Imagine a world where a bacterial infection contracted during routine surgery becomes impossible to treat. Where pneumonia — curable today with a few days of antibiotics — once again becomes a death sentence. This is not science fiction: it is the scenario we are moving toward if we do not seriously address antimicrobial resistance (AMR).

What Is AMR?

AMR occurs when bacteria, viruses, fungi, or parasites adapt to the drugs designed to fight them, rendering those drugs ineffective. It is a natural process, but human activities have dramatically accelerated it: the overuse and misuse of antibiotics in medicine, veterinary care, and agriculture has created ideal conditions for the selection and spread of resistant microorganisms. By the end of 2025, according to the World Health Organization (WHO), one in six laboratory-confirmed bacterial infections is already resistant to standard treatments.

The Numbers Behind a Silent Crisis

The data are unambiguous. In 2021, 1.14 million people died directly as a result of AMR worldwide, while another 4.71 million deaths were associated with drug-resistant infections (GRAM Project / The Lancet, 2024). Future projections are even more alarming: between 2025 and 2050, an estimated 39 million deaths will be directly attributable to bacterial resistance — equivalent to three deaths every minute for twenty-five years.

In Europe alone, AMR is responsible for more than 35,000 deaths per year, with a public health impact comparable to that of influenza, tuberculosis, and HIV/AIDS combined (ECDC data). The burden falls hardest on the most vulnerable: the elderly, immunocompromised patients, and newborns. Between 1990 and 2021, AMR deaths in adults over 70 increased by more than 80% — a trend set to worsen as global populations age.

Beyond a Health Problem

AMR has profound economic and societal consequences. The World Bank estimates that, without effective action, antimicrobial resistance could erode 3.8% of global GDP annually by 2050 and push 28 million people into poverty. Additional healthcare costs could reach $1 trillion per year globally.

When drugs stop working, the ripple effects are wide-reaching: hospital stays lengthen, cancer treatments and organ transplants become riskier, and routine surgeries turn into high-stakes procedures. According to the OECD, one in five bacterial infections in member countries is already resistant to antibiotic treatment.

A Borderless Threat: The One Health Approach

Bacteria do not respect national borders. Resistance genes circulate between humans, animals, and the environment through food chains, wastewater, intensive livestock farming, and international travel. This is why AMR cannot be tackled through clinical medicine alone: it requires an integrated approach known as One Health, coordinating human health, animal health, and environmental protection.

Hospital-acquired resistant infections are particularly dangerous: they account for just over 30% of all resistant cases, yet are responsible for more than 60% of AMR-related deaths (OECD data). Three bacteria — Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus — are responsible for nearly three-quarters of these deaths.

A Shrinking Drug Pipeline

Adding to the concern is the shortage of new antibiotics in development. Over the past five years, the pharmaceutical pipeline dedicated to AMR has shrunk by 35%: according to a 2026 report by the Access to Medicine Foundation, major pharmaceutical companies now have only 60 active projects, down from 92 in 2021. Without new effective drugs, acquired resistance could render even existing molecules useless.

What Can We Do?

The good news is that concrete tools exist to reverse the trend. The WHO has launched an updated global action plan for 2026–2036, and G7 and G20 governments have placed AMR among their international public health priorities. The OECD calculates that investing just €1.50 per person per year in prevention and surveillance measures would prevent 27,000 deaths and save €1.4 billion every year in EU/EEA countries alone.

Individual behavior matters too: using antibiotics only when prescribed, always completing a course of treatment, not purchasing them without a prescription, and reducing consumption of animal products from farms that use antimicrobials heavily. AMR is a collective threat that demands a collective response — and every choice, even the most everyday one, can make a difference.

Main sources: GRAM Project / The Lancet (2024); WHO Global AMR Action Plan 2026–2036; ECDC; World Bank; OCSE; Access to Medicine Foundation (2026); Commissione europea — DG Salute. 

Imagine a bacterial infection that persists despite antibiotic treatment. Or a medical device on which bacteria can attach, multiply and organise themselves into a community that is difficult to eliminate. In many of these cases, biofilms can play an important role. These structures allow microorganisms to live in communities and cope with unfavourable environmental conditions.

Biofilms are widespread in nature and can form on many different surfaces, from rocks in streams and industrial pipes to catheters, medical implants and body tissues. They are not simply aggregates of cells: they are organised communities embedded in an extracellular matrix that contributes to their stability and influences bacterial behaviour.

Understanding how biofilms form, how they function and why they are so difficult to eliminate is essential for developing new strategies to combat infections.

What is a biofilm?

A biofilm is a community of microorganisms attached to a surface or to one another and embedded in an extracellular matrix produced, in part, by the microorganisms themselves. This matrix consists of varying proportions of polysaccharides, proteins, lipids and extracellular nucleic acids.

