Investigation article published in European Journal of Wildlife Research

September 29^th, 2018

The Western European population of wild boar (Sus scrofa) has increased its distribution over the past several decades, and some populations have colonized areas strongly influenced by human activity. Wild boars are known carriers of antibiotic-resistant bacteria acquired from the environment, and urban populations of wild boars may be more exposed than their rural counterparts. In this work, we compared the frequency of antibiotic resistance in indicator bacteria (Escherichia coli, Enterococcus faecalis, Enterococcus faecium) isolated from urban wild boars with that from rural wild boars in NE Spain. We further assessed whether bacterial isolates from the urban wild boars had a higher probability of showing antibiotic resistance when their host was highly associated to urban features. Seventy-two and 100 bacterial isolates from urban and rural habitat, respectively, were screened for antibiotic resistance against a set of antibiotics (13 per bacterial species). We found a significantly higher frequency of E. faecium showing resistance to tetracycline (70.0% vs 36.4%) and high-level resistance to streptomycin (30.0% vs 4.5%) in urban wild boars compared to rural wild boars (p < 0.05). E. faecalis was more frequently resistant to trimethoprim in urban than rural wild boars (33.3% vs 0.0%, p < 0.05). In isolates from urban origin, 55.6% of the likelihood of detecting antibiotic resistance depended only on the bacterial species, being more likely in the enterococci than in E. coli. These results suggest that urban wild boars may be more exposed to certain antibiotic-resistant bacteria or antibiotic resistance genes that they may acquire from the urban environment, although implications are uncertain

Navarro-Gonzalez N., Castillo Contreras R., Casas Diaz E., Morellet N., Porrero MC., Molina-Vacas G., Torres RT., Fonseca C., Mentaberre G., Dominguez L., Lavin S. and Serrano E.

Carriage of antibiotic-resistant bacteria in urban versus rural wild boars

	Departamento de Medicina y Cirurgia Animal. Facultad de Veterinaria. Universitat Autònoma de Barcelona (UAB).
	Servicio de Ecopatología de Fauna Salvaje (SEFaS). Universitat Autònoma de Barcelona (UAB).
	Wildlife Ecology & Health group (WE&H). Universitat Autònoma de Barcelona (UAB).
	Biologie, Épidémiologie et Analyse de Risque en santé animale (BIOEPAR). Institut National de la Recherche Agronomique (INRA).
	Université Bretagne Loire.
	Departamento de Sanidad y de Anatomía Animal. Facultad de Veterinaria. Universitat Autònoma de Barcelona (UAB).
	Laboratoire de Comportement et Ecologie de la Faune Sauvage. Institut National de la Recherche Agronomique (INRA).
	Servicio de Zoonosis de Transmisión Alimentaria y Resistencia a Antimicrobianos (ZTA). Centro de Vigilancia Sanitaria Veterinaria (VISAVET). Universidad Complutense (UCM).
	Departament de Biologia Animal. Facultad de Biología. Universitat de Barcelona (UB).
	Departament of Biology & CESAM. University of Aveiro (UA).