The development of antimicrobial resistance is a major concern for human and animal health. This phenomenon calls into question the effectiveness of antimicrobial drugs and may worsen the prognosis of certain infectious diseases, with major consequences for human health. With this in mind, ANSES launched an internal request to conduct an assessment of the risks of emergent antimicrobial resistance phenomena due to patterns of antibiotic use in the veterinary sphere. Its goal is to specify the most appropriate measures to implement in the field of animal health in order to establish an effective antimicrobial resistance control policy. The opinion and expert appraisal report published today provide recommendations for each sector and animal species and will supplement the initiatives currently provided for in the draft law on the future of agriculture and by the Ecoantibio 2017 plan. The recommendations include discontinuing preventive use of antibiotics, reserving latest-generation antibiotics to clearly identified and strictly regulated situations, and giving preference to narrow-spectrum antibiotics.
Over the last decade, the development of antimicrobial resistance has become a major concern for human and animal health. Because of this, in 2011 the Ministry of agriculture launched a national plan, Ecoantibio 2017, to reduce the use of antibiotics in veterinary medicine over the 2012-2017 period and which aims to coordinate and potentiate the efforts of all those involved in the fight against antimicrobial resistance.
With this in mind, ANSES launched an internal request to conduct an assessment of the risks of emergent antimicrobial resistance due to patterns of antibiotic use in the veterinary sphere, in the various animal production sectors (ruminants, pigs, poultry, rabbits and fish), as well as in horses and household pets.
ANSES set up its study in three stages.
The first stage was to take an inventory of all the patterns of antibiotic use in the various animal production sectors. To do this, the Agency had at its disposal a number of methods and schemes for monitoring antimicrobial resistance in the animal health sector which have been in use for many years.
The second stage aimed to assess the risks of antimicrobial resistance associated with veterinary practices both in the livestock and household pet care sectors.
The third stage involved the drafting of regulations to reduce, prevent or abolish risk practices in veterinary medicine.
Agency conclusions and recommendations
Adverse benefit-to-risk ratio for preventive antibiotic treatments
While curative antibiotic treatment is the most appropriate solution for treating sick animals, other ways of using antibiotics are also employed in farms. Preventive treatment is used on healthy animals that are exposed to an infectious disease risk factor. This type of treatment can be either individual or collective.
Metaphylactic treatement is applied both to clinically ill animals and to animals in the same group which are still clinically healthy, but that have a high probability of being infected due to close contact with the sick animals in the group.
The Agency's experts emphasise that during preventive treatment, the risk of inducing resistance in the bacteria of commensal flora exists in all the treated animals, whereas the therapeutic benefit depends on the effective elimination of the pathogenic bacteria whose presence is only suspected. The benefit-to-risk ratio of preventive treatment therefore appears to be poor with regard to the risk of antimicrobial resistance, except for certain specific uses.
Metaphylactic treatment, which is suited to animals raised collectively, is considered by the experts to be a more acceptable type of use, since it may have a better benefit-to-risk ratio than preventive treatment when the modes of application are specified.
The awareness of sector players and their willingness to commit to cautious use of antibiotics has led ANSES to recommend the implementation of permanent methods for closely monitoring practices with regard to the administration of antibiotics in farms, according to animal species, sector and production type, in addition to the methods already in use.
In addition, the Agency emphasises the importance of including in the antibiotic resistance surveillance plans all living animals and animal-based products originating in farms in other countries.
As concerns controlling high risk practices in veterinary antibiotic therapy, ANSES recommends:
- Discontinuing the use of preventive antibiotic therapy,
- Reserving the use of latest-generation antibiotics (3rd and 4th generation cephalosporins and fluoroquinolones) to special circumstances which should be clearly defined beforehand according to the sector and strictly regulated,
- Preferring use of narrow-spectrum antibiotics, and carefully targeting the bacteria in question.
In addition, ANSES highlights the need to assess the impact of measures used to fight antimicrobial resistance through the use of specific surveys and monitoring methods. Furthermore, it emphasises that the fight against antimicrobial resistance also involves making methods available that effectively target specific antibiotic treatments and developing alternatives to the use of antibiotics under surveillance.
The work done in the context of this internal request also showed that better knowledge was needed of the mechanisms promoting the development and spread of antimicrobial resistance, of the circulation of resistance genes in the environment and in animal and human populations, and of the factors that prompt various antibiotic use patterns and their impact on antimicrobial resistance.
It is also necessary to encourage the development of indicators for promoting more targeted use of antibiotics, and in particular through improved veterinary antibiogrammes.