Raising awareness about the public health impact of antibiotic resistance is always a complex task; it is difficult to communicate effectively on this topic. Indeed, surveillance systems focus on specific bacteria-antibiotic combinations and are sometimes even limited to certain types of specimens. It is difficult to help a non-professional audience understand, for example, the significance of the incidence of diagnostic samples testing positive for MRSA (Methicillin-resistant Staphylococcus aureus), one of the most common bacteria-antibiotic pairs encountered in hospital settings. It is therefore necessary to have complementary indicators that allow the subject to be addressed in a comprehensive manner and are more easily understood by everyone.

This is the focus of this European study, which aimed to estimate the number of cases, the number of deaths, and the number of DALYs (Disability-Adjusted Life Years)⁽¹⁾ attributed to multidrug-resistant bacterial infections in Europe. The DALY indicator accounts for the total number of years lost due to death or disability, in this case as a result of a multidrug-resistant bacterial infection. It thus has the advantage of taking into account the duration of life impacted by a disease prior to death. The World Health Organization uses it in other studies on the global impact of diseases. This makes it possible to compare the burden of different diseases, which can help prioritize prevention efforts.

We focused on two criteria for selecting the multidrug-resistant bacteria to be included in the study: multidrug-resistant bacteria that most frequently cause infections (such as methicillin-resistant Staphylococcus aureus (MRSA) or third-generation cephalosporin-resistant Enterobacteriaceae (3GCE), for example), as well as emerging highly resistant bacteria. The latter are a major cause for concern because they are resistant even to last-resort treatments—that is, those used after all other treatments have failed. The risk of contracting an infection with one of these bacteria is that it could lead to a therapeutic dead end.

The data collected and reported to the ECDC (European Centre for Disease Prevention and Control) as part of the EARS-net network are subject to a standardized collection protocol for all European countries. This therefore represents an excellent example of European collaboration, providing reliable and comparable data on antibiotic resistance across many countries. It is this data that served as the basis for the study’s calculations.

The results of this study are deeply alarming. They confirm once again the significant burden that multidrug-resistant bacterial infections place on public health. Nearly 700,000 infections were reported in Europe in 2015, and 33,000 deaths were attributed to these infections! The DALY indicator offers a striking comparison: across Europe, the impact of multidrug-resistant bacterial infections—nearly 900,000 DALYs—is equivalent to that of influenza, tuberculosis, and AIDS combined. MRSA and multidrug-resistant Enterobacteriaceae are the bacteria that cause the most infections and deaths: nearly 70% of cases and 50% of deaths estimated in this study are due to these bacteria.

A comparison of these results with those of a previous study⁽³⁾, based on 2007 data, also shows that, overall, the number of infections and deaths caused by the 16 multidrug-resistant bacteria studied more than doubled between 2007 and 2015, even though for some bacteria, such as methicillin-resistant Staphylococcus aureus, they are decreasing in many European countries.
Finally, our study shows that the most affected populations are people over 65 and children under 1 year of age.
There is significant variation across Europe. In France, as in many other European countries, the impact of methicillin-resistant Staphylococcus aureus (MRSA)—which was the leading cause of multidrug-resistant bacterial infections a decade ago—has declined sharply, largely due to preventive measures implemented (notably enhanced hand hygiene in hospitals). In contrast, the impact of enterobacteria resistant to third-generation cephalosporins has increased considerably. This phenomenon is particularly concerning, because once a bacterium becomes resistant to this class of antibiotics, few treatment options remain for the patient. The antibiotics used as a last resort in these patients are carbapenems. Yet carbapenem-resistant Enterobacteriaceae (CRE) are already emerging. In France, for now, there are few CRE infections thanks to very strict control measures implemented in hospitals to prevent their spread.
But as resistance to third-generation cephalosporins increases, there is concern that the situation may spiral out of control. Some European countries, such as Greece and Italy, are in critical situations with very high rates of carbapenem resistance among Enterobacteriaceae.

Yet, means of prevention and control exist. Two key strategies enable the fight against antibiotic resistance: the proper use of antibiotics, on the one hand, and hygiene measures, on the other, with a comprehensive view of the problem: bacteria spread between the environment, animals, and humans. Prevention therefore relies on measures to limit antibiotic use to what is strictly necessary. Antibiotic consumption in human healthcare has not shown a downward trend in outpatient care since 2006. In healthcare facilities, antibiotic consumption has remained generally stable, and broad-spectrum antibiotics continue to be widely used. At the European level, France ranked 3rd and 8^th, respectively, among the countries with the highest antibiotic consumption in Europe in 2016. In animal health, a clear decrease in antibiotic consumption has been observed, but the reduction in the use of critically important antibiotic molecules still needs to be confirmed and further strengthened.

Preventing antibiotic resistance also relies on hygiene measures applied at each of these levels: washing hands upon returning home, or before and after caring for a person or animal, or after blowing one’s nose, for example. It is also important to follow the guidelines for using antibiotics prescribed by a doctor or veterinarian.
We all have a role to play in the fight against antibiotic resistance.