الفهرس 
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Abstract
Due to the over increasing in the number of resistant bacterial isolates to antibiotics all over the world; many researches have been carried out seeking for a better solution to this nightmare. Therefore, trials to find out novel alternatives to antibiotics for treatment of MDR bacteria using nanotechnology and/or natural oils are conducted in this study. In this study, thirty bacterial isolates were identified as E. coli; clinical isolate (n=15) were recovered from urine, stool, pus from wounds and food isolates (n=15) were recovered from cheese, milk, vegetables, meat and chicken meat. The isolated bacteria showed an observable high degree of antimicrobial resistance to several antibiotics especially; Ampicillin/Sulbactam, Amoxicillin/ Clavulanic acid, Cefoxitin and Cephalexin with either clinical or food isolates. However, Imipene was found to be relatively more effective against both clinical and food E. coli isolates but, Levofloxacin and Aztreonam showed higher activity against E. coli food isolates. The efficiency of two natural oils; cinnamon and clove out of five as antimicrobial agents was determined in -vitro by using agar well diffusion method. The obtained results indicated that these oils showed considerable antibacterial activity against both clinical and food E. coli isolates after dilution by DMSO even at low concentration. However, cinnamon and clove oil were found to be slightly effective against food isolates more than clinical isolates, with inhibition zone diameter 17-25 mm and 20-31 mm with food isolates and 11-26 mm and 10-19 mm against clinical isolates using cinnamon and clove, respectively. On the other hand, all isolates showed resistance to other oils, ginger, chamomile and thyme, even in crude or after dilution by DMSO Silver nanoparticles (Ag-NPs) were synthesized by chemical reduction Due to the over increasing in the number of resistant bacterial isolates to antibiotics all over the world; many researches have been carried out seeking for a better solution to this nightmare. Therefore, trials to find out novel alternatives to antibiotics for treatment of MDR bacteria using nanotechnology and/or natural oils are conducted in this study. In this study, thirty bacterial isolates were identified as E. coli; clinical isolate (n=15) were recovered from urine, stool, pus from wounds and food isolates (n=15) were recovered from cheese, milk, vegetables, meat and chicken meat. The isolated bacteria showed an observable high degree of antimicrobial resistance to several antibiotics especially; Ampicillin/Sulbactam, Amoxicillin/ Clavulanic acid, Cefoxitin and Cephalexin with either clinical or food isolates. However, Imipene was found to be relatively more effective against both clinical and food E. coli isolates but, Levofloxacin and Aztreonam showed higher activity against E. coli food isolates. The efficiency of two natural oils; cinnamon and clove out of five as antimicrobial agents was determined in -vitro by using agar well diffusion method. The obtained results indicated that these oils showed considerable antibacterial activity against both clinical and food E. coli isolates after dilution by DMSO even at low concentration. However, cinnamon and clove oil were found to be slightly effective against food isolates more than clinical isolates, with inhibition zone diameter 17-25 mm and 20-31 mm with food isolates and 11-26 mm and 10-19 mm against clinical isolates using cinnamon and clove, respectively. On the other hand, all isolates showed resistance to other oils, ginger, chamomile and thyme, even in crude or after dilution by DMSO Silver nanoparticles (Ag-NPs) were synthesized by chemical reduction method. Silver nanoparticles of average size 7.5 nm were obtained. Ag-NPs were examined and characterized by UV-Vis spectrophotometer, EDX, XRD, FTIR and TEM. On the other hand, all isolates observed resistance against, ZnO and MgO nanoparticles. The antibacterial activity of silver nanoparticles was determined in - vitro by agar well diffusion method. The obtained results revealed that Ag- NPs were effective against three out of the six selected E. coli isolates from clinical and food sources; with inhibition zone diameters ranged from 13-19 mm. The possibility of using natural oils or prepared nanoparticles for enhancing the antibacterial activities of many antibiotics were further studied using disc diffusion method. It was found that; the combination of natural oils with antibiotics was greatly effective by increasing the antibacterial activity of those antibiotics. The combination of Ag-NPs with certain antibiotics increased the antibacterial activity of those antibiotics, thus increasing the bacterial sensitivity to the tested antibiotics. Combination of antibiotics with Ag-NPs and/or cinnamon clove oils considerably increased the antibacterial activity of those antibiotics. Consequently, increasing the sensitivity of bacteria to the tested antibiotics. As a result of combination of Ag-NPs with natural oils, cinnamon or clove, the antibacterial activity increased, compared to individual treatments. Combining antibiotics with both natural oils and Ag-NPs not only increased their activity against MDR isolates but also significantly reduced their MICs. The most effective combination was cinnamon or clove plus