Whole Genome Sequencing of Escherichia coli and Enterococcus spp. in wildlife-livestock interface: a pilot study.

Objectives: This pilot study provides a multidisciplinary investigation to monitor livestock-wildlife interface. Ecological data, microbiological investigations, and whole genome sequencing were used to characterize eight bacterial isolates obtained from sympatric domestic and wild ruminants in Maiella National Park (Italy) in terms of genetic patterns of antimicrobial resistance.

Methods: Using selective culturing of fresh fecal samples of monitored and georeferenced populations of Apennine chamois, goats, red deer, and sheep, Escherichia coli, Enterococcus faecium, and Enterococcus faecalis isolates were isolated and subjected to minimum inhibitory concentration determination and whole genome sequencing.

Results: The analyzed isolates showed phenotypic and genotypic resistance to tetracycline and critically important antibiotics such as linezolid and carbapenems. Virulence genes related to biofilm regulation and Shiga toxins were also detected. Furthermore, serotypes related to nosocomial infections, harbouring plasmids recognized as important mobile resistance gene transmitters, were identified.

Conclusions: This multidisciplinary pilot study represents a promising initial step to identify the environmental drivers and the transmission routes of antimicrobial resistance and virulence factors, providing new data on bacteria from rare and endangered species such as Apennine chamois.