Reinventing the fight against bacteria,
one phage at a time.

Bacteria possess sophisticated antiviral defence systems capable of detecting bacteriophage infection and preventing viruses from spreading through a population. A new study published in Science has now uncovered an unusual mechanism used by one of the most widespread bacterial immune pathways: the bacterium detects infection when a phage enzyme directly modifies a host protein, transforming an essential viral activity into the signal that launches an antiviral response. The work was carried out by Samuel J. Hobbs, assistant professor of biochemistry at University of Utah Health, and Philip J. Kranzusch, professor of microbiology at Harvard Medical School. Their study, titled “Phage proteases activate CBASS antiphage immunity,” was published on October 1, 2026 and focuses on CBASS, or cyclic oligonucleotide-based antiphage signalling systems, a major family of bacterial defence pathways that can stop phage replication by triggering a powerful intracellular response. CBASS systems oper...

One of the fundamental problems in phage therapy is deceptively simple: given a patient's bacterial isolate and a collection containing hundreds or thousands of bacteriophages, which phage should be tested first? A study published in Nature Microbiology presents a machine-learning framework designed to answer that question directly from bacterial and phage genome sequences. Rather than relying on a predefined receptor, a particular bacterial lineage or previous knowledge of the molecular mechanisms controlling infection, the system attempts to predict whether an individual phage will infect an individual bacterial strain. The work was led by Avery J. C. Noonan and colleagues from Lawrence Berkeley National Laboratory, the University of California Berkeley and Pennsylvania State University, with Vivek K. Mutalik and Adam P. Arkin among the senior authors. The study brings together computational modelling, large phage–host interaction datasets and experimental genetic validation to ...

The European Medicines Agency will convene a major workshop dedicated to bacteriophage therapy on 30 October 2026, bringing together European and international regulators, scientists, clinicians, developers, healthcare professionals and patient representatives. Held at EMA headquarters in Amsterdam and simultaneously accessible online, the meeting will focus on one of the most persistent obstacles to the wider clinical development of phage therapy in Europe: how to regulate a treatment whose composition may need to change according to the bacterial strain infecting an individual patient. Bacteriophages do not always fit comfortably within the conventional pharmaceutical model. Most medicines are developed around an active substance and composition that remain well defined throughout development and after authorization. Personalized phage therapy can operate very differently. A patient's bacterial isolate may need to be tested against a library of phages, one or several matching vir...

When we created The Phage Therapy in 2025, our goal was simple: make reliable information about bacteriophages and phage therapy easier to find, understand and access. What started as a scientific information website has grown into something much larger. Today, researchers, clinicians, students, biotechnology professionals and people interested in bacteriophages visit The Phage Therapy from around the world. More than 103,000 visits have now been recorded since the beginning of the project. And the growth is accelerating. Last month, The Phage Therapy received almost 14,000 visits. This month, we have already passed 22,500. Our current traffic is now approaching an average of 900 visits every day. For a website dedicated to such a specialized scientific field, these numbers mean a lot to us. They show that there is a real need for a place where information about bacteriophages can be gathered, explained and made accessible. But we want to grow without changing what made this project us...

One of the biggest practical limitations of phage therapy is specificity. A bacteriophage capable of efficiently killing one bacterial strain may be completely ineffective against another strain of the same species, forcing clinicians to search through collections of viruses until they find a suitable match. Researchers at McMaster University have now identified a structural feature that may help explain why a minority of phages escape this constraint. In a study published in the Proceedings of the National Academy of Sciences , the team reports that phages able to infect a broader range of Pseudomonas aeruginosa strains display greater structural diversity in the portions of their tail fibres that directly contact the bacterial surface. McMaster professor Lori Burrows (left) and PhD candidate Ikram Qaderi have identified key markers that will make it easier to find phages with broader therapeutic potential. The work was led by Ikram Qaderi, a PhD candidate in Lori Burrows’ laborator...

Bacteriophages contain enormous numbers of genes whose functions remain unknown, even in viruses that have been studied for decades. That genomic “dark matter” is becoming increasingly important as phages move from model systems in molecular biology toward potential tools against multidrug-resistant bacterial infections. A study published in Nature Microbiology now introduces a high-throughput strategy designed to systematically determine which phage genes matter, when they matter and which bacterial defences they help viruses overcome. Fig. 1 | Combining transposition and CRISPR–Cas13a-based selection as HIDEN-SEQ for phage T4.a, Transposition introduces an anti-CRISPR gene (acr) randomly into TA dinucleotide sites within the phage genome. The acr expression inhibits CRISPR–Cas13a immunity and enables the selection of a library of phage transposon mutants. Deep sequencing of insertion sites is performed to quantify the abundance of transposon mutants before (as reference) and after e...

Researchers at the University of Wisconsin–Madison have used machine learning to redesign one of the most important properties of a bacteriophage: deciding which bacteria it can infect. Rather than simply asking an algorithm to make phage T7 more infectious, the team trained models to simultaneously control infectivity and specificity, producing engineered phages that could attack selected Escherichia coli strains while avoiding others. The work, published in Cell Systems , provides a striking demonstration of how artificial intelligence could eventually turn naturally occurring phages into more precisely programmable antibacterial agents. One promising approach to targeting unwanted bacteria is phage therapy, which uses naturally occurring and engineered viruses known as phages (illustrated above, resting on the surface of a host cell) to infect and destroy specific bacteria. Courtesy of the Raman Lab The study, Multiobjective learning and design of bacteriophage specificity , was le...