ASTM E2799

Testing of efficacy against biofilm using an adapted microwell biofilm plate assay (MBPA), based on ASTM E2799.

Overview

ASTM E2799 describes a standardised method for evaluating disinfectant efficacy against Pseudomonas aeruginosa biofilm using the MBEC assay. The laboratory uses an adapted microwell biofilm plate assay (MBPA), based on ASTM E2799, which allows multiple comparable biofilms to be tested in parallel.

The adapted method is particularly suitable for active substances, formulations and disinfectants whose activity against microorganisms in established biofilms is to be investigated.

Depending on the study objective, surviving culturable microorganisms can be enumerated quantitatively as colony-forming units (CFU). Alternatively, crystal violet staining with photometric optical density (OD) measurements can be used for qualitative to semi-quantitative assessment of biofilm biomass. This staining readout alone does not demonstrate killing of biofilm-associated microorganisms.

Testing can be adapted to your study objective, product concentration, contact time, exposure conditions, test organism and required readout. The test design and result interpretation are agreed for the specific project.

Typical applications

Active substances

For investigating antimicrobial active substances against biofilm-associated microorganisms in a microtitre plate-based model.

Formulations

For development projects, formulation comparisons and assessment of efficacy against biofilm under defined test conditions.

Disinfectants

For studies of disinfectant activity against microorganisms in established biofilms.

Frequently asked questions

What is the MBPA?

MBPA stands for Microwell Biofilm Plate Assay. It is a microtitre plate-based biofilm model used to investigate the effects of active substances, formulations or disinfectants on biofilm.

Do you use the MBEC assay device specified in ASTM E2799?

No. The laboratory uses an adapted MBPA – Microwell Biofilm Plate Assay – based on ASTM E2799. The test conditions and assessment are agreed according to the study objective, test substance and required reporting format.

Which samples are suitable for the adapted MBPA test?

The method is particularly suitable for active substances, formulations and disinfectants. For solid surfaces or materials, testing of anti-biofilm activity using ISO 4768 may be more appropriate.

How are the results assessed?

Depending on the study objective, assessment can involve enumeration of culturable microorganisms or qualitative to semi-quantitative evaluation of stained biofilm biomass using crystal violet and OD measurements. A biomass readout alone does not establish a reduction in viable microorganisms.