Silent Pandemic

WHO alarm: one in six infections is now resistant to antibiotics

40% increase in cases since 2018. Researchers trace a century of bacterial evolution, while new drugs, rapid diagnosis and more responsible use of treatment are needed

by Francesca Cerati

14 October 2025

4' min read

Translated by AI

Versione italiana

Key points

Southeast Asia and Eastern Mediterranean the most affected areas
"Gram-negative" bacteria: the most serious threat
A century of bacterial evolution reveals the origins of resistance
Drugs down, resistance up
Italy among the worst in Europe for antibiotic use
The WHO call: "Act now"

4' min read

Translated by AI

Versione italiana

By 2023, one in six people worldwide will have contracted a bacterial infection resistant to antibiotic treatment, according to a new global report by the World Health Organisation (WHO), based on data from the Global antimicrobial resistance and use surveillance system (Glass), which collects information from more than 100 countries.

The results show a growth in antimicrobial resistance (AMR) of 40% between 2018 and 2023, with an average annual increase of between 5% and 15%. Worldwide, infections caused by eight common bacteria - Escherichia coli, Klebsiella pneumoniae, Acinetobacter, Staphylococcus aureus, Streptococcus pneumoniae, Salmonella, Shigella and Neisseria gonorrhoeae - are the most affected.

Southeast Asia and Eastern Mediterranean the most affected areas

Antimicrobial resistance does not strike evenly. According to the WHO, in the regions of South-East Asia and the Eastern Mediterranean, one in three infections is now resistant to antibiotics, while in Africa the figure is one in five. The most vulnerable areas are also those where health systems do not have laboratories capable of identifying pathogens or treating them with effective drugs.

In many low- and middle-income countries, patients suffering from resistant infections not only do not receive the appropriate treatment, but also do not have access to basic antibiotics. "Antimicrobial resistance is outpacing advances in modern medicine, threatening the health of families worldwide," said Tedros Adhanom Ghebreyesus, WHO Director-General. "We need responsible use of antibiotics and equitable access to quality diagnosis and treatment.

Gram-negative bacteria: the most serious threat

Among the most dangerous bacteria are the Gram-negatives, which are particularly resistant and difficult to treat. In 2023, more than 40% of Escherichia coli strains and more than 55% of Klebsiella pneumoniae strains proved resistant to third-generation cephalosporins, the first-choice antibiotics for blood infections.

In Africa, resistance exceeds 70%, leaving doctors with very few therapeutic alternatives. Other life-saving antibiotics, such as carbapenems and fluoroquinolones, are also losing efficacy against E. coli, K. pneumoniae, Salmonella and Acinetobacter.

Carbapenemics resistance, once rare, is now rapidly increasing, forcing many countries to resort to 'last resort' drugs, which are often expensive, difficult to obtain and unavailable in the most fragile health systems.

A century of bacterial evolution reveals the origins of resistance

An investigation conducted by the Wellcome Sanger Institute and published in Science has reconstructed 100 years of bacterial evolution to understand how drug resistance has spread around the world.

Analysing more than 40,000 plasmids - tiny DNA structures that can be transferred between bacteria - from samples collected on six continents, the researchers discovered that a small minority of plasmids are responsible for most of the multidrug resistance (MDR) in circulation today. In other words, a few 'genetic super-vectors' have turned bacteria into organisms capable of surviving almost any treatment.

The oldest plasmids, dating back to the early decades of the 20th century, did not contain resistance genes; these evolved with the increasing use of antibiotics after the Second World War to create the resistant strains that are of concern to global health today.

'The massive use of antibiotics has reshaped the genetic landscape of bacteria, giving rise to plasmids that now carry multiple resistance genes,' explains Zamin Iqbal, Professor of Algorithmic and Microbial Genomics at the University of Bath. 'Understanding how they evolved is the first step to countering them.

Drugs falling, resistance rising

The global picture is aggravated by a crisis in pharmaceutical innovation. According to the most recent WHO reports, only 90 antibiotics are in development worldwide by 2025: of these, just 15 are considered innovative and only five show efficacy against at least one of the 'critical' bacteria on the WHO priority pathogen list.

In the meantime, resistance continues to spread faster than the ability to develop new drugs and the situation risks turning into a silent pandemic. The most up-to-date estimates, published in The Lancet, speak of more than 39 million cumulative deaths between 2025 and 2050 caused by drug-resistant infections, almost 2 million deaths per year by mid-century.

Italy among the worst in Europe for antibiotic use

In Italy, too, the trend is worrying. Antibiotic consumption has risen to 22.4 daily doses per 1,000 inhabitants, more than double the EU average. The European Medicines Agency (Ema) recently recommended a review of the use of azithromycin, an essential antibiotic for decades, to avoid its future ineffectiveness due to growing resistance.

The Ministry of Health, for its part, draws attention to healthcare-associated infections (HAIs), which increasingly affect patients in Italian hospitals and represent one of the main critical issues for the safety and sustainability of the healthcare system. These are infections that arise during hospitalisations or medical procedures and, due to resistance, require lengthy, costly and often ineffective treatment.

The WHO call: "Act now"

The World Health Organisation is calling on all countries to strengthen their surveillance and laboratory systems and provide reliable data on antimicrobial resistance by 2030. Despite progress - participation in the Glass programme has increased from 25 countries in 2016 to 104 in 2023 - almost half of the states have yet to report complete data, and many lack the infrastructure to generate reliable information.

The WHO also calls for the strengthening of 'One Health' strategies, which integrate human, animal and environmental health, and the updating of treatment guidelines according to local resistance patterns. Only a global and coordinated approach, the organisation concludes, can halt a crisis that threatens to set us back a century in the fight against infections.

If the 20th century was the century of antibiotics, the 21st must be the century of their defence, with prevention, diagnosis, research and responsibility.