Isolation, Identification And Basic Biological Characteristics Of Rabbit Dermatophytes In Qingdao Region

In this study the related researches were conducted to determine the main pathogens andoccurrence regularity of dermatophytosis; to establish a rapid, accurate molecular biologymethod of identifying fungal pathogens; and to comprehend the basic biologicalcharacteristics and sensitive anti-fungal drugs of rabbit dermatophytes. All these studies arevery meaningful for protecting the public health, and food safety. Therefore, we carried outthis research from three main aspects.Firstly, to further understand epidemiological characterization of dermatophytosis inQingdao region of Shandong province,880samples of scab and scurf (2009.6-2010.5) werecollected from the suspected rabbit, which were cultured with Sabouraud culture medium, andfungal hypha and spore were observed microscopically to identify the concrete species. At thesame time relevant epidemiological data were collected and analyzed statistically. The resultsshowed that the confirmed cases infected by dermatophytosis were163(18.4%), including thecases infected by T. mentagrophytes (45.1%), M. canis (34.6%), and M. gypseum (19.1%).0-3-month-old rabbits were most easily infected (14.3%), and the maximum of infection rateoccurred in summer (3.0%).Secondly, an accurate and rapid molecular method was established to identifydermatophytes from rabbits by microsatellite-primered polymerase chain reaction (PCR)combining NTSYS-pc2.10software. The DNAs of T. mentagrophyton, M. gypseum and M.canis were amplified by the primer (GACA)4, and then their DNA fingerprint polymorphismwas analyzed using NTSYS-pc2.10software. Based on the above results, the identificationmethod was confirmed. A total of21clinical isolates identified by morphology were alsoidentified by the method. The results showed that1) three kinds of rabbit dermatophytes haveobviously different DNA fingerprints;2) the rabbit dermatophytes of the same kind have highgenetic similarity (90%-100%);3). The identified results of clinical isolates by this methodwere consistent with the morphological identification results.At last, we studied the basic biological characteristics of common isolated dermatophytes (growth rate, conidia optimal growth environment, common antifungal susceptibility andpathogenicity). We measured the growth rates of these dermatophytes on five solid medium.the results showed that M. gypseum has the fastest growth; YEPD and malt extract media arethe optical culture materials for three kinds of pathogens. We also compared diffrernt mediafor conidia production and found that T. mentagrophytes and M. canis produced the mostconidia in the YEPD and in the MEA respectively. The results of diffusion methods whichwere used to detect sensitivity of eight common antifungal drugs of the three pathogenic fungishow all were resistant to FLU, FC and AMB. Animal models of guinea pig and rabbits wereestablished to detect the pathogenicity, and the results showed that the infection rate of thethree fungus reached up to100%. This research provides scientific evidence for furtherresearch of fungus.In conclusion, through the isolation and identification of rabbit dermatophytes from10rabbit farms, and the correlation analysis between the infection of the disease and theage/season of the rabbits, we learned its epidemiological characteristics in Qingdao region;using the NTSYS-pc2.10to analyse the SSR-PCR bands, we could quickly identify threekinds of common rabbit dermatophytes; through the research on the basic biologicalcharacteristics of the isolated dermatophytes, we learned more about the characteristics offungal pathogens. These results provide a theoretical basis for efficiently preventing rabbitdermatophytosis in this area.