A Proposed Framework for the Clinical Management of Neonatal "Culture-Negative" Sepsis

Predicting community acquired bloodstream infection in infants using full blood count parameters and C-reactive protein; a machine learning study

Early recognition of bloodstream infection (BSI) in infants can be difficult, as symptoms may be non-specific, and culture can take up to 48 h. As a result, many infants receive unneeded antibiotic treatment while awaiting the culture results. In this study, we aimed to develop a model that can reliably identify infants who do not have positive blood cultures (and, by extension, BSI) based on the full blood count (FBC) and C-reactive protein (CRP) values. Several models (i.e. multivariable logistic regression, linear discriminant analysis, K nearest neighbors, support vector machine, random forest model and decision tree) were trained using FBC and CRP values of 2693 infants aged 7 to 60 days with suspected BSI between 2005 and 2022 in a tertiary paediatric hospital in Dublin, Ireland. All models tested showed similar sensitivities (range 47% - 62%) and specificities (range 85%-95%). A trained decision tree and random forest model were applied to the full dataset and to a dataset containing infants with suspected BSI in 2023 and showed good segregation of a low-risk and high-risk group. Negative predictive values for these two models were high for the full dataset (> 99%) and for the 2023 dataset (> 97%), while positive predictive values were low in both dataset (4%-20%).   Conclusion: We identified several models that can predict positive blood cultures in infants with suspected BSI aged 7 to 60 days. Application of these models could prevent administration of antimicrobial treatment and burdensome diagnostics in infants who do not need them. What is Known: • Bloodstream infection (BSI) in infants cause non-specific symptoms and may be difficult to diagnose. • Results of blood cultures can take up to 48 hours. What is New: • Machine learning models can contribute to clinical decision making on BSI in infants while blood culture results are not yet known.

Prospective antimicrobial stewardship interventions by multidisciplinary teams to reduce neonatal antibiotic use in South Africa: the Neonatal Antimicrobial Stewardship (NeoAMS) study

BACKGROUND

Hospitalised neonates are vulnerable to infection and have high rates of antibiotic utilisation.

METHODS

Fourteen South African neonatal units (seven public, seven private sector) assembled multidisciplinary teams involving neonatologists, microbiologists, pharmacists, and nurses to implement prospective audit and feedback neonatal antimicrobial stewardship (NeoAMS) interventions. The teams attended seven online training sessions. Pharmacists conducted weekday antibiotic prescription reviews in the neonatal intensive care unit and/or neonatal wards providing feedback to the clinical teams. Anonymised demographic and NeoAMS interventions data were aggregated for descriptive purposes and statistical analysis.

FINDINGS

During the 20-week NeoAMS intervention in 2022, 565 neonates were enrolled. Pharmacists evaluated seven hundred antibiotic prescription episodes; rule-out sepsis (180; 26%) and culture-negative sepsis (138; 20%) were the most frequent indications for antibiotic prescription. For infection episodes with an identified pathogen, only 51% (116/229) of empiric treatments provided adequate antimicrobial coverage. Pharmacists recommended 437 NeoAMS interventions (0·6 per antibiotic prescription episode), with antibiotic discontinuation (42%), therapeutic drug monitoring (17%), and dosing (15%) recommendations most frequent. Neonatal clinicians' acceptance rates for AMS recommendations were high (338; 77%). Mean antibiotic length of therapy decreased by 24% from 9·1 to 6·9 days (0·1 day decrease per intervention week; p=0·001), with the greatest decline in length of therapy for culture-negative sepsis (8·2 days (95%CI 5·7-11·7) to 5·9 days (95% CI 4·6-7·5); p=0·032).

INTERPRETATION

This neonatal AMS programme was successfully implemented in heterogenous and resource-limited settings. Pharmacist-recommended AMS interventions had high rates of clinician acceptance. The NeoAMS intervention significantly reduced neonatal antibiotic use, particularly for culture-negative sepsis.

FUNDING

A grant from Merck provided partial support.