Its function goes far beyond that of a simple coating. The matrix holds cells together, promotes surface attachment and helps create a microenvironment in which bacteria can survive and interact. It can also influence the diffusion of substances and the availability of nutrients.

A biofilm may consist of a single bacterial species or a community of different microorganisms. Its composition and organisation depend on the type of microorganism, the colonised surface and the environmental conditions.

How does a biofilm form?

Biofilm formation is a dynamic process that develops through several stages. It begins when bacteria come into contact with a surface and attach to it. At this stage, the physical properties of the surface and specific bacterial molecules involved in recognition and adhesion can play a role.

The cells then begin to produce and accumulate components of the extracellular matrix. The community becomes more stable and grows, gradually developing a more complex structure. Different concentrations of oxygen and nutrients can arise within the biofilm, influencing cellular metabolism and activity.

The process does not necessarily end when the structure matures. Under certain conditions, some cells may detach and reach new surfaces, giving rise to other biofilms.

This ability to develop, reorganise and disperse makes biofilms dynamic biological systems whose formation depends on the continuous interaction between microorganisms and their environment.

One community, many different behaviours

One of the most interesting aspects of biofilms is that bacteria within them do not all behave in the same way. Cells exposed to the surrounding environment may have access to greater amounts of oxygen and nutrients, while those in the inner layers may grow more slowly and have reduced metabolic activity.

These differences contribute to the heterogeneity of the community and influence its response to external agents. Communication between bacteria can also play an important role. In some species, systems such as quorum sensing allow cells to detect signalling molecules and regulate the expression of specific genes in response to the conditions within the community.

A biofilm is therefore not an inert structure. It is an environment in which cells interact with one another and with the matrix, adapting their behaviour to the conditions they encounter.

Why are biofilms so difficult to eliminate?

The ability of biofilms to persist is one of the main challenges when pathogenic bacteria are involved. The extracellular matrix can hinder or slow the diffusion of certain substances, although its effect varies according to the composition of the biofilm and the properties of the molecule concerned.

Differences in metabolic activity also play a role. Some antibiotics are more effective against actively growing bacteria, whereas slow-growing cells may be less susceptible. Biofilms may also contain persistent subpopulations that can temporarily survive antibiotic exposure without necessarily being genetically resistant.

It is therefore important to distinguish between antibiotic resistance and tolerance. Resistance allows bacteria to grow in the presence of drug concentrations that would normally prevent their growth. Tolerance, by contrast, enables them to survive exposure for longer.

These mechanisms can contribute to the persistence of biofilm-associated infections and make them more difficult to eradicate. In some cases, treatment must be accompanied by interventions targeting the colonised surface or the medical device involved.

A problem also linked to antimicrobial resistance

Biofilms and antimicrobial resistance are distinct phenomena, but they can be closely connected. Conditions within a biofilm can help bacteria survive treatment and, in certain circumstances, facilitate the exchange of genetic material between microorganisms.

The scale of antimicrobial resistance makes it even more important to investigate these mechanisms. According to the World Health Organization (WHO), in 2023, approximately one in six laboratory-confirmed bacterial infections covered by global surveillance was resistant to antibiotics. Between 2018 and 2023, resistance increased in more than 40% of the pathogen–antibiotic combinations monitored. These figures concern bacterial resistance overall, not the prevalence of biofilms, but they highlight the need to expand the strategies available to combat infections. 

For this reason, biofilm research goes beyond the study of antibiotics. It also aims to understand how to prevent adhesion, weaken the extracellular matrix and interfere with the mechanisms that allow bacteria to organise themselves into persistent communities.

New ideas for combating biofilms inspired by bacteriophages

Among the approaches being investigated to combat biofilms are those inspired by bacteriophages, viruses that infect bacteria. During their evolution, some bacteriophages have developed proteins and enzymes capable of recognising specific bacterial structures or degrading components of the extracellular matrix.

These molecules are particularly interesting because they could make it possible to target specific components of a biofilm rather than acting exclusively on bacterial cells. Weakening the matrix or interfering with adhesion mechanisms could, under certain conditions, make the community more vulnerable to other treatments.

However, this is an evolving field of research. The effectiveness of these strategies must be verified experimentally and depends on several factors, including the bacterial species, the composition of the biofilm and the characteristics of the molecule used.

The aim is to identify targeted approaches that can complement existing strategies and broaden the options available for tackling persistent microbial communities.

Main sources: World Health Organization (WHO) – Global antibiotic resistance surveillance report 2025; European Centre for Disease Prevention and Control (ECDC) – Antimicrobial resistance: surveillance and disease data; European Medicines Agency (EMA) – Antimicrobial resistance in veterinary medicine.