Cross‐sectional study of antimicrobial‐resistant bacteria in horses. Part 1: Prevalence of antimicrobial‐resistantEscherichia coliand methicillin‐resistantStaphylococcus aureus

Abstract

SummaryReasons for performing study: The increasing prevalence of antimicrobial-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) and antimicrobial-resistant Escherichia coli represents a significant problem. However, the carriage of such bacteria by horses in the UK has not been well characterised. Objectives: To estimate the prevalence of nasal carriage of MRSA and faecal carriage of antimicrobial-resistant E. coli amongst horses in the general equine community of the mainland UK. Methods: A cross-sectional study of horses recruited by 65 randomly selected equine veterinary practices was conducted, with nasal swabs and faecal samples collected. Faecal samples were cultured for antimicrobial-resistant E. coli. Nasal swabs were cultured for staphylococcal species; methicillin-resistant isolates identified as S. aureus were characterised by SCCmec and spa gene typing. Multilevel logistic regression models were used to calculate prevalence estimates with adjustment for clustering at practice and premises levels. Spatial variation in risk of antimicrobial resistance was also examined. Results: In total, 650 faecal samples and 678 nasal swabs were collected from 692 horses located on 525 premises. The prevalence of faecal carriage of E. coli with resistance to any antimicrobial was 69.5% (95% CI 65.9-73.1%) and the prevalence of extended-spectrum b-lactamase (ESBL)-producing E. coli was 6.3% (95% CI 4.1-9.6%). The prevalence of nasal carriage of MRSA was 0.6% (95% CI 0.2-1.5%). Spatial analysis indicated variation across the UK for risk of carriage of resistant and multidrug-resistant (resistant to more than 3 antimicrobial classes) E. coli. Conclusions and potential relevance: Carriage of MRSA by horses in the community appears rare, but the prevalence of antimicrobial-resistant E. coli (including ESBL-producing E. coli) is higher. A high prevalence of antimicrobial-resistant bacteria could have significant health implications for the horse population of the UK.

Virulence, resistance, and genetic relatedness of Escherichia coli and Klebsiella sp. isolated from mule foals

“…While all FS E. coli isolates were susceptible to trimethoprimsulfamethoxazole, TW E. coli isolates showed 16% resistance. Similar resistance profiles were also found a in E. coli of fecal origin from young (Schoster et al, 2012) and adult (Maddox et al, 2012) healthy horses and may reflect the prevalence of circulating strains previously selected by the use of such drugs. The prevalence of resistant isolates was higher in H animals compared to S animals (55.1% and.…”

Explanation and Elaboration Document for the STROBE‐Vet Statement: Strengthening the Reporting of Observational Studies in Epidemiology—Veterinary Extension

“…To allow for an overall compliance proportion of approximately 60%, each practice was asked to recruit the next 20 horses seen on visits (a total of 1,300 horses).65 …”

Methicillin-Resistant Staphylococcus aureus (MRSA) in Food- Producing and Companion Animals and Food Products

“…CC398 isolated from nasal samples of horses in the Netherlands and Belgium exhibited high prevalence rates, 9.3 and 10.9%, respectively [227,229]. More than 25 spa-types have been reported, and three types, such as t011, t064 and t451, were the most widespread [230]. In addition, only three SCCmec types (IV, V, VI) have been discovered from horses [218].…”