Occurrence and molecular characteristics of ESBL/AmpC-producing Escherichia coli in faecal samples from horses in an equine clinic.

This research study investigates the instances and traits of ESBL/AmpC-producing Escherichia coli in horse fecal samples from an equine clinic in the Netherlands, highlighting their potential for causing hard-to-treat infections and the need for careful antimicrobial use.

Study Design and Findings

• The aim of the research was to examine the occurrence and related characteristics of ESBL/AmpC-producing Escherichia coli (E. coli) in fecal samples from horses kept in one equine clinic in the Netherlands.
• A total of 91 horse samples were used in this study, including both resident horses and patient samples.
• These E. coli types were identified through a combined disc diffusion test. Phylogenetic groups and MLST (Multi Locus Sequence Typing) were further determined, and ESBL/AmpC related genes were examined and sequenced with PCR (Polymerase Chain Reaction).
• The related plasmids – genetic structures in a cell that can replicate independently – were examined by transformation and PCR-based replicon typing. Subtyping of plasmids was done with plasmid MLST.
• A significant percentage of horses in the study, 76 out of 91, (about 84%) had at least one E. coli isolate with a confirmed ESBL/AmpC gene in their samples.
• Rather than one widespread strain, a diverse E. coli population was observed, including mostly E. coli from the B1 Phylogenetic group with bla CTX-M-1, indicating that just a nosocomial spread – infections got within a healthcare setting- was not solely responsible for the high incidence observed.

The Genes and Plasmid Types

• MLST analysis revealed that 47 E. coli sequence types (STs) were present, organized in four clusters of genetically related strains.
• Frequently found STs included ST10, ST641, ST1079 and ST1250.
• The genes bla CTX-M-1 and bla CTX-M-2 were most prevalent in the sample.
• Plasmid types varied as well, with type IncHI1 being the most frequently found, although plasmids from the IncF, IncI1 and IncN groups were also identified.

Conclusions and Implications

• The study revealed a high occurrence of ESBL-producing E. coli in faecal samples in horses kept in an equine clinic, and the variety of STs, ESBL genes and plasmid types suggests nosocomial transmission – a process by which bacteria spread within a healthcare setting.
• These ESBL E. coli types are potentially dangerous as they can cause infections that are difficult to treat in horses, thus the study suggests a need for prudent antimicrobial use to manage them.
• The research also underscores the need to assess the risk of transmission to humans in close contact with these horses, such as caretakers and veterinarians.