The role of C-reactive protein in the evaluation and management of infants with suspected sepsis

Relevance of enteroviruses in neonatal meningitis

INTRODUCTION

Enterovirus (EV) infections are the most frequent infections in the neonatal period and in many cases lead to hospital admission of the newborn (NB). The aim of this study was to determine the incidence of EV in the etiology of neonatal meningitis and to define the clinical characteristics of newborns with EV meningitis.

MATERIAL AND METHOD

Retrospective observational cohort study. Including 91 NBs with meningitis and gestational age greater than 34 weeks gestational age (GA) attended in our center over a period of 16 years.

RESULTS

The percentage of NBs with EV meningitis was higher than that of NBs with bacterial meningitis (BM) and accounted for 78% (n=71). Half of the NBs with EV infection had a history of epidemic environment among their caregivers. Fever was present in 96% of cases as a clinical sign and, in general, sensory disturbances represented the main neurological alterations. Antibiotics (ATB) were given to 71.4% of patients with EV infection. Detection of EV in CSF samples showed a high sensitivity for the diagnosis of EV meningitis. The most frequently implicated EV types were echovirus 11, coxsackievirus B5, echovirus 18, 25 and 7.

CONCLUSIONS

The results of this series show that enterovirus infection is a common cause of neonatal meningitis. These data underline the importance of rapid EV testing of infants with suspected meningitis. This allows early diagnosis and reduces antibiotic treatment, hospitalization time and related costs.

Biochemical surveillance versus clinical observation of term infants born after prolonged rupture of membranes - A quality assurance initiative

AIM

To examine whether biochemical surveillance vs clinical observation of term infants with prolonged rupture of membranes as a risk factor for early-onset sepsis is associated with differences in patient trajectories in maternity and neonatal intensive care units.

METHODS

A retrospective study of live-born infants with gestational age ≥ 37 + 0 weeks born after prolonged rupture of membranes (≥24 h) in four Norwegian hospitals 2017-2019. Two hospitals used biochemical surveillance, and two used predominantly clinical observation to identify early-onset sepsis cases.

RESULTS

The biochemical surveillance hospitals had more C-reactive protein measurements (p < 0.001), neonatal intensive care unit admissions (p < 0.001) and antibiotic treatment (p < 0.001). Hospitals using predominantly clinical observation initiated antibiotic treatment earlier in infants with suspected early-onset sepsis (p = 0.04) but not in infants fulfilling early-onset sepsis diagnostic criteria (p = 0.09). There was no difference in antibiotic treatment duration (p = 0.59), fraction of infants fulfilling early-onset sepsis diagnostic criteria (p = 0.49) or length of hospitalisation (p = 0.30), and no early-onset sepsis-related adverse outcomes.

CONCLUSION

The biochemical surveillance hospitals had more C-reactive protein measurements, but there was no difference in antibiotic treatment duration, early-onset sepsis cases, length of hospitalisation or adverse outcomes. Personnel resources needed for clinical surveillance should be weighed against the limitation of potentially painful procedures.

Time from symptom onset may influence C-reactive protein utility in the diagnosis of bacterial infections in the NICU

BACKGROUND

Taking into account the timing of C-reactive protein (CRP) testing may improve the performance of the test in diagnosing bacterial infections in the neonatal intensive care unit (NICU). We aimed to examine the yield of CRP, relative to time from symptoms onset.

METHODS

Enrolled were all NICU patients, for whom CRP was obtained as part of a sepsis workup. The time of symptoms onset and of blood draw was recorded. Patients were classified into bacterial and non-bacterial groups according to the National Healthcare Safety Network (NHSN) guidelines. The performance of CRP, CRP velocity, and CRP obtained before or after 6 hours from symptoms onset, was evaluated by receiver-operating characteristic (ROC) curve. Test characteristics were calculated using formulas based on Bayes' theorem.

RESULTS

Of 129 infants enrolled in the study, 21(16%) had a bacterial infection. A single CRP test and CRP velocity performed similarly in diagnosing bacterial infection, with area under ROC curve of 0.75 (95%CI: 0.61-0.89) and 0.77 (95% CI:0.66-0.88), respectively. The optimal cut-off value for a CRP test obtained <= 6 hours from symptoms onset was 1 mg/dL, whereas the optimal cut-off > 6 hours was 1.5 mg/dL. Using the optimal cut-off values increased the pre-test probability of 16%, to a post-test probability of 35-38%. For infants whose birth weight was < 1000 g, CRP performed poorly.

CONCLUSIONS

The optimal CRP cut-off used in the diagnosis of bacterial infections in NICU patients varies by the time from symptom onset. A "negative" CRP may support a clinical decision to stop empiric antimicrobial therapy, for infants whose blood cultures remain sterile.

Biomarkers of Neonatal Sepsis: From Being Mere Numbers to Becoming Guiding Diagnostics

Neonatal sepsis is a common cause of neonatal morbidity and mortality. The diagnosis of newborn sepsis is still difficult. Different early objective diagnostic tests or specific signs and symptoms, particularly in preterm infants, make it difficult to diagnose neonatal sepsis. This review article describes biomarkers and their role in the early diagnosis, treatment, and prognosis of neonatal sepsis. It also explores the possible advances and future prospects of these biomarkers. An ideal sepsis biomarker will not only help in the guidance of the use of antibiotics when not needed but also the duration of the course of antibiotics if sepsis is proven. It should also have high sensitivity, specificity, positive predictive value, and negative predictive value. These biomarkers hold a promising position in the management of neonatal sepsis and translate into use in clinical settings. Metabolomics, a diagnostic method based on detecting metabolites found in biological fluids, may open new possibilities in the management of critically ill newborns.

Bacteriological Profile and Predictors of Death Among Neonates With Blood Culture-Proven Sepsis in a National Hospital in Tanzania-A Retrospective Cohort Study

BACKGROUND

Neonatal sepsis is still a major cause of death and morbidity in newborns all over the world. Despite substantial developments in diagnosis, treatments, and prevention strategies, sepsis remains a common problem in clinical practice, particularly in low-resource countries.

METHODS

A retrospective cohort study of 238 neonates with positive blood culture-proven sepsis (in Muhimbili National Hospital) was conducted from January 2019 to December 2020. The outcomes of hospitalization were survival and death.

