Exploring the role of pathogen interactions in transitioning of ventilator-associated tracheobronchitis to pneumonia

• Applicants: Dr. Oliwia Makarewicz; Professor Dr. Alexander Mosig, Ph.D.
• Subject Area: Pneumology, Thoracic Surgery ; Medical Microbiology and Mycology, Hygiene, Molecular Infection Biology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 550487586

Pseudomonas aeruginosa (PA) and Staphylococcus aureus (SA) are amongst the two most common pathogens often associated with lung infections in healthcare settings, such as ventilator-associated pneumonia (VAP) or ventilator-associated tracheobronchitis (VAT). These bacteria can act antagonistically or synergistically, depending on their subtypes, phenotypes and different foci of infection. Staphylococcus. epidermidis (SE) and Candida albicans (CA) are common commensals and can be isolated from respiratory samples although they are not associated with pneumonia. The project intends to investigate the complex relationship between PA, SA, SE and CA in a multifaceted approach. First, clinical isolates from VAT/VAP or mechanically ventilated (MV) colonized patients will be genomically and microbiologically characterized and their biofilm forming capabilities and dynamics in mixed biofilms will be assessed in vitro. Secondly, these isolates will be further investigated in a lung-on-a-chip model and in an immune-humanised mouse model to elaborate the impact of the immune response as an essential effector. Specifically, the likely protective effect of SE and infection potentiating effect of CA colonization on SA and PA interactions and on pneumonia development will be studied in context of humanized host responses. Lastly, the bacterial populations will be studied in depth using single cell approaches to investigate the inter- and intra-species interaction from colonization to infection. Through these analyses we will elucidate the process of VAT to VAP progression as well as a potential probiotic use of SE in preventing VAP.

• DFG Programme: Research Grants
• International Connection: Belgium
• Partner Organisation: Fonds Wetenschappelijk Onderzoek - Vlaanderen ; Research Foundation Flanders (FWO)
• Cooperation Partners: Professor Dr. Samir Kumar-Singh; Professorin Dr. Surbhi Malhotra