اثر اشعه گاما و ماوراء بنفش بر سویه های استافیلوکوکوس اورئوس مقاوم به پنی سیلین ها

Nowadays, the multiple drug resistance and resistance to different antimicrobial are observed in a wide variety of bacteria. One of these agents is U.V. ray that sometimes used to sterilize the operation room space and utensils and gamma ray to sterilize some medical Instruments such as disposal syringes & cottons and etc. If resistance emerges against the above mentioned factor, fighting microbs by these factors will encounter more problems.             Therefore, In this research the multiple resistance of pathogenic strains of S. aureus isolated from different infections were studied. The M.I.C and M.B.C to penicillins were determined, using dilution tube method and plate cultured respectively. The influence of U.V ray on the growth of bacteria under hood of laminator flow was measured by photon-meter, during different times (0, 30, 60, 120, 240 Sec) at intensity of radiation 0.25 J/m2.S-1. The study of gamma ray on the growth of these bacteria were done by Iridium 192 source projector sentinel 660 as a gamma ray generator. Gamma irradiation was used at the intensity of 20 Gy/min and with dose of 500, 750 and 1000 Gray. The statistical study of the results obtained in different experiments was processed using S.A.S software. The standard strains were used as control and comparison.             In these results, the strains of S. aureus showed maximum and minimum of MIC = 0.125% - 65 µg/ml and MBC = 1-128 µg/ml, respectively. For the study of bacterial level of resistance to U.V. ray, The most important resistance strains to antibiotics have been selected. The mean number of the colonies grown in the culture medium area after 120 and 240 seconds of U.V. radiation were Log    N/No = 21.8, 6.9 respectively in the strain of Staphylococcus.             Resistance of isolated strains of S. aureus in this research was higher than those of standard strains.