AbstractsBiology & Animal Science

Multi-resistant Escherichia coli from wildlife

by Sebastian Günther

Institution: Freie Universität Berlin
Department: FB Veterinärmedizin
Year: 2015
Record ID: 1113633
Full text PDF: http://edocs.fu-berlin.de/diss/receive/FUDISS_thesis_000000098712


Summary Over the past decades multi-resistant Enterobacteriaceae like Extended-spectrum beta-lactamases (ESBL)-producing Escherichia (E.) coli have become a major challenge to infection control both in human and veterinary medicine. The spread of antimicrobial resistance occurs mainly by the acquisition of mobile genetic elements like resistance plasmids or the clonal spread of multi-resistant lineages. Most of the resistance genes in pathogens have evolved originally in long periods of evolution in environmental bacteria like the ESBL-enzyme family blaCTX-M which presumably originates from a soil Kluyvera species. Apparently within a half century of usage of antimicrobials in human and veterinarian clinics, the environmental resistome has made its way into bacteria of clinical importance. However, within the last years it became obvious that we have to consider the other side of the medal of this development as well: the transmission of pathogenic and now multi-resistant bacteria and/or their resistance genes back to the environment and subsequently to wildlife. My habilitation thesis focuses on multi-resistant E. coli as a prototype species for the spread of antimicrobial resistance into wildlife. E. coli represents a commensal of the gut of many birds and mammals including humans. Due to its omnipresence in faeces it is distributed to the environment where it can survive as well. For these reasons it has a long tradition as indicator bug of faecal pollution. Despite its commensal character E. coli is frequently implicated in intestinal and extra-intestinal infectious diseases the treatment of which requires the use of anti-infectives. Furthermore multi-resistant E. coli especially ESBL-producers are among the “super bugs” with pose a major threat to public health due to limited treatment options in case of infectious diseases. Summing up, this makes E. coli an ideal paradigmatic candidate for my research. In contrast to the wealth of studies dealing with ESBL-producing E. coli, be it in human, veterinary medicine or livestock breeding their presence and impact on the microbiota of wildlife has been addressed rarely. Nevertheless, due to the work of a small number of groups including my own wildlife has gained more attention in the last years as the occurrence of ESBL-producing E. coli in wildlife could implicate consequences like new reservoir functions and transmission pathways with impact on human and animal health due to the zoonotic potential of E. coli. My initial studies aimed at gaining detailed information on the host distribution of multi-resistant E. coli in avian and small mammal wildlife species. Two avian groups were identified as highly prevalent carriers of multi-resistant E. coli, namely birds of prey and waterfowl. But as we also observed passerines and other avian groups so the carriage of multi-resistant E. coli does not seem to be restricted, pointing towards the absence of host species dependence. The resistance patterns of the avian isolates are comparable to the ones that have been…