Infectious Diseases 2022

Campylobacter jejuni is considered as the main pathogen in human food-borne outbreaks worldwide. Over the past years, several studies have reported antimicrobial resistance (AMR) in C. jejuni strains. In Europe, the official monitoring of AMR comprises the testing of Campylobacter spp. from food-producing animals because this microorganism is responsible for human infections and usually predominant in poultry. Concerns are growing due to the current classification of C. jejuni by the WHO as a "high priority pathogen" due to the emergence of resistance to multiple drugs such as those belonging to the fluoroquinolones, macrolides and other classes, which limits the treatment alternatives.
The proportion of completely susceptible strains was very similar in isolates from humans and domestic animals (67,63% and 61,55%, respectively), while strains from the wild animal population found a significantly higher prevalence (95,49%). Most of these strains were collected from domestic animals (95,01%), largely poultry samples (81,21%), that showed a high level of resistance to nalidixic acid,  ciprofloxacin and tetracycline (67,39%,  67,27%  and  55,63%, respectively). The human isolates reproduced the same patterns reinforcing the direct association between the increase in the resistance profiles over time with veterinary practices in the control of pathogens in poultry. Fluoroquinolones had very high rates of resistant profiles since 2011 with a stable trend over the last decade. Conversely, erythromycin showed a slight increase in resistance levels mostly for poultry and swine, while wild animals and human strains had stable trends.  In conclusion, antibiotics released in animal production environments can interfere with the development of resistance profiles.