Treating infections caused by multidrug-resistant bacteria is becoming increasingly challenging. This is especially true for patients in intensive care units, where multiple bacterial infections resistant to most antibiotics can develop simultaneously. This is why scientists are actively exploring the potential of personalized phage therapy as a complement to traditional treatment.

In July 2026, a clinical case of a 40-year-old patient with severe lung infections caused by three multidrug-resistant bacteria: Acinetobacter baumannii , Klebsiella pneumoniae , and Stenotrophomonas maltophilia was published in the journal Nature Communications . Previous antibiotic treatment had failed to fully control the infection, so doctors decided to use personalized phage therapy.

What made this case unique was that there was no universal treatment. For each bacterium, the researchers individually selected bacteriophages capable of destroying the specific strain isolated from the patient. A total of seven courses of phage therapy were administered during the treatment, the composition of which was modified depending on the predominant bacteria in the lungs and their response to therapy. All stages of treatment were combined with antibiotic therapy and constant laboratory monitoring.

The results were encouraging. Treatment was accompanied by a reduction in bacterial load, body temperature, and levels of procalcitonin and interleukin-6—markers of inflammation. Furthermore, according to examination data, lung function improved. One of the bacteria, Acinetobacter baumannii , was completely eliminated. Meanwhile, the other two periodically reappeared due to shifting bacterial strains and the development of resistance to certain bacteriophages. This once again demonstrated that phage therapy requires constant monitoring and, if necessary, adjustments to the composition of phage preparations.

The authors emphasize that this clinical case demonstrates not only the potential of personalized phage therapy but also the complexity of its implementation. Unlike antibiotics, phage therapy may require individual selection and adaptation during treatment. Despite this, the study provides further important evidence that a personalized approach can help patients with severe multidrug-resistant infections when standard treatments no longer provide the desired results.