Avaliação do sinergismo entre os componentes da pasta ctz e o citronelol frente ao enterococcus faecalis

Abstract

The objective of this study was to evaluate the drug interaction between components of CTZ paste (chloramphenicol, tetracycline, zinc oxide and eugenol) and citronellol phytochemical against Enterococcus faecalis (ATCC 29212). The checkerboard test was performed to verify the interaction between substances, through the Fractional Inhibitory Concentration Index (IFIC). For this purpose, considering the Minimum Inhibitory Concentration (MIC) as the lowest concentration capable of inhibiting bacterial growth, 7 solutions were prepared of each component searched with the values: MIC, MIC/2, MIC/4, MIC/8, MICX2, MICX4, MICX8. Furthermore, control of the strain viability and sterility of the culture medium were performed. Assays were performed in triplicate and results were visually evaluated, considering whether or not the formation of clusters of cells at the bottom of the wells of microdilution plates. To assure the presence of viable micro-organisms on non-inhibitory concentrations, we used the pigment TCT 0.5% (2, 3, 5 triphenyl tetrazolium chloride), which reflects the activity of dehydrogenase enzymes, involved in the process of cellular respiration. After the checkerboard test, some results were verified as well as: additivity between tetracycline and chloramphenicol (IFIC: 0.625), indifference between tetracycline and eugenol (IFIC: 1.125), additivity between tetracycline and citronellol (IFIC: 0.75), indifference between chloramphenicol and eugenol (IFIC: 1.5), additivity between chloramphenicol and citronellol (IFIC: 0.625) and synergism between eugenol and citronellol (IFIC: 0.5). It was concluded that all combinations showed a positive drug interaction, enabling their associations or replacements without prejudice the antibacterial ability.