Bacteriophages: natural viruses that help fight bacterial infections

As antibiotic-resistant bacteria continue to rise, many patients suffering from chronic infections are looking for safe, personalised alternatives. Among them, phage therapy, based on the use of bacteriophages, is attracting renewed interest.

But what exactly are these “phages”? Are they viruses? Are they safe? And why is interest in them returning after a century of neglect? This article simply explains their nature, how they work, as well as their advantages and limitations, with internal and external links to reliable resources.

Bacteriophages, or phages, are natural viruses that infect and destroy only bacteria. Discovered in the early 20th century, they are found everywhere: in water, soil, and the human microbiome. To consider treatment, start with a free and confidential medical assessment.

Understanding bacteriophages

Structure and composition

A bacteriophage (20–200 nm) consists of: (1) a DNA/RNA genome, (2) a protective protein capsid, and (3) a tail/attachment fibres, depending on the family. See the diagram below.

Extreme precision: one phage, one target

Key-and-lock recognition between the phage fibres and bacterial receptors. This specificity justifies the phage sensitivity test, which matches the right phages to the patient’s bacterium while preserving the microbiome.

The main families of phages

Myoviridae (ex. T4), Siphoviridae (ex. λ), Podoviridae, Inoviridae…

Taxonomic revision (ICTV) → order Caudovirales. See references.

Major ecological role

Phages massively recycle bacterial biomass, particularly in the oceans, and may modulate

Life cycle: lytic vs lysogenic

Lytic (used clinically): injection, replication, lysis.
Lysogenic: dormant integration, not used in treatment.

In clinical practice, only strictly lytic phages are used. Practical details: phage treatments.

How do phages work?

Attachment to specific receptors → injection of genetic material → production of new phages → bacterial lysis → local self-amplification. This mechanism makes it possible to target the infection without disturbing the microbiome and may complement antibiotics.

To find out whether your case is eligible, request an assessment — the first step, with no obligation.

Advantages and limitations of bacteriophages

Advantages

High specificity: preserves beneficial bacteria. See FAQ.
Complementarity with antibiotics. See FAQ.
Adaptability of phage cocktails. See personalisation.
Self-limiting: phages decrease when the target disappears.
Good tolerability: adverse effects are rare and mild. See safety.

Limitations

Specificity means a phage sensitivity test is needed. See tests.
Tailor-made procedure: selection and preparation time. See timelines.
Regulatory framework: evolving from country to country. Our team in Georgia supports the process.

Safety and clinical experience

Phages are omnipresent in the environment and in our microbiome. They have an excellent safety profile: they do not enter human cells and are naturally eliminated after their action. Since the 1920s, thousands of patients have been treated in Tbilisi; read our testimonials and the scientific literature. For practical questions, browse the FAQ.

For an initial opinion, use our free assessment form or contact us.

Conclusion: a rational and supervised hope

Bacteriophages are precise biological tools serving personalised medicine, relevant in certain cases of resistant infections. First step: request a free assessment. You can also read: What is phage therapy? and Phage treatments.

Key takeaways

Phages target only bacteria.
An option to consider in certain resistant infections.
Long-term documented safety.
Personalised approach: start with the assessment.

FAQ

How long does a phage treatment last?

From a few days to several weeks, depending on the location and chronicity of the infection. Practical details: typical schedule.

Can phages and antibiotics be combined?

Yes, often synergistic. See our FAQ and publications.

Are phages dangerous for the microbiome?

No, their specificity preserves beneficial bacteria. More information: microbiome FAQ.

Structure of a bacteriophage under an electron microscope — The phage, a natural virus that targets only bacteria — educational diagram.

Illustration of bacterial lysis by a phage — Bacterial lysis releases new active phages through self-amplification.

Phage therapy laboratory in Tbilisi, Georgia — Eliava Institute (Tbilisi) — history of clinical phage therapy

Useful links

Internal links (sesoignerengeorgie.com)

Blog

Externes (références & institutions)

References

Lin DM, Koskella B, Lin HC. Phage therapy: An alternative to antibiotics in the age of multidrug resistance. World J Gastrointest Pharmacol Ther. 2017;8(3):162–173.
Abedon ST. Phage therapy pharmacology: calculating phage dosing. Adv Appl Microbiol. 2019;106:1–40.
Kortright KE et al. Phage therapy: a renewed approach. Clin Microbiol Rev. 2019;32(2):e00066-18.
Dublanchet A, Bourne S. The revival of phage therapy. Clin Microbiol Infect. 2020;26(6):801–808.
Kutateladze M, Adamia R. Phage therapy experience at the Eliava Institute. Front Microbiol. 2021;12:622.
Pirnay JP et al. Phage therapy safety and efficacy. Viruses. 2023;15(5):987.
World Health Organization. Bacteriophages and their use in combating antimicrobial resistance. WHO Europe, 2024.
Tagliaferri TL et al. Synergistic interactions between phages and antibiotics. Antibiotics (Basel). 2021;10(7):678.

Bacteriophages: natural viruses that target bacteria without affecting the microbiome