Microbiology Guide: Presence Absence (PA) Method and Media

Document ID

Document ID TE8848

Version

Version 4.0

Status

Status Published

Published Date

Published Date 09/06/2018
Question
Microbiology Guide: Presence Absence (PA) Method and Media
Summary
Microbiology Guide: Media and Equipment Selection; Presence Absence (PA) Method and Media
Answer
From: Microbiology Guide: Media and Equipment Selection


Media Selection Summary

Drinking Water and Recreational Water
Organism USEPA- Accepted (Y/N) Presumptive Media Confirmation Media
Total Coliforms Y LT/BCP Broth Disposable Bottles or LT/BCP Broth Ampules Brilliant Green Bile (BGB) Broth Tubes
Total Coliforms Y P/A Broth Ampules or Disposable P/A Test or P/A Test Kit BGB Broth Tubes
Total Coliforms N P/A Broth with MUG BGB Broth Tubes
Fecal Coliforms Y LT/BCP Broth Disposable Bottles or LT/BCP Broth Ampules EC Medium Tubes
Fecal Coliforms Y P/A Broth Ampules or Disposable P/A Test or P/A Test Kit EC Medium Tubes
Fecal Coliforms N PathoScreen™ Medium P/A Pillows Use Traditional Confirmation Media
E. Coli Y LT/BCP Broth Disposable Bottles or LT/BCP Broth Ampules EC Medium with MUG Tubes
E. Coli Y P/A Broth Ampules or Disposable P/A Test or P/A Test Kit EC Medium with MUG Tubes
E. Coli N P/A Broth with MUG No Confirmation Necessary

Media
  • Presence absensce media, Hach method 8319, Total Coliform
    • For water and wastewater
    • Media Packaging
      • Presence / Absence Test, pk/12 (Product # 2323212)
      • Presence / Absence Test pk/50 (Product # 2323250)
      • Presence / Absence Broth Ampules, pk/25 (Product # 2494925)
      • Brilliant Green Tubes, pk/15 (Product # 32215) - for Total Coliform
      • EC Medium MPN Tubes, pk/15 (Product # 1410415) - for Fecal Coliform
      • EC/Medium without Durham Tubes, pk/15 (Product # 2471515) - for E. Coli
        • Needed Accessory
          • UV long wave lamp,
            • Lamp, Ultraviolet, Portable (Product # 2415200)
            • Lamp, Ultraviolet, Long-Wave 115 Vac, 60 Hz (Product # 2184300)
            • Lamp, Ultraviolet, Long-Wave 230 Vac, 50 Hz (Product # 2184302)
 
  • Presence absensce media, Hach method 8364, Total and Ecoli Coliform
    • For water and wastewater
    • Media Packaging
      • Presence / Absence Test with MUG pk/12 (Product # 2401612)
      • Presence / Absence Test with MUG, pk/50 (Product # 2401650)
      • Presence / Absence Broth with MUG, Ampules, pk/25 (Product # 2495525)
    • Needed Accesory
      • UV long wave lamp,
        • Lamp, Ultraviolet, Portable (Product # 2415200)
        • Lamp, Ultraviolet, Long-Wave 115 Vac, 60 Hz (Product # 2184300)
        • Lamp, Ultraviolet, Long-Wave 230 Vac, 50 Hz (Product # 2184302)
 
  • Modified Colitag™ media, No Hach method reference, Total and Ecoli Coliform
    • For drinking water
    • Media Packaging
      • Hach Modified Colitag™ Presence-Absence media, pk/20 Snap-Pack (Product # 8888003)
      • Hach Modified Colitag™ Presence-Absence media, pk/100 Snap-Pack (Product # 8888004)
      • Hach Modified Colitag™ Presence-Absence media, pk/200 Snap-Pack (Product # 8888005)
    • Needed Accesory
      • UV long wave lamp,
        • Lamp, Ultraviolet, Portable (Product # 2415200)
        • Lamp, Ultraviolet, Long-Wave 115 Vac, 60 Hz (Product # 2184300)
        • Lamp, Ultraviolet, Long-Wave 230 Vac, 50 Hz (Product # 2184302)
      • Comparator for use with Hach Modified Colitag™ Presence-Absence Media (Product # 8888001)
      • Hach Modified Colitag™ Sterile 120 mL Sample Bottles, pk/100, Shrink-banded, Polystyrene (Product # 8888006)
 
  • PathoScreen™ Media, Hach method 10032, Hydrogen Sulfide Producing Bacteria
    • For drinking water, surface water, and recreational water. Advantage is international, remote field locations, and disaster / emergency situation.  Wide incubation temperature
    • Overview: Tests for hydrogen sulfide producing bacteria as the indicator organisms instead of testing for bacterial pathogens, common to fecal wastes, which can cause diseases such as typhoid fever and dysentery.  Common hydrogen sulfide producing bacteria include Salmonella, Citrobacter, Proteus, Edwardsiella and some species of Klebsiella.
    • Pathoscreen™ Field Test Kit (Product # 2859100)
    • Media packaging
      • PathoScreen™ Medium Presence / Absence Powder Pillows, pk/50 (Product # 2610696) - for 100 mL samples
      • PathoScreen™ PP 20 mL, pk/100 (Product # 2610796
Interpretation
  • Presence Absence media
    • Color change from reddish purple to yellow or yellow brown: record the test as presumptive positive for total coliform bacteria.
    • No color change: incubate for an additional 24 hours and recheck the sample for color change. If the color then changes from reddish purple to yellow or yellow brown record the test as presumptive positive for total coliform bacteria.
    • For non-EPA reporting, if an incubator is not used but the bottle is in a warm place, check the bottle at 24, 48, and 72 hours before recording the test as negative for total coliform bacteria. If the bottle is left at room temperature, do not consider the test negative until after five days.
    • If the sample still appears reddish purple after 48 plus or minus 3 hours of incubation, record the test as negative for total coliform bacteria. For PA media with MUG Examine the sample under long-wave UV light, 4–6 watts minimum. If the sample fluoresces: record the test as positive for E. coli.
 
  • Modified Colitag™ media
    • Visually examine each sample against the comparator.
    • If the sample color is yellow and of equal or greater color than the yellow comparator, the sample is positive for coliform bacteria.
    • If the sample is less yellow than the color of the yellow comparator, the sample is negative for coliform bacteria.
    • If a water sample has some background color, compare the inoculated sample to a control blank of the same water sample.
    • Use a long-wavelength (365 nm) UV lamp to examine the solution for fluorescence. If bright blue fluorescence is seen, E. coli bacteria are present.
    • If no fluorescence is seen, the sample is negative for E. coli bacteria.
 
  • PathoScreen™ media
    • Positive: color changes from yellow to black or black precipitate forms
    • Negative: No color change.  Incubate additional 12-24 hours and reevaluate. If there is no color change, record as negative.
    • If the sample is diluted, see method for dilution and calculation instructions
Media Decontamination
  • Recommendation:
    • Open each reacted P/A bottle and pipet in 5 mls of Clorox, (one can use a disposable plastic dropper).
    • Cap and invert… Let stand for 20-30 minutes.
    • After the waiting time, turn on cold water tap and pour the contents of each bottle down the drain as the water is running.  Rinse the bottle with cold tap water.
    • Dispose of the empty bottles and caps in a Contaminated plastic bag.  Tie off or knot the bag.
    • Write Cloroxed on the Contamination bag.  Place into normal trash container.

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