EFFECT OF DIODE LASER 675 nm ON THE BACTERIA INFECTED BURN WOUNDS

Abstract

This work aimed to study the effect of diode laser with wavelength 675 nm and power of 30 mW on bacteria infect burn wounds, an also to determine the suitable exposure time of irradiation to kill the main types of infectious pathogenic bacteria that contaminate burn wounds staphylococcus aure us E. co/i, Proteus in irab i/is and Pse udomonas aeruginusa without using selective photosensitizing dyes. The samples of the study were taken from a number of patients in Omdurman Teaching Hospital: The colonies obtained were prepared and counted by the serial dilution process, then irradiated by two ways of irradiation the first way was by focusing the laser beam on specific area located in the medium. And (he other one was by scanning The irradiation was carried out with different exposure time. The colonies were counted before and after irradiation. In case of using the first way of irradiation the colonies number of E.coli reduced from 22 at zero time to 21, 15, 9 0 at 45 second of exposure time, killing percentage reached 100%. In Proteus mirabilis the colonies number reduced from 17 at zero time to 14, 11, 10, 7, 3, 0 at 45 seconds of exposure time the kHing percentage was 100%. In case of Pseudomonas aeruginosa the colonies number reduced from 14 at zero time to 12, 9, 7, 4 , 3, 0 at 40 seconds of exposure time, the killing percentage was 100%, whereas in case of S.aureus the colonies number reduced from 19 to 18, 17, 16,,.15,12 at 45 second of exposure time, the killing percentage was only 37%. The second way of irradiation showed colonies reduction as follow: in case of E.coli the colonies number reduced from 1650 at zero time to 1548, 1426, 1212 69 at 180 seconds of exposure time the killing percentage reached 96%, in Proteus mirabilis the colonies number reduced from 870 at zero time to 874, 561 .... 0 at 180 seconds of exposure time (he killing percentage was 100%. In case of Pseudomonas aeruginosa the colonies number reduced from 1020 at zero time to 977, 881, 766,..... 245 at 180 second of exposure time the killing percentage reached 76%. S.aureus colonies reduced from 1420 at zero time to 1415, 1413 1284 at 180 seconds of exposure time the killing percentage was only 10%. Form the reduction in the number of the colonies, the results showed that diode laser with wavelength 675nm and power 30 mW has a good thermal effect in killing three types of bacteria infect burn wounds E.co/i, Proteus ,nirabilis and Pseuc/omonas auguries, where as the short exposure time of irradiation with out selective uptake of photosensitizing dye is not dH)ugh for killing Staphyloccus aureus which is considered as one of danger infections pathogenic bacteria.