Enhanced CD95 and interleukin 18 signalling accompany T cell receptor Vß21.3+ activation in multi-inflammatory syndrome in children.

Multisystem inflammatory syndrome in children is a post-infectious presentation SARS-CoV-2 associated with expansion of the T cell receptor Vß21.3+ T-cell subgroup. Here we apply muti-single cell omics to compare the inflammatory process in children with acute respiratory COVID-19 and those presenting with non SARS-CoV-2 infections in children. Here we show that in Multi-Inflammatory Syndrome in Children (MIS-C), the natural killer cell and monocyte population demonstrate heightened CD95 (Fas) and Interleuking 18 receptor expression. Additionally, TCR Vß21.3+ CD4+ T-cells exhibit skewed differentiation towards T helper 1, 17 and regulatory T cells, with increased expression of the co-stimulation receptors ICOS, CD28 and interleukin 18 receptor. We observe no functional evidence for NLRP3 inflammasome pathway overactivation, though MIS-C monocytes show elevated active caspase 8. This, coupled with raised IL18 mRNA expression in CD16- NK cells on single cell RNA sequencing analysis, suggests interleukin 18 and CD95 signalling may trigger activation of TCR Vß21.3+ T-cells in MIS-C, driven by increased IL-18 production from activated monocytes and CD16- Natural Killer cells.

Enhanced diagnosis of severe bacterial and fungal respiratory infection in children using a rapid syndromic array-case report.

Background: A microbiological cause of infection is infrequently identified in critically unwell children with a respiratory infection. Molecular diagnostic arrays provide an alternative. These tests are becoming more broadly available, but little is known about how clinicians interpret the results to impact clinical decision making. Case Description: Here we describe three cases of bacterial and fungal lower respiratory tract infection (LRTI) diagnosed in the paediatric intensive care unit (PICU) using a custom 52 respiratory pathogen TaqMan array card (TAC). Firstly, an early diagnosis of Candida albicans pneumonia was made with the support of the TAC in a trauma patient who received prolonged mechanical ventilation. The pathogen was only identified on microbiological cultures after further clinical deterioration had occurred. Secondly, a rare case of psittacosis was identified in an adolescent with acute respiratory distress, initially suspected to have multisystem inflammatory syndrome in children (MIS-C). Finally, Haemophilus influenzae pneumonia was identified in an infant with recurrent apnoeas, initially treated for meningitis. Two diagnoses would not have been established using commercially available arrays, and pathogen-specific diagnoses were established faster than that of routine microbiological culture. Conclusions: The pathogens included on molecular arrays and interpretation by a multidisciplinary team are crucial in providing value to PICU diagnostic services. Molecular arrays have the potential to enhance early pathogen-specific diagnosis of LRTI in the PICU.

Short-duration selective decontamination of the digestive tract infection control does not contribute to increased antimicrobial resistance burden in a pilot cluster randomised trial (the ARCTIC Study).

OBJECTIVE: Selective decontamination of the digestive tract (SDD) is a well-studied but hotly contested medical intervention of enhanced infection control. Here, we aim to characterise the changes to the microbiome and antimicrobial resistance (AMR) gene profiles in critically ill children treated with SDD-enhanced infection control compared with conventional infection control. DESIGN: We conducted shotgun metagenomic microbiome and resistome analysis on serial oropharyngeal and faecal samples collected from critically ill, mechanically ventilated patients in a pilot multicentre cluster randomised trial of SDD. The microbiome and AMR profiles were compared for longitudinal and intergroup changes. Of consented patients, faecal microbiome baseline samples were obtained in 89 critically ill children. Additionally, samples collected during and after critical illness were collected in 17 children treated with SDD-enhanced infection control and 19 children who received standard care. RESULTS: SDD affected the alpha and beta diversity of critically ill children to a greater degree than standard care. At cessation of treatment, the microbiome of SDD patients was dominated by Actinomycetota, specifically Bifidobacterium, at the end of mechanical ventilation. Altered gut microbiota was evident in a subset of SDD-treated children who returned late longitudinal samples compared with children receiving standard care. Clinically relevant AMR gene burden was unaffected by the administration of SDD-enhanced infection control compared with standard care. SDD did not affect the composition of the oral microbiome compared with standard treatment. CONCLUSION: Short interventions of SDD caused a shift in the microbiome but not of the AMR gene pool in critically ill children at the end mechanical ventilation, compared with standard antimicrobial therapy.

