PhD defence H. (Hongzhen) Zhu

Below is a brief summary of the dissertation:

Respiratory tract infections are a major global health burden, particularly among children under five years old, accounting for almost one million pneumonia-related deaths each year. the most severe manifestation of a respiratory tract infection is pneumonia, which develops when harmful bacteria or viruses reach the lower respiratory tract. Here, the bacteria or viruses attach to and invade the airway epithelial cells. This process initiates local inflammation and damages the epithelial cells. Inflammation mediators then recruit immune cells to the site of infection, leading to an exudative response within the alveoli. The subsequent accumulation of fluid and cellular debris disrupts gas exchange and oxygenation, underlying the clinical severity of pneumonia. This thesis investigates airway infections caused by bacteria from the Mycoplasmataceae family, specifically Mycoplasma pneumoniae and Ureaplasma species. Mycoplasma pneumoniae is associated with community-acquired pneumonia in children, while Ureaplasma species are linked to bronchopulmonary dysplasia (BPD) in neonates. By examining the host immune response and the inflammation induced by these bacteria, we aimed to clarify how they drive respiratory disease, in order to improve the treatment of children infected with them.