Neonatal bacterial sepsis

Neonatal sepsis remains one of the key challenges of neonatal medicine, and together with preterm birth, causes almost 50% of all deaths globally for children younger than 5 years. Compared with advances achieved for other serious neonatal and early childhood conditions globally, progress in reducing neonatal sepsis has been much slower, especially in low-resource settings that have the highest burden of neonatal sepsis morbidity and mortality. By contrast to sepsis in older patients, there is no universally accepted neonatal sepsis definition. This poses substantial challenges in clinical practice, research, and health-care management, and has direct practical implications, such as diagnostic inconsistency, heterogeneous data collection and surveillance, and inappropriate treatment, health-resource allocation, and education. As the clinical manifestation of neonatal sepsis is frequently non-specific and the current diagnostic standard blood culture has performance limitations, new improved diagnostic techniques are required to guide appropriate and warranted antimicrobial treatment. Although antimicrobial therapy and supportive care continue as principal components of neonatal sepsis therapy, refining basic neonatal care to prevent sepsis through education and quality improvement initiatives remains paramount.

Case report: Acute severe hyponatremia-induced seizures in a newborn: a community-acquired case and literature review

Severe neonatal hyponatremia represents a critical electrolyte imbalance with potentially severe neurological outcomes, a condition rarely documented in community-acquired, full-term newborns. This report underscores a unique case of a 23-day-old, previously healthy, full-term male neonate experiencing severe hyponatremia that precipitated seizures, underscoring the urgency of prompt recognition and intervention. The neonate presented with symptoms including vomiting, groaning, chills, fixed staring, and limb tremors. Critical findings upon admission encompassed hypothermia, hypotension, tachycardia, and tachypnea accompanied by significant weight loss. The clinical presentation was marked by dehydration, lethargy, weak crying, a fixed gaze, irregular breathing, and coarse lung sounds, yet a distended abdomen, hypertonic limb movements, and recurrent seizures were observed. Immediate interventions included establishing IV access, rewarming, mechanical ventilation, seizure management, volume expansion, dopamine for circulatory support, and initiation of empirical antibiotics. Diagnostic evaluations revealed a sodium ion concentration of 105.9 mmol/L, while amplitude-integrated electroencephalography (aEEG) detected pronounced seizure activity characterized by a lack of sleep-wake rhythmicity, noticeable elevation in both the lower and upper amplitude margins, and a sustained decrease in the lower margin voltage dropping below 5 μV, presenting as sharp or serrated waveforms. The management strategy entailed rapid electrolyte normalization using hypertonic saline and sodium bicarbonate, anticonvulsant therapy, and comprehensive supportive care, with continuous aEEG monitoring until the cessation of seizures. Remarkably, by the third day, the neonate's condition had stabilized, allowing for discharge in good health 10 days post-admission. At a 16-month follow-up, the child exhibited no adverse neurological outcomes and demonstrated favorable growth and development. Our extensive review on the etiology, clinical manifestations, aEEG monitoring, characteristics of seizures induced by severe neonatal hyponatremia, treatment approaches, and the prognosis for seizures triggered by severe hyponatremia aims to deepen the understanding and enhance clinical management of this complex condition. It stresses the importance of early detection, accurate diagnosis, and customized treatment protocols to improve outcomes for affected neonates. Additionally, this review accentuates the indispensable role of aEEG monitoring in managing neonates at elevated risk for seizures. Yet, the safety and efficacy of swiftly administering hypertonic saline for correcting severe hyponatremia-induced seizures necessitate further investigation through medical research.

Antibiotic use in infants at risk of early-onset sepsis: results from a unicentric retrospective cohort study

BACKGROUND

Antibiotic use for early-onset sepsis represents a high percentage of antibiotic consumption in the neonatal setting. Measures to assess infants at risk of early-onset sepsis are needed to optimize antibiotic use. Our primary objective was to assess the impact of a departmental guideline on antibiotic use among term infants with suspected EOS not confirmed, in our neonatal unit.

METHODS

Retrospective cohort study, to compare antibiotic use in term infants during a baseline period of January to December 2018, and a postintervention period from October 2019, to September 2020, respectively. The primary outcome was antibiotic use measured by days of therapy, the antibiotic spectrum index, the antibiotic use rate, and the length of therapy.

