The Antimicrobial Activity Of Flourescent Brightener Combined With Antifungal Agents Against Trichophyton Rubrum

Trichophyton rubrum is the main pathogenic fungus causes dermatophytoses, accounting for about 60% in the total. Various antifungal drugs were developed, which have serious side effects and drug tolerance. And the most antifungal agents aim at specific fungal ergosterol biosynthesis pathways, and few at the cell wall synthesis pathways. Therefore, the discovery and research of new drugs and its derivatives which target at the synthesis pathways of cell wall are significant for clinical therapy and drug tolerance of superficial mycosis which caused by dermatophytes.Objective:The antimicrobial activity and mechanism of action of fluorescent brightener CBS to Trichophyton rubrum were confirmed, the synergistic effect between fluorescent brightener CBS and antifungal drugs was analyzed, the formula including antifungal drugs and fluorescent brightener CBS was optimized through uniform design, the treatment effect was tested by animal model, the new antifungal drugs would be further developed based on the fluorescent brightener CBS.Methods:Filter paper dispersion method was used to test the antibacterial effect of CBS in different concentration to the microorganism including Trichophyton rubrum and other pathogenic bacteria; confront culture on the glass slide and microscopic observation were used to study the antibacterial mechanism of fluorescent brightener CBS to Trichophyton rubrum; the synergy effect between CBS and antifungal drugs was determined by using modified CLSI M38- A2; the optimal formula was obtained from simulation equation built by the uniform design method and SPSS software, which was assessed on Trichophyton rubrum infection model established.Results:① Drug susceptibility test was proved that Trichophyton rubrum are extremely sensitive to fluorescent brightener CBS at concentration of 5 mg/ml and 10 mg/ml, Microsporum gypseum and Escherichia coli were high sensitive to fluorescent brightener CBS,Staphylococcus aureus was sensitive to it.② It indicated that CBS acts on the hyphae wall of Trichophyton rubrum, and its hyphae was shrinked and rupturedas time goes on.③ Analyzed by modified CLSI M38- A2 and SPSS software, when the concentration of CBS is 2.5 mg/ml, the inhibitory effect was the best. synergistic effect existed between ketoconazole and CBS,when their concentrations was 2 ug/ml, 2.5 mg/ml respectively, the inhibitory effect on Trichophyton rubrum was the strongest; synergistic effect existed between terbinafine and CBS too, when their concentration was 0.0625 ug/ml, 5mg/ml respectively, the inhibitory effect on Trichophyton rubrum was the strongest;④Uniform design combined with the verification test was to get the optimal combination, the results is that concentration of CBS, ketoconazole, terbinafine, SDS and azone were 1.861 mg/ml, 1.5 ug/ml, 0.175 ug/ml, 0.0774 mg/ml, 6 mg/ml respectively, theory inhibition rate is 75.34 %; verification test inhibition rate is 77.355 %.⑤ Trichophyton rubrum infection model was builted by guinea pigs successfully, which was treated by optimal formula drug and single drug respectively, overall treatment time of optimal formula drugis shortened average six days compared with single drug.