LSTM’s Seminar Series continued this week with a presentation by Dr Debby Bogaert, from the Department of Paediatric Immunology at the University Medical Centre Utrecht, Utrecht, The Netherlands. Her presentation entitled: The role of the respiratory ecosystem in susceptibility to respiratory infection in infants, was introduced by LSTM’s Dr Daniela Ferreira.
Dr Bogaert began by looking at the global burden of respiratory disease in children, pointing out that while there has been a concerted international effort to prevent it, it remains among the leading causes of death in young children across the world.
The main reservoir for respiratory pathogens, both viral and bacterial, is the upper respiratory tract. From there, pathogens, such as Streptococcus pneumoniae, might spread either locally or systemically, causing diseases ranging from otitis to life-threatening pneumonia and meningitis. Given the fact that the majority of healthy children are colonised with these pathogens, Dr Bogaert and her group have set out to answer the question as to why some children will get ill and others will not. She explained the importance of the human microbiome, which is the collection of commensals and pathogens that are present in the human body, pointing out its importance in stimulating the immune system, the development of the mucosal and skin barriers and containment of invading or resident pathogens. Dr Bogaert hypothesizes that specific microbiota in the upper respiratory tract are associated with either respiratory health and disease and speculates that these so called ‘microbiota profiles’ are in turn related to environmental factors, including feeding type and antibiotics.
Given the fact that children are susceptible to respiratory infections from the moments following birth she explained that her group designed a study, sampling children at different time points from the moment of birth until the age of 9 months. DNA is extracted from the samples and she explained the process of gene sequencing to look at the abundance of the different bacteria present and how quantities of various bacteria change over time, looking at reasons for these changes through the detailed questionnaires taken with each sample.
Dr Bogaert’s work, along with other studies that she talked through, show that certain environmental factors have a big impact on the profile of the microbiome and its changes. These include the method of delivery, with different bacteria present in children delivered vaginally or by C-section and feeding type; whether children are bottle or breast fed. She discussed some studies that studied how the profile of bacteria changes during periods of illness and looked at the impact that antibiotics may have.
She concluded by saying that there are still questions that need to be answered to see how different profiles can apparently be associated with fewer periods of sickness and if profiles can relate to the severity of illness, and calling for bigger cohorts of children to be recruited to continue the work. Dr Bogaert is collaborating with Dr Ferreira to examine how respiratory microbiome profiles are associated with susceptibility or protection following pneumococcal exposure in human challenged with pneumococcus using LSTM’s EHPC model.