Prevalence of extended-spectrum cephalosporin-, carbapenem-, and fluoroquinolone-resistant members of the family Enterobacteriaceae isolated from the feces of horses and hospital surfaces at two equine specialty hospitals.

The study investigates the prevalence of antibiotic-resistant bacteria within the Enterobacteriaceae family, particularly those resistant to extended-spectrum cephalosporins, carbapenems, and fluoroquinolones, in the feces of hospitalised horses and on hospital surfaces. The research establishes that horses under hospitalisation may contribute to the spread of antibiotic-resistant bacteria.

Methods

• Fecal and environmental samples were collected from two hospitals – The Ohio State University Galbreath Equine Center (OSUGEC) and a private referral equine hospital in Kentucky (KYEH).
• Feces samples were processed within 24 hours of admission, followed by a test after 48 hours and between 3-7 days of hospitalisation.
• The samples underwent an enrichment process before being inoculated on selective media designed to promote the growth of Enterobacteriaceae bacteria exhibiting resistance to extended-spectrum cephalosporins, carbapenems, and fluoroquinolones.

Results

• A total of 358 fecal samples from 143 horses were evaluated.
• There was a noticeable increase in the growth of resistant bacteria – particularly, AmpC β-lactamase, extended-spectrum beta-lactamase, and fluoroquinolone-resistant Enterobacteriaceae, after the horses were hospitalized for 48 hours as compared to the samples collected within the first 24 hours.
• Horses in the Kentucky hospital were found to be more likely to host fluoroquinolone-resistant bacteria.
• In the Ohio hospital, between 68% and 82% of the sampled surfaces harbored antibiotic-resistant Enterobacteriaceae. The bacteria types were distributed similarly in the Kentucky hospital, albeit in generally lower proportions (between 32%-52% of surfaces).

Conclusions

• The findings indicate the presence of antimicrobial-resistant bacteria in both the feces of hospitalized horses and within the hospital environment.
• The study also suggests that the process of hospitalization might lead to an increased presence of clinically important antimicrobial-resistance genes in the feces of horses.