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Is blaCTX-M-1 Riding the Same Plasmid Among Horses in Sweden and France?
Agnese Lupo1, Marisa Haenni1, Estelle Saras1
11 Université de Lyon-ANSES , Unité Antibiorésistance et Virulence Bactériennes, Lyon, France .
Abstract:
A predominance of the blaCTX-M-1/IncHI1 plasmid combination in horses has been reported in Czech-Republic, Denmark, and The Netherlands. To clarify a possible specific plasmid epidemiology of blaCTX-M-1 in horses in a European perspective, a collection of 74 extended-spectrum beta-lactamase-producing Escherichia coli recovered from diseased horses in France and Sweden during the period 2009-2014 was investigated in respect of their genetic relatedness, plasmid content, and molecular features. Overall, 80% of E. coli isolates from diseased horses harbored blaCTX-M-1 on large IncHI1 plasmids with plasmid sequence type (pST) 2 and pST9 more prevalent in Sweden and France, respectively. In French isolates, IncI1/pST3 plasmids were also identified. The CTX-M-1-producing E. coli belonged principally to the clonal complex 10. ST641, together with its single locus variant, and ST1730 constituted two other major groups. The rep-PCR clustering highlighted a clonal dissemination of E. coli CTX-M-1 producers in different regions of the same country and during several years. The STs found in our isolates were also reported in The Netherlands, suggesting a common source of contamination in Europe, although only further cooperative investigation will clarify this issue. On the other hand, the spread of IncI1/pST3 plasmids among horses constitutes another worrisome issue considering their successful spread in other animal hosts such as chicken or bovines. Monitoring evolution and propagation of antimicrobial resistance in equine environment is a priority to avoid further propagation of antimicrobial resistance mechanisms threatening human and animal health.
Insights
Extended-spectrum beta-lactamase-producing Escherichia coli carrying blaCTX-M-1 on IncHI1 plasmids are prevalent in horses across Europe. Clonal dissemination and specific plasmid types highlight the need for monitoring antimicrobial resistance in equine populations.
Area of Science:
- Veterinary microbiology
- Antimicrobial resistance
- Molecular epidemiology
Background:
- The blaCTX-M-1 gene on IncHI1 plasmids is frequently found in horses in several European countries.
- Understanding the epidemiology of this resistance mechanism in horses is crucial for public and animal health.
Purpose of the Study:
- To investigate the genetic relatedness, plasmid content, and molecular features of extended-spectrum beta-lactamase-producing Escherichia coli in horses from France and Sweden.
- To clarify the European perspective on the plasmid epidemiology of blaCTX-M-1 in equine populations.
Main Methods:
- Analysis of 74 extended-spectrum beta-lactamase-producing Escherichia coli isolates from diseased horses (2009-2014).
- Investigation of genetic relatedness using rep-PCR.
- Characterization of plasmid content, including plasmid sequence types (pSTs).
- Identification of Escherichia coli sequence types (STs).
Main Results:
- 80% of isolates harbored blaCTX-M-1 on large IncHI1 plasmids.
- pST2 and pST9 were prevalent in Sweden and France, respectively; IncI1/pST3 plasmids were found in French isolates.
- CTX-M-1-producing E. coli primarily belonged to clonal complex 10, with ST641 and ST1730 also significant.
- rep-PCR indicated clonal dissemination within countries over several years.
- Identical STs were reported in The Netherlands, suggesting a potential common European source.
Conclusions:
- The blaCTX-M-1/IncHI1 plasmid combination is widespread in European horses, with distinct plasmid sequence types in France and Sweden.
- Clonal spread of resistant E. coli strains occurs within countries.
- The presence of IncI1/pST3 plasmids in horses is concerning due to their established spread in other livestock.
- Continuous monitoring of antimicrobial resistance in equine environments is essential to prevent further spread impacting human and animal health.
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