Genotyping Analysis Of Aspergillus Fumigatus From Clinical Settings In Different Regions Of China

Background: In recent years, with the increase of the number of hospital patientswith severe immunodeficiency, invasive aspergillosis has become the leading cause ofdeath after an important pathogen Candida in blood ward, organ transplant centersand intensive care unit patients. The Aspergillus fumigatus is the most importantpathogen. Different strengths pathogenic strains due to different countries and regions,study of the various regions of the pathogenic Aspergillus fumigatus with themolecular phylogeny help to determine the epidemiological characteristics ofpathogenic strains of Aspergillus populations relations.Objectives:To investigate the strain distribution of Aspergillus fumigatus fromdifferent regions of China for CSP typing of these clinical strains were identifiedthrough morphology, microscopic characteristics, temperature test, and β-tubulinmolecular biology methods combined with the sources of clinical strains,acomprehensive understanding of the different regions of China pathogenic Aspergillusfumigatus strain distribution. NCCLS M38-A procotol was carried out for antifungalsusceptibility testing of these Aspergillus fumigatus isolates, it is also provide clinicaltreatment and take preventive measures for us and compare the differences in thesusceptibility to some antifungal agents between different genotypes and differentregions of Aspergillus fumigatus.Methods: In order to identify the112clinical isolates from Beijing, Shanghai,Fujianand Hebei,the following methods including morphological tests, microscopiccharacteristics, temperature test, and β-tubulin molecular biology methods werecarried out in the present study. Classic A.fumigatus was typed by CSP genesequencing and subsequently analyzed with the international nomenclature. Themorphological tests contain microscopic examination and analysis of size, surface,color, and shape of the cultured colony. Temperature Test: Aspergillus fumigatusstrains initially identified by morphological methods were placed in48℃,45℃,42℃and37℃incubator for3-7days, colonies were observed growth, thus identificationto a different branch. The glass beads were used to extract DNA and the β-tubulin were used for PCR reaction, The region was sequenced. Sequences were assembledand edited with Mega5.0software, The sequences were visually corrected. Thecorrected sequences were blasted in the Genbank data. Finally, CSP typing wasapplied to a collection of112clinical Aspergillus fumigatus isolates from differentregions of China for understanding the different geographical distribution. NCCLSM38-A procotol was carried out for antifungal susceptibility testing of theseAspergillus isolates to understand the differences in the susceptibility to someantifungal agents between different genotypes and different regions of Aspergillusfumigatus.Results:112of Aspergillus fumigatus isolated from clinical were identified viamacro-and micro-morphological characteristics as classical Aspergillus fumigatus. allstrains could grow at48℃and β-tubulin sequences for Aspergillus fumigatus inGenbank was98%concordance for classic Aspergillus fumigatus. All strains wereidentified as classic A.fumigatus with11genotypes,one of which had not beenreported previous.Study of the biological characteristics of newly discoveredgenotype strains found their colony morphology, growth rate and optimum growthtemperature show no significant difference with other strains. Type t04A,t03,t01weremost commom in our study. In this study we observed12isolates of CSP type t10were found in Fujian. what,s more Shanghai and Beijing only find one. No statisticaldifference was found in the susceptibility to amphotericin B, itraconazole, fluconazoleamong the7genotypes of Aspergillus fumigatus.But there is statistical difference inthe susceptibility to itraconazole between the Southern Region and Northern region ofAspergillus fumigatus.Conclusions: A significant difference was observed in the genotype of Aspergillusfumigatus from clinical settings in different regions of China. Type t10was primarilyfound in the warmer climate of southern region. There is no significant difference inthe susceptibility to some antifungal agents between different genotypes ofAspergillus fumigatus.But there is some difference in the susceptibility to some to itraconazole between the Southern Region and Northern region of Aspergillusfumigatus..