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

Evaluation of systemic inflammatory indices in the diagnosis of early onset neonatal sepsis in very low birth weight infants

BACKGROUND

Previously, not six systemic inflammatory indices were evaluated in the diagnosis of early onset sepsis (EOS) in very low birth weight (VLBW, <1500g) premature infants.

OBJECTIVES

We evaluated the effectiveness of systemic inflammatory indices in the diagnosis of EOS in VLBW infants.

METHODS

Premature infants with birth weight <1500 g were included in the study. Six systemic inflammatory indices including neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), systemic immune-inflammation index (SII), pan-immune-inflammation value (PIV), and systemic inflammation response index (SIRI) were compared in patients with EOS (treatment group) and without EOS (control group).

RESULTS

Of 917 infants enrolled, 204 infants were in the EOS group and 713 infants comprised the control group. NLR, MLR and SIRI values were significantly higher in the EOS group than in the control group (p < 0.001). The AUC value of SIRI for the predictivity of EOS was 0.803.

CONCLUSIONS

The SIRI can be used together with other parameters as both an easily accessible and the reliable systemic inflammatory indices in the diagnosis of EOS in VLBW preterm infants.

Can C-reactive protein be used as a surrogate marker of IL-6 in a broad array of clinical entities?

Background: C-reactive protein (CRP) is commonly performed, whereas cytokine testing is limited to research. Aims: To determine CRP correlation to cytokines IL-6, IL-1β and TNF-α. Results: Consecutive samples (n = 307) were collected over 24 h. Ninety-six patients (31%) had acute infections, and 23 patients (7.5%) had autoimmune or inflammatory disease presentations. A strong correlation between CRP and two IL-6 assays (r = 0.74 and r = 0.71; p < 0.001) was present. CRP did not correlate with IL-1β and TNF-α across the data set. Bacterial infection had a significantly higher CRP and IL-6 (p < 0.001), while only CRP was elevated in inflammatory and autoimmune diseases (p < 0.001). Discussion: CRP may be used as a surrogate marker of IL-6 levels in the routine diagnostic laboratories.

Advancement in biomarker based effective diagnosis of neonatal sepsis

Neonatal sepsis is considered as alarming medical emergency and becomes the common global reason of neonatal mortality. Non-specific symptoms and limitations of conventional diagnostic methods for neonatal sepsis mandate fast and reliable method to diagnose disease for point of care application. Recently, disease specific biomarkers have gained interest for rapid diagnosis that led to the development of electrochemical biosensor with enhanced specificity, sensitivity, cost-effectiveness and user-friendliness. Other than conventional biomarker C-reactive protein to diagnose neonatal sepsis, several potential biomarkers including Procalcitonin (PCT), Serum amyloid A (SAA) and other candidates are extensively investigated. The present review provides insights on advancements and diagnostic abilities of protein and nucleotide based biomarkers with their incorporation in developing electrochemical biosensors by employing novel fabrication strategies. This review provides an overview of most promising biomarker and its capability for neonatal sepsis diagnosis to fulfil future demand to develop electrochemical biosensor for point-of-care applications.

Current Status and Problems of Newborn Infection Management at a Regional Hospital in Japan

PURPOSE

To clarify neonatal bacterial infection management in near term and term infants at a regional hospital in Japan.

METHODS

Between 2018 and 2020, of 729 births, 236 patients who underwent blood examination at least twice by the age of 3 days, were included. Data from the medical records were analyzed retrospectively.

RESULTS

Median gestational age was 39 weeks, with 116 boys (49.1%) and 202 vaginal deliveries (85.6%). There were 37 cases of maternal group B streptococcus, 24 cases of premature rupture of membranes for more than 24 hours (PROM group), and 107 cases of amniotic fluid turbidity at birth (AFT group). Comparing groups, C-reactive protein (CRP) was significantly lower in the cesarean section (C/S) group (median 0.22 mg/dL; p < 0.05), and higher in the AFT group (0.44 mg/dL; p < 0.05). There were 77 positive cultures, (p < 0.05). Antibiotics were administered more frequently in cesarean section (19 cases; p < 0.001) and less in the PROM group (2 cases; p < 0.01).