RESULTS

In total, 45.4% mortality resulted from 238 neonates who had sepsis exclusively based on blood culture positivity. A significant association was found between very low birth weight (VLBW), hyperglycemia, mechanical ventilation, and high neonatal mortality. Among the different clinical presentations of neonatal sepsis, lethargy, vomiting, and respiratory distress were found to be frequently associated with neonatal mortality. Furthermore, sepsis with Gram-negative bacteria and early-onset sepsis were also associated with high neonatal mortality. Of the 108 neonatal deaths, the largest proportion (40%) was observed with Staphylococcus aureus, and the remaining 38% was caused by Klebsiella, 14% by Escherichia coli, 5% by Pseudomonas, 4% by Acinetobacter, and 2% by Streptococcus. No neonatal deaths from Serratia infection were observed. The overall resistance of isolated organisms to the recommended first-line antibiotics was 84% for ampicillin and 71.3% for gentamicin. The resistance pattern for the recommended second-line antibiotics was 76.2% for ceftriaxone, 35.9% for vancomycin, and 17.5% for amikacin.

CONCLUSION

VLBW, early-onset sepsis, clinical and laboratory parameters like lethargy, vomiting, and hyperglycemia, sepsis with Gram-negative bacteria, and being on mechanical ventilation are strong predictors of death in neonatal sepsis. In addition, this study discovered extraordinarily high resistance to conventional antibiotics. These findings give light on the crucial aspects to consider in preventing this disease and poor outcomes.

Aptamer-based biosensors for the diagnosis of sepsis

Sepsis, the syndrome of infection complicated by acute organ dysfunction, is a serious and growing global problem, which not only leads to enormous economic losses but also becomes one of the leading causes of mortality in the intensive care unit. The detection of sepsis-related pathogens and biomarkers in the early stage plays a critical role in selecting appropriate antibiotics or other drugs, thereby preventing the emergence of dangerous phases and saving human lives. There are numerous demerits in conventional detection strategies, such as high cost, low efficiency, as well as lacking of sensitivity and selectivity. Recently, the aptamer-based biosensor is an emerging strategy for reasonable sepsis diagnosis because of its accessibility, rapidity, and stability. In this review, we first introduce the screening of suitable aptamer. Further, recent advances of aptamer-based biosensors in the detection of bacteria and biomarkers for the diagnosis of sepsis are summarized. Finally, the review proposes a brief forecast of challenges and future directions with highly promising aptamer-based biosensors.

C-reactive protein in infants with no evidence of early-onset sepsis

OBJECTIVE

C-reactive protein (CRP) is one of the most extensively used biomarkers in the investigation of early-onset sepsis (EOS). Current evidence suggests the normal kinetics of serum CRP should be considered when evaluating infants for presumable EOS. The current study aimed to evaluate the CRP kinetics, and to establish percentiles in a cohort of term and near-term infants with no evidence of confirmed or clinical EOS.

METHODS

We retrospectively reviewed the medical records of all neonates ≥34 weeks' gestation screened for presumable EOS, from January until December 2019. We also recorded the clinical management, the blood culture, serial CRP, and white blood cell count analysis of each infant. All infants that received antibiotics for confirmed or presumed EOS were excluded from the analysis.

RESULTS

During the study period, 145 infants were detected; 109 (75%) term and 36 (25%) preterm. Term infants had significantly higher median values of CRP at all time points in comparison to preterm infants. Term infants presented a significant rise of CRP at 24 and 36 h, with a peak at 24 h (median 4 (range 1-12) mg/L). Preterm infants had a significant rise of CRP at 24 but not at 36 h, with a peak at 24 h (median 3 (range 1-9) mg/L). In term infants, the 90th percentile of CRP at 24 h was 10.80 mg/L and the 97th percentile was 12.00 mg/L. In preterm infants, the 90th percentile of CRP at 24 h was 7.60 mg/L and the 97th percentile was 8.00 mg/L.

CONCLUSIONS

Term and near-term asymptomatic infants had a rise in CRP during the first days of life. Term infants had a more pronounced CRP response in comparison to preterm infants.

Predictors of serious bacterial infections using serum biomarkers in an infant population aged 0 to 90 days: a prospective cohort study

OBJECTIVE

Young febrile infants represent a vulnerable population at risk for serious bacterial infections (SBI). We aimed to evaluate the diagnostic accuracy of components of the complete blood count in comparison with C-reactive protein (CRP) to predict SBI among febrile infants.

DESIGN AND SETTING

Prospective cohort study conducted in a tertiary emergency department between December 2018 and November 2019.

PATIENTS

We included febrile infants ≤3 months old with complete blood count results. We analysed their white blood cell count (WBC), absolute neutrophil ratio (ANC), neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio, mean platelet volume to platelet count ratio, and compared these to the performance of CRP.

MAIN OUTCOME MEASURES

SBIs were defined as urinary tract infection, bacteraemia, bacterial meningitis, sepsis, pneumonia, skin and soft tissue infection, bacterial enteritis, septic arthritis or osteomyelitis.

RESULTS

Of the 187 infants analysed, 54 (28.9%) were diagnosed with SBI. Median values of WBC, ANC, NLR and CRP were significantly higher in infants with SBI: WBC (13.8 vs 11.4×10⁹/L, p=0.004), ANC (6.7 vs 4.1×10⁹/L, p<0.001), NLR (1.3 vs 0.9, p=0.001) and CRP (21.0 vs 2.3 mg/L, p<0.001), compared with those without. CRP had the best discriminatory values for SBI, with area under the curve (AUC) of 0.815 (95% CI 0.747 to 0.883), compared with WBC, ANC and NLR. A predictive model consisting of WBC, ANC and NLR in combination with clinical parameters, had an AUC of 0.814 (95% CI 0.746 to 0.883). There was increased discriminative performance when this predictive model was combined with CRP, (AUC of 0.844, 95% CI 0.782 to 0.906).

CONCLUSION

In young febrile infants, CRP was the best discriminatory biomarker for SBI. WBC, ANC and NLR when used in combination have potential diagnostic utility in this population.

Serum C-Reactive Protein Levels in Healthy Neonates in Different Gestational and Postnatal Ages

There is paucity of normative data on serum C-reactive protein (CRP) in neonates. In Part I of study, we compared CRP in healthy neonates (from 28°/7 weeks to 416/7 weeks of gestation) between various gestational and postnatal age groups in first week. We planned recruitment of 50 participants each in 'term', 'late preterm' and 'moderate-to-very preterm' groups, equally divided in '24-95 h' and '96-168 h' postnatal age sub-groups. In Part II of study, we assayed CRP weekly in moderate-to-very preterm neonates until day 28 to evaluate its trend. Among 154 subjects, term neonates had higher CRP, with highest values among term infants aged 24-95 h. Barring postnatal age, maternal/perinatal factors did not affect CRP levels. CRP did not change significantly over 28 days in moderate-to-very preterm neonates. In conclusion, serum CRP in healthy neonates is highest among term infants aged 24-95 h and does not vary significantly in the first month of life among moderate-to-very preterm infants.

