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March/April 2009
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biofilms

A Pseudomonas aeruginosa biofilm grown in the Centers for Disease Control and Prevention biofilm reactor has a mushroom-like architecture (top) as compared to the slab architecture of a P. aeruginosa biofilm grown in the drip flow reactor (bottom).

Biofilm

Biofilm, which is defined as microorganisms living in a self-organized cooperative community, is still under the radar for many industry, medical, professional and regulatory agencies. A newly approved ASTM International standard is the latest in a series of biofilm standards being developed by Committee E35 on Pesticides and Alternative Control Agents.

The new standard, E2647, Test Method for Quantification of a Pseudomonas aeruginosa Biofilm Grown Using a Drip Flow Biofilm Reactor with Low Shear and Continuous Flow, is under the jurisdiction of Subcommittee E35.15 on Antimicrobial Agents.

The standard describes how to grow a repeatable P. aeruginosa biofilm using a drip flow biofilm reactor. “The goal is to grow a biofilm that is relevant to the environment where a disinfectant will be applied, then test the disinfectant under real use conditions,” says Darla Goeres, assistant research professor, Center for Biofilm Engineering, Montana State University, and an E35 member. Biofilm grown in a drip flow reactor could represent biofilms found in a wide variety of places, including cooling towers, produce sprayers, on food processing conveyor belts, on catheters and in lungs infected with cystic fibrosis.

“The primary user of this standard is any industrial, government and/or academic laboratory interested in conducting biofilm research,” says Goeres. “In particular, the drip flow reactor has generated a lot of interest with companies and research laboratories interested in medically relevant biofilms.” Goeres also notes that an important difference between bacteria in suspension and biofilm bacteria is that biofilm is tolerant to high concentrations of disinfectants or antibiotics.

Currently, E35.15 is working on a guide that will describe properties of the various biofilm growth methods and issues that must be considered when working with biofilm bacteria.

CONTACT

Technical Information: Darla Goeres, Center for Biofilm Engineering, Montana State University, Bozeman, Mont.

Phone: 406-994-2440

ASTM Staff: Jennifer Rodgers

Phone: 610-832-9694