CRITERION™ m PA-C AGAR

Cat. no. C7960 CRITERION™ m PA-C Agar 70gm
Cat. no. C7961 CRITERION™ m PA-C Agar 500gm
Cat. no. C7962 CRITERION™ m PA-C Agar 2kg
Cat. no. C7963 CRITERION™ m PA-C Agar 10kg
Cat. no. C7964 CRITERION™ m PA-C Agar 50kg

INTENDED USE

Hardy Diagnostics CRITERION™ m PA-C Agar is recommended for the selective recovery and enumeration of Pseudomonas aeruginosa from water samples by membrane filtration.

This dehydrated culture medium is a raw material intended to be used in the making of prepared media products, which will require further processing, additional ingredients, or supplements.

SUMMARY

Many different methods have been used to enumerate Pseudomonas aeruginosa from water samples. The most-probable-number (MPN) procedures result in satisfactory recovery of P. aeruginosa, but are not suitable for large-volume water testing and lack precision. The membrane filter (MF) techniques eliminate these deficiencies.

Levin and Cabelli formulated m PA Agar as a selective membrane filter medium for P. aeruginosa.(1) m PA Agar contains kanamycin, nalidixic acid, sulfapyridine and cycloheximide to achieve a moderately selective medium. The original formulation was modified by raising the pH and altering the content or concentration of ingredients.(2,3) The resulting medium was designated m PA-B Agar. Both formulations are found in the Standard Methods for the Examination of Water and Wastewater.(4)

Brodsky and Ciebin further modified those media by removing sulfapyridine and cycloheximide and produced m PA-C Agar.(5) This formulation allowed P. aeruginosa to be enumerated after only 24 hours of incubation compared to 72 hours for m PA-B Agar and 96 hours for a presumptive MPN test.(5)

CRITERION™ m PA-C Agar contains yeast extract and lysine which provide necessary growth nutrients. Lactose, sucrose, and xylose are sources of fermentable carbohydrates. The salts provide essential ions and sodium chloride provides osmotic balance. Phenol red is the pH indicator, which becomes yellow when acid is produced during fermentation. Kanamycin inhibits protein synthesis in gram-positive organisms and nalidixic acid blocks replication of susceptible gram-negative bacteria.(6)

FORMULA

Gram weight per liter: 35.0gm/L
Sodium Thiosulfate 5.0gm
Lysine 5.0gm
Sodium Chloride 5.0gm
Yeast Extract 2.0gm
Magnesium Sulfate 1.5gm
Lactose 1.25gm
Sucrose 1.25gm
Xylose 1.25gm
Ferric Ammonium Citrate 0.80gm
Phenol Red 80.0mg
Nalidixic Acid 37.0mg
Kanamycin 8.0mg
Agar 12.0gm

Final pH 7.2 +/- 0.1 at 25ºC.

* Adjusted and/or supplemented as required to meet performance criteria.

STORAGE AND SHELF LIFE

Store the sealed bottle(s) containing dehydrated culture medium at 2-30ºC. Dehydrated culture medium is very hygroscopic. Keep lid tightly sealed. Protect dehydrated culture media from moisture and light. The dehydrated culture media should be discarded if it is not free-flowing or if the color has changed from its original pinkish-beige.

Store the prepared culture media at 2-8ºC.

PRECAUTIONS

METHOD OF PREPARATION FOR DEHYDRATED CULTURE MEDIA

1. Suspend 35.0gm of the dehydrated culture media in 1 liter of distilled or deionized water.

2. Heat with frequent agitation and boil for one minute to completely dissolve the powder. DO NOT AUTOCLAVE.

3. Cool to 45-50ºC. and pour into sterile 50mm petri plates. Use media within one week after preparation.

4. Test samples of the prepared media for performance using typical control cultures.

PROCEDURE AND INTERPRETATION OF RESULTS

For information on procedures and interpretation of results, consult listed references or refer to the prepared media Instructions for Use (IFU) for Cat. No. G150.

LIMITATIONS

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as autoclaves, incinerators, and incubators, etc., are not provided.

QUALITY CONTROL

Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Pseudomonas aeruginosa
ATCC ® 27853
MF 18-24hr 35°C Aerobic Growth; no color change
Escherichia coli
ATCC ® 25922
B 18-24hr 35°C Aerobic Partial to complete inhibition
Proteus mirabilis
ATCC ® 12453
B 18-24hr 35°C Aerobic Partial to complete inhibition; no swarming

User Quality Control

PHYSICAL APPEARANCE

CRITERION™ m PA-C Agar powder should appear homogeneous, free-flowing, and pinkish-beige in color. The prepared media should appear clear, slightly opalescent, and medium to dark orange-red to pinkish-red in color.

REFERENCES

1. Levin and Cabelli. 1972. Appl. Microgiol.; 24:864.

2. Carson, Peterson, Favero, Doto, Collins, and Lecin. 1975. Appl. Microbiol.; 30:935.

3. Dutka and Kwan. 1977. Appl. Environ. Microbiol.; 33:240.

4. American Public Health Association. Standard Methods for the Examination of Water and Wastewater, APHA, Washington, D.C.

5. Brodsky and Ciebin. 1978. Appl. Environ. Microbiol.; 36:36.

6. Estevez. Bacteriologic plate media: review of mechanisms of action. 1984. Lab. Med.; 15:258.


ATCC is a registered trademark of the American Type Culture Collection.

062916gr