Environmental Factors Affecting Biofilm Formation In Escherichia Coli And Staphylococcus Aureus

ABSTRACT

The purpose of the research work was to evaluate three methods for detection of biofilm formation in Staphylococcus aureus and Escherichia coli under many environmental conditions such as incubation time, pH. oxygen availability, carbon source, Nacl (salt) concentration etc... The bacterial strains were screened by Tissue culture plate (TCP) method, Tube method (TM) and Congo red agar (CRA) method with different media such as Trypticase-soy agar, MacConkey agar, Brain Heart infusion agar and Nutrient agar. The whole screening shows that Staphylococcus SI) displayed a bioulim positive phenotype under the optimized condition on the tissue culture plate method. Though different content of the medium significantly influenced the quantity of produced bio film. The contact surface also served as another means of determining the relationship between time contact and biofilm formation. Crystal violet assay was performed to quantify the biofilm formation based on the value of optical density as it is shown in the work.