RESULTS

We included 71 infants in the baseline period and 66 infants in the postintervention period. Compared to those in the baseline period, there was a significant reduction in overall antibiotic measures in the postintervention period, (P < 0.001). The total days of therapy/1000 patient-days decreased from 63/1000 patient-days during the baseline period to 25.8/1000 patient-days in the postintervention period, representing a relative reduction of 59%. The antibiotic use rate decreased by more than half of the infants, from 3.2% during the baseline period to 1.3% in the postintervention period.

CONCLUSIONS

The use of a departmental guideline to assess infants at risk of early-onset sepsis based on their clinical condition and prompt discontinuation of antibiotics, is a simple and low-cost measure that contributed to an important decrease in antibiotic use.

Neurodevelopmental Outcome after Culture-Proven or So-Called Culture-Negative Sepsis in Preterm Infants

(1) Background: Prematurity is a serious condition associated with long-term neurological disability. This study aimed to compare the neurodevelopmental outcomes of preterm neonates with or without sepsis. (2) Methods: This single-center retrospective case-control study included infants with birth weight < 1500 g and/or gestational age ≤ 30 weeks. Short-term outcomes, brain MRI findings, and severe functional disability (SFD) at age 24 months were compared between infants with culture-proven or culture-negative sepsis or without sepsis. A chi-squared test or Mann-Whitney U test was used to compare the clinical and instrumental characteristics and the outcomes between cases and controls. (3) Results: Infants with sepsis (all sepsis n = 76; of which culture-proven n = 33 and culture-negative n = 43) were matched with infants without sepsis (n = 76). Compared with infants without sepsis, both all sepsis and culture-proven sepsis were associated with SFD. In multivariate logistic regression analysis, SFD was associated with intraventricular hemorrhage (OR 4.7, CI 1.7-13.1, p = 0.002) and all sepsis (OR 3.68, CI 1.2-11.2, p = 0.021). (4) Conclusions: All sepsis and culture-proven sepsis were associated with SFD. Compared with infants without sepsis, culture-negative sepsis was not associated with an increased risk of SFD. Given the association between poor outcomes and culture-proven sepsis, its prevention in the neonatal intensive care unit is a priority.

Markers of platelet activation foR identification of late onset sEpsis in infaNTs: PARENT study protocol

BACKGROUND

Newborns are at high risk of sepsis. At present there is no definitive "rule in" blood test for sepsis at the point of clinical concern. A positive blood culture remains the gold standard test for neonatal sepsis, however laboratory markers that correlate prospectively with culture positive sepsis could aid clinicians in making decisions regarding administration of empiric antibiotic therapies.

METHODS

This multi-site, prospective observational study will take place in two neonatal intensive care units (National Maternity Hospital and Rotunda Hospital, Dublin). Neonates born at less than 34 weeks will be enroled and informed consent obtained prior to late onset sepsis work up. If at any point subsequently during their neonatal intensive care stay they develop signs and symptoms of possible sepsis requiring blood culture, an additional sodium citrate sample will be obtained. Infants will be categorised into three groups as follows: (i) culture positive sepsis, (ii) culture negative sepsis where an infant receives 5 days of antibiotics (iii) non sepsis. Our primary outcome is to establish if differential platelet/endothelial activation can prospectively identify neonatal culture positive late onset sepsis.

TRIAL REGISTRATION NUMBER

NCT05530330 IMPACT: Preterm infants are a high risk group for the development of sepsis which is a major cause of mortality in this population. Platelets have been associated with host response to invasive bacterial infections both in animal models and translational work. A positive blood culture is the gold standard test for neonatal sepsis but can be unreliable due to limited blood sampling in the very low birth weight population. This study hopes to establish if platelet/endothelial associated plasma proteins can prospectively identify late onset neonatal sepsis.

Identifying immune signatures of sepsis to increase diagnostic accuracy in very preterm babies

Bacterial infections are a major cause of mortality in preterm babies, yet our understanding of early-life disease-associated immune dysregulation remains limited. Here, we combine multi-parameter flow cytometry, single-cell RNA sequencing and plasma analysis to longitudinally profile blood from very preterm babies (<32 weeks gestation) across episodes of invasive bacterial infection (sepsis). We identify a dynamically changing blood immune signature of sepsis, including lymphopenia, reduced dendritic cell frequencies and myeloid cell HLA-DR expression, which characterizes sepsis even when the common clinical marker of inflammation, C-reactive protein, is not elevated. Furthermore, single-cell RNA sequencing identifies upregulation of amphiregulin in leukocyte populations during sepsis, which we validate as a plasma analyte that correlates with clinical signs of disease, even when C-reactive protein is normal. This study provides insights into immune pathways associated with early-life sepsis and identifies immune analytes as potential diagnostic adjuncts to standard tests to guide targeted antibiotic prescribing.