Rapid Detection of Antimicrobial Resistance Genes in Critically Ill Children Using a Custom TaqMan Array Card.

Bacteria are identified in only 22% of critically ill children with respiratory infections treated with antimicrobial therapy. Once an organism is isolated, antimicrobial susceptibility results (phenotypic testing) can take another day. A rapid diagnostic test identifying antimicrobial resistance (AMR) genes could help clinicians make earlier, informed antimicrobial decisions. Here we aimed to validate a custom AMR gene TaqMan Array Card (AMR-TAC) for the first time and assess its feasibility as a screening tool in critically ill children. An AMR-TAC was developed using a combination of commercial and bespoke targets capable of detecting 23 AMR genes. This was validated using isolates with known phenotypic resistance. The card was then tested on lower respiratory tract and faecal samples obtained from mechanically ventilated children in a single-centre observational study of respiratory infection. There were 82 children with samples available, with a median age of 1.2 years. Major comorbidity was present in 29 (35%) children. A bacterial respiratory pathogen was identified in 13/82 (16%) of children, of which 4/13 (31%) had phenotypic AMR. One AMR gene was detected in 49/82 (60%), and multiple AMR genes were detected in 14/82 (17%) children. Most AMR gene detections were not associated with the identification of phenotypic AMR. AMR genes are commonly detected in samples collected from mechanically ventilated children with suspected respiratory infections. AMR-TAC may have a role as an adjunct test in selected children in whom there is a high suspicion of antimicrobial treatment failure.

A qualitative investigation of paediatric intensive care staff attitudes towards the diagnosis of lower respiratory tract infection in the molecular diagnostics era.

Background: In the past decade, molecular diagnostic syndromic arrays incorporating a range of bacterial and viral pathogens have been described. It is unclear how paediatric intensive care unit (PICU) staff diagnose lower respiratory tract infection (LRTI) and integrate diagnostic array results into antimicrobial decision-making. Methods: An online survey with eleven questions was distributed throughout paediatric intensive care societies in the UK, continental Europe and Australasia with a total of 755 members. Participants were asked to rate the clinical factors and investigations they used when prescribing for LRTI. Semi-structured interviews were undertaken with staff who participated in a single-centre observational study of a 52-pathogen diagnostic array. Results: Seventy-two survey responses were received; most responses were from senior doctors. Whilst diagnostic arrays were used less frequently than routine investigations (i.e. microbiological culture), they were of comparable perceived utility when making antimicrobial decisions. Prescribers reported that for arrays to be clinically impactful, they would need to deliver results within 6 h for stable patients and within 1 h for unstable patients to inform their immediate decision to prescribe antimicrobials. From 16 staff interviews, we identified that arrays were helpful for the diagnosis and screening of bacterial LRTI. Staff reported it could be challenging to interpret results in some cases due to the high sensitivity of the test. Therefore, results were considered within the context of the patient and discussed within the multidisciplinary team. Conclusions: Diagnostic arrays were considered of comparable value to microbiological investigations by PICU prescribers. Our findings support the need for further clinical and economic evaluation of diagnostic arrays in a randomised control trial. Trial registration: Clinicaltrials.gov, NCT04233268. Registered on 18 January 2020. Supplementary Information: The online version contains supplementary material available at 10.1007/s44253-023-00008-z.

Studying Trends of Auto-Regulation in Severe Head Injury in Paediatrics (STARSHIP): protocol to study cerebral autoregulation in a prospective multicentre observational research database study.

INTRODUCTION: Studying cerebral autoregulation, particularly PRx (Pressure Reactivity Index), is commonly employed in adult traumatic brain injury (TBI) and gives real-time information about intracranial pathophysiology, which can help in patient management. Experience in paediatric TBI (PTBI) is limited to single-centre studies despite disproportionately higher incidence of morbidity and mortality in PTBI than in adult TBI. PROJECT: We describe the protocol to study cerebral autoregulation using PRx in PTBI. The project called Studying Trends of Auto-Regulation in Severe Head Injury in Paediatrics is a multicentre prospective ethics approved research database study from 10 centres across the UK. Recruitment started in July 2018 with financial support from local/national charities (Action Medical Research for Children, UK). METHODS AND ANALYSIS: The first phase of the project is powered to detect optimal thresholds of PRx associated with favourable outcome in PTBI by recruiting 135 patients (initial target of 3 years which has changed to 5 years due to delays related to COVID-19 pandemic) from 10 centres in the UK with outcome follow-up to 1-year postictus. The secondary objectives are to characterise patterns of optimal cerebral perfusion pressure in PTBI and compare the fluctuations in these measured parameters with outcome. The goal is to create a comprehensive research database of a basic set of high-resolution (full waveforms resolution) neuromonitoring data in PTBI for scientific use. ETHICS AND DISSEMINATION: Favourable ethical approval has been provided by Health Research Authority, Southwest-Central Bristol Research Ethics Committee (Ref: 18/SW/0053). Results will be disseminated via publications in peer-reviewed medical journals and presentations at national and international conferences. TRIAL REGISTRATION NUMBER: NCT05688462.

