Risk factors associated with the abundance of antimicrobial resistance gene tet(W) and class 1 integron (intl1) in pigs in the Netherlands
Summary
Antimicrobial resistance (AMR) poses a substantial threat to public health in the 21st century. This research investigates the relationship between the abundance of antimicrobial resistance gene( tet(W) and class 1 integron (intl1)) and various risk factors related to tetracycline use, farm characteristics, hygiene, biosecurity, animal care, cleaning, planning, feeding and water supply, on Dutch pig farms. A longitudinal study was conducted on 36 pig farms, with samples collected at two time points, with a 12-month interval between them. On each farm, swab samples were taken from 60 pigs, who were then pooled by 6 pigs within the same age category. At the same time questionnaires were filled by veterinarians and farmers. qPCR was performed to quantify the abundance of tet(W) and intl1 along with the 16S rRNA gene used for the normalization of ARG copies. Associations between the abundance of antimicrobial resistant genes and different risk factors were assessed using a mixed-effects model. The results highlight the effectiveness of interventions aimed at reducing antimicrobial use in livestock. In the model covering all farms, it was determined that the use of early-life antibiotics, switching the piglets after the third day, and providing water via a nipple were significantly associated with the abundance of tet(W). These resistance genes were linked to the annual loss of sows, as well as cleaning and feeding procedures, in farrow-to-finish farms. According to our research, the annual number of piglets per sow and the existence of quarantine procedures were associated to the abundance of class 1 integron genes. While this study provides valuable insights into AMR in pig farming, cautious interpretation is advised due to its data-driven nature.