# Exploring the Prevalence of Antimicrobial Resistance in Salmonella and commensal Escherichia coli from Non-Traditional Companion Animals: A Pilot Study

## TL;DR

This pilot study found high antimicrobial resistance in E. coli from non-traditional small mammals, highlighting a potential public health risk.

## Contribution

The study is the first to investigate AMR in commensal E. coli and Salmonella from non-traditional companion animals in the Valencia region.

## Key findings

- High prevalence of antimicrobial resistance (85%) and multidrug resistance (82.6%) was observed in commensal E. coli strains.
- Quinolone resistance was detected in E. coli, a high-priority antimicrobial in human medicine.
- No antimicrobial resistance was found in the isolated Salmonella strain.

## Abstract

Companion animal ownership has evolved to new exotic animals, including small mammals, posing a new public health challenge, especially due to the ability of some of these new species to harbour zoonotic bacteria, such as Salmonella, and spread their antimicrobial resistances (AMR) to other bacteria through the environment they share. Therefore, the objective of the present pilot study was to evaluate the current epidemiological AMR situation in commensal Escherichia coli and Salmonella spp., in non-traditional companion animal small mammals in the Valencia region. For this purpose, 72 rectal swabs of nine different species of small mammals were taken to assess the antimicrobial susceptibility against 28 antibiotics. A total of one Salmonella enterica serovar Telelkebir 13,23:d:e,n,z15 and twenty commensal E. coli strains were isolated. For E. coli strains, a high prevalence of AMR (85%) and MDR (82.6%) was observed, although neither of them had access outside the household. The highest AMR were observed in quinolones, one of the highest priority critically important antimicrobials (HPCIAs) in human medicine. However, no AMR were found for Salmonella. In conclusion, the results showed that small mammals’ commensal E. coli poses a public health risk due to the high AMR found, and the ability of this bacterium to transmit its resistance genes to other bacteria. For this reason, this pilot study highlighted the need to establish programmes to control AMR trends in the growing population of new companion animals, as they could disseminate AMR to humans and animals through their shared environment.