ABSTRACT
To re-identify and further group 25 isolates of Trichosporon spp. identified morphologically previously, sequences of D1/D2 region of large subunit (LSU) of ribosomal DNA (rDNA) of 25 tested strains for identification and those of ribosomal intergenic space 1 (IGS1) region of 11 strains for sub-grouping were detected. The identifications of tested strains were changed except 6 strains. According to the alignment of the IGS1 region, 6 T. asahii isolates tested fell into 4 groups and 5 T. faecale isolates into 3 groups. Polymorphism of 2 T.japonicum isolates was found in 10 positions. With the alignments obtained in this research compared with the relative GenBank entries, it was found that T. asahii, T.faecale and T.japonicum species were divided into 7, 3 and 2 subtypes respectively. Morphological and biophysical methods are not sufficient for Trichosporon spp. identification. Sequencing becomes neces-sary for Trichosporon diagnosis. There is obvious diversity within a species.
ABSTRACT
Objectives To identify the route and time of transmission by Candida species from mothers' vagina to their neonates' mouth.Methods Specimens for fungal cultures were obtained from vaginal discharge of mothers just before delivery and also from the mouth of their offspring just after birth.Eleven mother-infant pairs were investigated.Candida species was identified based on morphology,biochemical analysis,and sequencing of D1/D2 domain of the large subunit of ribosomal DNA (LSUrDNA).Electrophoretic karyotyping (EK) and random amplified polymorphic DNA analysis (RAPD) were performed to search for DNA homology.Results Candida isolates (16 strains) from 8 mother-infant pairs were identified as Candida albicans by 100% homology of their D1/D2 sequences with reference strain C.albicans Y-12983 (GenBank access No.U45776).Similarly,4 strains from two mother-infant pairs and 2 isolates from the other pair were identified as Candida glabrata and Candida krusei,respectively,by 100% homology in sequences alignment of the domains with reference strains,C.glabrata Y-65(U44808) and C.krusei Y-5396 (U76347).The same EK profiles were found for each C.albicans or C.krusei strain pair from both mother and her neonate.Although different EK bands with various molecular size were generated for each C.glabrata isolate pair,they were still considered to be homologous based on the fact that main EK bands were identical.Each isolate pair from mother and her infant presented almost the same RAPD profile,except for one pair,isolates F7n and F7m,which showed minor diverse DNA bands.Conclusion Eleven Candida isolates from neonates have identical molecular characteristics with their mother's isolates.Vertical transmission may be the main pathway of Candida spp.from mothers to their neonates.
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Objective To investigate the DNA polymorphism of Pseudallescheria boydii and Scedosporium apiospermum and to analyze the relationship between random amplification of polymorphic DNA (RAPD) patterns and geographic origins.Methods The genomic DNAs of 13 Pseudallescheria boydii strains and 18 Scedosporium apiospermum strains isolated from 5 countries were amplified with RAPD technique.Results All strains tested were classified into 31 patterns by combination of the results obtained with 3 primers.The cluster tendency was identified based on species difference,namely,P.boydii or S.apiospermum strains,however,no such cluster tendency was revealed based on geographic origins of the most of strains,by dendrogram analysis.Conclusions The infraspecific variability of P.boydii and S.apiospermum is considerable.The cluster tendency of RAPD profiles is of consistency with morphological properties of P.boydii and S.apiospermum to some degree,however,is of no correlation with geographic origins of the pathogenic strains.