The Effect of Diode Laser on Growth of some Gram-Negative Bacteria
Rafidain Journal of Science,
2020, Volume 29, Issue 4, Pages 25-31
AbstractThe Laser is distinguished of it’s the ability to kill or inhibit the growth of bacterial cells and spores, the effect of laser with (650 nm wavelength and a capacity of 50 mw/cm2 and a distance of 10 cm) were studied on the growth of four species of gram-negative bacteria: Shigella spp., Entereobacter cloacae, Morganella morganii, and Entereobacter hormaechei, All of them isolated from an eradicated gallbladder were diagnosed with conventional methods. After isolation and identification, the bacterial suspensions were prepared separately for each bacterium understudy, then were exposure to the laser beam for a period of (0,2,5) minutes, respectively, after that 0.1 ml of bacterial suspension for timings (0,2,5) min. were transported to the Muller-Hinton agar with triplicate.
After incubation, the results showed a clear decrease in the number of developing colonies, and the intensity of the killing was associated with direct relationship with increasing the time of exposure. The results also showed a variation in the bacterial sensitivity under study to killing by laser, Where the isolate E.cloacae recorded decreasing in the number of its colonies from 144 before exposure to 80 and 28 colonies after (2 and 5) minutes of exposure with a killing percentage of 45% and 81% respectively, E.hormaechei isolates also recorded decreasing in the number of its colonies from109 before exposure to 62 and 25 colonies, with a killing percentage reaching 43% and 77% respectively after (2 and 5) of exposure, as well as the number of Shigella spp colonies decreased from 180 before exposure to 134 and 97 colonies with a killing percentage of 26% and 64% after (2 and 5) exposure respectively, in addition, M.morganii isolates witnessed decreasing in the number of its developing colonies after exposure to the laser beam from 233 colonies before exposure to 148 and 120 colonies after (2 and 5) minutes of exposure with percentage of killing reaching 37% and 48% respectively.
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