# Antimicrobial Resistance Profile of Urinary Bacterial Isolates from Hospitalized Companion Dogs Reveals a Potential Public Health Risk in South Korea

## TL;DR

This study found high levels of antibiotic resistance in bacteria from hospitalized dogs in South Korea, including resistance to last-resort antibiotics, highlighting a public health risk.

## Contribution

The study provides new surveillance data on multidrug-resistant bacteria in companion animals and identifies a dangerous resistance gene in E. coli.

## Key findings

- 73.91% of isolated bacteria were multidrug-resistant, including resistance to carbapenems.
- An E. coli strain was found to carry the blaNDM-1 resistance gene.
- Escherichia coli was the most common uropathogen in hospitalized dogs.

## Abstract

Antibiotic resistance in companion animals is becoming a serious public health concern. When bacteria develop resistance to multiple antibiotics, they can spread from animals to humans, making infections harder to treat. This study examined urine samples from companion animals hospitalized with urinary tract infections over two years. Three types of bacteria were most commonly found: Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Alarmingly, nearly three-quarters of these bacteria were resistant to multiple antibiotics, including some “last-resort” antibiotics called carbapenems. Additionally, one E. coli strain carried a dangerous resistance gene called blaNDM-1, which makes bacteria extremely difficult to treat. These findings highlight why veterinarians must use antibiotics carefully and why companion animal owners should follow treatment instructions accurately. The health of companion animals and human families is connected, as what affects one can affect the other. Better infection control in veterinary hospitals and smarter antibiotic use can help protect both animal and human health.

Emerging antimicrobial resistance (AMR) in companion animals represents a global health concern as they serve as potential reservoirs for multidrug-resistant (MDR) bacteria, which can be transmitted to humans. Herein, we provide comprehensive surveillance data on resistance patterns in veterinary hospital settings, focusing on urinary tract infection. A total of 23 bacterial strains were isolated from urine specimens of hospitalized companion animals suspected of urinary tract infections (UTIs) between 2022 and 2024. 16S rRNA sequencing analysis revealed that Escherichia coli (47.8%), Klebsiella pneumoniae (21.7%), and Pseudomonas aeruginosa (8.7%) were predominant uropathogens. Minimum inhibitory concentration and minimum bactericidal concentration tests were employed to analyze AMR patterns across different classes of antibiotics. Moreover, antimicrobial susceptibility test exhibited 73.91% MDR according to the standard definition given by the Clinical and Laboratory Standards Institute (CLSI) M100 guidelines. Most Gram-negative bacteria have been shown to be resistant to beta-lactam antibiotics, especially carbapenems. Notably, an E. coli strain was confirmed to possess the blaNDM-1 gene encoding the carbapenemase New Delhi metallo-β-lactamase. These findings support the implementation of targeted infection control measures and evidence-based treatment protocols to preserve antimicrobial efficacy in companion animal medicine to minimize potential public health risks through the One Health approach.