Efficacy of Topical Therapy of Some Natural Products in Comparison with Ciprofloxacin Against Pseudomonas aeruginosa in Induced Burns

Despite recent advances in antimicrobial chemotherapy and burns management, infection continues to be an important problem in the burns. Treatment of multi-drug resistant Pseudomonas aeruginosa, which causes burn infection, is a big challenge in clinics and needs novel strategies. Failure of the current treatment strategies to control many cases of burns infections, the local and systemic adverse effects that are produced by many topical antibiotics (especially in infants, children, pregnant ladies, and elderly
people), and the delay of healing caused by many antiseptics, make a strong motive to find out a new, safe and effective topical products. Many recent studies were done to find out natural products that have antimicrobial properties, and enhance the healing process. The present study included two experiments each one with different tests. First Experiment: (in vitro study) This study aimed to investigate the in vitro activity of different types of honey, aqueous garlic extract of local market, different origin of olive oil against P. aeruginosa in comparison to the antibiotics used in treatment of burns infection by using disk diffusion method and agar dilution MICs assay. Honey, garlic exerted a good in vitro antimicrobial activity against all tested isolates with the Mean±SE inhibition zone in mm (12.1± 0.41, 11.25 ± 0.27, 11.05 ± 0.29, 12.9 ±0.29) and MICs {(20% - 10%), 20%, 20%, 5%} for Sider, Acacia, Eucalyptus, aqueous garlic extract respectively, while olive oil had no activity against any tested isolates, so that it excluded from in vivo study. Also this study has been done to evaluate the interaction between each of these agents and then synergy testing with a known antimicrobial agent (ciprofloxacin) which revealed that the interaction between them were indifference. Isolation of plasmid DNA of P. aeruginosa isolates by salting out method revealed that the tested isolates indicated different plasmid bands when electrophoresis was performed. Second Experiment: (in vivo study) In this experiment 48 Swiss albino mice were divided into five groups, eight mice in each group. In these groups, burn was induced in the dorsal area using a heated metal bar placed in boiling water for 15 minutes. Only four groups were challenged with same isolate in which three groups were treated with the tested agents (aqueous garlic extract, Sider honey and ciprofloxacin) at second and eighth hrs post challenge on day one and twice daily on day 2 and 3. Whereas, the burned not treated groups (infected and not infected) were used as positive control. Also a group of 8 mice was left without burning, infection or treatment to exclude any external factor. The in vivo burn model data revealed that topical administration of aqueous garlic extract (5%) and Sider honey (20%) significantly extended the survival of mice for 5-6 and 4-5 days respectively, comparing with survival of the untreated group. While topical administration of ciprofloxacin (0.3%) extended the survival of mice for 3-4 days. These findings indicated that Sider honey, Acacia honey, Eucalyptus honey and garlic extract have in vitro antipseudomonal effect but with little variation in their potency, where the Sider honey was the more potent one between honey groups. Whereas different origin of olive oil showed no antipseudomonal effect. However, further investigations were done in the in vivo study indicated that topical Sider honey and aqueous garlic extract effectively extended the survival of the experimentally infected mice.