CONCLUSIONS

There were no asymptomatic cases of CRP >2 mg/dL, and no cases of severe sepsis in normal neonatal deliveries. CRP levels were elevated in the AFT group, where culture was positive, but few antibiotics were administered. In the C/S group, antibiotics were administered if respiratory symptoms occurred unless the CRP level was high. Further, all patients in PROM group who received antibiotics had any symptoms, suggesting that routine blood tests may not be necessary.

Inflammatory Biomarker Profiles in Very Preterm Infants within the Context of Preeclampsia, Chorioamnionitis, and Clinically Diagnosed Postnatal Infection

Preterm delivery can be precipitated by preeclampsia or infection, and preterm infants are at heightened risk of postnatal infection. Little is known about the ontogeny of inflammatory biomarkers in extremely preterm infants. We hypothesized that suspected prenatal infection (clinical chorioamnionitis or spontaneous preterm labor) and clinically diagnosed postnatal infection would be associated with unique biomarker signatures, and those patterns would be influenced by the degree of prematurity. Venous blood was collected daily for the first week and weekly for up to 14 additional weeks from 142 neonates born at 22-32 weeks gestation. A custom array was utilized to measure monocyte chemoattractant protein-1 (MCP-1) and interleukin-6 (IL-6). C-reactive protein (CRP) levels were obtained from the electronic medical record. Independent of gestational age, MCP-1 was significantly increased (p < 0.001) in association with maternal preeclampsia, but MCP-1 was decreased (p < 0.01), and CRP was increased (p < 0.01) in the presence of chorioamnionitis with funisitis. IL-6 and CRP were both increased in infants diagnosed with postnatal infection, with peak levels observed on days 2 and 3, respectively. In conclusion, suspected prenatal and postnatal infections and non-infectious complications of pregnancy are associated with unique biomarker profiles, independent of gestational age, including over a 2-fold increase in MCP-1 among newborns of mothers with preeclampsia. Further, in those clinically diagnosed with a postnatal infection in the absence of antenatal infection concerns, IL-6 increases before CRP, emphasizing a potential role for expanded biomarker screening if antibiotics are initially avoided in infants delivered for maternal indications.

Proteomics identifies lipocalin-2 in neonatal inflammation associated with cerebrovascular alteration in mice and preterm infants

Staphylococcus (S.) epidermidis is the most common nosocomial coagulase-negative staphylococci infection in preterm infants. Clinical signs of infection are often unspecific and novel markers to complement diagnosis are needed. We investigated proteomic alterations in mouse brain after S. epidermidis infection and in preterm infant blood. We identified lipocalin-2 (LCN2) as a crucial protein associated with cerebrovascular changes and astrocyte reactivity in mice. We further proved that LCN2 protein expression was associated with endothelial cells but not astrocyte reactivity. By combining network analysis and differential expression approaches, we identified LCN2 linked to blood C-reactive protein levels in preterm infants born <28 weeks of gestation. Blood LCN2 levels were associated with similar alterations of cytokines and chemokines in both infected mice and human preterm infants with increased levels of C-reactive protein. This experimental and clinical study suggests that LCN2 may be a marker of preterm infection/inflammation associated with cerebrovascular changes and neuroinflammation.

[A pilot study of plasma interleukin-6 and interleukin-27 in differential diagnosis of acute respiratory distress syndrome and neonatal respiratory distress syndrome in preterm infants]

OBJECTIVES

To study the significance of interleukin-6 (IL-6) and interleukin-27 (IL-27) in the differential diagnosis of acute respiratory distress syndrome (ARDS) and neonatal respiratory distress syndrome (NRDS) in preterm infants.

