TOPIC A

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TOPIC A

• Applied and Environmental Microbiology

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What is a TMDL

• TMDL Total Maximum Daily Load
• TMDL is the maximum quantity of a specific
  pollutant that a body of water can have to meet
  water quality standards
• Standards are set by City, County or State
• Varies depending on type of water
• TMDL levels are lower for potable water than for
  recreational water
• Varies depending on type of pollutant
• TMDL for E. coli is lt126cells /100ml
• TMDL for Enterococci is lt33cells/ 100ml

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What is an Indicator Organism

• An indicator organism is an organism whose
  presence or absence can indicate the
  contamination of an environment
• Ex of fecal coliform indicator organisms
• E. coli, Citrobacter freundii, Klebsiella
  pneumoniae
• Ex of non-coliform fecal indicator organisms
• Streptococcus bovis (cow)
• Streptococcus equinis (horse)
• Streptococcus faecalis and S. faecium (all
  organisms)

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Culture Based Methods for detecting Fecal
Contamination

• MPN (Most Probable Number) Method

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Culture Based Methods for detecting Fecal
Contamination

• Membrane Filtration
• Filters sample through a membrane w/ small pore
  sizecaptures bacteria
• Filter is placed on FC agar containing aniline
  blue.
• Fecal coliforms produce acid that reacts w/
  analine blue causing the colonies to appear blue
• Absence/presence test
• Place sample into tube containing
• Bromcresol purple
• Lactose and lauryl tryptose
• Durham tube
• If yellow color and gas production result
• Positive for presence of bacteria

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Non-Culture Based Method and Viral Method

• Non-culture based
• Extract DNA, PCR, sequence, identify
• Viral
• Look for the presence of specific viruses that
  are correlated/found in the fecal material of
  animals