In vitro investigation of effects of commercially available food and fabric paints in different colors, on Methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa

Objective: The aim of this study to determine, the antibacterial effects of red, blue, green and yellow fabric and nutrient dyes, which were commonly used in our daily life on Methicillin Resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa with different concentration. Methods: Serial dilutions of commercially available green, red, yellow, and blue fabric and food dyes in sterile saline were prepared. One milliliter from each concentration of dyes was splitted into the tubes. McFarland 0.5 standard were used to adjust the turbidity of bacterial suspensions of P. aeruginosa and S. aureus standard strains. This suspension of each strain dispensed 100 microliters to all food and fabric dyes concentrations and incubated at 37°C. After overnight incubation 1 microliter suspension from each tube is plated on Mueller Hinton agar to determine bactericidal with sterile disposable loop. After incubation of these plates at 37°C for 18 - 24 hours, colonies were counted. Results: Green, yellow and red colors of fabric and food dyes were inhibited MRSA, and they showed significantly less effect against P. aeruginosa. However, blue fabric and food dye antibacterial affects, were greater than other colors against MRSA and also against P. aeruginosa. Conclusion: In this study, we determined that inhibition effect of food and fabric dyes, on bacterial growth can be variable belong to the color and concentration of dye. Our in vitro findings were indicated that colors of dyes can be a factor to inhibit bacterial contamination and true color choice will be helpful for painting especially high risk places for bacterial contamination. J Clin Exp Invest 2015; 6 (3): 274-27