METHODS

The preterm infants with the manifestation of respiratory distress who were treated in the Neonatal Diagnosis and Treatment Center, Children's Hospital of Chongqing Medical University, from March to November 2021, were enrolled in this prospective study. According to the diagnosis results, they were divided into two groups: ARDS group (n=18) and NRDS group (n=20). ELISA was used to measure the plasma levels of IL-6 and IL-27. The receiver operating characteristic (ROC) curve was used to analyze the value of each index in the diagnosis of ARDS.

RESULTS

The ARDS group had significantly higher plasma levels of IL-6 and IL-27 than the NRDS group (P<0.05). The ROC curve analysis showed that IL-6 had an area under the ROC curve (AUC) of 0.867 for the diagnosis of ARDS, with a sensitivity of 61.1% and a specificity of 95.0% at the cut-off value of 56.21 pg/mL. The ROC curve analysis also showed that IL-27 had an AUC of 0.881 for the diagnosis of ARDS, with a sensitivity of 83.3% and a specificity of 80.0% at the cut-off value of 135.8 pg/mL.

CONCLUSIONS

Plasma IL-6 and IL-27 can be used as biological indicators for early differential diagnosis of ARDS and NRDS in preterm infants.

Comparison of Two Predictive Models of Sepsis in Critically Ill Patients Based on the Combined Use of Inflammatory Markers

Background

Sepsis is a systemic inflammatory response due to infection, resulting in organ dysfunction. Timely targeted interventions can improve prognosis. Inflammation plays a crucial role in the process of sepsis. To identify potential sepsis early, we developed and validated a nomogram model and a simple risk scoring model for predicting sepsis in critically ill patients.

Methods

The medical records of adult patients admitted to our intensive care unit (ICU) from August 2017 to December 2020 were analyzed. Patients were randomly divided into a training cohort (70%) and a validation cohort (30%). A nomogram model was developed through multivariate logistic regression analysis. The continuous variables included in nomogram model were transformed into dichotomous variables. Then, a multivariable logistic regression analysis was performed based on these dichotomous variables, and the odds ratio (OR) for each variable was used to construct a simple risk scoring model. The receiver operating characteristic curves (ROC) were constructed, and the area under the curve (AUC) was calculated.

Results

A total of 2074 patients were enrolled. Finally, white blood cell (WBC), C-reactive protein (CRP), interleukin-6 (IL-6), procalcitonin (PCT) and neutrophil-to-lymphocyte ratio (NLR) were included in our models. The AUC of the nomogram model and the simple risk scoring model were 0.854 and 0.842, respectively. The prediction performance of the two models on sepsis is comparable (p = 0.1298).

Conclusion

This study combining five commonly available inflammatory markers (WBC, CRP, IL-6, PCT and NLR) developed a nomogram model and a simple risk scoring model to predict sepsis in critically ill patients. Although the prediction performance of the two models is comparable, the simple risk scoring model may be simpler and more practical for clinicians to identify potential sepsis in critically ill patients at an early stage and strategize treatments.

Predicting Neonatal Early Onset Sepsis: A 14-Year Cohort Study

BACKGROUND

In many infants, treatment is started for suspicion of early onset sepsis (EOS), of whom the majority do not have an infection. Early prediction of the absence of a culture-proven sepsis (CPS) would significantly reduce the time of antibiotic treatment and hospitalization. Our objective was to analyze 3 criteria in infants with CPS: positive blood culture (BC) at 24 hours after the onset of suspicion of EOS (OSEOS), C-reactive protein (CRP) ≥10 mg/L and clinical signs of infection, so we can consequently consider to stop antibiotic treatment in infants without these criteria.

METHODS

We included all infants with suspicion of EOS from 2007 until 2020. The proportion was calculated of (1) infants with CPS with, at 24 hours, a positive BC and/or CRP ≥10 mg/L and/or clinical signs of infection and (2) infants without CPS with CRP <10 mg/L between 12 and 24 hours after OSEOS.

