In addition, this percentage was significantly higher among CD14+ cells than CD3+, CD4+, and CD8+ cells in septic patients who had positive blood cultures (n = 16). Serum interleukin-6 levels were correlated with the percentages of CD14+, CD3+, CD4+, and CD8+ cells exhibiting nuclear factor-[kappa]B activity, and serum IL-10 levels were correlated with the percentages of CD14+, CD3+, and CD4+ cells exhibiting nuclear factor-[kappa]B activity.

CONCLUSIONS

Nuclear factor-[kappa]B in peripheral blood mononuclear cells was activated in children with sepsis and was related the severity of sepsis.