Effect of probiotics on C-reactive protein levels in preterm infants: Secondary analysis of a randomized controlled trial

BACKGROUND

Excessive inflammation is associated with adverse outcomes in preterm infants. C- reactive protein (CRP) is a marker of inflammation/infection. Probiotics have anti-inflammatory properties. Randomized controlled trials (RCTs) in preterm infants have not reported effect of probiotics on CRP.

AIM

To evaluate effect of probiotics on CRP in preterm infants who had participated in a RCT of Bifidobacterium breve (B. breve) m-16v.

METHODS

Data on all infants (GA <33 weeks, n = 159) enrolled in the RCT was analyzed. For study purpose, CRP <15 mg/L and ≤10 mg/L was considered normal for the first week, and thereafter respectively. Mixed logistic regression modelling was used to assess probiotic effect on CRP levels.

RESULTS

There were 1579 CRP measurements (Probiotic: 851 vs. Placebo: 728). Baseline characteristics and number [Median (IQR)] of CRP estimations per infant [l0 (5, 20) vs. 10 (6, 17), p = 0.861] were comparable between probiotic vs. placebo group. There was no significant difference in the proportion of infants with high CRP over time (treatment by weekly time points interaction, p = 0.187), and across all time points between probiotic and placebo group (adjusted OR: 1.62, 95% CI: 0.91-2.88, p = 0.102)CONCLUSION:B. breve m-16v did not decrease CRP levels in preterm infants born <33 weeks.

C-Reactive Protein (CRP) levels in neonatal meningitis in England: an analysis of national variations in CRP cut-offs for lumbar puncture

Background

Recent National Institute for Health and Care Excellence (NICE) CG149 guidelines suggest considering performing a lumbar puncture (LP) to investigate for meningitis in early-onset sepsis in a neonate when a C-reactive protein (CRP) level >10mg/L, but the evidence for this recommendation is poorly defined.

Methods

Data on trust-wide LP protocols, neonatal meningitis incidence, lumbar punctures, and CRP levels seen in cases of neonatal meningitis were asked of all 137 trusts in England that recorded a birth in 2017. Our local Kingston Hospital data on every LP performed was obtained to estimate the specificity of CRP rises.

Results

73/123 (59.3%) of trusts follow the NICE CG149 recommendation of considering an LP if the CRP >10mg/L. The national incidence of neonatal meningitis was 0.467/1,000 births, and an LP was performed in 1.37% of all babies, which was significantly higher in trusts considering the CRP > 10mg/L cut-off. A CRP > 10mg/L cut-off sensitivity was 88.9% based on the highest CRP level 4 days around the LP from national data of 199 cases; specificity was 78.8% based on our single-unit analysis.

Conclusions

Proposing a universal CRP > 10mg/L cut-off for a lumbar puncture has been counter-productive in England. Following it generates significantly more LPs, to the point that 40.7% of trusts have chosen not to follow it. It also has poor sensitivity missing over 11% of meningitis. We therefore do not recommend a universal cut-off, rather considering the whole clinical picture (including prematurity) when considering whether to do an LP.

A Case of Upper Limb Osteomyelitis and Septic Arthritis Presenting as Pseudoparalysis in a Two-Week-Old

Pseudoparalysis presenting in infants is a rare manifestation, where infection and trauma are the principle differentials. We present a case of a two-week-old baby boy with pseudoparalysis who was initially diagnosed as Erb's palsy when presented in the emergency department and later re-presented with signs of sepsis. A later diagnosis of osteomyelitis of the humerus and septic arthritis of the shoulder was made. Despite antibiotic therapy and surgical drainage, the proximal epiphysis of his humerus remains abnormal; however, he has no apparent functional deficit of his right arm at four-year follow-up.

Comparison of Four Days Versus Seven Days Duration of Antibiotic Therapy for Neonatal Pneumonia: A Randomized Controlled Trial

OBJECTIVE

To compare the effect of 4 day course (study group) with 7 day course (control group) of antibiotic treatment in neonatal pneumonia, on treatment success rate.

METHODS

This randomized controlled trial was conducted in a tertiary teaching hospital. Seventy, term and near-term neonates with pneumonia who had clinical remission by 48 h of antibiotic therapy were included. The neonates were randomized to receive a total of 4 d of antibiotics (Group 1) or 7 d of antibiotics (Group 2). The outcome measure was treatment failure in each group within 3 d of discharge.

RESULTS

The treatment success rate of both the groups was 100%. There was a significant reduction in the duration of hospital stay (p < 0.001), antibiotic usage (p < 0.001), and cost (p < 0.001) in the 4 d group. On follow up till 28 d of enrollment, no infective morbidity was found in either group.

CONCLUSIONS

For term and near-term neonates who become clinically asymptomatic within 48 h of antibiotic therapy, 4 d of antibiotic therapy is as effective and safe as 7 d of antibiotic therapy, with significant reduction in hospital stay, antibiotic usage and cost.

The usefulness of C-reactive protein in predicting malaria parasitemia in a sub-Saharan African region

BACKGROUND

Malaria remains a leading cause of childhood mortality in sub-Saharan Africa. Identifying patients who are at risk for severe manifestations at presentation still remains challenging. This study examines whether a semi-quantitative test on C-Reactive Protein (CRP) could be useful for rapidly predicting the presence or absence of malarial parasitemia in febrile children.

METHOD

Data were collected from children with fever or a history of fever at the Agogo Presbyterian Hospital in the Ashanti Region of Ghana. Haematological measurements, microscopic detection of plasmodium species and semi-quantitative CRP measurements with a membrane-based immunoassay for whole blood were performed. CRP was classified as positive when the measured level was ≥ 10 mg/l.