RESULTS

The BC showed growth of a pathogenic microorganism in 50 of 4120 included infants (1.2%). Time to positivity was ≥24 hours in 8 (16%) infants, of whom 7 infants had a raised CRP and/or clinical symptoms of infection within 24 hours. In 1095 (74%) of infants without CPS in whom CRP was measured between 12 and 24 hours after OSEOS, CRP was <10 mg/L.

CONCLUSION

A combination of BC, CRP, and clinical signs of infection can diagnose 98% (49/50) of infants with CPS 24 hours after OSEOS. Based on normal CRP and the absence of a positive BC, the decision to stop antibiotics could have been brought forward to 24 hours in 74% of infants.

Salivary Interleukin-6 and C-Reactive Protein/Mean Platelet Volume Ratio in the Diagnosis of Late-Onset Neonatal Pneumonia

Neonatal pneumonia is a serious respiratory infectious disease with a high rate of case fatality in developing countries. Salivary cytokines could serve as interesting noninvasive markers in the diagnosis of neonatal pneumonia. The aim was to assess the diagnostic role of salivary and serum interleukin-6 (IL-6), C-reactive protein/mean platelet volume (CRP/MPV) ratio, and the combination of these markers in the diagnosis of late-onset neonatal pneumonia in full-term neonates. Seventy full-term neonates, 35 with late-onset neonatal pneumonia and 35 controls, were enrolled in this prospective case-control study. Complete blood count (CBC), salivary and serum IL-6, and CRP concentrations were measured for all the study subjects. The sensitivity, specificity, positive predictive value, and negative predictive value of salivary IL-6, serum IL-6, and CRP/MPV ratio for the diagnosis of late-onset neonatal pneumonia were determined. At the cutoff point of >34 pg/ml, salivary IL-6 showed 82.86% sensitivity and 91.43% specificity. CRP/MPV ratio showed a sensitivity of 97.14% and specificity of 85.71% at a cutoff value > 0.88. The combination of salivary IL-6 and CRP/MPV ratio improved the sensitivity and specificity to 100%. The current study shows for the first time that both salivary IL-6 and CRP/MPV ratio are suitable markers for the diagnosis of late-onset neonatal pneumonia in full-term neonates.

Neonatal bloodstream infections

PURPOSE OF REVIEW

Neonatal bloodstream infections (BSI) are a major contributor to morbidity and mortality within neonatal intensive care units. BSI, including central line-associated BSI, have decreased over the past 15 years but remain common in extremely preterm infants. The purpose of this review is to highlight recent advances in the causes, diagnosis, management, and prevention of neonatal BSI.

RECENT FINDINGS

Continued quality improvement efforts and bundles have reduced BSI incidence, and novel approaches are highlighted. An update of emerging pathogens as well as traditional pathogens with novel antimicrobial resistance, which are an increasingly common cause of neonatal BSI, is included. Finally, current and future investigations into serum or noninvasive biomarkers for neonatal BSI are reviewed.

SUMMARY

Neonatal BSIs continue to decrease due to enhanced infection control and prevention techniques. However, many challenges remain, including emerging bacterial and fungal resistance and the continued need for novel diagnostics that hasten time to pathogen identification and effective treatment. This review of the past 18 months highlights the rapid changes in this area. Ongoing efforts to reduce the morbidity and mortality caused by neonatal BSI must remain a priority.

The potential value of plasma receptor interacting protein 3 in neonates with culture-positive late-onset sepsis

Background

Late-onset sepsis (LOS) is a systemic inflammatory response syndrome in neonates, and the molecular mechanism of LOS is incompletely characterized. The purpose of this study was to explore the potential value of receptor interacting protein 3 (RIP3) in LOS.

