This article is more than 1 year old
Important research uncovers new information about Pseudomonas aeruginosa lung infections
The researchers found differences in which variants of Pseudomonas aeruginosa (P. aeruginosa) cause infections in people with CF and people who do not have CF. They also found out why these differences exist. This research was funded by our CF Innovation Hub on lung health at the University of Cambridge led by Professor Floto. Here we explain more about their research and what they found.
How did P. aeruginosa evolve and adapt to cause such serious lung infections?
Dr Weimann and colleagues analysed over 9,800 samples of P. aeruginosa lung infection, from people with CF, people with chronic obstructive pulmonary disease (COPD) and people with non-CF bronchiectasis. It turns out that only 21 variants or ‘epidemic clones’ of P. aeruginosa are responsible for causing over half of all P. aeruginosa infections across the world. Over the last 200 years, epidemic clones have repeatedly emerged in different locations. As people began to move around so did these bugs, and they’re now widespread across the globe.
Having infected the lungs, these bacteria then evolve in different ways to become even more specialised for a particular lung environment. What is remarkable is that some of these P. aeruginosa clones mainly infect people with CF, and some only infect people who do not have CF. This suggests a complex interplay between human and bacterial genetics.
What makes infection-causing variants different to other variants of P. aeruginosa?
To understand this the researchers conducted genetic analysis of the bacteria. They found that the epidemic clones gained new genes from different species of bacteria nearby. These new genes made them more able to survive in the lungs compared to other variants.
Macrophages are cells in the body that help fight infection. The researchers found that the variants of P. aeruginosa causing lung infections in people with CF could survive in their macrophages. This is a remarkable feat as macrophages usually destroy bacteria by engulfing and digesting them.
Prof Floto and colleagues did additional studies to understand this result in more detail. Looking at the properties of macrophages with CF mutations and those without, they uncovered new evidence to understand why people with CF are susceptible to infections.
Our research on Pseudomonas has taught us about the biology of CF and revealed important ways we might be able to improve immunity against invading bacteria in CF and potentially other conditions.
Professor Floto, Director of the UK Cystic Fibrosis Innovation Hub at the University of Cambridge and Royal Papworth Hospital and senior author on this study
From a clinical perspective, this study has revealed important information about Pseudomonas. The focus has always been on how easily this infection can spread between people with CF, but we’ve shown that it can spread with worrying ease between other people, too. This has very important consequences for infection control in hospitals, where it is not uncommon for an infected individual to be on an open ward with someone potentially very vulnerable
Collaborating across the world
It took a lot of work to gather information to do the analysis. Researchers from other labs at the University of Cambridge to researchers in Canada shared their genetic data and samples with colleagues at the Innovation Hub. Other studies in the publication have involved collaborating with scientists with expertise in working with zebrafish to gene editing.
“These results have important implications for preventing the spread of Pseudomonas aeruginosa lung infections in the future, for people with CF and for those with other lung conditions. We’re incredibly proud to have supported scientists at the Innovation Hub who conducted this research and some of their collaborators who were funded through our Strategic Research Centre programme. Without your generous donations to the Trust this work would not have been possible, thank you,” said Dr Lucy Allen, Director of Research and Healthcare Data at Cystic Fibrosis Trust.
You can read more about the study in the press release from the University of Cambridge, and read the research paper in full online: Aaron Weimann et al. ,Evolution and host-specific adaptation of Pseudomonas aeruginosa. Science385,eadi0908(2024). DOI:10.1126/science.adi0908
To read more about the CF Innovation Hub, read our CF Innovation Hub impact report published in April 2024.
Read more about the Innovation Hub
With your help, we will find the answers to make sure more people with CF live longer, healthier lives. Donate today and help us unite for a life unlimited.