Significance and Use
Vegetative biofilm bacteria are phenotypically different from suspended cells of the same genotype. Biofilm growth reactors are engineered to produce biofilms with specific characteristics. Altering either the engineered system or operating conditions will modify those characteristics.
The purpose of this test method is to direct a user in how to grow, sample and analyze a Pseudomonas aeruginosa biofilm under low fluid shear and close to the air/liquid interface using the drip flow reactor. The Pseudomonas aeruginosa biofilm that grows has a smooth appearance and is loosely attached. Microscopically, the biofilm is sheet-like with few architectural details. This laboratory biofilm could represent those found on produce sprayers, on food processing conveyor belts, on catheters, in lungs with cystic fibrosis and oral biofilms, for example. The biofilm generated in the drip flow reactor is also suitable for efficacy testing. After the 54 h growth phase is complete, the user may add the treatment in situ or harvest the coupons and treat them individually. Research has shown that P. aeruginosa biofilms grown in the drip flow reactor were less resistant to disinfection than biofilms grown under high shear conditions.
1.1 This test method specifies the operational parameters required to grow a repeatable Pseudomonas aeruginosa biofilm close to the air/liquid interface in a reactor with a continuous flow of nutrients under low fluid shear conditions. The resulting biofilm is representative of generalized situations where biofilm exists at the air/liquid interface under low fluid shear rather than representative of one particular environment.
1.2 This test method uses the drip flow biofilm reactor. The drip flow reactor (DFR) is a plug flow reactor with laminar flow resulting in low fluid shear. The reactor is versatile and may also be used for growing and/or characterizing different species of biofilms.
1.3 This test method describes how to sample and analyze biofilm for viable cells. Biofilm population density is recorded as log colony forming units per surface area.
1.4 Basic microbiology training is required to perform this test method.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
Method9050 C.1.a Buffered Dilution Water Preparation Eaton, A. D., Clesceri, L. S., and Greenberg, A. E., Eds., Standard Methods for the Examination of Water and Waste Water, 19th Edition, American Public Health Association, American Water Works Association, Water Environment Federation, Washington, DC, 1995.
D5465 Practice for Determining Microbial Colony Counts from Waters Analyzed by Plating Methods
biofilm; coupon; growth reactor; Pseudomonas aeruginosa; reactor; sampling; shear;
ICS Number Code 13.060.30 (Sewage water)
ASTM International is a member of CrossRef.
Citing ASTM Standards
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