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Bacteriophage lysis of Enterococcus host strains: a tool for microbial source tracking?
Sarah E Purnell1, James E Ebdon, Huw D Taylor
1Environment & Public Health Research Unit, School of Environment and Technology, Cockcroft Building, University of Brighton, Lewes Road, Brighton, BN2 4GJ, United Kingdom. S.E.Purnell@Brighton.ac.uk
Environmental Science & Technology
|November 4, 2011
Summary
Researchers isolated Enterococcus host strains for microbial source tracking (MST) using bacteriophage (phage). Seven strains showed 100% specificity for cattle, human, or pig fecal samples, indicating potential for water quality monitoring.
Area of Science:
- Environmental Microbiology
- Molecular Biology
- Water Quality Monitoring
Background:
- Microbial Source Tracking (MST) is crucial for identifying fecal pollution sources in water bodies.
- Bacteriophage (phage)-based methods offer a promising avenue for MST due to their host specificity.
- Enterococcus species are commonly used indicators of fecal contamination but require robust MST tools.
Purpose of the Study:
- To isolate and characterize Enterococcus host strains for developing simple bacteriophage-based MST tools.
- To evaluate the specificity and sensitivity of these Enterococcus strains in detecting phages from various fecal sources.
- To identify specific Enterococcus strains with high accuracy for tracking cattle, human, and pig fecal pollution.
Main Methods:
- Isolation of presumptive Enterococcus host strains from diverse environmental samples in southern England.
- Screening of 390 Enterococcus strains for phage detection capabilities in wastewater and fecal samples (cattle, pigs, sheep).
- Ranking of phage-detecting strains (n=147) based on source specificity and phage detection levels (PFU/mL).
- Further testing of highly specific strains (n=29) with human and nonhuman fecal samples to determine specificity and sensitivity.
Main Results:
- A total of 147 out of 390 Enterococcus strains detected phages.
- Twenty-nine strains showed host specificity and detected >100 PFU/mL.
- Seven strains demonstrated 100% specificity for cattle, human, or pig fecal sources.
- Specificity ranged from 44-100% and sensitivity from 17-83% across tested strains.
- Cattle-specific isolates included Enterococcus casseliflavus, E. mundtii, and E. gallinarum.
- Human and pig-specific isolates were identified as Enterococcus faecium or Enterococcus faecalis.
Conclusions:
- Enterococcus host strains, particularly those infected by specific phages, show significant potential for microbial source tracking.
- The simplicity, cost-effectiveness, and high specificity of this phage-based approach make it a valuable tool for water quality management.
- This method can effectively differentiate between cattle, human, and pig fecal pollution sources in environmental waters.
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