Resistance Patterns, mcr-4 and OXA-48 Genes, and Virulence Factors of Escherichia coli from Apennine Chamois Living in Sympatry with Domestic Species, Italy

SIMPLE SUMMARY: Antimicrobial resistance is a global threat involving human, animal, and environmental health. Evidence of antibiotic resistance was found in pets, livestock, humans, in uncontaminated environments, or in animals never treated with antibiotics. In order to provide new data, this study was carried out in the protected area of the Maiella National Park (Central Italy) sampling wild and domestic ungulates that share or do not share grazing lands. The analysis was realized by combining the georeferenced data of animals and the microbiological investigations starting from fresh fecal samples. The Escherichia coli isolates were tested for antibiotics particularly relevant in human health. Even if the selected molecules are not currently used in veterinary medicine, evidence of resistant bacteria was found in sympatric wild and domestic animals, as well as in non-sympatric domestic animals. The detection of colistin resistance gene mcr-4 and carbapenems resistance genes OXA-48 was reported for the first time in wild ungulates in Italy and in Europe. More investigations are necessary, but these preliminary results highlight the importance of continuing studies for the early detection of emerging resistance patterns. ABSTRACT: The aim of this study was to determine and characterize potential resistance mechanisms against selected Critically Important Antibiotics in Escherichia coli isolates collected from wild and domestic ruminants living in the Maiella National Park, in Central Italy. A total of 38 isolates were obtained from red deer, Apennine chamois, cattle, sheep, and goats grazing in lands with different levels of anthropic pressure. Antimicrobial susceptibility was determined by Minimal Inhibitory Concentration testing, showing phenotypic resistance to colistin, meropenem, or ceftazidime in 9 isolates along with one bacterial strain being resistant to three of the tested antibiotics. In addition, the biomolecular assays allowed the amplification of the genes conferring the colistin (mcr-4), the carbapenems (OXA-48), penicillins and cephalosporins (TEM, SHV, CMY-1, CMY-2) resistance. In order to describe the potential pathogenicity of isolates under study, virulence genes related to Shiga toxin-producing (STEC) and enteropathogenic (EPEC) pathovars were identified. This study is the first report of mcr-4 and OXA-48 genes in resistant E. coli harboring virulence genes in Italian wildlife, with special regard to Apennine chamois and red deer species. The multidisciplinary approach used in this study can improve the early detection of emerging antibiotic resistance determinants in human-animal-environment interfaces by means of wildlife monitoring.