Game changer or gimmick: inflammatory markers to guide antibiotic treatment decisions in neonatal early-onset sepsis

BACKGROUND

The diagnosis of neonatal early-onset sepsis (EOS) is challenging, and inflammatory markers are widely used to guide decision-making and therapies.

OBJECTIVES

This narrative review presents the current state of knowledge regarding the diagnostic value and potential pitfalls in the interpretation of inflammatory markers for EOS.

SOURCES

PubMed until October 2022 and searched references in identified articles using the search terms: neonatal EOS, biomarker or inflammatory marker, and antibiotic therapy or antibiotic stewardship.

CONTENT

In situations with a high or low probability of sepsis, the measurements of inflammatory markers have no impact on the decision to start or stop antibiotics and are just gimmick, whereas they may be a game changer for neonates with intermediate risk and therefore an unclear situation. There is no single or combination of inflammatory markers that can predict EOS with high probability, allowing us to make decisions regarding the start of antibiotics based only on inflammatory markers. The main reason for the limited accuracy is most probably the numerous noninfectious conditions that influence the levels of inflammatory markers. However, there is evidence that C-reactive protein and procalcitonin have good negative predictive accuracy to rule out sepsis within 24 to 48 hours. Nevertheless, several publications have reported more investigations and prolonged antibiotic treatments with the use of inflammatory markers. Given the limitations of current strategies, using an algorithm with only moderate diagnostic accuracy may have a positive impact, as reported for the EOS calculator and the NeoPInS algorithm.

IMPLICATIONS

As the decision regarding the start of antibiotic therapy is different from the process of stopping antibiotics, the accuracy of inflammatory markers needs to be evaluated separately. Novel machine learning-based algorithms are required to improve accuracy in the diagnosis of EOS. In the future, inflammatory markers included in algorithms may be a game changer reducing bias and noise in the decision-making process.

Heart rate and oxygen saturation patterns in very low birth weight infants with early onset sepsis and histologic chorioamnionitis

BACKGROUND

Chorioamnionitis and early onset sepsis (EOS) in very low birth weight (VLBW,< 1500 g) infants may cause a systemic inflammatory response reflected in patterns of heart rate (HR) and oxygenation measured by pulse oximetry (SpO2). Identification of these patterns might inform decisions about duration of antibiotic therapy after birth.

OBJECTIVE

Compare early HR and SpO2 patterns in VLBW infants with or without early onset sepsis (EOS) or histologic chorioamnionitis (HC).

STUDY DESIGN

Retrospective study of placental pathology and HR and SpO2 in the first 72 h from birth in relation to EOS status for inborn VLBW NICU patients 2012-2019.

RESULT

Among 362 VLBW infants with HR and SpO2 data available, clinical, or culture-positive EOS occurred in 91/362 (25%) and HC in 81/355 (22%). In univariate analysis, EOS was associated with higher mean HR, lower mean SpO2, and less negative skewness of HR in the first 3 days after birth. HC was associated with higher standard deviation and skewness of HR but no difference in SpO2. In multivariable modeling, significant risk factors for EOS were mean HR, gestational age, HC, mean SpO2, and skewness of SpO2.

CONCLUSION

HR and SpO2 patterns differ shortly after birth in VLBW infants exposed to HC or with EOS, likely reflecting a systemic inflammatory response.

Less is more: Antibiotics at the beginning of life

Antibiotic exposure at the beginning of life can lead to increased antimicrobial resistance and perturbations of the developing microbiome. Early-life microbiome disruption increases the risks of developing chronic diseases later in life. Fear of missing evolving neonatal sepsis is the key driver for antibiotic overtreatment early in life. Bias (a systemic deviation towards overtreatment) and noise (a random scatter) affect the decision-making process. In this perspective, we advocate for a factual approach quantifying the burden of treatment in relation to the burden of disease balancing antimicrobial stewardship and effective sepsis management.

