Surveillance of Neonatal Endotracheal Tube Colonisation

Overview

Babies in neonatal intensive care units (NICUs) sometimes need help breathing using a breathing tube (endotracheal tube, or ETT) connected to a breathing machine (ventilator). Over time, bacteria and other substances can build up on the inside of these tubes. This build-up may contribute to infections, inflammation, or breathing problems, but we do not fully understand how often this occurs or what is present within the tubes used in UK NICUs. This surveillance study will collect breathing tubes that have been removed from babies who have been ventilated for more than 12 hours as part of their normal clinical care. No additional procedures or interventions will be performed on babies, and the tubes would otherwise be discarded. Researchers will examine the used tubes and any respiratory secretions (mucus) associated with them. Laboratory testing will identify any bacteria or other microorganisms present and analyse the chemical composition that has accumulated within the tubes and respiratory secretions. By studying these samples, we hope to better understand how breathing tubes become colonised over time and how this may relate to infection and lung health in newborn babies. This study aims to identify the microorganisms that colonises ETT and map them in a contemporary UK neonatal cohort. The information gained from this study may help improve infection surveillance, guide future research, and support the development of strategies to reduce complications associated with mechanical ventilation in vulnerable newborn infants.

Every year, over 90,000 babies, including 20,000 preterm infants, are admitted to UK neonatal units. Globally, 13.4 million babies are born prematurely and are at high-risk of dying or developing long-term disease or disability. Preterm infants are more susceptible to late-onset infections (LOIs, which include bacterial, viral and fungal) due to their immature immune systems, with reduced innate and adaptive immunity. These occur after 72 hours of age and are associated with significant mortality (13-19%) and morbidity in high-risk infants. Published studies, have demonstrated LOIs in preterm infants are associated with the development of bronchopulmonary dysplasia (BPD), a life-long severe breathing condition caused by infection, inflammation and abnormal lung development. Ventilator-associated pneumonia (VAP) is a leading cause of LOI in infants, causing significant mortality, morbidity and increasing length of ventilation and hospital stay. In preterm infants, LOIs are associated with a 2-4-fold increase in neurodevelopmental impairment (NDI) and cerebral palsy. Both LOIs and BPD are associated with severe NDI, which is estimated to reduce the infant's life expectancy by 15 years and increase NHS costs by £19,000. In England and Wales in 2020, 55% of preterm infants born at \<28 weeks gestation either died or had severe BPD, and 88% were ventilated soon after birth for an average of 12 days, equating to \>23,000 ETT ventilated days in this population alone. Newborn infants admitted to neonatal units have never gone home and so in most cases acquire LOIs in hospital i.e., hospital-acquired infections. Many require life support from medical devices such as endotracheal tubes (ETT), nasogastric tubes, intravenous lines and incubators. Whilst lifesaving, up to 76% of these devices become colonised with pathogenic microbial biofilms, usually within 24 hours of use. Microbial attachment, or colonisation, to the surface of medical device can develop into surface-associated "slime layers", these are up to 1000 times more resistant to antibiotic and host immune system clearance making eradication unlikely. In ventilated preterm infants, 82% of ETTs become colonised and this is associated with a 4.5-fold increase in the risk of septicaemia. Even prepared but unused neonatal ETTs rapidly become colonised with up to three different organisms in 79% of cases. These biofilms pose an infection risk to highly vulnerable infants, especially those born prematurely where an adverse airway microbiome is associated with BPD progression and severity. Every year in Europe and North America alone, over 38,000 surviving preterm babies develop BPD, affecting long-term respiratory health and cognitive development. Neonatal antimicrobial clinical trials aimed at reducing LOI and/or BPD do not address the optimal approach of avoiding or significantly reducing antimicrobial use (antibiotic stewardship), which can result in resistance, by using novel approaches to prevent biofilm formation and subsequent infection. At present, there is a paucity of data of microbial biofilm colonisation of ETT in a contemporary UK neonatal population. We proposed conducting the first surveillance study on microbial colonisation and biofilm transformation in ETT in two neonatal units in the UK. This surveillance study will provide invaluable data, helping us to better understand biofilm formation within the neonatal population, and map the common neonatal pathogens in a contemporary UK neonatal cohort. The results from this surveillance study will inform the planning of future research to reduce biofilm colonisation within ETT.