Cat. no. G133 m-PA Agar, 15x60mm Plate, 11ml 10 plates/bag


Hardy Diagnostics m-PA Agar is recommended for the cultivation and enumeration of Pseudomonas aeruginosa in water by membrane filtration.

This product is not intended to be used for the diagnosis of human disease.


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 make it moderately selective. This formulation is found in the Standard Methods for the Examination of Water and Wastewater.(4)


Ingredients per liter of deionized water:*

Sodium Thiosulfate 6.8gm
L-Lysine Hydrochloride 5.0gm
Sodium Chloride 5.0gm
Xylose 2.5gm
Yeast Extract 2.0gm
Sucrose 1.25gm
Lactose 1.25gm
Ferric Ammonium Citrate 800.0mg
Sulfapyridine 176.0mg
Cycloheximide 150.0mg
Phenol Red 80.0mg
Nalidixic Acid 37.0mg
Kanamycin 8.5mg
Agar 15.0gm

Final pH 7.2 +/- 0.2 at 25ºC.

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


Storage: Upon receipt store at 2-8ºC. away from direct light. Media should not be used if there are any signs of deterioration (shrinking, cracking, or discoloration), contamination, or if the expiration date has passed. Product is light and temperature sensitive; protect from light, excessive heat, moisture, and freezing.



1. Filter water sample through a sterile 47mm, 0.45um gridded filter.

2. Place the membrane filter on the surface of prepared m-PA Agar plates. Avoid trapping bubbles between the agar and filter.

3. Invert plates and incubate for 72 hours at 41.5ºC.

Consult the standard method for additional information regarding the m-PA membrane filter technique.(4)


0.8-2.2mm colonies that are flat in appearance with light outer rims and brownish to greenish-black centers are indicative of Pseudomonas aeruginosa. All such colonies should be counted and reported as total count per volume of water sampled. Dilution factors must taken into account.

Milk Agar may be used to confirm counts of typical and atypical colonies. Consult standard methods for more information.(4)



Standard microbiological supplies and equipment such as loops, other culture media, swabs, applicator sticks, incinerators, and incubators, etc., as well as serological and biochemical reagents, are not provided.


Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Pseudomonas aeruginosa
ATCC® 27853
MF 18-24hr 35°C Aerobic Growth
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


m-PA Agar should appear clear, and medium orange red to rose red in color.

P. aeruginosa growing on m-PA Agar

Pseudomonas aeruginosa (ATCC® 27853) filtered through a white membrane (Cat. no. A045H047A) and growing on m-PA Agar (Cat. no. G133). Incubated aerobically for 24 hours at 35ºC.

P. aeruginosa growing on m-PA Agar

Pseudomonas aeruginosa (ATCC® 27853) growing on m-PA Agar (Cat. no. G133). Incubated aerobically for 24 hours at 35ºC.

m-PA Agar

Uninoculated plate of m-PA Agar (Cat. no. G133).


1. Levin and Cabelli. 1972. Appl. Microbiol.; 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. 1984. Bacteriologic plate media: review of mechanisms of action. Lab. Med.; 15:258.

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