In vitro Evaluationof the Antimi- crobial Activity of a Topical Skin Preparation Containing 0.1% Polyhexanide vs a Topical Skin Prepa-ration Containing 1% Silver Sulfadiazine
Aim: The effective in vitro antibacterial activity on Staphylococcus aureus (S.aureus), Pseudomonas aeruginosa (P.aeruginosa), Klebsiella pneumoniae (K.pneumoniae),Escherichia coli (E.Coli) and the combination of S.aureus and K. pneumonia of a topical cream based on 0.1% polyhexanidewas compared to a topical cream based on 1% silver sulfadiazine.A topical cream containing 0,1% gentamicin was used as a positive control and a white blank topical cream was used as negative control. Materials and Methods: The in vitro antibacterial activities were determined by agar well-diffusion assay. Two-way Analysis of Variance (ANOVA) was used to test, by calculation of P-values, for significant antiseptic activity in bacteria treated with 0.1% polyhexanide topical cream compared to 1% silver sulfadiazine and to the negative and positive controls. Results: Among the derivatives tested, all the active topical creams analyzed were able to reduce microbial strains. The topical cream based on 0.1% polyhexanide showed a significantly higher antibacterial efficacy in comparison to the topical cream based on 1% silver sulfadiazine on S. aureus and K. pneumonia and on the combination of S. aureus and K. pneumoniae,while no significant difference was detected between the antibacterial activity of the two topical creams against P. aeruginosa and E. coli. Conclusion: These results provide a further insight into the antibacterial activity of polyhexanide and its non-inferiority compared to silver sulfadiazine towards certain bacterial strains (P. aeruginosa and E. coli) and superiority towards other (S. aureus and K. pneumoniae)and support the use of 0.1% Polyhexanide topical preparation for the treatment of wounds that are infected or at risk of infection.