ISO 7899-2 (2000) medium: Slanetz and Bartley

Media control Water quality 

Microorganisms and performance criteria for testing selective media 'Slanetz and Bartley' for Enumeration of Intestinal enterococci used in Water quality  microbiology by comparing with a non-selective reference medium according to ISO 11133.

  • 1 Quantitative control of Productivity

  • Red-maroon-pink colonies. The characteristic reaction of  on Slanetz and Bartley
    The characteristic reaction of Enterococcus faecalis on Slanetz and Bartley: Red-maroon-pink colonies.

    Best Practice Slanetz and Bartley

    Quantitative control of Productivity solid medium

    1. Use a quantitative reference material or test suspension with a known number of Enterococcus faecalis.
    2. Dilute this material so 50 to 120 cfu is inoculated on the Slanetz and Bartley by membrane filtration method.
    3. Place the membrane on the surface of the agar under test (Slanetz and Bartley).
    4. Do this also for the reference media (TSA).
    5. Incubate at (36 ± 2) °C for (44 ± 4) h.
    6. Count the colonies on the medium under test (Slanetz and Bartley) and the reference media (TSA).
    7. Calculate the productivity ratio PR. The criteria is: PR ≥ 0,5.
    8. If the PR exceeds 1,4 identify the reason.
    9. For this the total count of colonies obtained on the culture medium under test (Slanetz and Bartley) is divided by the total count of colonies obtained on the defined reference medium (TSA).
    Calculate the productivity ratio PR as follows: PR  NS
    N0
    Ns = total count test medium
    N0 = total count reference medium

    Control strain WDCM number Ref. media Incubation Criteria Characteristic reaction
    Enterococcus faecalis TSA (36 ± 2) °C for (44 ± 4) h PR ≥ 0,5 Red-maroon-pink colonies
    Enterococcus faecium
    The best practice for Quantitative control of Productivity for media control of 'Slanetz and Bartley' is based on the data displayed in this table according ISO 11133.
  • 2 Quantitative control of Productivity

  • Red-maroon-pink colonies. The characteristic reaction of  on Slanetz and Bartley
    The characteristic reaction of Enterococcus faecalis on Slanetz and Bartley: Red-maroon-pink colonies.

    Best Practice Slanetz and Bartley

    Quantitative control of Productivity solid medium

    1. Use a quantitative reference material or test suspension with a known number of Enterococcus faecalis.
    2. Dilute this material so 50 to 120 cfu is inoculated on the Slanetz and Bartley by membrane filtration method for example 0.1 mL suspension.
    3. Place the membrane on the surface of the agar under test (Slanetz and Bartley).
    4. Do this also for the reference media (Media batch Slanetz and Bartley already validated).
    5. Incubate at (36 ± 2) °C for (44 ± 4) h.
    6. Count the colonies on the medium under test (Slanetz and Bartley) and the reference media (Media batch Slanetz and Bartley already validated).
    7. Calculate the productivity ratio PR. The criteria is PR ≥ 0,7.
    8. If the PR exceeds 1,4 identify the reason.
    9. For this the total count of colonies obtained on the culture medium under test (Slanetz and Bartley) is divided by the total count of colonies obtained on the defined reference medium (Media batch Slanetz and Bartley already validated).
    Calculate the productivity ratio PR as follows: PR  NS
    N0
    Ns = total count test medium
    N0 = total count reference medium

    Control strain WDCM number Ref. media Incubation Criteria Characteristic reaction
    Enterococcus faecalis Media batch Slanetz and Bartley already validated (36 ± 2) °C for (44 ± 4) h PR ≥ 0,7 Red-maroon-pink colonies
    Enterococcus faecium
    The best practice for Quantitative control of Productivity for media control of 'Slanetz and Bartley' is based on the data displayed in this table according ISO 11133.
  • Qualitative control of Selectivity

  • Best Practice Slanetz and Bartley

    Qualitative control of Selectivity solid medium

    1. Use a reference material or test suspension with a known number of Escherichia coli and Staphylococcus aureus.
    2. Streak the test strain (Escherichia coli and Staphylococcus aureus) as a single line on the media under test (Slanetz and Bartley).
    3. Multiple strains can be streaked on the plate as long no crossing occurs.
    4. Use a 1 µl loop in case of a concentration of at least 10000 cfu or a 10 µl loop in case of a concentration between 1000 and 10000 cfu.
    5. Incubate at (36 ± 2) °C for (44 ± 4) h.
    6. Asses the amount of growth as, 0 for no growth, 1 for weak growth or 2 for good growth.
    7. For this medium (Slanetz and Bartley) and standard (ISO 7899-2) combination the criteria is: "Total inhibition (0).

    Control strain WDCM number Ref. media Incubation Criteria Characteristic reaction
    Escherichia coli or (36 ± 2) °C for (44 ± 4) h Total inhibition (0) No growth
    + Staphylococcus aureus or
    The best practice for Qualitative control of Selectivity for media control of 'Slanetz and Bartley' is based on the data displayed in this table according ISO 11133.