DISINFECTANT ACTIVITY AGAINST BACTERIA BIOFILM FORMED

In the last years the frequency of infections caused by multiresistant bacteria has increased, causing high mortality worldwide. Due to these factors, measures have to be taken to control the spread of these bacteria and microorganisms. An important action to reduce these infections is through the disinfection of the environment and materials used in hospitals. The disinfectant has a huge range of use as food industries, pharmacies, hospitals due to its great antimicrobial effect against bacteria, fungi and viruses in their vegetative forms. Therefore, the search for new antimicrobials has become extremely important for public health. The objective of our project was to develop disinfectants containing oregano oil, silver nanoparticles and the mixture of both to act against bacterial biofilms. The disinfectants were formulated in the Department of Pharmaceutical Sciences of the Health Sciences Center, at UEL. The disinfectants were produced with the following compositions: only natural compound (oregano oil) with disinfectant base, only silver nanoparticles with disinfectant base and association of oregano oil with silver nanoparticles. All with fixed concentrations. Strains of Staphylococcus aureus (BEC 9393) and Escherichia coli (EAEC) were used. The identification of the action of the disinfectants was performed by the MTT method (biofilm cell viability) in which 200 μL MTT was added in the concentration of 0.5 mg / ml, it was allowed to stand for 2 hours and then solvent and the absorbance reading on the Elisa spectrophotometer at 570nm. Two times of contact with the disinfectants were tested for each bacteria, 60 and 15 minutes. For E. coli the disinfectants at the 15 and 60 minute times did not present great differences in the efficiency of the disinfectants, since they varied between 95 and 99% efficacy, efficacy is the percentage of non-viable cells compared to the positive control. Regarding the viability of S. aureus cells was higher than that of E. coli, this means that the efficiencies of the compounds were lower for S. aureus. Being that the greater efficiency was the compound with oregano oil and silver nanoparticles in the time of 60 minutes, which had efficacy of 93%. The disinfectants produced showed that it has the potential to promote cellular inviability in biofilms, however it is still necessary to test different concentrations.