Antimicrobial resistance in relation to the persistence of antimicrobial residues after treatment of farm animals

Input for risk management (RESRISK)

The aims of this project are to determine the residual antimicrobial concentrations in faeces of broilers treated with antibiotics and the longitudinal effect on antimicrobial resistance in commensal E. coli and on the microbiome in relation to the persistence of the antimicrobials, under experimental and field conditions. The antimicrobials which will be used are amoxicillin (non-persistent), doxycycline or enrofloxacin (persistent). Furthermore, determination of the minimal selective concentration (MSC) will be done for the used antimicrobials. This will be conducted in vitro for commensal E. coli and other bacterial species isolated from broiler faeces. Thereafter to investigate the effect of residual concentrations after treatment on the persistence of resistant bacteria a mathematical model will be used. Parameters for this model will be selected before starting with the data collection experiments. After the model has been created it will be refined with data from field experiments. The model should incorporate the effect of antimicrobial residues on antimicrobial resistance selection and give indications about which type of antimicrobial and which concentration should be used to prevent selection for and spread of resistance.

Aram Swinkels