Comparative effect of different visible light energy on bacterial growth

The purpose of this work was to examine the influence of non-coherent polarized light upon growth of bacteria (Staph. aureus, E. coli, Pseudomonas aeruginosa), and develop attractive approach by reduce incubation time in medical diagnosis laboratory. Experiments were designed to test the main hypothesis that this kind of polychromatic light can produce decimal reductions in numbers of bacteria. The survival of bacterial cells was monitored by Optical density (O.D.), cell number per milliter and colony forming units (CFU) before and after exposure of the suspended bacteria to visible light. Bacterial cultures were exposed to light for different periods (15, 30, 45, 60, 90 and 120 minutes). The source of non-coherent polarized light was NARVA-lamp (Germany) with the following technical characteristics: wavelength 400?2000 nm and light intensity 82.14 w/m2. Results for all strains showed decrease at f the first 15 min. more over with use of blue later red color filter. While slightly increase in bacterial count in response to an irradiation time of 30, 45, 60, 90, 120 min., moreover with cool white and green. Bacterial counts after treatments displayed a linear relationship with the total count of bacteria before treatments as well as the percentage surviving bacteria and irradiation time. In green and white color were found to get more bacterial cell or less phototoxic effect, while the cell number significantly higher than starting number. That?s mean improve growth rate during the incubation of patient samples, exactly in case of low growing bacteria.