ASTM: D5246: Pseudomonas aeruginosa in Water
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Official Method Name
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Standard Test Method for Isolation and Enumeration of Pseudomonas aeruginosa from Water |
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Current Revision
| Reapproved 1998. Current edition approved May 15, 1992. Published September 1992. |
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Media
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WATER |
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Instrumentation
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Plate Count |
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Method Subcategory
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Microbiological |
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Method Source
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Citation
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Brief Method Summary
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A water sample is passed through a 0.45 um or equivalent membrane filter. The filter carrying the retained organisms is placed on a selective medium (M-PA-C) and is incubated at 41.5 +/- 0.5oC for 48 to 72 h. The resulting pink-brown to black colonies of Pseudomonas aeruginosa are counted and reported per 100 mL of the sample. Colonies may be verified on skim milk agar. |
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Scope and Application
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This test method covers the isolation and enumeration of Pseudomonas aeruginosa ( P. aeruginosa ) from surface waters; recreational waters; ground water, water supplies; especially rural nonchlorinated sources; waste water; and saline waters. The detection limit of this test method is one microorganism per 100 mL. This test method was used successfully with reagent water and it is the user's responsibility to ensure the validity of this test method for waters of untested matrices. |
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Applicable Concentration Range
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1 and greater CFU/100 mL |
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Interferences
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For certain samples, bacterial cells may have been exposed to adverse environmental factors that lower their probability for survival and growth on a membrane filter medium. This effect may be pronounced in this test method due to the presence of antibiotics and the elevated incubation temperature. The selection of an appropriate dilution volume is essential. Too small a dilution volume may fail to detect any P. aeruginosa organisms, while too large a volume may cause an overabundance of colonies that would interfere with an accurate count. Chemicals or a combination of chemicals in certain samples can have a toxic effect upon P. aeruginosa when concentrated. Turbidity in samples may clog filter or effect color detection of organisms that develop on the filter. Water samples containing residual chlorine can be detrimental to P. aeruginosa. Utilize the procedure defined in Practices D 3370 to address chlorinated water samples. |
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Quality Control Requirements
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Sample Handling
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Collect the sample according to Practices D 3370, refrigerate, and analyze the sample within 6 h. |
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Maximum Holding Time
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6h |
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Relative Cost
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Unknown |
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Sample Preparation Methods
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