Methods

63 neonates with LOS supported by positive culture and 79 neonates without sepsis were enrolled in this study from September 2019 to March 2021. Plasma RIP3 was detected by enzyme-linked immunosorbent assay (ELISA) and assessed along with the whole blood hypersensitive C-reactive protein (hs-CRP) level and platelet count (PLT). Differences in RIP3, hs-CRP and PLT between the two groups were compared. Changes in the three indicators in sepsis were also observed after treatment. The diagnostic value of indicators for LOS was evaluated by receiver operating characteristic (ROC) curve analysis.

Results

In the sepsis group, RIP3 and hs-CRP levels were significantly higher than those in the control group (RIP3, p < 0.0001; hs-CRP, p < 0.0001), and PLT was significantly lower than that in the control group (p < 0.0001). After treatment, RIP3 and hs-CRP levels among septic survivors were significantly decreased (p < 0.0001) and PLT significantly improved (p = 0.0216). With RIP3 > 15,845.19 pg/mL, hs-CRP > 5.00 mg/L, and PLT < 204.00 × 10⁹/L as the positive criteria, the sensitivity values of the three indicators in the diagnosis of LOS were 69.8%, 60.3%, 60.3%, respectively, and the specificity values were 92.4%, 96.2%, 79.8%, respectively. The combination of RIP3, hs-CRP and PLT had a sensitivity of 77.8% and specificity of 97.5%.

Conclusions

RIP3 may contribute to the early diagnosis of LOS and monitoring of treatment effect. The combined detection of RIP3, hs-CRP and PLT may be more effective than individual detection in the diagnosis of LOS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06636-0.

Neonatal sepsis at point of care

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

Antibiotic Resistance Patterns of Bacterial Isolates from Neonatal Sepsis Patients at University Hospital of Leipzig, Germany

Neonatal sepsis caused by resistant bacteria is a worldwide concern due to the associated high mortality and increased hospitals costs. Bacterial pathogens causing neonatal sepsis and their antibiotic resistance patterns vary among hospital settings and at different points in time. This study aimed to determine the antibiotic resistance patterns of pathogens causing neonatal sepsis and to assess trends in antibiotic resistance. The study was conducted among neonates with culture proven sepsis at the University Hospital of Leipzig between November 2012 and September 2020. Blood culture was performed by BacT/ALERT 3D system. Antimicrobial susceptibility testing was done with broth microdilution method based on ISO 20776-1 guideline. Data were analyzed by SPSS version 20 software. From 134 isolates, 99 (74%) were gram positive bacteria. The most common gram positive and gram negative bacteria were S. epidermidis, 51 (38%) and E. coli, 23 (17%), respectively. S. epidermidis showed the highest resistance to penicillin G and roxithromycin (90% each) followed by cefotaxime, cefuroxime, imipenem, oxacillin, and piperacillin-tazobactam (88% each), ampicillin-sulbactam (87%), meropenem (86%), and gentamicin (59%). Moreover, S. epidermidis showed raising levels of resistance to amikacin, gentamicin, ciprofloxacin, levofloxacin, moxifloxacin, and cotrimoxazol. Gram positive bacteria showed less or no resistance to daptomycin, linezolid, teicoplanin, and vancomycin. E. coli showed the highest resistance to ampicillin (74%) followed by ampicillin-sulbactam (52%) and piperacillin (48%). Furthermore, increasing levels in resistance to ampicillin, ampicillin-sulbactam, piperacillin, and cefuroxime were observed over the years. Encouragingly, E. coli showed significantly declining trends of resistance to ciprofloxacin and levofloxacin, and no resistance to amikacin, colistin, fosfomycin, gentamicin, imipenem, piperacillin-tazobactam, and tobramycin. In conclusion, this study demonstrates that gram positive bacteria were the leading causes of neonatal sepsis. Bacterial isolates were highly resistant to first and second-line empiric antibiotics used in this hospital. The high levels of antibiotic resistance patterns highlight the need for modifying empiric treatment regimens considering the most effective antibiotics. Periodic surveillance in hospital settings to monitor changes in pathogens, and antibiotic resistance patterns is crucial in order to implement optimal prevention and treatment strategies.