2023-10-11 11:58:00
This article is republished from The Conversation sous licence Creative Commons. Lire l’article original.
At the end of June, the National Agency for Food, Environmental and Occupational Health Safety (ANSES) published an opinion concerning the priority list of bacteria/antibiotic family pairs to be monitored in animals due to their impact on public health. Here’s what you need to remember.
How do resistances emerge?
Any use of antibiotics, whether in humans or animals, exerts selection pressure: initially very effective, antibiotics massively eliminate sensitive bacteria.
However, it happens that some bacteria prove capable of resisting them. These survive and, favored by the disappearance of sensitive bacteria, multiply without competition. This is how resistant populations emerge against which antibiotics become ineffective.
Such antibiotic-resistant bacteria can not only develop in people treated with antibiotics, but also in the environment (when it is contaminated by discharges containing antibiotics) or in farm and pet animals, when antibiotics are used in veterinary medicine.
In the latter case, resistant bacteria can be transmitted to humans either through close contact with said animals, or indirectly, through the environment or through the consumption of contaminated food products.
Bacteria/antibiotic family pairs to be monitored as a priority in animals
Eleven pairs of bacteria/antibiotic family to be monitored as a priority in animals in France appear on the first list drawn up by ANSES. Among them, five are classified as high priority:
Enterobacterales/carbapenems: Enterobacterales are a bacterial order that includes several species, for example Escherichia coli or bacteria like Salmonellacommonly found in the intestines of humans and other animals. Various species of Enterobacterales can cause infections, including urinary, intestinal, or respiratory infections. However, some of these bacteria have developed resistance to antibiotics. This is the case, for example, of strains resistant to carbapenems, which are broad-spectrum antibiotics, used only in hospitals to treat the most serious infections. The emergence of carbapenem-resistant Enterobacterales is a major public health problem. The resistance of these bacteria to several classes of antibiotics can lead to therapeutic dead ends.
Third and fourth generation Enterobacterales/cephalosporins (C3G/C4G): Some strains of Enterobacterales have developed resistance to C3G/C4G, critically important antibiotics used to treat severe infections in both humans and animals. In veterinary medicine, carrying out an antibiogram prior to their prescription is required.
Staphylococcus aureus/méticilline (SARM) : S. aureus (or Staphylococcus aureus) is a bacteria that can be found on the skin and in the nasal passages of humans without causing health problems. However, under certain conditions (injury, surgery, immune weakening…), it can cause various infections, such as skin infections, respiratory tract infections, or even blood infections. THE Staphylococcus aureus Methicillin-resistant, also called MRSA, is a staphylococcus that has developed resistance to several antibiotics, including methicillin. Since the latter is ineffective in treating an infection caused by MRSA, this limits the choice of treatments.
Enterobacterales/fluoroquinolones : Just like C3G/C4G, fluoroquinolones are antibiotics of critical importance in humans and animals.
Enterobacterales/polymyxines : colistin is the best-known antibiotic among those belonging to polymyxins. It is used in veterinary medicine, particularly in animal production sectors. In human medicine, due to its toxicity, colistin is only prescribed for the treatment of severe human infections linked to bacteria resistant to all other therapeutic options. The resistance of certain strains to colistin is problematic due to the strong capacity for dissemination of a resistance gene, mcr-1identified in animals and humans worldwide.
The circulation of methicillin-resistant Staphylococci aureus must be monitored, particularly in pig farms. Diego San/Unsplash
Evolution of resistances
An analysis of epidemiological data collected in France currently makes it possible to nuance the transmission of bacterial strains resistant to antibiotics between animals and human beings.
Epidemiological surveillance data show that if resistance to carbapenems is occasionally detected in dogs and cats, it is likely linked to contact with humans carrying this resistant bacteria, because this family of antibiotics is not used. in veterinary medicine.
Resistance to other families of antibiotics in production animals (cattle, pigs, poultry) and companion animals (dogs and cats) has been decreasing over the last ten years, thanks to efforts to control the use of antibiotics. in the animal sector.
Vigilance must, however, be exercised regarding the strains of Staphylococcus aureus methicillin resistantan important antibiotic from the penicillin family. In 2006, cases of infections in several hospitals in the Netherlands highlighted that these resistant bacteria actually came from pig farms.
In France, a survey carried out in several pig farms showed that the levels of this resistance increased significantly between 2008 and 2021, going from 3% to more than 40%. Furthermore, surveillance data reveal, for the year 2021, high proportions in dogs, with an increasing trend since 2018.
In its opinion, ANSES recommends improving this epidemiological surveillance by using sequencing methods allowing analyzes of the entire genome of the five high priority bacteria/antibiotic family pairs, in order to be able to assess the contribution of the animal reservoir in transmission to human beings of such resistant bacteria, and to evaluate the presence of genetically mobile elements that can promote the transmission of genes coding for this resistance to antibiotics.
Concerning methicillin-resistant Staphylococci aureus, ANSES underlines the need to be vigilant against MRSA in the animal sector through the implementation of one-off surveys, in order to detect animals that may play the role of transient carriers and which may be involved in the dissemination and persistence of MRSA in the human population.
Beware of imported foods
In France, the transmission of bacterial resistance between animals and humans is controlled thanks to biosecurity measures on farms, good hygiene practices in veterinary clinics and via cooking food (heat kills resistant bacteria antibiotics).
However, international trade and the movement of people, animals and food products intensify the risk of rapid spread of antibiotic-resistant bacteria. This is the case, for example, of farmed shrimp imported from Asia, which may be contaminated with antibiotic-resistant bacteria. To deal with it, the decision (UE) 2020/1729 requires monitoring of antibiotic resistance, but only in meat imported from countries outside the European Union.
ANSES therefore recommends extending this monitoring to products from fishing, in order to avoid the introduction into France of new resistant bacteria, or even multi-resistant bacteria (in other words, resistant to several families of antibiotics), which represent a major threat to public health.
Antibiotic resistance is everyone’s business!
In human medicine, everyone remembers the slogan “Antibiotics are not automatic”, used in awareness campaigns aimed at reducing the systematic use of antibiotics.
Its counterpart in veterinary medicine, “antibiotics, as needed, when needed”, has helped to draw the attention of professions in the animal sector to the proper use of veterinary antibiotics.
The problem of antibiotic resistance is particularly emblematic of the concept One Health (“One Health”), according to which human, animal and environmental health are interconnected and interdependent.
To combat this major problem, it is necessary to strengthen measures to prevent and control the transmission of antibiotic resistance between humans, animals and the environment. It is at this price that we can hope to succeed in preserving the effectiveness of antibiotics, and therefore our ability to fight against bacterial infections in the future.
This article was written by Elissa Khamisse, Scientific Coordinator of expertise in animal health and nutrition, National Agency for Food, Environmental and Occupational Health Safety (ANSES) with the support of Eric Oswald, Chairman of the ANSES “antiboresistance in animals” working group
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