Cerebral ultrasound abnormalities in preterm infants caused by late-onset sepsis

Neurosonography: Shaping the future of neuroprotection strategies in extremely preterm infants

This review aims to explore the current application of Cranial Ultrasound Screening (CUS) in the diagnosis and treatment of brain diseases in extremely preterm infants. It also discusses the potential role of emerging ultrasound-derived technologies such as Super Microvascular Structure Imaging (SMI), Shear Wave Elastography (SWE), Ultrafast Doppler Ultrasound (UfD), and 3D ventricular volume assessment and automated segmentation techniques in clinical practice. A systematic search of medical databases was conducted using the keywords "(preterm OR extremely preterm OR extremely low birth weight) AND (ultrasound OR ultrasound imaging) AND (neurodevelopment OR brain development OR brain diseases OR brain injury OR neuro*)" to identify relevant literature. The titles, abstracts, and full texts of the identified articles were carefully reviewed to determine their relevance to the research topic. CUS offers unique advantages in early screening and monitoring of brain diseases in extremely preterm infants, as it can be performed at the bedside without the need for anesthesia or special monitoring. This technique facilitates early detection and intervention of conditions such as intraventricular hemorrhage, white matter injury, hydrocephalus, and hypoxic-ischemic injury in critically ill preterm infants. Continuous refinement of the screening and follow-up processes provides reliable clinical decision-making support for healthcare professionals and parents. Emerging ultrasound technologies, such as SWE, SMI, and UfD, are being explored to provide more accurate and in-depth understanding of brain diseases in extremely preterm infants. SWE has demonstrated its effectiveness in assessing the elasticity of neonatal brain tissue, aiding in the localization and quantification of potential brain injuries. SMI can successfully identify microvascular structures in the brain, offering a new perspective on neurologic diseases. UfD provides a high-sensitivity and quantitative imaging method for the prevention and treatment of neonatal brain diseases by detecting subtle changes in red blood cell movement and accurately assessing the status and progression of brain diseases. CUS and its emerging technologies have significant applications in the diagnosis and treatment of brain diseases in extremely preterm infants. Future research aims to address current technical challenges, optimize and enhance the clinical decision-making capabilities related to brain development, and improve the prevention and treatment outcomes of brain diseases in extremely preterm infants.

Monoclonal antibodies effectively potentiate complement activation and phagocytosis of Staphylococcus epidermidis in neonatal human plasma

Central line associated bloodstream infections (CLABSI) with Staphylococcus epidermidis are a major cause of morbidity in neonates, who have an increased risk of infection because of their immature immune system. As especially preterm neonates suffer from antibody deficiency, clinical studies into preventive therapies have thus far focused on antibody supplementation with pooled intravenous immunoglobulins from healthy donors (IVIG) but with little success. Here we study the potential of monoclonal antibodies (mAbs) against S. epidermidis to induce phagocytic killing by human neutrophils. Nine different mAbs recognizing Staphylococcal surface components were cloned and expressed as human IgG1s. In binding assays, clones rF1, CR5133 and CR6453 showed the strongest binding to S. epidermidis ATCC14990 and CR5133 and CR6453 bound the majority of clinical isolates from neonatal sepsis (19 out of 20). To study the immune-activating potential of rF1, CR5133 and CR6453, bacteria were opsonized with mAbs in the presence or absence of complement. We observed that activation of the complement system is essential to induce efficient phagocytosis of S. epidermidis. Complement activation and phagocytic killing could be enhanced by Fc-mutations that improve IgG1 hexamerization on cellular surfaces. Finally, we studied the ability of the mAbs to activate complement in r-Hirudin neonatal plasma conditions. We show that classical pathway complement activity in plasma isolated from neonatal cord blood is comparable to adult levels. Furthermore, mAbs could greatly enhance phagocytosis of S. epidermidis in neonatal plasma. Altogether, our findings provide insights that are crucial for optimizing anti-S. epidermidis mAbs as prophylactic agents for neonatal CLABSI.