RESULTS

During 548 visits, thick blood film results could be obtained from 541 patients, 270 (49.3%) yielded parasitemia with Plasmodium spp. Whereas malaria parasites were detected in only a few patients (7.1%) with normal CRP levels (< 10mg/l), more than a half of patients with an increased CRP concentration (≥ 10 mg/l) were parasite positive (OR 14.5 [CI 4.4-47.6], p<0.001). Patients with increased CRP levels had more than an eight-fold likelihood for parasitemia after correction for other parameters (adjusted OR 8.7 [CI 2.5-30.5], p<0.001). Sensitivity, specificity as well as positive predictive and negative predictive values of CRP for malaria were 99.3% (CI 96.2%-100%), 9.2% (CI 6.4%-12.8%), 31.7% (CI 27.4%-36.1%) and 97.0% (CI 84.2%-99.9%), respectively.

CONCLUSION

The semi-quantitative method of measuring CRP is cheap, rapid and easy to perform but not useful in predicting parasitemia and malaria. However, due to its high negative predictive value, it could have a role in identifying those patients unlikely to be presenting with clinical malaria.

Mean platelet volume in preterm: a predictor of early onset neonatal sepsis

Background: Early onset sepsis (EOS) is potentially life-threatening problem especially in preterm. EOS diagnosis is challenging due to its non-specific signs and laboratory tests. Mean platelet volume (MPV) has been used as predictor of many inflammatory diseases.Objectives: To assess the correlation between serial MPV measurement and EOS occurrence in preterm infants and to determine MPV effectiveness in combination with C reactive protein (CRP) to diagnose EOS and mortality prediction.Methods: The study was carried out on 95 preterm infants with antenatal risk factor for EOS. Blood samples were taken for complete blood count (CBC) including MPV evaluated at birth (cord blood) and at 72 h of life. CRP analyzed on days 1 and 3, subsequently patients were identified in two groups: sepsis (n = 28) and no-sepsis (n = 67).Results: MPV was significantly higher on both day 1 (10.23 ± 0.92) fl and day 3 (10.77 ± 1.16) fL in the sepsis group compared with no-sepsis (8.11 ± 0.29) fl and (8.53 ± 0.42) fl, respectively. MPV of 8.6 fL was identified as cut off value in patients probably resulting in sepsis with a sensitivity of 97.14% and a specificity of 100%. MPV of 10.4 fl was determined as cut off value in patients possibly resulting in death with a sensitivity of 70% and a specificity of 82.5%. The combination of both MPV and CRP on day 1 resulted in improving performance of MPV with higher negative predictive value (93.1%) and higher sensitivity (80%).Conclusion: High cord blood and day 3 MPV can be used as surrogate marker for prediction of EOS and associated mortality in preterm neonates.

Use of biomarkers in pediatric sepsis: literature review

Despite advances in recent years, sepsis is still a leading cause of hospitalization and mortality in infants and children. The presence of biomarkers during the response to an infectious insult makes it possible to use such biomarkers in screening, diagnosis, prognosis (risk stratification), monitoring of therapeutic response, and rational use of antibiotics (for example, the determination of adequate treatment length). Studies of biomarkers in sepsis in children are still relatively scarce. This review addresses the use of biomarkers in sepsis in pediatric patients with emphasis on C-reactive protein, procalcitonin, interleukins 6, 8, and 18, human neutrophil gelatinase, and proadrenomedullin. Assessment of these biomarkers may be useful in the management of pediatric sepsis.

Comparative diagnostic test evaluation of serum procalcitonin and C-reactive protein in suspected bloodstream infections in children with cancer

PURPOSE

To compute diagnostic test properties of C-reactive protein (CRP) and serum procalcitonin (PCT) levels in bloodstream infections in children with cancer and suspected sepsis, in comparison with blood culture as the gold standard.

METHODOLOGY

Consecutive paediatric cancer patients, aged ≤14 years, with clinically suspected bloodstream infections were evaluated with blood culture and assay of PCT and CRP levels. Blood culture was taken as the gold standard for comparison. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), likelihood ratio (LR) and receiver operating characteristic (ROC) with area under ROC curve (AUC) were calculated to assess the diagnostic test performance for PCT and CRP.Results/Key findings. The ROC curve for PCT was better than that for CRP, with an AUC of 0.751 for PCT at a cut-off of 2.25 ng ml-1. The AUC for CRP was 0.638 at a cut-off of 8.0 mg dl-1. Among the three cut-off values of PCT selected from the ROC curve applicable to the patients under study, the cut-off value of ≥0.49 ng ml-1 had the maximum sensitivity of 81.4 % and an NPV of 94.67 %; ≥2.25 ng ml-1 had a sensitivity and specificity of 65.12 and 71.6 %, respectively, and ≥6.47 ng ml-1 had a maximum specificity of 82.10 %. For CRP, the cut-off value of ≥5.3 mg dl-1 had the maximum sensitivity of 72.09 %; ≥8.0 mg dl-1 had a sensitivity and specificity of 58.14 and 68.09 %, respectively, and ≥8.4 mg dl-1 had the maximum specificity of 70.04 %.

CONCLUSION

PCT is a better serological marker for excluding bloodstream infections than CRP. The cut-off value of 0.49 ng ml-1 with a negative predictive value of 94.67 % will be ideal in a clinical setting of immune-compromised children with suspected sepsis.

Pathway cross-talk network analysis identifies critical pathways in neonatal sepsis

BACKGROUND

Despite advances in neonatal care, sepsis remains a major cause of morbidity and mortality in neonates worldwide. Pathway cross-talk analysis might contribute to the inference of the driving forces in bacterial sepsis and facilitate a better understanding of underlying pathogenesis of neonatal sepsis.

OBJECTIVE

This study aimed to explore the critical pathways associated with the progression of neonatal sepsis by the pathway cross-talk analysis.

METHODS

By integrating neonatal transcriptome data with known pathway data and protein-protein interaction data, we systematically uncovered the disease pathway cross-talks and constructed a disease pathway cross-talk network for neonatal sepsis. Then, attract method was employed to explore the dysregulated pathways associated with neonatal sepsis. To determine the critical pathways in neonatal sepsis, rank product (RP) algorithm, centrality analysis and impact factor (IF) were introduced sequentially, which synthetically considered the differential expression of genes and pathways, pathways cross-talks and pathway parameters in the network. The dysregulated pathways with the highest IF values as well as RP<0.01 were defined as critical pathways in neonatal sepsis.

RESULTS

By integrating three kinds of data, only 6919 common genes were included to perform the pathway cross-talk analysis. By statistic analysis, a total of 1249 significant pathway cross-talks were selected to construct the pathway cross-talk network. Moreover, 47 dys-regulated pathways were identified via attract method, 20 pathways were identified under RP<0.01, and the top 10 pathways with the highest IF were also screened from the pathway cross-talk network. Among them, we selected 8 common pathways, i.e. critical pathways.