The rapid detection of respiratory pathogens in critically ill children.

PURPOSE: Respiratory infections are the most common reason for admission to paediatric intensive care units (PICU). Most patients with lower respiratory tract infection (LRTI) receive broad-spectrum antimicrobials, despite low rates of bacterial culture confirmation. Here, we evaluated a molecular diagnostic test for LRTI to inform the better use of antimicrobials. METHODS: The Rapid Assay for Sick Children with Acute Lung infection Study was a single-centre, prospective, observational cohort study of mechanically ventilated children (> 37/40 weeks corrected gestation to 18 years) with suspected community acquired or ventilator-associated LRTI. We evaluated the use of a 52-pathogen custom TaqMan Array Card (TAC) to identify pathogens in non-bronchoscopic bronchoalveolar lavage (mini-BAL) samples. TAC results were compared to routine microbiology testing. Primary study outcomes were sensitivity and specificity of TAC, and time to result. RESULTS: We enrolled 100 patients, all of whom were tested with TAC and 91 of whom had matching culture samples. TAC had a sensitivity of 89.5% (95% confidence interval (CI95) 66.9-98.7) and specificity of 97.9% (CI95 97.2-98.5) compared to routine bacterial and fungal culture. TAC took a median 25.8 h (IQR 9.1-29.8 h) from sample collection to result. Culture was significantly slower: median 110.4 h (IQR 85.2-141.6 h) for a positive result and median 69.4 h (IQR 52.8-78.6) for a negative result. CONCLUSIONS: TAC is a reliable and rapid adjunct diagnostic approach for LRTI in critically ill children, with the potential to aid early rationalisation of antimicrobial therapy.

Screening for Factors Influencing Parental Psychological Vulnerability During a Child's PICU Admission.

OBJECTIVES: To identify the risks of developing post-traumatic stress disorder (PTSD) and/or depression in parents following their child's PICU admission using a brief screening instrument and to examine the associations with these risks. DESIGN: A cross-sectional parental survey. SETTING: A general 13-bed PICU at a large teaching hospital. SUBJECTS: One hundred and seven parents of 75 children admitted to the PICU. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: All parents completed the 10-item Posttraumatic Adjustment Screen (PAS) before discharge. The PAS assesses risk factors known to be associated with poorer psychological outcome, including psychosocial variables pretrauma and peritrauma, and acute stress. Parents' scores on the PAS indicated that 64 (60%) were at risk of developing PTSD and 80 (75%) were at risk of developing depression following their child's admission. Univariate analyses suggested that psychosocial variables, such as preexisting stressors and a history of previous mental health problems, were more strongly associated with PAS risk scores for PTSD and depression than medical or sociodemographic factors. In logistic regression analyses, a history of previous mental health problems was significantly associated with risk of developing PTSD and depression (p < 0.001) explaining 28% and 43% of the variance in these outcomes. CONCLUSIONS: This study suggests that a significant number of parents on PICU are potentially at risk of developing PTSD and/or depression postdischarge and that psychosocial factors, pretrauma and peritrauma, are stronger determinants of this risk, and of acute distress, than other variables. Identification of vulnerable parents during admission, using a measure such as the PAS, could facilitate the targeting of support and monitoring, acutely and postdischarge, at those who might be most likely to benefit.

Rapid Assay for Sick Children with Acute Lung infection Study (RASCALS): diagnostic cohort study protocol.

