Pathotypes and Antimicrobial Susceptibility of Escherichia Coli Isolated from Wild Boar ( Sus scrofa) in Tuscany

Abstract

Simple Summary

In recent years, in geographic areas such as Central Italy, the wild boar population has greatly increased. Although wildlife represents a fundamental resource for ecosystems and biodiversity, wild animals could act as reservoirs for different pathogens, representing an issue for human and domestic animal health. This investigation reports the presence and circulation of pathogenic and antimicrobial-resistant Escherichia coli in wild boar hunted in Tuscany (Italy). Different pathotypes, responsible for human and animal diseases, were detected. Furthermore, resistance to commonly used antibiotics was detected in a large percentage of isolates. Considering the possibility of contact between wild boars, domestic animals, and humans, active monitoring of pathogens is essential for epidemiological purposes.

Abstract

Wild boar are among the most widespread wild mammals in Europe. Although this species can act as a reservoir for different pathogens, data about its role as a carrier of pathogenic and antimicrobial-resistant Escherichia coli are still scarce. The aim of this study was to evaluate the occurrence of antimicrobial-resistant and pathogenic Escherichia coli in wild boar in the Tuscany region of Italy. During the hunting season of 2018–2019, E. coli was isolated from 175 of 200 animals and subjected to antimicrobial resistance tests and PCR for detection of resistance and virulence factor genes. The highest resistance rates were against cephalothin (94.3%), amoxicillin–clavulanic acid (87.4%), ampicillin (68.6%), and tetracycline (44.6%). The most detected resistance genes were bla _{CMY -2} (54.3%), sul1 (38.9%), sul2 (30.9%), and tetG (24.6%). Concerning genes encoding virulence factors, 55 of 175 isolates (31.4%) were negative for all tested genes. The most detected genes were hlyA (47.4%), astA (29.1%), stx2 (24.6%), eaeA (17.1%), and stx1 (11.4%). E. coli was classified as Shiga toxin-producing E. coli (STEC) (21.7%), enterohemorrhagic E. coli (EHEC) (6.3%), enteroaggregative E. coli (EAEC) (5.1%), and atypical enteropathogenic E. coli (aEPEC) (3.4%). Enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), and typical enteropathogenic E. coli (tEPEC) were not detected. Our results show that wild boars could carry pathogenic and antimicrobial-resistant E. coli, representing a possible reservoir of domestic animal and human pathogens.