Antimicrobial Resistance Profile and ExPEC Virulence Potential in Commensal Escherichia coli of Multiple Sources

Area of Science:

• Microbiology
• Genetics
• Public Health

Background:

• Commensal Escherichia coli (E. coli) are found in various animal hosts and humans.
• These bacteria can harbor antimicrobial resistance (AMR) and virulence-associated genes (VAGs).
• Commensal E. coli may serve as reservoirs for extra-intestinal pathogenic E. coli (ExPEC).

Purpose of the Study:

• To characterize the genetic AMR and virulence profiles of commensal E. coli.
• To evaluate the role of commensal E. coli as reservoirs for ExPEC VAGs.
• To assess the potential of commensal E. coli as ExPEC pathogens.

Main Methods:

• Analysis of 279 commensal E. coli isolates from diverse sources (food-producing animals, pets, wildlife, humans).
• Phenotypic antimicrobial resistance (AMR) testing.
• Genetic profiling for ExPEC virulence-associated genes (VAGs) and sequence types (STs).

Main Results:

• High rates of phenotypic resistance to tetracycline, sulfamethoxazole/trimethoprim, streptomycin, and sulfisoxazole were observed.
• Poultry and rabbit sources were significantly associated with AMR, including resistance to quinolones, streptomycin, and sulfonamides.
• Pandemic and emerging ExPEC STs were identified, carrying numerous VAGs and exhibiting phenotypic resistance, indicating potential pathogenicity.
• Commensal flora showed variable resistance and VAG distribution, highlighting their role as reservoirs.

Conclusions:

• Commensal E. coli, particularly from poultry and rabbits, harbor significant antimicrobial resistance and virulence factors.
• These commensal strains, including pandemic and emerging ExPEC types, represent a reservoir for ExPEC and potential pathogens.
• Understanding these reservoirs is crucial for One Health approaches to combat AMR and ExPEC infections.