Comparison of approaches for source attribution of ESBL-producing Escherichia coli in Germany.
Authors: Perestrelo Sara, Correia Carreira Guido, Valentin Lars, Fischer Jennie, Pfeifer Yvonne, Werner Guido, Schmiedel Judith, Falgenhauer Linda, Imirzalioglu Can, Chakraborty Trinad, Käsbohrer Annemarie
Journal: PloS one
Summary
# Editorial Summary: Source Attribution of ESBL-Producing E. coli in Germany Understanding where antibiotic-resistant bacteria originate is critical for controlling their spread, yet pinpointing sources of extended-spectrum beta-lactamase (ESBL)-producing E. coli infections in humans has proven notoriously difficult. Researchers analysed existing German datasets comprising ESBL-producing E. coli isolates from multiple animal species (cattle, pigs, poultry, dogs and horses), nosocomial (hospital-acquired) infections, and community-dwelling humans, then used statistical modelling to match human cases with likely sources based on genetic fingerprinting, phylogenetic classification and antimicrobial resistance profiles. Whilst all animal sources contributed to human infections, nosocomial sources showed substantially stronger epidemiological links to human cases than any livestock or companion animals—a finding that underscores human-to-human transmission as a dominant route, though notably, some human subtypes could not be traced to any identified source. For equine practitioners, these results suggest that whilst horses do shed ESBL-producing E. coli, they represent a relatively minor transmission pathway to humans compared with healthcare settings; nonetheless, the One Health framework the authors advocate—integrating animal, environmental and food data—will be essential for developing more complete source attribution models that can better identify and mitigate zoonotic antibiotic resistance risks affecting equine, livestock and human medicine.
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Practical Takeaways
- •While horses and other livestock can carry ESBL-producing E. coli, human-to-human transmission (particularly in healthcare settings) represents the primary risk pathway for community infections—hygiene protocols should prioritize this route
- •Equine practitioners should be aware that horses are potential reservoirs for resistant bacteria, but direct zoonotic transmission to humans appears less significant than healthcare-associated transmission
- •A coordinated One Health approach integrating animal, environmental, and human surveillance data is needed to effectively monitor and control ESBL-producing E. coli transmission
Key Findings
- •All animal sources (cattle, pig, chicken, dog, horse) contributed to human ESBL-producing E. coli cases, but nosocomial infections were more closely related to human cases than animal sources
- •Some ESBL-producing E. coli subtypes were species-specific while others appeared only in human populations
- •Human-to-human transmission was identified as a more significant pathway than zoonotic transmission for community-acquired ESBL-producing E. coli colonization
- •A source attribution model was successfully developed to track transmission pathways and can be applied to monitor future antimicrobial resistance trends