Early Diagnosis of Late-Onset Neonatal Sepsis Using a Sepsis Prediction Score

Sepsis represents a common cause of morbidity in the Neonatal Intensive Care Unit (NICU). Our objective was to assess the value of clinical and laboratory parameters in predicting septicemia (positive blood culture) in NICU infants. In the first part of the present study (derivation cohort) we retrospectively reviewed the clinical files of 120 neonates with symptoms of suspected sepsis and identified clinical and laboratory parameters associated with proven sepsis on the day the blood culture was taken, as well as 24 h and 48 h earlier. These parameters were combined into a sepsis prediction score (SPS). Subsequently (validation study), we prospectively validated the performance of the SPS in a cohort of 145 neonates. The identified parameters were: temperature instability, platelet count < 150,000/mm³, feeding volume decrease > 20%, changes in blood glucose > 50%, CRP > 1 mg/dL, circulatory and respiratory deterioration. In the retrospective cohort, on the day the blood culture was obtained, a SPS ≥ 3 could predict sepsis with 82.54% sensitivity, 85.96% specificity, 5.88 PLR (Positive Likelihood Ratio), 0.20 NLR (Negative Likelihood Ratio), 86.67% PPV (Positive Predictive Value), 81.67% NPV (Negative Predictive Value) and 84.17% accuracy. In the prospective cohort, on the day the blood culture was obtained, a SPS ≥ 3 could predict sepsis with 76.60% sensitivity, 72.55% specificity, 2.79 PLR, 0.32 NLR, 83.72% PPV, 62.71% NPV and 75.17% accuracy. We concluded that this combination of clinical and laboratory parameters may assist in the prediction of septicemia in NICUs.

Artificial and human intelligence for early identification of neonatal sepsis

Artificial intelligence may have a role in the early detection of sepsis in neonates. Machine learning can identify patterns that predict high or increasing risk for clinical deterioration from a sepsis-like illness. In developing this potential addition to NICU care, careful consideration should be given to the data and methods used to develop, validate, and evaluate prediction models. When an AI system alerts clinicians to a change in a patient's condition that warrants a bedside evaluation, human intelligence and experience come into play to determine an appropriate course of action: evaluate and treat or wait and watch closely. With intelligently developed, validated, and implemented AI sepsis systems, both clinicians and patients stand to benefit. IMPACT: This narrative review highlights the application of AI in neonatal sepsis prediction. It describes issues in clinical prediction model development specific to this population. This article reviews the methods, considerations, and literature on neonatal sepsis model development and validation. Challenges of AI technology and potential barriers to using sepsis AI systems in the NICU are discussed.

Association of lower vitamin a levels in neonates and their mothers with increased risk of neonatal late-onset sepsis: A case-control study

BACKGROUND

In developing countries, neonatal sepsis is one of the major causes of mortality and morbidity. Vitamin A deficiency also affects the immune system severely and is associated with various neonatal infections. We aimed to compare maternal and neonatal vitamin A levels among neonates with and without late-onset sepsis.

MATERIAL AND METHODS

40 eligible infants were entered into this case-control study according to inclusion criteria. The case group included 20 term or near-term infants who had late-onset neonatal sepsis from three to seven days of life. The control group consisted of 20 term or near-term infants who were icteric hospitalized neonates without sepsis. Demographic, clinical and paraclinical features, as well as neonatal and maternal vitamin A levels, were compared between the two groups.

RESULTS

The average gestational age of the neonates was 37.1 ± 1.2, ranging from 35 to 39 days. There was a significant difference between the septic and non-septic groups in terms of white blood cell and neutrophil count, C-reactive protein, and neonatal and maternal vitamin A levels. A Spearman correlation analysis showed a significant direct correlation among maternal and neonatal vitamin A levels (correlation coefficient = 0.507; P-value = 0.001). Multivariate regression analysis showed that neonates' vitamin A level had a significant direct association with sepsis (OR: 0.541; P-value=0.017).

CONCLUSION

Our findings demonstrated the association of lower vitamin A levels in neonates and their mothers with an increased risk of late-onset sepsis, which emphasizes the importance of the consideration of vitamin A level evaluation and its appropriate neonatal and maternal supplementation.