A new study published today in Nature Communication from the Department of Biology at the University of Oxford has found the first direct evidence of the migration of antibiotic-resistant bacteria from a patient’s gut microbiome to the lungs. Application of the results of this study could save lives, as it highlights the importance of preventing pathogenic bacteria from moving from the intestine to other organs where they can cause serious infections.
The study was conducted on a patient carrying the bacteria Pseudomonas aeruginosa as part of their gut microbiome. This species is one of the main causes of infections in hospitals, and particularly resistant to antibiotics. Whereas Pseudomonas is generally not considered harmful when integrated into a healthy gut microbiota, it can cause serious infections in the lungs of hospitalized patients.
While in hospital, the patient was treated with the antibiotic Meropenem for a suspected urinary tract infection (UTI). Meropenem treatment caused the destruction of non-resistant bacteria in the intestine and lungs, andantibiotic resistant mutants of Pseudomonas were able to grow and proliferate.
Pseudomonas was later found to jump from the intestine to the patient’s lungs during antibiotic treatment, where it developed even higher levels of antibiotic resistance.
With AMR being a growing concern in hospitals, it is essential to prevent the spread of AMR bacteria to other vital organs such as the lungs in vulnerable patients. However, the origin of the bacteria that cause these serious infections can be difficult to determine. This study shows how the gut microbiome can act as a reservoir of RAM pathogens that can travel to the lungs where they have the potential to cause life-threatening diseases such as pneumonia.
The results of this study suggest that eliminating AMR pathogens from the gut microbiome of hospitalized patients could help prevent serious infections, and it highlights how antibiotic use can have profound impacts on bacteria that don’t. are not really the target of antibiotic treatment.
The researchers tested the patient throughout his hospital stay to track the duration of his infection with Pseudomonas. They used a genetic approach, creating a time-calibrated bacterial family tree that allowed them to analyze the progression and location of the infection, as well as its evolution. They also found great genetic diversity in the gut, which also suggests that the microbiome could be a reservoir for the onset of AMR.
Fortunately, the patient in this case had an immune response to the AMR bacteria in his lungs, preventing the infection from causing pneumonia. However, many people in critical conditions, especially during the winter, have weakened immune systems, which means the body is less able to fight off disease. AMR policies often focus on reducing infections from external sources, but understanding how AMR can develop and spread in a patient is just as vital.
The researchers now intend to assess how frequently bacterial gut-to-lung translocation occurs in vulnerable patients by collecting samples from a much larger cohort.
Professor Craig MacLean, a professor in the Department of Biology, said:
“There is a clear need to develop new approaches to address the challenges posed by antimicrobial resistance. Our study shows how gut-lung translocation and antibiotic use can combine to promote the spread of AMR in the same patient. Such knowledge is needed to develop new interventions to prevent resistant infections. For example, our study highlights a potential benefit of eliminating RAM bacteria like Pseudomonas aeruginosa gut microbiota of hospitalized patients, even when these bacteria do not actually cause infection.
‘AMR pathogens can be difficult to eliminate from patients once they become established, and our work also highlights the importance of avoiding unnecessary antibiotic use and developing antibacterial treatments that only target bacteria. that actually cause infection.
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