Antimicrobial resistance in bacteria isolated from diseased horses in France

Abstract

Summary Background Horses are one of the potential reservoirs of antimicrobial resistance (AMR) determinants that could be transferred to human subjects. Objective To describe the AMR patterns of major bacteria isolated from diseased horses in France. Study design Retrospective observational study. Methods Data collected between 2012 and 2016 by RESAPATH, the French national surveillance network for AMR, were analysed. Only antimicrobials relevant in veterinary and human medicine for the isolated bacteria were considered. Mono‐ and multidrug resistance were calculated. The resistance proportions of major equine diseases were assessed and compared. Where data permitted, resistance trends were investigated using nonlinear analysis (generalised additive models). Results A total of 12,695 antibiograms were analysed. The five most frequently isolated bacteria were Streptococcus spp., Escherichia coli, Pseudomonas spp., Staphylococcus aureus, Pantoea spp. and Klebsiella spp. The highest proportions of resistance to gentamicin were found for S. aureus (22.1%) and Pseudomonas spp. (26.9%). Klebsiella spp. and E. coli had the highest proportions of resistance to trimethoprim‐sulfamethoxazole (15.5 and 26.2%, respectively). Proportions of resistance to tetracycline were among the highest for all the bacteria considered. Resistance to third‐generation cephalosporins was below 10% for all Enterobacteriaceae. The highest proportions of multidrug resistance (22.5%) were found among S. aureus isolates, which is worrying given their zoonotic potential. From 2012 to 2016, resistance proportions decreased in Pseudomonas spp. isolates, but remained the same for S. aureus. For Streptococcus spp. and E. coli, resistance proportions to trimethoprim‐sulfamethoxazole increased. Main limitations Since antibiograms are not systematic analyses, any selection bias could impact the results. Conclusions Such studies are essential to estimate the magnitude of the potential threat of AMR to public health, to design efficient control strategies and to measure their effectiveness. These findings may also guide the initial empirical treatment of horse diseases.

Monitoring antimicrobial resistance in bacteria isolated from horses

“…Staphylococcal species were also commonly isolated from upper respiratory tract samples 5. These findings are in general agreement with previous reports from France, Canada and New Zealand 6-8…”

“…5 These findings are in general agreement with previous reports from France, Canada and New Zealand. [6][7][8] The type of growth observed on culture plates is an important consideration for diagnostic laboratory personnel in deciding whether to proceed to antimicrobial susceptibility testing of isolates. However, it may be difficult to interpret the clinical significance of isolates when present in mixed growth of two or more organisms or if the growth of the isolate is pure but scant.…”

“…However, systematic surveillance systems for AMR in veterinary clinical samples are frequently lacking, and surveillance of this kind is not currently carried out for AMR in horses. Even systems such as the RESAPATH network in France,12 which is a national passive surveillance system that includes equine samples, have the inherent biases associated with voluntary submission of results by laboratories and selection of cases for sampling by practising vets 7…”

Retrospective assessment of perioperative antimicrobial use for elective arthroscopy in horses

“…Penicillin can be effective, but β‐lactamase production by staphylococci and Enterobacteriaceae is common, rendering this drug ineffective. Gentamicin has some efficacy against staphylococci but is more effective against gram‐negative pathogens . Trimethoprim‐sulfonamide combinations typically have good in vitro efficacy against staphylococci, streptococci, and Enterobacteriaceae .…”

“…Gentamicin has some efficacy against staphylococci but is more effective against gram‐negative pathogens . Trimethoprim‐sulfonamide combinations typically have good in vitro efficacy against staphylococci, streptococci, and Enterobacteriaceae . In man and in dogs, the first generation cephalosporin cefazolin is widely used, but, while its pharmacokinetics have been assessed in horses, it was not administered to horses at this institution.…”