One of the more common and important resistance mechanisms is caused by extended spectrum beta lactamase (ESBL/AmpC) producing bacteria and carbapenemase producing bacteria. Carriage of these genes, usually encoded on plasmids, results in resistance to extended spectrum cephalosporins, which are considered of critical importance in human health care. ESBL/AmpC-producing E. coli and Salmonella spp. have been reported in animals and therefore production and companion animals are considered a reservoir of ESBL/AmpC-producers. We are studying the prevalence and dissemination of ESBL/AmpC and carbapenemase producing Enterobacteriaceae within various animal species, as well as potential transmission between animals and humans. In addition, we do more fundamental research on plasmids that are a common vehicle for dissemination of not only ESBL/AmpC genes, but also resistance determinants that cause resistance to other classes of antimicrobials and genes involved in metabolic processes of bacteria.
Transmission of MRSA ST398
Worldwide, methicillin-resistant Staphylococcus aureus (MRSA) is an important coloniser in animals and an opportunistic pathogen in humans. During the last decade Livestock-Associated (LA-)MRSA of sequence type (ST) 398 has emerged in Europe and Northern America. The transmission of MRSA ST398 from livestock to humans has been reported in many countries and contact with livestock is recognised as a risk factor for the transmission to humans. Although this type of MRSA is believed to have adapted to livestock, ST398 is able to colonise and cause infections in humans. The recent observed adaptation of LA-MRSA originating from pigs to humans in Denmark further highlights the need to reduce LA-MRSA colonisation in pigs and subsequent transmission to humans. Pig farms act as reservoir of LA-MRSA and we are investigating methods to reduce the prevalence of colonised livestock or reduction of shedding by positive animals to reduce exposure, and thus the presence of LA-MRSA in humans.
Reducing antimicrobial consumption in animals
A major driver for the emergence of antimicrobial resistance originating in animals is the use of antimicrobials in animals. Antimicrobials are mostly prescribed by veterinarians and administered to animals by farmers and pet owners. If we want veterinarians to prescribe less antimicrobials and farmers and pet owners to use less antimicrobials in their animals, we need to know what drives their current prescribing and antimicrobial use practices and what potentially could drive them to change these practices. Knowledge on these drivers or barriers to change antimicrobial prescribing and/or use practices might offer leads for interventions aiming at a reduction of antimicrobial consumption in animals. In our group, we investigate these behavioural aspects surrounding antimicrobial use in animals and develop and implement intervention studies to lower antimicrobial use in animals.