The Study Of Molecular Epidemiology And Candida Gene Sequence Analysis For Oral Fungi Of In-patients In General Hospital

Objective:We had genotyped the oral candida from140in-patients in14departments from our hospital in the same period(78cases were oral fungal infection and62cases were fungal carrier). Combined with clinical data, we had analyzed the infection of the same fungal with different genotype in same department and different departments. We had identified the connection and difference of the strains from the same department and got the resource of the infection, provide the evidence of the prevention and control measures of the general hospital fungal infections, especially the oral cavity fungal infection. We also compared the compliance of CHROMagar chromogenic medium and gene sequence analysis identification to verify the accuracy of CHROMagar.Methods:Samples of Candida from140in-patients, oral in our hospital were identified by CHROMagar chromogenic medium, then investigated by DNA extraction and gene sequence analysis. We amplified the rDNA’s ITS area of the pathogenic fungi using the all-purpose primers-ITS1and ITS4for the fungi by PCR. Then we use the Sequencher software, Genebank database and the CLUSTAL software to muti-compare the sequence in the database. We built the N-J tree by Mega software which can identify various strains affinity through phylogenetic tree. And we compared the identification result of the two methods.Results:The identified result of CHROMagar chromogenic identification of140 culture positive cases were97strains of Candida albicans,15strains of Candida tropicalis,12strains of Candida glabrata,4strains of Candida krusei and12other strains. Gene sequence analysis identified91strains of Candida albicans,21strains of Candida tropicalis,15strains of Candida parapsilosis,4strains of Pichia caribbica,8strains of Meyerozyma guilliermondii and one strains of Uncultured Clavispora clone. The Candida albicans were often found in the department of infection in the Department of Hematology, Department of Respiratory Medicine, Department of Gastroenterology. Except the Department of Hematology, Department of hepatobiliary surgery and Department of Respiratory each have one strain with the significant evolutionary difference, the sequence of other strains had the similarity accounted more than96%. The different strains in different department also has no significance difference in evolution, their affinity is very close. CHROMagar chromogenic medium and sequence analysis of Candida albicans coincidence rate was96.7%. the coincidence rate of identification of tropical candida was66.7%. The identification of other Candida like C.glabrata and C.krusei were completely not met the expectation.Conclusion:There was no significant difference in the evolution of the strains from the inner departments. Their affinity indicated that it can be infected by horizontal transmission. The different strains from different departments also had no significant difference in the genotype of the strains, indicating that there is possible infection with horizontal transmission. CHROMagar chromogenic medium and sequence analysis of other Candida like C.glabrata and C.krusei coincidence rate were completely not met the expectation. So CHROMagar chromogenic medium can not accurately identified Candida, especially for non-albicans Candida.