CONCLUSIONS

In this study, we systematically tracked 8 critical pathways involved in neonatal sepsis by integrating attract method and pathway cross-talk network. These pathways might be responsible for the host response in infection, and of great value for advancing diagnosis and therapy of neonatal sepsis.

Characteristics of neonates with culture-proven bloodstream infection who have low levels of C-reactive protein (≦10 mg/L)

Background

Elevated C-reactive protein (CRP) level is widely used in clinical practice as a marker to distinguish between neonates with or without sepsis. However, some neonates with bacteremia have a CRP level within the normal range and they are not well characterized.

Methods

All episodes of neonatal culture-proven bloodstream infections (BSIs) between July 2004 and June 2012 were enrolled. Patients characteristics were compared for three CRP groups (low, ≤ 10 mg/L; intermediate, 11–100 mg/L; and high, > 100 mg/L) using the Chi-square test and one-way ANOVA. The sepsis-attributable mortality rates were compared using logistic regression analyses.

Results

Of 986 episodes of neonatal BSI, 247 (25.1 %) had CRP ≤10 mg/L at the onset of clinical sepsis. In the low CRP group, patients had lower gestational age and birth weight, and an earlier occurrence of BSI. Patients with underlying gastrointestinal pathology, renal disorders, cholestasis, and pulmonary hypertension had a non-significant elevated CRP level at the onset of sepsis. In the blood culture of the low CRP group, coagulase-negative staphylococci (CoNS) were relatively more common (55.9 %, p < 0.001) than the other two groups, although one-fourth were infected with gram-negative bacilli (19.0 %), fungi (2.8 %), or polymicrobial pathogens (3.6 %). Of the BSIs with initial low CRP, 29.1 % were treated with inadequate antibiotics, 13.0 % progressed to septic shock, and 5.3 % had infectious complications. The sepsis-attributable mortality rate was lower in the low CRP group (4.9 %) than in the high CRP group (13.6 %).

Conclusions

A considerable proportion of neonatal BSIs had a normal or low initial CRP level (≤10 mg/L), which was more likely to occur in low birth weight or extremely preterm infants, those with earlier onset of sepsis, and those infected with CoNS. Plasma CRP level should not be used to rule out severe culture-proven sepsis or guide the empirical choice of antibiotics.

Markedly raised levels of C-reactive protein are associated with culture-proven sepsis or necrotising enterocolitis in extremely preterm neonates

AIM

A serious inflammatory process is suspected when C-reactive protein (CRP) is very high, and we established the causes and outcomes when CRP was >100 mg/L in neonates.

METHODS

We retrospectively reviewed all 277 episodes where CRP exceeded 100 mg/L between January 2007 and December 2011 at a tertiary neonatal unit.

RESULTS

Of the 6025 neonates admitted during the study period, 258 had CRP >100 mg/L at least once. The overall mortality rate was 44/258 (17%); 36 died within 7 days of CRP >100 mg/L, and 34 were extremely preterm infants. CRP exceeded 100 mg/L in 106 infants within the first 3 days of life - 74 term, 25 preterm and seven extremely preterm - with no infection identified in 81%. In contrast, infections were found in 87% of the 171 episodes from day four of life - 129 extremely preterm, 23 preterm and 19 term - predominantly coagulase-negative staphylococcus sepsis and necrotising enterocolitis.

CONCLUSION

Markedly elevated CRP in the first 3 days of life was most likely to affect term neonates (74/106) with no infectious cause (81%). However, CRP >100 mg/L from the fourth day of life was most likely to affect extremely preterm neonates (129/171) and have an infectious cause (87%).

Early onset neonatal sepsis: diagnostic dilemmas and practical management

Early onset neonatal sepsis is persistently associated with poor outcomes, and incites clinical practice based on the fear of missing a treatable infection in a timely fashion. Unnecessary exposure to antibiotics is also hazardous. Diagnostic dilemmas are discussed in this review, and suggestions offered for practical management while awaiting a more rapidly available 'gold standard' test; in an ideal world, this test would be 100% sensitive and 100% specific for the presence of organisms.

A mathematical algorithm for detection of late-onset sepsis in very-low birth weight infants: a preliminary diagnostic test evaluation

OBJECTIVE

To study the diagnostic ability of RALIS (computerized mathematical algorithm and continuous monitoring device) to detect late onset sepsis among very low birth weight preterm neonates.

METHODS

Randomly chosen 24 very low birth weight infants with proven sepsis were compared to 22 infants without sepsis. The clinical parameters were retrospectively collected from the medical records. The ability of RALIS to detect late onset sepsis was calculated.

RESULTS

RALIS positively identified 23 of the 24 infants with sepsis (sensitivity 95.8%). It indicated sepsis alert median 2.0 days earlier than clinical suspicion. A false positive alert was indicated in 23% (5/22) infants. The specificity, and positive and negative predictive ability of RALIS were 77.3%. 82.1% and 94.4%, respectively.

CONCLUSION

RALIS may aid in the early diagnosis of late onset sepsis in very low birth weight preterm infants.

Detecting infection in neonates: promises and challenges of a salivary approach

Premature newborns present unique challenges for the caregiver. Their clinical fragility and immature immune system places them at increased risk for bacterial and viral infections. Current clinical standard of care mandates invasive phlebotomy to assess an infant for an infection. However, serial blood draws can lead to blood transfusions and the infliction of noxious stimuli to this vulnerable population. Salivary screening for common neonatal morbidities, such as infections, could vastly improve the care for these infants and positively affect their long-term clinical outcomes. Recent technological advancements have improved our ability to detect thousands of proteins and/or microbes from a single salivary sample, making noninvasive assessment in neonates a possibility. This article reviews the clinical applications and challenges associated with integrating salivary analysis for infectious surveillance into the neonatal population.

Comparative evaluation of C-reactive protein in peripheral blood of patients with healthy gingiva, gingivitis and chronic periodontitis: A clinical and particle-enhanced turbidimetric immuno-analysis

Background:

C-reactive protein (CRP), an acute-phase protein monitored as a marker of inflammatory status, has been identified as a major risk factor for various systemic diseases. It is a reliable marker to infectious burdens and/or inflammation. The aim of this study was to compare and evaluate the systemic levels of CRP in the serum sample of the patients with healthy gingiva, gingivitis, and chronic periodontitis.

