Risk of companion animal to human transmission of antimicrobial resistance during different types of animal infection

The close contact of pets with humans provides excellent opportunities for interspecies transmission of resistant bacteria and their resistance genes in either direction. Infections in humans due to antimicrobial resistant bacteria originating from pets are becoming a concern. While any animal-human contact offers a chance of transmission, it is generally accepted that a high bacterial burden and high antimicrobial resistance gene copy numbers are present during an active infection. There is a gap of knowledge on the dynamics of transmission and selection of antimicrobial resistance at the pet-human interface. Animals may exchange antimicrobial-resistant bacteria and resistance genes with humans, but the extent to which this happens is unknown. PET-Risk will evaluate the transfer of antimicrobial resistance between pets and household members during animal infections and determine which type of infection (skin and soft tissue vs. urinary tract infections) presents a higher risk of transmission to humans. Furthermore, in a longitudinal study we will collect samples of infected animals under antimicrobial treatment, and their household members at several time points, which will allow the assessment of critical control points at which interventions could substantially affect the spread of resistance. The causality and directionality of pet-human spread of resistance genes will be established by using state-of-the-art techniques in order to design and evaluate preventive and intervening measures for reducing the public health risks of antimicrobial resistance.

The close contact of pets with humans provides excellent opportunities for interspecies transmission of resistant bacteria and their resistance genes in either direction. Infections in humans due to antimicrobial resistant bacteria originating from pets are becoming a concern. While any animal-human contact offers a chance of transmission, it is generally accepted that a high bacterial burden and high antimicrobial resistance gene copy numbers are present during an active infection. There is a gap of knowledge on the dynamics of transmission and selection of antimicrobial resistance at the pet-human interface. Animals may exchange antimicrobial-resistant bacteria and resistance genes with humans,
but the extent to which this happens is unknown. PET-Risk will evaluate the transfer of antimicrobial resistance between pets and household members during animal infections and determine which type of infection (skin and soft tissue vs. urinary tract infections) presents a higher risk of transmission to humans. Furthermore, in a longitudinal study we will collect samples of infected animals under antimicrobial treatment, and their household members at several time points, which will allow the assessment of critical control points at which interventions could substantially affect the spread of resistance. The causality and directionality of pet-human spread of resistance genes will be established by using state-of-the-art techniques in order to design and evaluate preventive and intervening measures for reducing the public health risks of antimicrobial resistance.

This proposal will produce a great amount of data and thus several possible outputs of great
epidemiological and public health importance will be created. Several outcomes can be expected
but, based on the current knowledge we predict the:
-Identification of higher quantities of beta-lactam resistance genes (load) in the pet and
human's faeces/swabs during and after infection, compared to the control group (WP2.1.).
-Identification of similar antimicrobial resistance genes (resistome richness) in the pet and
human's faeces/swabs during and after infection (WP2.2.). The analyses of this data will
possibly lead to the identification of new/unknown antimicrobial resistance genes in both
samples' type.
-Identification of similar beta-lactam resistance mechanisms and resistance gene-containing
genetic elements (presence of the same bacteria, or plasmids, or other mobile genetic
elements) in the pet and human's faeces/swabs during and after infection (WP3). The
analyses of this data will possibly lead to the identification of new/unknown antimicrobial
resistance mechanisms in both samples' type.
-Identification of the risk represented by each type of infection (SSTI vs UTI) in the
transmission of antimicrobial resistance (WP4).
-Identification of risk factors for the acquisition of antimicrobial resistance through statistical
analyses (WP4) of the data collected in WP1 (epidemiological and behaviour questionnaires)
in accordance to the data generated in WP2 (richness) and WP3 (presence/load).
-Identification of the critical control points (e.g. before or after antimicrobial treatment), where
infection control measures are urgently needed.
-Establishment of infection control guidelines for the prevention of antimicrobial resistance
spread.