Potential of Enterococcus faecalis as a human fecal indicator for microbial source tracking

Area of Science:

• Environmental microbiology
• Water quality monitoring
• Bacterial source tracking

Background:

• Human fecal contamination poses significant health risks and requires effective monitoring.
• A fecal indicator bacterium with a limited host range simplifies microbial source tracking.
• Enterococcus faecalis is suggested to have a restricted host range, making it a candidate for study.

Purpose of the Study:

• To investigate the host range of Enterococcus faecalis.
• To develop methods for rapid isolation and identification of Enterococcus faecalis.
• To assess the utility of Enterococcus faecalis and ribotyping for prioritizing watershed contamination.

Main Methods:

• Isolation of fecal streptococcal bacteria from various animal sources (Canada goose, cattle, deer, dog, human, chicken, swine).
• Speciation of presumptive enterococci using the API 20 Strep system.
• Development of selective media for Enterococcus faecalis isolation.
• Ribotyping of Enterococcus faecalis isolates for strain differentiation.

Main Results:

• Enterococcus faecalis was identified in isolates from dogs, humans, and chickens.
• Selective media successfully isolated Enterococcus faecalis and excluded dog isolates.
• Ribotyping clearly differentiated human and chicken Enterococcus faecalis strains.

Conclusions:

• Enterococcus faecalis exhibits a limited host range, primarily associated with dogs, humans, and chickens.
• Combining Enterococcus faecalis detection with ribotyping offers a promising approach for identifying sources of fecal contamination.
• This method can aid in prioritizing watersheds for cleanup efforts based on human fecal pollution levels.