Geographic sharing of ribotype patterns in Enterococcus faecalis for bacterial source tracking.

Area of Science:

• Environmental microbiology
• Molecular epidemiology
• Bacterial source tracking

Background:

• Enterococcus faecalis has a limited host range, potentially leading to increased geographic sharing of its ribotype patterns.
• Such sharing is advantageous for bacterial source tracking (BST) applications.
• The study investigates the actual geographic distribution of E. faecalis ribotypes.

Purpose of the Study:

• To determine the extent of geographic sharing of Enterococcus faecalis ribotype patterns.
• To assess the feasibility of using ribotyping for bacterial source tracking.
• To evaluate the correlation between ribotype patterns and geographic distance.

Main Methods:

• Collected 752 Enterococcus faecalis isolates from wastewater treatment plants across diverse US locations and Puerto Rico.
• Utilized RiboPrinter technology for bacterial ribotyping.
• Analyzed ribotype data at various similarity indices and tolerance levels.
• Employed Mantel test to assess the correlation between ribotype patterns and geographic distance.

Main Results:

• A high number of unique ribotypes (66%) were unshared even at stringent criteria.
• Relaxing matching criteria still resulted in a substantial proportion of unshared ribotypes.
• No significant correlation was found between ribotype patterns and geographic distance.
• Sharing of ribotype patterns did not increase with decreasing geographic distance.

Conclusions:

• Enterococcus faecalis ribotype patterns are not significantly shared geographically.
• The limited geographic sharing challenges the effectiveness of ribotyping for bacterial source tracking.
• Constructing a comprehensive database for BST using this method would be impractical and costly.