Ever more often, bacteria, viruses, fungi and parasites stop responding to the medicines designed to treat them, such as antibiotics. This antimicrobial resistance (AMR) poses a growing threat, with an estimated 8.22 million deaths globally in 2050.

Armed conflicts are escalating the situation: conflicts in Iraq, Syria, Afghanistan, and Ukraine have shown alarmingly high rates of multidrug-resistant (MDR) organisms colonising war wounds. These MDR pathogens can then spread from soldiers to civilians.

A promising tool against AMR are bacteriophages, or phages: viruses that specifically infect and kill bacteria. While robust evidence from randomised controlled trials is still limited, successful use in individual cases demonstrates their therapeutic potential.

Dr Kārlis Rācenis experienced a case like this with a Ukrainian soldier. He is Vice-Dean of Science, Faculty of Medicine, Riga Stradiņš University (Latvia), member of the RSU Phage Research Group, and keynote speaker at the workshop 'Phage therapy as a tool against antimicrobial resistance: From civilian healthcare to conflict medicine' on 30 September 2026, organised by the European Parliament's Panel for the Future of Science and Technology (STOA).

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Could you walk us through the wartime case from Ukraine - the infection, why phage therapy was chosen, and how combining phages with antibiotics affected the outcome?

Kārlis Rācenis: The patient was a Ukrainian soldier treated in Riga for femoral osteomyelitis after combat trauma, infected with multidrug-resistant Klebsiella pneumoniae. Seven surgeries and seven different antibiotic regimens failed to resolve it.

At that stage, there were no options but a high-level leg amputation with partial pelvic resection or phage therapy. Although our phage bank held no match to this strain, the team had a leftover two-phage cocktail, originally developed with collaborators in Geneva, Switzerland, for an unrelated kidney-transplant patient. We were lucky, because when tested against the soldier's isolate (the separated strain), it worked. Later, sequencing showed that the two infections shared the same bacterial sequence type.

Phages were given intravenously before surgery and then locally into the wound via catheter for about 12 days alongside antibiotics. The infection cleared, the leg was reconstructed, and the patient returned to Ukraine and, after rehabilitation, could walk on his own.

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What was the most significant practical or regulatory obstacle you faced treating this patient?

Kārlis Rācenis: For this patient, the clock was the obstacle: with the infection spreading and amputation the only fallback, any delay in sourcing and approving phages carried a real risk.

The risk was also related to a structural gap rather than anything specific to his case - Europe has no dedicated legal framework for phage therapy. Latvia’s cases, for instance, are handled as 'magistral preparations' (custom-made medications prepared in a pharmacy to meet the specific medical needs of a single patient) under pharmacopeia rules, requiring a multidisciplinary team approval each time.

Further, phages cannot be manufactured in my country, so production happens abroad, adding time and logistics to each case. Together, they can delay treatment or, in the worst case, make it impossible to treat patients in time.

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Beyond phages, what other therapies are being explored as alternatives for multidrug-resistant infections?

Kārlis Rācenis: To my knowledge, real-world options are limited: expensive, fast-tracked new antibiotics or drastic surgery - cutting away tissue until reaching healthy, uninfected blood supply, similar to pre-antibiotic-era medicine.

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What makes phage therapy work, and what does that mean for patient safety?

Kārlis Rācenis: Phages are living viruses, so there are far more of them to find, isolate, and produce than there are antibiotics. Combining phages with antibiotics also exploits a 'trade-off' effect: as bacteria evolve resistance to a phage, they tend to lose the genes that made them resistant to antibiotics, becoming susceptible again - part of why the two treatments together outperform either alone.

On safety, we have monitored the immune system and found a neutralising immune response to the phages. This was likely cross-reactive from prior phage exposure in daily life rather than a specific reaction to this treatment, but that did not affect the clinical outcome.

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Is phage therapy used as an alternative to antibiotics today - as a routine second-line option, or still mainly as a last-resort measure?

Kārlis Rācenis: Currently, it is a last-resort measure: without randomised-trial evidence, phages can't be approved as conventional drugs. However, this kind of highly personalised treatments should be evaluated differently, since running separate trials for every bacteria-phage-indication combination is impractical and, in some cases, unethical given the characteristics of the receiving patients, who are typically out of options.

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How does REPhRAME, a Horizon Europe-funded project on phage therapy and recurrent urinary tract infections, support phage therapy beyond battlefield settings?

Kārlis Rācenis: REPhRAME, led by Maria Vehreschild, is designed as a proof of concept. It pairs phage therapy for an acute infection with microbiota transplantation. This research addresses why these urinary infections recur, aiming to prove both elements can work - a strong test case because it affects large numbers of women and targets the root cause, not just the acute episode.

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What would you want EU citizens and policymakers to take away as the most urgent single action needed to move phage therapy from compassionate use to routine practice?

Kārlis Rācenis: My main message for policymakers would be about the need to have, at minimum, clear regulatory guidance. Not treatment guidelines, since those are already being developed by German colleagues, but legal and regulatory guidance that enables, rather than restricts, phage use in complicated, multidrug-resistant infections.

Two practical initiatives would support this framework: a shared European phage bank, potentially organised at a regional level (for instance across the Baltics), bringing together existing collections rather than scattered across individual institutions; and making registration in a treatment registry obligatory across Europe, since currently only successful cases tend to get reported.

In addition, there should be clear treatment indications for phage therapy in cases such as antibiotic-resistant infections, complicated infections where patients face loss of a limb or their life, and cases of antibiotic intolerance or allergies that rule out antibiotics. However, these indications are not needed for chronic infections rooted in a structural problem that needs surgery to be resolved.

More information and watch live (or the recording) online:

• STOA workshop on 30/9/2026 at 15h CEST in the European Parliament: 'Phage therapy as a tool against antimicrobial resistance'