Chromosome length polymorphism in clinical isolates of Candida parapsilosis

Abstract

Chromosome length polymorphism in clinical isolates of Candida parapsilosls. APMIS 106: 941-946, 1998. Chromosome length polymorphism among 24 clinical isolates of Candida parapsilosis obtained from several human sources was analysed using pulsed-field gel electrophoresis. The isolates, from both superficial and deep infections, comprised a miscellaneous collection from the oral cavity, blood cultures, ear infections, wwnd secrete, a venous catheter and peritoneal dialysis fluid. Contour-clamped homogenous field electrophoresis using a hexagonal electrode was used for pulsed field gel electrophoresis. The chromosome numbers varied from seven to nine and their sizes ranged from 0.75 to 2.6 Mb. According to the electrophoretic karyotype patterns the 24 isolates could be divided into 9 profiles. However, the majority (18 isolates) fell into 3 groups comprising 7, 8 and 9 chromosomes, containing 5, 11, and 2 isolates, respectively. The remaining six isolates, all of which were from either an oral or another superficial site of isolation, could be categorized into a further six groups. These data confirm previous observations on the genomic heterogeneity of clinical isolates of C. parapsilosis, and illustrate the possible commonality in strains from related clinical habitats.

Biotyping and Virulence Properties of Skin Isolates of Candida parapsilosis

“…It is known that C. parapsilosis is genotypically heterogeneous, its karyotype extending from six to nine chromosomesized bands in all different source groups (3,4,13,22,23,29,30). Variability in the chromosomal asset has been confirmed here with the skin isolates, although none of them had nine chromosomal bands or showed the peculiar features of some blood isolates with the absence of a whole chromosome-sized region at less than 1.6 Mb or the presence of unusually lowmolecular-weight bands.…”

Genomic diversity of oral Candida krusei isolates as revealed by DNA fingerprinting and electrophoreric karyotyping

“…In fungi imperfecti, devoid of a reproductive cycle, the phenomenon of chromosome translocation is thought to contribute to chromosome length polymorphism with resultant intraspec-ies genetic diversity (31). As the electrophoretic karyotypes of yeasts could be described in terms of the profile of chromosome-sized DNA using pulsed-field gel electrophoresis, some contend that the latter is the ideal technique to delineate intraspecies karyotypes of medically important yeasts (24,32). The characterisation of a strain by PFGE is based on variations in both the number and the profile of chromosomal DNA bands generated within a gel pulsed with variable electric fields.…”

“…The plugs were then suspended in 100 p1 of solution containing 1% lauryl sarcosine and 100 mg of proteinase K, and incubated at 50°C for 24 h, after which another 100 mg of proteinase K was added and incubated for another 24 h. Alternatively, after the lyticase digestion, the agarose plugs containing the spheroplasts were lysed in 1% sodium dodecyl sulphate (SDS) in solution A, by incubating overnight at 37°C. The plugs were then washed three times with 50 mM EDTA (pH 8.0) and loaded onto 0.8% (WN) agarose gel (Sigma) in 1 XTBE (23,24).…”

Characterization of the genetic diversity in superficial and systemic human isolates of Candida parapsilosis by randomly amplified polymorphic DNA (RAPD)

“…There are a number of previous studies which claim that the genetic polymorphism of C. parapsilosis could be used for typing this species (Lott et al 1993;Fernando & Samaranayake 1998;Vazquez et al 1991;Carruba et al 1991;Branchini et al 1994). Nonetheless, there is no consensus as to the ideal tool for this purpose.…”

“…In another study, Lin et al (1995) biotyped 45 clinical isolates of C. parapsilosis which according to the API 20C system demonstrated three distinct isoenzyme profiles that were confirmed by sequence heterogeneity of the internally transcribed spacer sequence flanking the 5.8s RNA gene. We too recently studied the chromosome length polymorphism of C. parapsilosis using contour-clamped homogeneous field electrophoresis (CHEF) and were able to define 9 genotypes amongst 24 clinical isolates, each subtype with 7-9 chromosomes (Fernando & Samaranayake 1998). On the other hand, Pontieri et al (1996) described 18 subtypes amongst 46 C. parapsilosis isolates from soil, vagina and blood, with each type demonstrating 8 to 10 chromosomes.…”