A new study, entitled, “Pseudomonas aeruginosa adaptation in the nasopharyngeal reservoir leads to migration and persistence in the lungs,” conducted at the University of Liverpool’s Institute of Infection and Global Health, UK, published in Nature Communications, and led by the group of the Professors Aras Kadioglu and Craig Winstanley, show for the first time a new reservoir of infection, the nasopharynx, by Pseudomonas aeruginosa that may explain recurrent infections and the development of chronic lung infection in patients with cystic fibrosis (CF).
These two research groups, in joint collaboration, established a new model that closely mimics the human disease situation and enables the study of Pseudomonas aeruginosa infection in that context. They showed for the first time that Pseudomonas aeruginosa colonized the nasopharynx, the upper part of the throat behind the nose, for long periods before migrating into the lungs causing chronic infection.
“We have discovered that the nasopharynx acts as a silent reservoir for bacteria from which more serious infections in the lungs can develop,” said the joint first author of the study, microbiologist Dr. Jo Fothergill. “This finding may explain why patients often suffer from recurrent infections with the same bacterial strain as continual re-infection of the lungs from the upper airways can take place,” added the other first author, immunologist Dr Dan Neill.
Pseudomonas aeruginosa is usually not infectious to humans, but in CF or immune-incompetent patients, weak or failed immune systems can induce infections that are resistant to antibiotics, leading to chronic lung disease and ultimately to respiratory failure. Notably, in CF patients, recurrent lung infections with Pseudomonas aeruginosa are the main cause of morbidity and mortality.
The novel finding that bacteria first establishes in the upper respiratory tract before infecting the lungs and developing into chronic lung infection, contrary to previous studies that focused only in the lungs, is a step forward in the understanding of recurrent infections by Pseudomonas aeruginosa in CF patients. “A better understanding of the way these bacteria colonize and adapt to the human body provides important new information about how we might prevent this process in more vulnerable people,” said Professor Kadioglu, one of the senior authors of the study. Finally, the researchers conclude that this study is a major contribution for the development of more effective treatments by targeting the bacteria infection at initial site and stage of infection before the establishment of lung chronic infection, since at this stage the use of antibiotics is not a viable option.