Hematologic Aspects of Early and Late-Onset Sepsis in Preterm Infants

Role of systemic immune-inflammatory index in early diagnosis of sepsis in newborns with CHD

OBJECTIVE

Congenital heart diseases (CHD) are the most common causes of birth defects that have increased the risk of infections. Neonatal sepsis is a life-threatening condition and early diagnosis can be life-saving. We aimed to evaluate the potential role of the systemic immune-inflammatory index in the early diagnosis of neonatal sepsis.

METHODS

A retrospective cohort study was conducted on 166 newborns with a diagnosis of neonatal sepsis who were admitted to our hospital with CHD between January 2017 and June 2021. Haematological indices including neutrophil/lymphocyte ratio, platelet/lymphocyte ratio, and systemic immune-inflammatory index were calculated for all patients at the time of diagnosis of neonatal sepsis (sepsis). The sepsis values of these indices were compared with the admission values (pre-sepsis) of the patients.

RESULTS

The mean gestational age and birth weight of the patients were 38.36 ± 1.42 weeks and 3057.75 ± 484.68 g. It was found that absolute neutrophil count, systemic immune-inflammatory index, neutrophil/lymphocyte ratio, but not platelet/lymphocyte ratio were significantly increased at the time of sepsis. The receiver operating characteristic curve showed that systemic immune-inflammatory index, neutrophil/lymphocyte ratio, and absolute neutrophil count have predictive ability to define neonatal sepsis among newborns with CHD. The systemic immune-inflammatory index produced an area under the curve receiver operating characteristic curve of 0.76 (70% sensitivity, 70.5% specificity). To discriminate neonatal sepsis, the cut-off values of systemic immune-inflammatory index, neutrophil/lymphocyte ratio, and absolute neutrophil count were 517.19, 2.62, and 9210/mm³, respectively.

CONCLUSION

As an easily accessible and reliable indicator, systemic immune-inflammatory index may be used in combination with the other parameters in the early diagnosis of neonatal sepsis.

New Diagnostic Possibilities for Early Onset Neonatal Sepsis: Red Cell Distribution Width to Platelet Ratio

Aims: Red cell distribution width to platelet ratio (RPR) has been reported as a useful inflammatory marker and prognostic indicator of adult inflammatory diseases. In the present study, red cell distribution width (RDW) and RPR parameters, which are parts of a complete blood count analysis, were compared to the traditional C reactive protein (CRP) and procalcitonin (PCT) parameters to investigate the potential to predict early onset sepsis (EOS) in neonates with or without positive blood cultures. Methods: An observational, retrospective cohort study was conducted to evaluate newborns born in our hospital. Results: RDW, RPR, CRP, PCT, Immature to total neutrophil ratio (I/T), and white blood cell (WBC) counts were higher in suspected and proven EOS compared to control group. Conclusion: We believe that RPR may be used in diagnosis of early onset neonatal sepsis and may be a good alternative to other tools as a readily available biomarker.

Neonatal Sepsis

Neonatal sepsis is associated with severe morbidity and mortality in the neonatal period. Clinical manifestations range from subclinical infection to severe local or systemic infection. Neonatal sepsis is divided into three groups as early-onset neonatal sepsis, late-onset neonatal sepsis and very late-onset neonatal sepsis according to the time of the onset. It was observed that the incidence of early-onset neonatal sepsis decreased with intrapartum antibiotic treatment. However, the incidence of late-onset neonatal sepsis has increased with the increase in the survival rate of preterm and very low weight babies. The source of the causative pathogen may be acquisition from the intrauterine origin but may also acquisition from maternal flora, hospital or community. Prematurity, low birth weight, chorioamnionitis, premature prolonged rupture of membranes, resuscitation, low APGAR score, inability to breastfeed, prolonged hospital stay and invasive procedures are among the risk factors. This article reviews current information on the definition, classification, epidemiology, risk factors, pathogenesis, clinical symptoms, diagnostic methods and treatment of neonatal sepsis.

Meconium microbiota predicts clinical early-onset neonatal sepsis in preterm neonates

Background: Early-onset neonatal sepsis (EONS) remains one of the leading causes of morbidity and mortality related to premature birth, and its diagnosis remains difficult. Our goal was to evaluate the intestinal microbiota of the first meconium of preterm newborns and ascertain whether it is associated with clinical EONS.Methods: In a controlled, prospective cohort study, samples of the first meconium of premature infants with a gestational age (GA) ≤32 weeks was obtained at Hospital de Clínicas de Porto Alegre and DNA was isolated from the samples. 16S rDNA based microbiota composition of preterm infants with a clinical diagnosis of EONS was compared to that of a control group.Results: 40 (48%) premature infants with clinical diagnosis of EONS and 44 (52%) without EONS were included in the analysis. The most abundant phylum detected in both groups, Proteobacteria, was more prevalent in the sepsis group (p = .034). 14% of variance among bacterial communities (p = .001) correlated with EONS. The genera most strongly associated with EONS were Paenibacillus, Caulobacter, Dialister, Akkermansia, Phenylobacterium, Propionibacterium, Ruminococcus, Bradyrhizobium, and Alloprevotella. A single genus, Flavobacterium, was most strongly associated with the control group.Conclusion: These findings suggest that the first-meconium microbiota is different in preterm neonates with and without clinical EONS.

