Microbial Water Quality Issues

1
Microbial Water Quality Issues

• What is the source of fecal indicator bacteria?
• What is the health risk?
• When fecal indicator bacteria are present
• When fecal indicator bacteria are absent
• From different sources
• Timeliness of results
• Is water the only concern?

2
Waterborne Diseases

• CDC waterborne disease cases
• 940, 000 cases of illness per year
• Possibly 900 deaths per year
• EPA (840-B-00-002)
• 25 of our nations 300, 000 miles of streams,
  rivers, and coastal shorelines are impaired by
  pathogens
• EPA Beach Watch (http//www.epa.gov/ost/beaches)
• 24 of reporting beaches were closed at least
  once in 2000 due to high fecal indicator bacteria
  concentrations

3
Culture vs Non Culture
Non Cultured Based
Culture Based
Extract
Selective Isolation
Pick Colony
PCR amplify
Verify ID
PCR amplify
DGGE
T-RFLP
RIBOTYPING
MARS
PFGE
REP-PCR
MICROARRAY
4
Goals of Source Tracking Study

• Develop a technique to identify source of fecal
  contamination
• Non culture based
• Organism(s) of interest are dominant organisms in
  human/animal feces
• Distinguish from naturally occurring background
  bacteria

• Field test this technique and compare to other
  source tracking methods and criteria for
  measuring fecal contamination

5
DNA Fingerprinting by T-RFLP
Cow
Cow
6
T-RFLP Goose.Deer comparison
Goose-1
Goose-2
Deer-1
Deer-2
7
Where are we?

• What has been done
• Collection of fecal samples
• Major fecal bacterial groups have been targeted
• Where we are now
• Beginning DNA analysis of fecal samples
• Selecting target bacterial groups
• Future work
• Optimizing the technique
• Field testing methods

8
Source Tracking Study

• Identify and Characterize Likely Sources
  (Samples from different stocks, different
  seasons)

• Sampling Strategy (Flow conditions, Seasonal,
  Agricultural Practices)
• Hydrological characterization (ground water and
  surface water flow)
• Measure Fecal Associated Chemical Contaminants
• Inorganic-Nitrate, Ammonium, Phosphate
• DOC (8033) Steroids Pharmaceuticals

9
EPA Strategy for Waterborne Microbial Disease

• Establish a uniform criteria and monitoring
  requirements for pathogens across all water uses
• INDICATORS, INDICATORS, INDICATORS

• Concerns with this strategy
• Will a uniform criteria properly address all
  health concerns for all water uses?
• How adequate are indicators for predicting health
  risk?

• Bioterrorism threats to our waters are being
  addressed in a separate strategic plan

10
Indicators of Fecal Contamination

• MOST INDICATORS ARE HARMLESS, ESSENTIAL, AND
  BENEFICIAL MICRORGANISMS
• Indicate the possibility there is or was a
  source of fecal contamination
• Little is know about what controls the
  distribution, and survivability of fecal
  bacteria
• Easy to grow and detect but require 24 hours
• Current recommended indicators represent a small
  percentage of the total fecal bacteria therefore
  decreases the sensitivity of the test

11
Commonly Used Indicators
Indicator Advantages Concerns
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12
Pathogens and Fecal Indicators

• Many pathogens are not associated with fecal
  contamination
• Pathogens associated with fecal contamination may
  have different transport and survival mechanisms
• Some pathogens are naturally occurring
  (opportunist pathogens)
• Changes in the environment can cause
  proliferation
• Compromised populations at risk

13
Determining Water Quality

• Quantify fecal indicator bacteria
• Total coliforms
• Fecal coliforms
• E. coli (EPA recommended)
• Enterococci (EPA recommended)
• Clostridium perfringens
• Coliphage

14
EPA Recommendations
15
Fecal Indicator and H. pylori Results Alaska
Rivers
Colony Forming Units (CFU) per 100 ml water sample
16
Fecal Indicator and H. pylori Results Alaska
Village Drinking Waters
Colony Forming Units (CFU) per 100 ml water sample
17
Fecal Indicator and H. pylori Results Iroquois
River, Sugar Creek, and Potomac River
Colony Forming Units (CFU) per 100 ml water sample
18
Challenges to Pathogen Research

• Techniques developed for clinical applications
  (adapt for field)
• Detection Limits- increase test sensitivity,
  concentrate specific cells (e.g. immunocapture)
• Generalized Technique- universal gene (e.g.
  toxins), better indicator species?, chemical
  proxy
• Culturing-Safe laboratory conditions, special
  facilities
• Persistence- survivability, growth?,
  susceptibility to environmental conditions,
  (e.g. UV, temperature)
• Transport- variations in media (freshwater vs
  saltwater, sediments, ground water vs surface
  water)