The Effect of Silver Nanoparticles on Wounds Contaminated with Pseudomonas aeruginosa in Mice: An Experimental Study

The microorganisms have been usually noted as the major cause of delayed wound healing. Pseudomonas aeruginosa is the most common pathogen causing these infections. Silver nanoparticles (AgNPs) show ample antibacterial activities. In present study, the effect of AgNPs alone and in combination with tetracycline investigated on inoculated wounds with Pseudomonas aeruginosa in mice. Twenty mice anesthetized and full-thickness skin wounds created on back of them and the bacterial suspension added to each wound bed. Wound infection assessed using total count of bacterial load and also wound healing monitored, macroscopically. In all groups treatments applied topically in the wound bed: AgNPs, tetracycline, AgNPs along with tetracycline and normal saline in control group. The tetracycline along with AgNPs achieved 100% wound closure on day 12. In the AgNPs group, the percentage of wound contraction has close figures compared to tetracycline and normal saline as 98, 99 and 79 percent, respectively. By day 12, all of the treated groups with AgNPs, tetracycline and AgNPs along with tetracycline showed decreases in surface bacterial concentration compared with control group. Also, significant decrease (P < 0.001) in deep skin bacterial counts in the AgNPs, tetracycline and AgNPs along with tetracycline compared with control group at any time point. Application of AgNPs along with tetracycline is more effective than AgNPs and tetracycline alone to reduce the bacterial load whilst wound macroscopic contraction increased. These findings support use of the AgNPs in combination with antibacterial medicine for the treatment of infectious skin wounds.