The prognostic value of NIRS in preterm infants with (suspected) late-onset sepsis in relation to long term outcome: A pilot study

Late-onset sepsis is frequently seen in preterm infants and is associated with poor neurodevelopmental outcome. White matter damage is proposed as substrate of poor outcome, with contributing factors as regional hypoxia and effects of cytokines on oligodendrocytes. We investigated the relation between cerebral oxygenation during (suspected) late-onset sepsis and neurodevelopmental outcome. Prospective cohort study, including preterm infants (gestational age <32 weeks and/or birthweight <1500 grams) with (suspected) late-onset sepsis underwent NIRS registration during the first 72 hours of suspected late-onset sepsis. At two years corrected age neurodevelopment was scored using the Bayley Scales of Infant Development-II. Thirty-two infants were included. Twenty-seven infants were identified with proven late-onset sepsis and five infants had clinical sepsis without positive blood culture. In this study, late-onset sepsis was predominantly caused by coagulase negative staphylococci (CoNS) (72%). All NIRS values were within normal limits. No association was found between NIRS and impaired neurodevelopmental outcome (n = 4) at corrected age two years: composite cognitive score 105 (80-115), composite motor score 103 (82-118) (median and range). In this pilot study, late-onset sepsis (predominantly caused by CoNS with a relatively mild clinical course), was not associated with aberrant NIRS values, nor with impaired neurodevelopmental outcome. Further research might establish our findings and elucidate effects of other micro-organisms on cerebral perfusion.

Neurodevelopmental outcome at 2 years of age in preterm infants with late-onset sepsis

Late-onset sepsis is associated with impaired neurodevelopmental outcome in preterm infants. This prospective cohort study aims to establish the effect of sepsis after 72 h of life on cognitive, psychomotor, and language development of preterm infants (below 32 weeks gestational age and/or below 1500 g). At 2 years corrected age, neurodevelopmental outcome was tested using Bayley's Scales of Infant Development-II, Lexilijst (lexical development questionnaire), and behavior checklists. Of 117 patients included, 85 experienced blood culture-proven infection. Coagulase-negative staphylococci were responsible for 55% of the episodes. No significant differences were found in cognitive, motor, and behavioral scores or lexiquotient comparing patients with versus no proven infection. When comparing three groups (coagulase-negative staphylococci, other, and negative blood culture), a significant difference was found in composite cognitive scores (p = 0.016), in favor of the coagulase-negative staphylococci group versus other causal agent group (p = 0.007). No significant differences were found in other subscales.Conclusion: In this cohort, no differences were found in neurodevelopmental outcome at 2 years corrected age between proven and no proven infection groups; confirmation in larger cohorts with a control group is needed. Patients encountering coagulase-negative staphylococci sepsis showed a significant better cognitive outcome compared to other causal agents. What is Known: • Late-onset sepsis is associated with impaired neurodevelopmental outcome in preterm infants. What is New: • Preterm infants encountering late-onset sepsis by coagulase-negative staphylococci show a better cognitive outcome in comparison to other causal infectious agents in this cohort. • No differences were found in neurodevelopment at 2 years of age in preterm infants with suspected lateonset sepsis, between proven and no proven infection groups. Confirmation is needed in larger cohorts with a substantial control group.

Beyond sepsis: Staphylococcus epidermidis is an underestimated but significant contributor to neonatal morbidity

Staphylococcus epidermidis accounts for the majority of cases of neonatal sepsis. Moreover, it has been demonstrated to be associated with neonatal morbidities, such as bronchopulmonary dysplasia (BPD), white matter injury (WMI), necrotizing enterocolitis (NEC) and retinopathy of prematurity (ROP), which affect short-term and long-term neonatal outcome. Imbalanced inflammation has been considered to be a major underlying mechanism of each entity. Conventionally regarded as a harmless commensal on human skin, S. epidermidis has received less attention than its more virulent relative Staphylococcus aureus. Particularities of neonatal innate immunity and nosocomial environmental factors, however, may contribute to the emergence of S. epidermidis as a significant nosocomial pathogen. Neonatal host response to S. epidermidis sepsis has not been fully elucidated. Evidence is emerging regarding the implication of S. epidermidis sepsis in the pathogenesis of neonatal inflammatory diseases. This review focuses on the interplay among S. epidermidis, neonatal innate immunity and inflammation-driven organ injury.

New Threats from an Old Foe: Methicillin-Resistant Staphylococcus aureus Infections in Neonates

Methicillin-resistant Staphylococcus aureus (MRSA) is a ubiquitous human inhabitant and one of the important pathogens of neonatal infections. MRSA is associated with significant mortality and morbidity, especially in very immature preterm neonates. Moreover, MRSA may be implicated in adverse long-term neonatal outcomes, posing a substantial disease burden. Recent advances in molecular microbiology have shed light on the evolution of MRSA population structure and virulence factors, which may contribute to MRSA epidemic waves worldwide. Equipped with remarkable genetic flexibility, MRSA has successfully developed resistance to an extensive range of antibiotics including vancomycin, as well as antiseptics. In the face of these new challenges from MRSA, our armamentarium of anti-infective strategies is very limited and largely dependent on prevention measures. Active surveillance cultures followed by decolonization may be a promising approach to control MRSA infections, with its efficacy and safety in the specific population of neonates yet to be addressed by large multicenter studies.