Materials and Methods:

A total of 60 systemically healthy patients were selected and divided into three groups: Patients with healthy gingiva (Group A), patients with generalized gingivitis (Group B) and patients with chronic periodontitis (Group C). Peripheral blood was collected and high-sensitive (hs)-CRP levels were estimated in the serum samples by using the particle-enhanced turbidimetric immuno-assay technique using a commercially available kit.

Results:

The mean hs-CRP level in Group A recorded was 0.437 ± 0.216, Group B was 0.771 ± 0.384 and Group C was 2.285 ± 0.381. A significantly elevated hs-CRP level was found in Group C as compared with Group B and A (P < 0.05). However, a moderate, but statistically significant increase in the hs-CRP levels was observed in Group B as compared with Group A (P < 0.05). The percentage of patients with elevated levels of hs-CRP >2 mg/l was significantly higher in Group C.

Conclusion:

The patients with chronic periodontitis demonstrated a mean hs-CRP levels higher than the patients with gingivitis and with healthy gingiva. Furthermore, with the increasing inflammation, the hs-CRP levels increased proportionately.

Management of neonatal sepsis at Muhimbili National Hospital in Dar es Salaam: diagnostic accuracy of C-reactive protein and newborn scale of sepsis and antimicrobial resistance pattern of etiological bacteria

Background

We determined the accuracy of Rubarth’s newborn scale of sepsis and C- reactive protein in diagnosing neonatal sepsis and assessed antimicrobial susceptibility pattern of etiological bacteria.

Methods

This cross sectional study was conducted at Muhimbili National Hospital in Dar es Salaam, Tanzania between July 2012 and March 2013. Neonates suspected to have sepsis underwent physical examination using Rubarth’s newborn scale of sepsis (RNSOS). Blood was taken for culture and antimicrobial sensitivity testing, full blood picture and C – reactive protein (CRP) performed 12 hours apart. The efficacy of RNSOS and serial CRP was assessed by calculating sensitivity, specificity, negative and positive predictive values, receiver operating characteristics (ROC) analysis as well as likelihood ratios (LHR) with blood culture result used as a gold standard.

Results

Out of 208 blood samples, 19.2% had a positive blood culture. Single CRP had sensitivity and specificity of 87.5% and 70.9% respectively, while RNSOS had sensitivity of 65% and specificity of 79.7%. Serial CRP had sensitivity of 69.0% and specificity of 92.9%. Combination of CRP and RNSOS increased sensitivity to 95.6% and specificity of 56.4%. Combination of two CRP and RNSOS decreased sensitivity to 89.1% but increased specificity to 74%. ROC for CRP was 0.86; and for RNSOS was 0.81.

For CRP the LHR for positive test was 3 while for negative test was 0.18, while for RNSOS the corresponding values were 3.24 and for negative test was 0.43.

Isolated bacteria were Klebsiella spp 14 (35%), Escherichia coli 12 (22.5%), Coagulase negative staphlococci 9 (30%), Staphylococcus aureus 4 (10%), and Pseudomonas spp 1 (2.5%). The overall resistance to the WHO recommended first line antibiotics was 100%, 92% and 42% for cloxacillin, ampicillin and gentamicin, respectively. For the second line drugs resistance was 45%, 40%, and 7% for ceftriaxone, vancomycin and amikacin respectively.

Conclusions

Single CRP in combination with RNSOS can be used for rapid identification of neonates with sepsis due to high sensitivity (95.6%) but cannot exclude those without sepsis due to low specificity (56.4%). Serial CRP done 12hrs apart can be used to exclude non-cases. This study demonstrated very high levels of resistance to the first-line antibiotics.

Management of the neonate at risk for early-onset Group B streptococcal disease (GBS EOD): new paediatric guidelines in Belgium

Despite group B streptococcal (GBS) screening in late pregnancy and intrapartum antimicrobial prophylaxis, early-onset sepsis in neonates remains a common source of neonatal morbidity and mortality especially in preterm neonates. The identification of neonates with early-onset sepsis is usually based on perinatal risk factors. Clinical signs are aspecific and laboratory tests are not sensitive. Therefore, many clinicians will overtreat at-risk infants. Inappropriate treatment with antibiotics increases the risk for late-onset sepsis, necrotizing enterocolitis, mortality, and prolongs hospitalisation and costs. In 2003, the Belgian Health Council published guidelines for the prevention of perinatal GBS infections. This report presents the Belgian paediatric management guidelines, which have been endorsed by the Belgian and Flemish societies of neonatology and paediatrics. The most imported changes in the 2014 guidelines are the following: recommendations for a lumbar puncture; clarification of normal spinal fluid parameters and blood neutrophil indices corrected for gestation age; specific timing for diagnostic testing after birth; no indication for diagnostic testing in asymptomatic newborns unless additional risk factors; a revised algorithm for management of neonates according to maternal and neonatal risk factors; and premature infants described as those below 35 weeks instead of 37 weeks. The guidelines were made on the basis of the best evidence and on expert opinion when inadequate evidence exists.

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.

C-reactive protein: a marker of neonatal stress?

AIM

To assess whether blood values of C-reactive protein (CRP) in healthy term newborns, are influenced by stress.

MATERIAL AND METHODS

Since different types of delivery (vaginal delivery [VD], emergency C-section [EMCS] and elective C-section [ELCS]) are notoriously characterized by different levels of stress for the baby, these three groups were used as models of different levels of stress. The mean CRP values of the three groups obtained in the first hours of life were compared.

RESULTS

We retrieved 1012 babies. Median values (3rd-97th ct) were: 0.05 (0.01-0.46), 0.17 (0.02-1.54), 0.30 (0.04-1.77), 0.43 (0.05-1.31), 0.40 (0.04-1.13) at 12, 24, 48, 72 and 96 h, respectively. Mean values in babies born after VD were statistically higher than those born after C-section, and higher CRP values were present in EMCS with respect to ELCS.

CONCLUSION

This study described normal blood CRP values in a wide population of term babies. An influence of the type of delivery on blood CRP is evident, and this may be explained by the different amount of perinatal stress induced by anyone of the three types of delivery we considered.

Neonatal infectious diseases: evaluation of neonatal sepsis

Neonatal sepsis remains a feared cause of morbidity and mortality in the neonatal period. Maternal, neonatal, and environmental factors are associated with risk of infection, and a combination of prevention strategies, judicious neonatal evaluation, and early initiation of therapy are required to prevent adverse outcomes. This article reviews recent trends in epidemiology and provides an update on risk factors, diagnostic methods, and management of neonatal sepsis.