INTRODUCTION: Lower respiratory tract infection (LRTI) is the most commonly treated infection in critically ill children. Pathogens are infrequently identified on routine respiratory culture, and this is a time-consuming process. A syndromic approach to rapid molecular testing that includes a wide range of bacterial and fungal targets has the potential to aid clinical decision making and reduce unnecessary broad spectrum antimicrobial prescribing. Here, we describe a single-centre prospective cohort study investigating the use of a 52-pathogen TaqMan array card (TAC) for LRTI in the paediatric intensive care unit (PICU). METHODS AND ANALYSIS: Critically ill children with suspected LRTI will be enrolled to this 100 patient single-centre prospective observational study in a PICU in the East of England. Samples will be obtained via routine non-bronchoscopic bronchoalveolar lavage which will be sent for standard microbiology culture in addition to TAC. A blood draw will be obtained via any existing vascular access device. The primary outcomes of the study will be (1) concordance of TAC result with routine culture and 16S rRNA gene sequencing and (2) time of diagnostic result from TAC versus routine culture. Secondary outcomes will include impact of the test on total antimicrobial prescriptions, a description of the inflammatory profile of the lung and blood in response to pneumonia and a description of the clinical experience of medical and nursing staff using TAC. ETHICS AND DISSEMINATION: This study has been approved by the Yorkshire and the Humber-Bradford Leeds Research Ethics Committee (REC reference 20/YH/0089). Informed consent will be obtained from all participants. Results will be published in peer-reviewed publications and international conferences. TRIAL REGISTRATION NUMBER: NCT04233268.

Low diagnostic yield and time to diagnostic confirmation results in prolonged use of antimicrobials in critically ill children.

Background: Broad-spectrum antimicrobial therapy is a key driver of antimicrobial resistance. Here, we aimed to review indications for antimicrobial therapy, determine the proportion of suspected bacterial infections that are confirmed by culture, and assess the time taken for microbiology test results to become available in the paediatric intensive care unit (PICU). Methods: A single-centre prospective observational cohort study of 100 consecutive general PICU admissions from 30 October 2019 to 19 February 2020. Data were collected from the hospital medical record and entered into a study database prior to statistical analysis using standard methods. Results: Of all episodes of suspected infection, 22% of lower respiratory tract infection, 43% of bloodstream and 0% of central nervous system infection were associated with growth on microbiology culture. 90% of children received antimicrobial therapy. Hospital-acquired infection occurred less commonly than primary infection, but an organism was grown in a greater proportion (64%) of cultures. Final laboratory reports for negative cultures were issued at a median of 120.3 hours for blood cultures and 55.5 hours for endotracheal tube aspirate cultures. Conclusions: Despite most critically children receiving antimicrobial therapy, infection was often not microbiologically confirmed. Novel molecular diagnostics may improve rationalisation of treatment in this population.

Predicting use of high-flow nasal cannula therapy following extubation in paediatrics.

BACKGROUND: High-flow nasal cannula (HFNC) therapy is widely used for respiratory support within paediatrics, most commonly used as a supportive measure in acute respiratory failure, aiming to avoid invasive mechanical ventilation (IMV). It is increasingly being used following extubation of critically ill children potentially at a higher risk of requiring re-intubation. Less data indicate the use for post-extubation HFNC therapy or possible clinical outcomes of this therapy. AIMS AND OBJECTIVES: To identify reasons for, and variables to predict, the use of HFNC therapy post-extubation. DESIGN: This was a retrospective case-control study. METHODS: All children admitted to a nine-bedded regional paediatric intensive care unit requiring IMV between 18 December 2017 and 28 November 2018 were identified. The demographic data and bedside clinical and laboratory variables of the patients requiring HFNC therapy were compared with those who did not require HFNC. RESULTS: There was no statistical difference in the median age and weight of children receiving HFNC therapy post-extubation compared with children not receiving it. In a logistic regression model, the highest ventilation (peak inspiratory pressure) and oxygen requirements in the first 24 hours of admission, along with the presence of comorbidity and use of HFNC therapy prior to intubation, predicted the use of HFNC following extubation, (r2 0.42, area under the receiver operating curve 0.843, P < .0001). CONCLUSIONS: The direct correlation between high initial ventilatory requirements and pre-existing comorbidity was significant for the use of post-extubation HFNC therapy. This may be useful to stratify children in the use of HFNC therapy post-extubation in the critically ill population. RELEVANCE TO CLINICAL PRACTICE: This study provides evidence that it may be possible to predict the use of HFNC therapy post-extubation. Avoiding unnecessary use of this therapy improves patient care while providing a positive economic impact.