For the first time, the University of Oxford has discovered that drug-resistant bacteria can move from the intestines to the lungs

Researchers at the University of Oxford have published a new study in the journal Nature Communications that has found for the first time that drug-resistant bacteria can migrate from a patient's intestines to the lungs
.
The discovery is important and may be able to save patients' lives, as it underscores the need to stop pathogenic bacteria from moving from the intestines to other organs to avoid causing serious infections
.

The study was conducted
in a patient carrying Pseudomonas aeruginosa.
This bacterium is one of the leading causes of nosocomial infections and is particularly resistant to antibiotics
.
When Pseudomonas implant into healthy intestinal flora, it is not generally considered dangerous, but it can cause serious infections
in the lungs of hospitalized patients.

During hospitalization, the patient is treated
with the antibiotic meropenem for suspected urinary tract infection.
Drug treatment results in the killing of non-resistant bacteria in the gut and lungs, while antibiotic-resistant Pseudomonas mutants grow and proliferate
.

Later, they found that Pseudomonas aeruginosa transferred from the intestine to the patient's lungs during antibiotic treatment, where it evolved higher levels of
antibiotic resistance.

With growing concern about antibiotic resistance in hospitals, preventing the spread of resistant bacteria to other vital organs is critical
for vulnerable patients.
However, the source of the bacteria that causes serious infections is difficult to determine
.
This study shows how the gut microbiota acts as a reservoir for drug-resistant pathogens that can metastasize to the lungs and cause life-threatening diseases
such as pneumonia.

The study's findings also show that eliminating drug-resistant pathogens from the gut microbiome of hospitalized patients can prevent serious infections, and highlight how antibiotic use can have a profound impact
on bacteria beyond the true target.

The researchers tested patients during their hospitalization to track the duration
of Pseudomonas aeruginosa infection.
Using a genetic method, they built a time-calibrated bacterial family tree that allowed them to analyze the progression and location of infection, as well as the evolution
of bacteria.
They also found a high degree of genetic diversity in the gut, suggesting that the microbiome may be a reservoir for resistance formation
.

Fortunately, the patient developed an immune response to drug-resistant bacteria in his lungs, preventing the infection from causing pneumonia
.
However, for many critically ill patients, especially during the winter months, the immune system is weaker, which means that the body is less
able to fight off disease.
The strategy for preventing resistance is often to reduce infection from external sources, but understanding how resistance develops and spreads in patients is equally critical
.

The researchers intend to take samples from a larger study cohort in order to assess how often
gut bacteria metastasize to the lungs in susceptible patients.

Professor Craig MacLean of the Department of Biology at the University of Oxford said: "It is clear that we need to develop new ways to deal with the challenges
posed by drug resistance.
Our research shows how gut-lung translocations and antibiotic use combine to drive the spread
of resistant bacteria in patients.
”

"Once drug-resistant pathogens form in a patient, they are difficult to clear.

Our work also highlights the importance of avoiding the misuse of antibiotics and the importance of
developing antimicrobial therapies that only target the bacteria that actually cause the infection.
”

Original search

Wheatley, R.
M.
, Caballero, J.
D.
, van der Schalk, T.
E.
et al.
Gut to lung translocation and antibiotic mediated selection shape the dynamics of Pseudomonas aeruginosa in an ICU patient.
Nat Commun 13, 6523 (2022).
https://doi.
org/10.
1038/s41467-022-34101-2