ASTM E2799-22. Standard test method for testing disinfectant efficacy against Pseudomonas aeruginosa Biofilm using the MBEC assay.
Test not accredited yet in our laboratory.
Bacterial biofilms are clusters of bacteria living in a self-organized community attached to surfaces, interfaces or each other embedded in a matrix of extracellular polymeric substances of microbial origin. Biofilm bacteria are phenotypically different from suspended planktonic cells of the same genotype.
The ASTM E2799 standard describes the use of the MBEC (Minimum Biofilm Erradication Concentration) Assay in evaluating the efficacy of disinfectant against Pseudomonas aeruginosa biofilm. The MBEC assay device consists of a plastic lid with 96 pegs and a receiver plate with 96 individual wells. Biofilm is established on the pegs under batch conditions. The established biofilm is transferred to a receiver plate for disinfectant efficacy testing. The wells in the receiver plate are filled with appropriate sterility, growth, and neutralizer controls and disinfectant samples. This test includes 8 test concentrations, which must be serial dilutions with a dilution factor of 1/2, and with 5 replicates of each dilution. After a specified contact time, the peg lid is placed in a new receiver plate containing neutralizer. The device is placed in a sonicator to remove the biofilm and samples from each well are then diluted, plated and the viable cells enumerated. The logarithmic reduction in viable cells is calculated comparing the density (log UFC) in wells with treated biofilms and untreated controls. Optionally, qualitative MBEC determination can be performed by adding liquid medium to the recovery plate and incubating it for 24 hours. Subsequently, the turbidity is analyzed and the MEBC, the minimum concentration of disinfectant that eradicates the biofilm, is determined as the lowest concentration in which there is no growth observed in the majority of the five wells.