A preliminary report on critical antimicrobial resistance in Escherichia coli, Enterococcus faecalis, and Enterococcus faecium strains isolated from healthy dogs in Chile during 2021-2022

Antimicrobial Resistance (AMR) represents one of the main current threats to global public health; where production animals, companion animals, humans, and the environment play a significant role in its dissemination. However, little attention has been given to companion animals as reservoirs and disseminators of relevant antimicrobial resistant bacteria, especially in South American countries such as Chile. For this reason, this research aimed to estimate the prevalence of AMR to different critical antibiotics at a screening level in commensal bacteria such as E. coli and Enterococcus spp., isolated from healthy pet dogs in the Metropolitan Region of Chile, studying their geographical distribution and evaluating associations of phenotypic resistance to different antibiotics. Thus, in E. coli we detected AMR to all critical drugs assessed, including 34.1% to amoxicillin, 20.1% to colistin, 15.7% to enrofloxacin, and 9.2% to cefotaxime. On the other hand, AMR prevalence in E. faecalis was 8.1% for ampicillin and 3.4% for vancomycin; while for E. faecium the AMR prevalence was 19.1% for ampicillin and 10.2% for vancomycin. Additionally, significant differences in prevalence of the different possible AMR were detected according to their geographical distribution, suggesting the existence of various risk factors and stressing the need to establish mitigation measures specific to the differences identified.