Ag- NPs, with synergistic and additive effect that enhanced the activity against MDR isolates. Due to the over increasing in the number of resistant bacterial isolates to antibiotics all over the world; many researches have been carried out seeking for a better solution to this nightmare. Therefore, trials to find out novel alternatives to antibiotics for treatment of MDR bacteria using nanotechnology and/or natural oils are conducted in this study. In this study, thirty bacterial isolates were identified as E. coli; clinical isolate (n=15) were recovered from urine, stool, pus from wounds and food isolates (n=15) were recovered from cheese, milk, vegetables, meat and chicken meat. The isolated bacteria showed an observable high degree of antimicrobial resistance to several antibiotics especially; Ampicillin/Sulbactam, Amoxicillin/ Clavulanic acid, Cefoxitin and Cephalexin with either clinical or food isolates. However, Imipene was found to be relatively more effective against both clinical and food E. coli isolates but, Levofloxacin and Aztreonam showed higher activity against E. coli food isolates. The efficiency of two natural oils; cinnamon and clove out of five as antimicrobial agents was determined in -vitro by using agar well diffusion method. The obtained results indicated that these oils showed considerable antibacterial activity against both clinical and food E. coli isolates after dilution by DMSO even at low concentration. However, cinnamon and clove oil were found to be slightly effective against food isolates more than clinical isolates, with inhibition zone diameter 17-25 mm and 20-31 mm with food isolates and 11-26 mm and 10-19 mm against clinical isolates using cinnamon and clove, respectively. On the other hand, all isolates showed resistance to other oils, ginger, chamomile and thyme, even in crude or after dilution by DMSO Silver nanoparticles (Ag-NPs) were synthesized by chemical reduction method. Silver nanoparticles of average size 7.5 nm were obtained. Ag-NPs were examined and characterized by UV-Vis spectrophotometer, EDX, XRD, FTIR and TEM. On the other hand, all isolates observed resistance against, ZnO and MgO nanoparticles. The antibacterial activity of silver nanoparticles was determined in - vitro by agar well diffusion method. The obtained results revealed that Ag- NPs were effective against three out of the six selected E. coli isolates from clinical and food sources; with inhibition zone diameters ranged from 13-19 mm. The possibility of using natural oils or prepared nanoparticles for enhancing the antibacterial activities of many antibiotics were further studied using disc diffusion method. It was found that; the combination of natural oils with antibiotics was greatly effective by increasing the antibacterial activity of those antibiotics. The combination of Ag-NPs with certain antibiotics increased the antibacterial activity of those antibiotics, thus increasing the bacterial sensitivity to the tested antibiotics. Combination of antibiotics with Ag-NPs and/or cinnamon clove oils considerably increased the antibacterial activity of those antibiotics. Consequently, increasing the sensitivity of bacteria to the tested antibiotics. As a result of combination of Ag-NPs with natural oils, cinnamon or clove, the antibacterial activity increased, compared to individual treatments. Combining antibiotics with both natural oils and Ag-NPs not only increased their activity against MDR isolates but also significantly reduced their MICs. The most effective combination was cinnamon or clove plus Ag- NPs, with synergistic and additive effect that enhanced the activity against MDR isolates.method. Silver nanoparticles of average size 7.5 nm were obtained. Ag-NPs were examined and characterized by UV-Vis spectrophotometer, EDX, XRD, FTIR and TEM. On the other hand, all isolates observed resistance against, ZnO and MgO nanoparticles. The antibacterial activity of silver nanoparticles was determined in - vitro by agar well diffusion method. The obtained results revealed that Ag- NPs were effective against three out of the six selected E. coli isolates from clinical and food sources; with inhibition zone diameters ranged from 13-19 mm. The possibility of using natural oils or prepared nanoparticles for enhancing the antibacterial activities of many antibiotics were further studied using disc diffusion method. It was found that; the combination of natural oils with antibiotics was greatly effective by increasing the antibacterial activity of those antibiotics. The combination of Ag-NPs with certain antibiotics increased the antibacterial activity of those antibiotics, thus increasing the bacterial sensitivity to the tested antibiotics. Combination of antibiotics with Ag-NPs and/or cinnamon clove oils considerably increased the antibacterial activity of those antibiotics. Consequently, increasing the sensitivity of bacteria to the tested antibiotics. As a result of combination of Ag-NPs with natural oils, cinnamon or clove, the antibacterial activity increased, compared to individual treatments. Combining antibiotics with both natural oils and Ag-NPs not only increased their activity against MDR isolates but also significantly reduced their MICs. The most effective combination was cinnamon or clove plus Ag- NPs, with synergistic and additive effect that enhanced the activity against MDR isolates.