Study Reveals Enterococcus Enhances E. coli Defense Mechanisms in Dogs and Poultry
A recent study has uncovered how Enterococcus faecalis (EF) boosts the survival of two pathogenic Escherichia coli (E. coli) subtypes—uropathogenic E. coli (UPEC) and avian pathogenic E. coli (APEC)—by significantly increasing their production of protective capsular “slime.” This discovery may pave the way for specialized treatments against E. coli infections in dogs and poultry.
Key Findings
- Capsule Production: UPEC and APEC strains produced 5 to 16 times more protective exopolysaccharide slime in the presence of EF. This capsule shields bacteria from immune responses and antibiotics.
- Impact on Infections:
- Dogs: UPEC is a leading cause of urinary tract infections (UTIs), a common ailment in small animal medicine and a major reason for antibiotic use.
- Poultry: APEC is a significant contributor to poultry mortality worldwide, leading to bloodstream infections.
Mechanism of Interaction
EF enhances E. coli’s ability to:
- Survive in Low-Iron Environments: EF helps E. coli thrive in challenging environments like the urinary tract or bloodstream.
- Increase Virulence: EF-responsive strains of E. coli had specific virulence and capsule production genes, enabling faster growth and stronger defenses.
Experimental Insights
- Iron-Restricted Cultures: EF presence increased growth rates and capsule production in EF-responsive E. coli strains.
- Chicken Embryo Model: Mortality rates were higher in embryos co-infected with EF-responsive strains than those infected with non-responsive strains or EF alone.
- Genomic Analysis: Virulence genes and iron-acquisition mechanisms were found predominantly in EF-responsive strains.
Implications
- Enterococcus as an “Armorer”: EF not only aids E. coli survival in low-iron conditions but also reinforces its protective capabilities.
- Therapeutic Potential: Insights from this study could lead to the development of vaccines or targeted therapies to combat EF and pathogenic E. coli co-infections.
Research Support
The study, published in PLOS ONE, was conducted by a team from North Carolina State University with support from the U.S. Food and Drug Administration GenomeTrakr program and the U.S. Department of Agriculture Animal Plant Health Inspection Service.
This research emphasizes the complex interplay between bacterial species in infections and highlights opportunities for innovative treatments to address these co-infections effectively.