Time course of C-reactive protein and inflammatory mediators after neonatal surgery

OBJECTIVE

To characterize the perioperative course of C-reactive protein (CRP) and inflammatory mediators in neonates ≤44 weeks' corrected gestational age.

STUDY DESIGN

Prospective study of CRP and inflammatory mediators interleukin (IL)-1β, IL-6, IL-8, IL-10, and tumor necrosis factor-α in 55 neonates undergoing thoracic or abdominal surgery.

RESULTS

In the absence of infection, CRP increased after surgery, peaking on post-operative day 2. The perioperative patterns of CRP differed by diagnosis and inflammatory state. Surgery alone did not cause an increase in CRP because in 13 of 55 infants (24%), CRP remained <1.0 mg/dL at all time points. For thoracic procedures, patent ductus arteriosus ligation showed the least post-operative increase in CRP, and patients undergoing repair of congenital diaphragmatic hernia or tracheoesophageal fistula had a greater response. Abdominal procedures with low CRP response included repair of imperforate anus and pyloric stenosis, while gastroschisis repair and bowel reanastomosis after necrotizing enterocolitis were accompanied by a robust CRP response. IL-6 concentrations peaked on post-operative day 1 and correlated with the post-operative day 2 CRP peak (r=0.398, P=.004). The additional inflammatory mediators measured were not informative.

CONCLUSIONS

The range and time course of perioperative CRP differ by diagnosis. Serial measurements may be more informative than CRP magnitude.

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.

Urinary neutrophil gelatinase-associated lipocalin is a promising biomarker for late onset culture-positive sepsis in very low birth weight infants

Need for the early identification of sepsis in very low birth weight (VLBW) infants has led to the search for reliable biomarkers. This study aims to determine whether urinary neutrophil gelatinase-associated lipocalin (uNGAL) rises in culture-positive sepsis and, if so, is elevated at the time sepsis is suspected. This is a prospective study of 91 VLBW infants whose urine was collected daily for uNGAL analysis. In 65 episodes of suspected sepsis, four groups were identified: a) culture-positive sepsis; b) single culture positive for Staphylococcus epidermidis; c) and d) negative culture with antibiotic treatment for >or=7 d and <7 d, respectively. Daily means of uNGAL of each group were estimated for comparison. Mean uNGAL in group A (179 ng/mL) was significantly elevated on the day blood culture was drawn (day 0) compared with the mean of healthy VLBW infants (6.5 ng/mL), and to the means in groups B, C, and D (p<0.05). In group A, mean uNGAL was significantly elevated on day 0 and daily for 5 days when compared with that of the day before culture (p<0.05 to <0.005). uNGAL shows promise as an early marker for culture-positive sepsis in VLBW infants.

Early high C-reactive protein in infants with open abdominal wall defects does not predict sepsis or adverse outcome

AIM

To study CRP values and relate it to outcome in infants with antenatal diagnosis of gastroschisis, exomphalos and other surgical conditions.

METHODS

Over five years, infants admitted to our neonatal unit with gastroschisis, exomphalos and other surgical diagnoses were identified. Serum CRP measurements in first 5 days were studied. Group one included 33 gastroschisis patients, group two, 18 exomphalos patients, and group three, 38 patients with other surgical diagnoses. Outcome measures included TPN days, time to full feeds and duration of hospitalization.

RESULTS

Infants with gastroschisis were more premature (36.9 vs 38.1 weeks) with lower birth weights (2515 vs 3078 g), than infants with exomphalos. CRP values on admission in gastroschisis group were significantly higher than exomphalos and other diagnoses groups (33.7 +/- 6.4 vs 8.8 +/- 6.0 vs 5.7 +/- 2.0, respectively, p < 0.05). All blood cultures were sterile. There was no relationship between high CRP and death or adverse outcome (TPN days, time to full feeds or duration of hospitalization) in the gastroschisis group.

CONCLUSION

Infants with gastroschisis exhibit high early CRP, which may not indicate sepsis or adverse outcome. This increase can complicate the assessment of these infants. Clinicians should be aware of this finding as it could inform management decisions in this group.

Procalcitonin values after dialysis is closely related to type of dialysis membrane

BACKGROUND

Infections account for considerable morbidity and mortality in patients with chronic renal failure undergoing hemodialysis (HD). Diagnosis of infection in HD patients is challenging because the most used laboratory parameters may be increased even in the absence of infection. In this setting, procalcitonin (PCT) could be useful for detection of systemic bacterial infections.

METHODS

We measured high sensitivity C Reactive Protein (hsCRP) and PCT serum levels before and immediately after dialysis in 44 HD patients (22 treated with high- and 22 with low-flux membranes), without history of infections.

RESULTS

Patients on HD by high-flux membranes, but not by low-flux membranes, displayed mean PCT values significantly decreased after dialysis (high-flux: 0.50 vs. 0.26 ng/mL, p=0.005; low-flux: 0.41 vs. 0.42 ng/mL, p=0.863). HsCRP levels were unchanged. HsCRP correlated with PCT values both before and after HD only in patients on HD by low-flux membranes (r=0.51 and 0.47 before and after HD respectively; p<0.05).

CONCLUSIONS

Although PCT is considered a sensitive and specific diagnostic and prognostic marker of systemic bacterial infection, we suggest that specific reference ranges might be developed in patient with impaired renal function, also showing that and its clinical usefulness might be limited in patients undergoing HD with high-flux membranes.

Neonatal C-reactive protein value in prediction of outcome of preterm premature rupture of membranes: comparison of singleton and twin pregnancies

AIM

The clinical importance of preterm premature rupture of the membranes (PPROM) is its relationship to maternal and neonatal mortality and morbidity, especially in twin pregnancies. The aim of this study was to determine and compare the role of inflammatory factors as predictors of the PPROM outcome between singleton and twin pregnancies.

METHODS

The medical records of 22 twins delivered between 28 and 34 weeks and complicated by PPROM were reviewed at the Al-Zahra Hospital in Tabriz, Iran. Also among singletons, 55 cases of matched gestational age were randomly selected as a control group. Three laboratory indices of neonatal white blood cell (WBC) count and C-reactive protein (CRP) in the two groups were measured immediately after delivery and the effects of two factors on neonatal outcome were assessed.

RESULTS

In singletons, there was adverse relationship between the mean of WBC count and duration of latency (P = 0.007). Also, a positive relationship between the means of ventilation time and WBC count in second twins was found (P = 0.034). Positive CRP was the main predictor of neonatal intensive care unit admission in both singletons (odds ratio: 4.929, P = 0.042) and first twins (odds ratio: 9.000, P = 0.005). However, positive CRP did not influence the existence of metabolic acidosis or duration of latency in either of the two groups.