Use of mean platelet volume in the assessment of intrauterine infection in newborns with combined thrombocytopenia and leukopenia at birth

Objective: Intrauterine stress can be reflected on hematological disturbance at birth. Thrombocytopenia and leukopenia may be a result of exposure to maternal hypertensive disorders but may also indicate fetal inflammatory response to intrauterine infection, prompting empiric antibiotics use during the initial assessment after birth. Emerging data suggest long-term adverse health outcomes associated with antibiotics exposure early in life. In this report, we sought to assess the use of mean platelet volume (MPV) at birth in predicting fetal inflammatory response in newborns with combined thrombocytopenia and leukopenia.Materials and methods: This is a retrospective study from a single academic medical center. Data were collected prospectively on all newborns with thrombocytopenia and leukopenia within the first 24 h of life. The primary outcome was a composite of fetal tachycardia, premature preterm rupture of membrane with preterm labor, and histological evidence of chorioamnionitis/funisitis/villitis on placental pathology reports evaluated using a multiple logistical regression analysis.Results: The prevalence of combined thrombocytopenia and leukopenia was 5.8% (99 out of 1693 newborns) during the study period. The prevalence was highly associated with gestational age (R² = 0.873). Twenty-four (32.4%) had abnormal MPV values at birth, defined as MPV > 9 or < 7 fL. Newborns with abnormal MPV had lower platelet counts and were more likely to have I:T ratio ≥0.2. In a univariate analysis, abnormal MPV (OR: 6.205, 95% CI: 1.923-20.022, p = .002), I:T ratio ≥0.2 (OR: 8.462, 95% CI: 1.396-51.281, p = .02), and platelet counts (OR: 98.4, 95% CI: 96.9%-99.9%, p = .035) were each significantly associated with a positive composite outcome. In a multivariate analysis, only abnormal MPV remained significantly associated with an increased likelihood of having a positive composite outcome, with an OR of 3.922 (95% CI: 1.094-14.06, p = .036).Conclusions: MPV may be a more reliable marker than I:T ratio ≥0.2 for fetal inflammatory response in newborns with combined thrombocytopenia and leukopenia during the initial assessment of intrauterine infection. Future prospective studies are required to confirm findings from this report.

Screening and Serial Neutrophil Counts Do Not Contribute to the Recognition or Diagnosis of Late-Onset Neonatal Sepsis

OBJECTIVE

To determine the validity of screening and serial neutrophil counts in predicting the absence/presence of late-onset sepsis (LOS) in infants with central venous catheters.

STUDY DESIGN

Retrospective study of infants admitted to the neonatal intensive care unit (2009-2013) at Parkland Hospital with a central venous catheter and ≥1 LOS evaluations. Infants were categorized as proven or suspect LOS or uninfected based on results of blood cultures, clinical illness, and duration of antibiotics. Receiver operating curves (ROCs) were constructed to predict the absence or presence of LOS using Manroe reference ranges for total and immature neutrophils and the immature to total neutrophil ratio at 0, 12, and 24 hours after blood culture and the neutrophil value score, which assesses serial values.

RESULTS

Of the 497 infants with a central venous catheter, 179 underwent ≥1 LOS evaluations, and 140 of 179 (78%) had ≥1 complete evaluations (2 blood cultures and neutrophil values at 0, 12, and 24 hours), resulting in 188 complete LOS evaluations. The gestational age was 28 ± 4 weeks and LOS evaluation occurred at 29 ± 34 days (SD; 4-197 days). Sixty-one (35%) infants had proven LOS, 48 (23%) were suspect, and 71 (38%) were noninfected. ROC comparing proven vs noninfected was ≤0.56 for total neutrophils, immature neutrophils, and immature to total neutrophil ratio at 0, 12, and 24 hours and similar for proven + suspect vs noninfected. ROC for neutrophil value scores and absence of LOS was 0.56.

CONCLUSIONS

Screening neutrophil values are poor predictors of LOS in neonates with a central venous catheter, as are serial neutrophils and the neutrophil value score. Alternative biomarkers are needed.

Can Fetal Umbilical Venous Blood Be a Reliable Source for Admission Complete Blood Count and Culture in NICU Patients?

BACKGROUND

Minimizing initial neonatal blood draws and their associated pain is important. The placenta has ample fetal blood that is otherwise discarded; obtaining admission laboratory evaluations from fetal umbilical venous blood (FUVB) may provide a suitable alternative.

OBJECTIVE

We hypothesized that obtaining an aerobic bacterial blood culture (BCX) and a complete blood count with manual differential (CBC/diff) from FUVB is feasible and yields results comparable to those obtained directly from the neonate.

STUDY DESIGN

BCX and CBC/diff were attempted on paired samples from FUVB (in the delivery room) and neonatal blood (shortly after NICU admission) of 110 patients. The paired t test, Pearson's correlation coefficient (R), and multivariable linear regression were used for data analysis.

