Susceptibility Of Dermatophytes In Canine And Feline And Efficacy Evaluation Of Voriconazole Gel

In recent years,with the development of pet industry,canine and feline dermatophytosis has gradually become one of the most common clinical diseases,due to the characteristics of dermatophytosis with a wide incidence,long treatment cycle and easy recurrence,it has been gradually paid attention to.At present,the commonly used anti-dermatophyte drugs in pet clinic are single,and the drug resistance of pathogenic dermatophytes is increasing year by year due to the inability to identify the pathogenic bacteria and the abuse of drug dose,the recurrence rate is also increasing,and the treatment of tinea infection is becoming more and more difficult.Voriconazole belongs to a new triazole antifungal drug.In recent years,many in vitro and animal studies have demonstrated that voriconazole has high efficacy against dermatophytes including Trichophyton and Microsporum and Epidermophyton,and can treat dermatophyte infections with low sensitivity to terbinafine and itraconazole.In this experiment,449 canine and feline skin disease cases were collected from June 2019 to December 2020 in Harbin,and a total of 89 dermatophyte pathogens were collected.Species were identified by fungal culture and PCR with internal transcribed spacer primers.The minimum inhibitory concentration values of the collected clinical strains against ketoconazole,terbinafine and voriconazole were determined with reference to the M38-A2 protocol of the American Committee for Clinical Laboratory Standards.The MIC values of all dermatophytes were statistically analyzed using SPSS 22.0 statistical software to compare the antibacterial effects of the three drugs against canine and feline dermatophytes.The efficacy of ketoconazole ointment,terbinafine gel and self-made voriconazole gel was compared.Microsporum canis,Microsporum gypseum and Trichophyton mentagrophytes spores were used to model guinea pigs.The results showed that there were three main epidemics of dermatophytes in canine and feline in Harbin,including 58 cases(65.2%)of Microsporum canis,18 cases(20.2%)of Trichophyton mentagrophytes,and 13 cases(14.6%)of Microsporum gypseum.In vitro susceptibility testing was performed using the CLSI M38-A2 protocol,and the MIC values of ketoconazole,terbinafine,and voriconazole against M.canis ranged from 0.25 to 1μg/mL,0.016 to0.125μg/mL,and 0.008 to 0.031μg/mL.MIC values for susceptibility testing against M.gypseum ranged from 1 to 4μg/mL,0.031 to 0.125μg/mL,and 0.008 to 0.016μg/mL.MIC values for susceptibility testing against T.mentagrophytes ranged from 0.5 to 4μg/mL,0.008 to 0.031μg/mL,and 0.016 to 0.063μg/mL.The Kruskal-Wallis test was performed using the three dermatophytes as the overall,and there was a significant difference in the MIC values of the three drugs against canine and feline dermatophytes.The mean order of MIC values for susceptibility testing was:terbinafine < voriconazole < ketoconazole.Self-made voriconazole gel can obviously inhibit the growth of bacteria,inhibit the growth and reproduction of superficial fungi on the body surface of animals,and achieve the purpose of treating dermatophytosis.It is superior to commercial ketoconazole ointment and terbinafine gel in animal experiments.