Titanium dioxide nanoparticles (TiO2 NPs) were studied as antibacterial agents at different concentrations against clinical and environmental bacterial isolates without UV or photocatalytic activation. Five TiO2 NPs concentrations (20µg/ml,50µg/ml, 100µg/ml,500µg/ml and 1000µg/ml) were studied against 15 bacterial species:10 clinical isolates and 5 environmental isolates) compared with antibiotics Amikacin(AK)and Levloxacin(LEV).Only500µg/ml concentration of TiO2 NPs was active against 7 bacterial isolates (3 clinical and 4 environmental), and 1000µg/ml concentration of TiO2 NPs was effective against 9 isolates (6 clinical and 3 environmental ). These concentrations were mixed with the antibiotics Levloxacin LEV and Amikacin AK to investigate the possibility of synergistic activity against studied bacteria. Bacterial isolate's response or sensitivity to the antibiotic and TiO2 NPs mixture was varied; AK plus 500µg/ml TiO2 NPs concentration showed increased inhibitory activity against 7 isolates (3 clinical, 4 environmental) and 1000µg/ml TiO2 NPs mixed with AK showed increased inhibition activity against one environmental bacterial isolates, where Ak mixed with 500 and Ak plus 1000 µg/ml showed the same effect as the antibiotic alone or less.LEV antibiotic shows no difference in the effect on all 9 bacteria (7 clinical and 2 environmental), while LEV mixed with 500 µg/ml have increased inhibition zones on 4 bacteria (2 clinical, 2 environmental) , and LEV mixed with 1000µg/ml have higher effect than the antibiotic alone on three isolates (2 clinical,1 environmental). Keywords: antibiotic; titanium nanoparticles dioxide; antibacterial.

Resistance to antibiotics is rapidly spreading across the globe, posing a new health-care challenge for all countries. Bacterial biofilms are three-dimensional formations made up of cells encased in a matrix of polymeric, making cells resistant to the drugs and the immune system. As a result, new tactics for inhibiting the production of the EPS matrix may lead to more efficient use of already available antibiotics. The mechanism of vitamins C effect on boosting the effectiveness of several anti-bacterial drugs was investigated in this study, the target isolates were obtained from University of Mosul/ Biology department/ bacterial culture collections and evaluated qualitatively and quantitatively. The isolates involved: Staphylococcus aureus, Escherichia coli ,Klebsiella sp., Serratia marcescens and Pseudomonas aeroginosa. Antibiotic sensitivity tests and biofilm producing assay results revealed that the majority of the isolates were resistant to a range of antibiotics and had a large capacity for biofilm formation when grown on a cover glass surface. Vitamin C is an antioxidant, a scavenger of active metabolites. The Minimum Inhibitory Concentration (MIC) of Vitamin C against selected isolates had been determined, and all further experiments used concentrations below the MIC. Our results showed that Vit.C pre-treatment enhance the bactericidal effect of antibiotic and increases bacterial susceptibility to antibiotics. Using light microscopy, experiments of sub inhibitory doses of Vitamin C revealed good suppression of selected isolates biofilm development on the cover glass surface. Vitamin C can be utilized as an antibiotic adjuvant in combination with antibiotic and has effective biofilm inhibition, caused by multidrug-resistant bacteria, according to evidence.

Bacterial lipases are a highly versatile class of hydrolytic enzymes which catalyze the hydrolysis of triglycerol to glycerol and fatty acids. They play an important role in biotechnological and industrial processes, including oleo chemical, food, pharmaceutical detergent formulation, cosmetic, leather, textile, and paper industries applications. Tremendous interest among scientists and industrialists has been arisen in the last decade in microbial lipases due to their versatility and ease of mass production. In the current work, natural oils such as Triglyceride, Tween 20, Tween 80, Olive oil, Sweet almond, Celery oil, Sesame, Rosemary oils were implemented to enhance lipase production by soil and pathogenic bacterial isolates. Results revealed that triglyceride and tween 80 had the best enhancing activity for lipase production in most isolates. It was also shown that Pseudomonas and Bacillus were the most potential lipase producing bacteria. A novel modified tributary agar was prepared by the addition of Sudan blue dye and used for the detection of lipase producers. It was shown to give a very clear zone even in the case of weak producing strains as compared to the original medium. Specific lipase activity had been determined Staphylococcus aureus (in the present research. The highest lipase activity was demonstrated by Pseudomonas (4.5u/ml), while Staphylococcus aureus did not show any lipase activity.

Bacterial lipases are a highly versatile class of hydrolytic enzymes which catalyze the hydrolysis of triglycerol to glycerol and fatty acids. They play an important role in biotechnological and industrial processes, including oleo chemical, food, pharmaceutical detergent formulation, cosmetic, leather, textile, and paper industries applications. Tremendous interest among scientists and industrialists has been arisen in the last decade in microbial lipases due to their versatility and ease of mass production.In the current work, natural oils such as Triglyceride, Tween 20, Tween 80, Olive oil, Sweet almond, Celery oil, Sesame, Rosemary oils were implemented to enhance lipase production by soil and pathogenic bacterial isolates. Results revealed that triglyceride and tween 80 had the best enhancing activity for lipase production in most isolates. It was also shown that Pseudomonas and Bacillus were the most potential lipase producing bacteria.A novel modified tributary agar was prepared by the addition of Sudan blue dye and used for the detection of lipase producers. It was shown to give a very clear zone even in the case of weak producing strains as compared to the original medium.