RESULTS

Positive BCXs were found in 9 of 108 FUVB samples compared to 1 of 91 neonatal samples. Three out of 9 FUVB cultures were true pathogens, including 2 Escherichia coli and 1 viridans group streptococcus, all with negative corresponding paired neonatal cultures. There was 1 positive neonatal BCX, E. coli, with a negative paired FUVB culture. Neonatal hemoglobin (Hb), platelets (PLT), and white blood cells (WBC) all significantly (p < 0.0001) correlated with the paired FUVB samples (R = 0.50, 0.49, and 0.84, respectively). Hb, PLT, and WBC values were clinically comparable but statistically higher in neonatal blood (the differences were 2.3 g/dL, 30,000 cells/μL, and 2,800 cells/μL, respectively; p < 0.007 for all comparisons).

CONCLUSIONS

FUVB is suitable for obtaining CBC/diff. FUVB is an appropriate second source for BCX as it yields additional true pathogens. Our findings may support the presence of "culture-negative sepsis" in some neonates.

Turkish Neonatal Society guideline on neonatal infections-diagnosis and treatment

Neonatal infections are a major cause of morbidity and mortality in the first month of life, especially in developing countries. Despite advances in neonatology, neonatal infections still haves clinical importance because of nonspecific signs and symptoms, no perfect diagnostic marker, and interference with non-infectious diseases of newborns. Diagnosis is typically made by clinical and laboratory findings. Empiric antibiotic therapy should be started in a newborn with signs and symptoms of infection after cultures are taken according to the time of the signs and symptoms, risk factors, admission from community or hospital, focus of infection, and antibiotic susceptibility estimation. Treatment should be continued according to clinical findings and culture results. Intrapartum antibiotic prophylaxis, proper hand washing, aseptic techniques for invasive procedures, appropriate neonatal intensive care unit design, isolation procedures, and especially breast milk use are needed to prevent infections. The use of diagnosis and treatment protocols increases clinical success.

Thrombocytopenia in neonatal sepsis: Incidence, severity and risk factors

Objectives

Thrombocytopenia is a frequent problem in neonatal sepsis and is among the most predictive, independent risk factors for sepsis-associated mortality. This study aims to clarify the occurrence, severity and duration of thrombocytopenia in neonatal sepsis.

Study design

A cohort study was carried out among all neonates with proven culture positive sepsis that were admitted to a tertiary NICU between 2006 and 2015 (n = 460). The occurrence, severity and duration of thrombocytopenia were recorded, as well as major bleedings and potential risk factors for mortality in neonatal sepsis.

Results

Sepsis was diagnosed in 460 of 6551 neonates (7%). Severe thrombocytopenia (platelets ≤50*10⁹/L) occurred in 20% (92/460) of septic neonates. The median time for platelets to rise >100*10⁹ was 6.0 days (interquartile range 4.0–7.0). On multivariate analysis, maternal hypertension, intravascular thrombosis and Gram negative (as opposed to Gram positive) sepsis were independently associated with thrombocytopenia in neonatal sepsis. In severe thrombocytopenia, 10% (9/92) suffered a severe IVH, compared to 5% (20/356) in neonates with platelets >50*109/L (p = 0.125). 10% (9/92) suffered a pulmonary hemorrhage, compared to 2% (9/368) in neonates with platelets >50*109/L (p = 0.001). On multivariate analysis, thrombocytopenia and Gram negative (as opposed to Gram positive) sepsis were independently associated with neonatal mortality.

Conclusions

Thrombocytopenia is independently associated with maternal hypertension, intravascular thrombosis and Gram negative sepsis. Thrombocytopenia in neonatal sepsis increases the risk of mortality nearly four-fold, with another six-fold increase in mortality in case of Gram negative sepsis.

Delayed development of systemic immunity in preterm pigs as a model for preterm infants

Preterm neonates are highly sensitive to systemic infections in early life but little is known about systemic immune development following preterm birth. We hypothesized that preterm neonates have immature systemic immunity with distinct developmental trajectory for the first several weeks of life, relative to those born at near-term or term. Using pigs as a model, we characterized blood leukocyte subsets, antimicrobial activities and TLR-mediated cytokine production during the first weeks after preterm birth. Relative to near-term and term pigs, newborn preterm pigs had low blood leukocyte counts, poor neutrophil phagocytic rate, and limited cytokine responses to TLR1/2/5/7/9 and NOD1/2 agonists. The preterm systemic responses remained immature during the first postnatal week, but thereafter showed increased blood leukocyte numbers, NK cell proportion, neutrophil phagocytic rate and TLR2-mediated IL-6 and TNF-α production. These immune parameters remained different between preterm and near-term pigs at 2-3 weeks, even when adjusted for post-conceptional age. Our data suggest that systemic immunity follows a distinct developmental trajectory following preterm birth that may be influenced by postnatal age, complications of prematurity and environmental factors. Consequently, the immediate postnatal period may represent a window of opportunity to improve innate immunity in preterm neonates by medical, antimicrobial or dietary interventions.