CONCLUSION

Neonatal WBC count was a predictor for the duration of latency in singletons and for ventilation time in twins. Positive neonatal CRP was an important factor for the prediction of neonatal intensive care unit admission in both types of pregnancy; its role in twins is clearer than in singletons.

C-reactive protein velocity to distinguish febrile bacterial infections from non-bacterial febrile illnesses in the emergency department

Introduction

C-reactive protein (CRP) is a real-time and low-cost biomarker to distinguish febrile bacterial infections from non-bacterial febrile illnesses. We hypothesised that measuring the velocity of the biomarker instead of its absolute serum concentration could enhance its ability to differentiate between these two conditions.

Methods

We prospectively recruited adult patients (age ≥ 18 years) who presented to the emergency department with fever. We recorded their data regarding the onset of fever and accompanying symptoms. CRP measurements were obtained upon admission. CRP velocity (CRPv) was defined as the ratio between CRP on admission and the number of hours since the onset of fever. Patients were diagnosed by clinical symptoms, blood cultures and imaging studies, and the diagnoses were confirmed by an infectious disease specialist. The efficacy of CRPv as a diagnostic marker was evaluated by using receiver operator curves (ROC). Excluded were patients who did not know the time fever started with certainty, patients with malignancy, patients with HIV infection and patients who had been using antibiotics upon presentation.

Results

Of 178 eligible patients, 108 (60.7%) had febrile bacterial infections (mean CRP: 63.77 mg/L, mean CRPv: 3.61 mg/L/hour) and 70 (39.3%) had non-bacterial febrile illnesses (mean CRP: 23.2 mg/L, mean CRPv: 0.41 mg/L/hour). The area under the curve for CRP and CRPv were 0.783 (95% confidence interval (CI) = 0.717 to 0.850) and 0.871 (95% CI = 0.817 to 0.924), respectively. In a 122-patient subgroup with a CRP level of less than 100 mg/L, the area under the curve increased from 0.689 (95% CI = 0.0595 to 0.782) to 0.842 (95% CI = 0.77 to 0.914) by using the CRPv measurements.

Conclusions

CRPv improved differentiation between febrile bacterial infections and non-bacterial febrile illnesses compared with CRP alone, and could identify individuals who need prompt therapeutic intervention.

C-Reactive Protein, Detected with a Highly Sensitive Assay, in Non-Infected Newborns and Those with Early Onset Infection

SUMMARY: BACKGOUND: The aim of this study was to investigate C-reactive protein (CRP), measured by a highly sensitive method (hsCRP) in non-infected newborns and in those with suspected early onset bacterial infection (EOBI) as well as to test whether EOBI would be detectable earlier by hsCRP than by a nephelometric CRP (nsCRP) assay (thresholds > 10 mg/l) or IL-8. PATIENTS AND METHODS: 106 neonates with signs of infection comprised the suspected EOBI group. 134 neonates with risk factors but confirmed exclusion of EOBI served as non-infected controls. RESULTS: In the non-infected group, hsCRP in the first 6 h after birth was low (0.7 mg/l; SD 0.16 mg/l) but showed an increase to 4.11 mg/l (SD 3.33 mg/l) at 72 h (p < 0.001 vs. 6 h). The sensitivity of hsCRP (cut-off 0.3 mg/l) vs. nsCRP for EOBI was 0.46 vs. 0.23 at 6 h after clinical suspicion. Of all parameters measured, IL-8 had the highest sensitivity and specificity to detect EOBI at 6 h (0.60 and 0.90), but declined after 12 and 24 h. CONCLUSION: Lowering the CRP detection threshold by a highly sensitive assay did not improve diagnostic accuracy for EOBI.

Hematological indices, inflammatory markers and neutrophil CD64 expression: comparative trends during experimental human endotoxemia

CD64 is a high-affinity Fc(gamma)RI receptor expressed by activated neutrophils that has been recently evaluated as a potential sepsis parameter. In the present study, the kinetics of neutrophil membrane CD64 expression were examined during a standardized inflammatory response, using a human endotoxemia model, and compared with hematological indices, CRP, cytokines and interleukins. Ten healthy subjects received 2 ng/kg intravenous Escherichia coli lipopolysaccharide (LPS). After administration of LPS, neutrophil CD64 showed a biphasic response, characterized by a first increase from 108.5 +/- 7.5 to 133 +/- 6 AFU after 1 h (P = 0.047) and a second increase that started at 6 h and reached its maximum of 167 +/- 13 AFU at 22 h (P < 0.0001). CRP concentrations increased to 40 +/- 5 mg/dl 22 h after the administration of LPS. The cytokines and interleukins reached their maximum response within 1-2 h. The maximum values of pro-inflammatory cytokines (TNF-alpha, IFN-gamma and IL-6) correlated with the CD64 expression at 22 h after LPS administration (r(2) = 0.76, r(2) = 0.78, r(2) = 0.81, respectively, all P < 0.05), whereas this correlation was not found for the anti-inflammatory IL-10 (r(2) = 0.058, P = 0.54), suggesting that neutrophil CD64 expression might be a quantitative marker for innate immunity that could easily be used in the clinical setting.

C-reactive protein collaborates with plasma lectins to boost immune response against bacteria

Although human C-reactive protein (CRP) becomes upregulated during septicemia, its role remains unclear, since purified CRP showed no binding to many common pathogens. Contrary to previous findings, we show that purified human CRP (hCRP) binds to Salmonella enterica, and that binding is enhanced in the presence of plasma factors. In the horseshoe crab, Carcinoscorpius rotundicauda, CRP is a major hemolymph protein. Incubation of hemolymph with a range of bacteria resulted in CRP binding to all the bacteria tested. Lipopolysaccharide-affinity chromatography of the hemolymph co-purified CRP, galactose-binding protein (GBP) and carcinolectin-5 (CL5). Yeast two-hybrid and pull-down assays suggested that these pattern recognition receptors (PRRs) form pathogen recognition complexes. We show the conservation of PRR crosstalk in humans, whereby hCRP interacts with ficolin (CL5 homologue). This interaction stabilizes CRP binding to bacteria and activates the lectin-mediated complement pathway. We propose that CRP does not act alone but collaborates with other plasma PRRs to form stable pathogen recognition complexes when targeting a wide range of bacteria for destruction.