Eugen Pfeifer
@eugenpfeifer.bsky.social
Junior Professor @
MICALIS, Jouy-en-Josas, INRAE (France)
Passionated about gut phages, especially the temperate and episomal ones (phage-plasmids).
MICALIS, Jouy-en-Josas, INRAE (France)
Passionated about gut phages, especially the temperate and episomal ones (phage-plasmids).
We believe that its phages are the key players!
By targeting these dominant bacteria, these phages create opportunities for other bacterial species to re-colonize, ultimately helping to regain diversity in the gut!
By targeting these dominant bacteria, these phages create opportunities for other bacterial species to re-colonize, ultimately helping to regain diversity in the gut!
July 28, 2025 at 8:41 AM
We believe that its phages are the key players!
By targeting these dominant bacteria, these phages create opportunities for other bacterial species to re-colonize, ultimately helping to regain diversity in the gut!
By targeting these dominant bacteria, these phages create opportunities for other bacterial species to re-colonize, ultimately helping to regain diversity in the gut!
We believe that "Kill-the-Winner" dynamics are at play: Antibiotics create a disturbance allowing certain bacteria to flourish.
Parabacteroides distasonis is one of those, and typically thrives after cephalosporin treatment.
What wasn't fully understood was why it loses its dominance.
Parabacteroides distasonis is one of those, and typically thrives after cephalosporin treatment.
What wasn't fully understood was why it loses its dominance.
July 28, 2025 at 8:41 AM
We believe that "Kill-the-Winner" dynamics are at play: Antibiotics create a disturbance allowing certain bacteria to flourish.
Parabacteroides distasonis is one of those, and typically thrives after cephalosporin treatment.
What wasn't fully understood was why it loses its dominance.
Parabacteroides distasonis is one of those, and typically thrives after cephalosporin treatment.
What wasn't fully understood was why it loses its dominance.
3rd: Despite the initial loss of some phage species, we saw a temporary and significant increase in the number of dominant, virulent phages. But why?
July 28, 2025 at 8:41 AM
3rd: Despite the initial loss of some phage species, we saw a temporary and significant increase in the number of dominant, virulent phages. But why?
2nd: Gut phages are unique to each individual (nothing new) and here we show that your unique phage "fingerprint" largely persists even after strong perturbations. So, in a way, your phages remain truly yours!
July 28, 2025 at 8:41 AM
2nd: Gut phages are unique to each individual (nothing new) and here we show that your unique phage "fingerprint" largely persists even after strong perturbations. So, in a way, your phages remain truly yours!
We studied the dynamics of gut phage populations in healthy individuals who received antibiotic treatment: 3rd Gen Cephalosporins.
1st: Antibiotics💊do not only just affect bacteria🦠 but also their viruses. We observed a 20% decrease in the richness+diversity, but (lucky us) it recovers over time!
1st: Antibiotics💊do not only just affect bacteria🦠 but also their viruses. We observed a 20% decrease in the richness+diversity, but (lucky us) it recovers over time!
July 28, 2025 at 8:41 AM
We studied the dynamics of gut phage populations in healthy individuals who received antibiotic treatment: 3rd Gen Cephalosporins.
1st: Antibiotics💊do not only just affect bacteria🦠 but also their viruses. We observed a 20% decrease in the richness+diversity, but (lucky us) it recovers over time!
1st: Antibiotics💊do not only just affect bacteria🦠 but also their viruses. We observed a 20% decrease in the richness+diversity, but (lucky us) it recovers over time!
A great example:
Parabacteroides distasonis known to bloom after treatment🦠➡️🔋and only when its phages were absent.
But when they (phages) were around and burst 📈 P. distasonis bacteria were hardly detectable 🦠➡️🪫
Parabacteroides distasonis known to bloom after treatment🦠➡️🔋and only when its phages were absent.
But when they (phages) were around and burst 📈 P. distasonis bacteria were hardly detectable 🦠➡️🪫
February 10, 2025 at 9:55 AM
A great example:
Parabacteroides distasonis known to bloom after treatment🦠➡️🔋and only when its phages were absent.
But when they (phages) were around and burst 📈 P. distasonis bacteria were hardly detectable 🦠➡️🪫
Parabacteroides distasonis known to bloom after treatment🦠➡️🔋and only when its phages were absent.
But when they (phages) were around and burst 📈 P. distasonis bacteria were hardly detectable 🦠➡️🪫
🧐We believe these phages help gut recovery! 🛡️
They prevent bacterial blooms of (e.g., antibiotic-resistant) species that would otherwise dominate the gut.
They prevent bacterial blooms of (e.g., antibiotic-resistant) species that would otherwise dominate the gut.
February 10, 2025 at 9:55 AM
🧐We believe these phages help gut recovery! 🛡️
They prevent bacterial blooms of (e.g., antibiotic-resistant) species that would otherwise dominate the gut.
They prevent bacterial blooms of (e.g., antibiotic-resistant) species that would otherwise dominate the gut.
💥 Most surprising: some phages thrived the day after treatment! More than on any other day.
🚀 BUT: these phages were virulentand NOT induced prophages. So, what is their role 🤔?
🚀 BUT: these phages were virulentand NOT induced prophages. So, what is their role 🤔?
February 10, 2025 at 9:55 AM
💥 Most surprising: some phages thrived the day after treatment! More than on any other day.
🚀 BUT: these phages were virulentand NOT induced prophages. So, what is their role 🤔?
🚀 BUT: these phages were virulentand NOT induced prophages. So, what is their role 🤔?
So, what happens to gut phages after antibiotics?🤔 20% of them vanished after treatment 📉, but over time, recovery occurred
📌The response was highly individual-specific, reinforcing the uniqueness of each person’s microbio- and phageome!
📌The response was highly individual-specific, reinforcing the uniqueness of each person’s microbio- and phageome!
February 10, 2025 at 9:55 AM
So, what happens to gut phages after antibiotics?🤔 20% of them vanished after treatment 📉, but over time, recovery occurred
📌The response was highly individual-specific, reinforcing the uniqueness of each person’s microbio- and phageome!
📌The response was highly individual-specific, reinforcing the uniqueness of each person’s microbio- and phageome!
We found >6400 phage species🧮, lots of high quality🌟, most predicted to be temperate, ca. 1900🆕 ones, and (super exciting!) a lot are also phage-plasmids!
February 10, 2025 at 9:55 AM
We found >6400 phage species🧮, lots of high quality🌟, most predicted to be temperate, ca. 1900🆕 ones, and (super exciting!) a lot are also phage-plasmids!
🧐We fine-tuned the analysis of the phageome part taken from the CEREMI trial🔍
Briefly: 22 volunteers (healthy background) received antibiotic treatment💊 typical for a clinical setting. Their 💩 were analyzed over a period up to 180 days after treatment for phages and bacteria
Briefly: 22 volunteers (healthy background) received antibiotic treatment💊 typical for a clinical setting. Their 💩 were analyzed over a period up to 180 days after treatment for phages and bacteria
February 10, 2025 at 9:55 AM
🧐We fine-tuned the analysis of the phageome part taken from the CEREMI trial🔍
Briefly: 22 volunteers (healthy background) received antibiotic treatment💊 typical for a clinical setting. Their 💩 were analyzed over a period up to 180 days after treatment for phages and bacteria
Briefly: 22 volunteers (healthy background) received antibiotic treatment💊 typical for a clinical setting. Their 💩 were analyzed over a period up to 180 days after treatment for phages and bacteria