Escherichia coli O157:H7 in wild boars (Sus scrofa) and Iberian ibex (Capra pyrenaica) sharing pastures with free-ranging livestock in a natural environment in Spain

Abstract

Background: Wild ungulates have greatly increased in abundance and range throughout Europe. This new situation presents a concern for public health because many wild ungulates are known reservoirs of zoonotic pathogens.Objectives: In this work, we tested for the presence of the zoonotic pathogen Escherichia coli O157:H7 in free-ranging livestock and sympatric wild boars (Sus scrofa) and Iberian ibex (Capra pyrenaica) in NE Spain from 2009 to 2011. In addition, antimicrobial resistance and virulence factors were assessed.Animals and methods: In total, individual fecal samples were obtained from 117 hunter-harvested wild boars and 160 Iberian ibexes. Fifty-five samples were obtained from cattle (5 herds, 380 animals in total) and four from the only horse herd in the Natural Park ‘Ports de Tortosa i Beseit’ (32 animals). Fecal samples were processed according to the ISO 16.654:2001 protocol to obtain E. coli O157 based on immunomagnetic separation. In addition, a multiplex polymerase chain reaction (PCR) targeting nine virulence factors characteristic of human pathotypes was performed. The prevalence was compared between host species with Fisher's exact test.Results: Four wild boars (3.41%, 95% CI = 0.94–8.52) and two Iberian ibexes (1.25%, 95% CI = 0.15–4.4) carried E. coli O157:H7, which was not found in livestock feces (n = 59, 95% CI = 0–8.94). All E. coli O157:H7 isolates were susceptible to all antimicrobial agents tested.Conclusions: These results indicate that when prevalence in co-habiting livestock is low, wild ungulates do not seem to play an important role as reservoirs of E. coli O157:H7.