Candida glabrata strain relatedness by new microsatellite markers

Abstract

We investigated six microsatellite markers to type 85 unrelated and 118 related isolates of Candida glabrata from 36 patients. Three new markers were selected from the complete sequence of CBS138 and three previously described markers, RPM2, MTI and ERG3 were used. We found a genetic diversity of 0.949 by combining four of them. By applying the new microsatellite markers GLM4, GLM5 and GLM6 we were able to discriminate 29 isolates, originally identified by the more established markers, RPM2, MTI and ERG3. When epidemiologically closely related isolates from 36 patients were typed, 25 patients (72%) exhibited identical or highly related multilocus genotypes. We noted a microvariation in 4 of the patients. This minor change of one locus could be explained by a single step mutation. Since one of these patients had not received antifungal treatment; thus, the relationship between genome variation and antifungal therapy remains controversial. We can conclude from our analysis of these new microsatellite markers that they are highly selective and therefore should be considered as a useful typing system for differentiating related and unrelated isolates of C. glabrata, as well as being able to detect microvariation.

Evaluation of Polymorphic Locus Sequence Typing for Candida glabrata Epidemiology

“…Correspondingly, the diversity indexes (excluding epidemiological replicates; see below) were 0.94 and 0.91. These values are comparable to those obtained with other typing methods and strain sets (14,24,32,34,35).…”

“…The most widely applied include (i) multilocus sequence typing (MLST), which analyzes 6 relatively conserved housekeeping loci for single nucleotide polymorphisms (SNPs) (29,30), (ii) pulsed-field gel electrophoresis (PFGE), which compares total DNA banding patterns with or without restriction enzyme digestion (14,23,31), (iii) multilocus variable-number tandem-repeat analysis (MLVA, also known as microsatellite analysis), which examines length variation in 6 to 9 PCR-amplified loci that contain polymorphic tandem repeats (32)(33)(34)(35), and (iv) random amplification of polymorphic DNA (RAPD), which compares banding patterns following PCR with a nonspecific primer (26,36). In general, these methods are comparable in their strain resolution, achieving diversity indexes of ca.…”

Fluconazole and Echinocandin Resistance of Candida glabrata Correlates Better with Antifungal Drug Exposure Rather than with MSH2 Mutator Genotype in a French Cohort of Patients Harboring Low Rates of Resistance

“…Ten previously described STRs markers VNTR2bis, VNTR3, VNTR4, VNTR5, VNTR6, VNTR8, VNTR9 (Brisse et al, 2009), GLM5, GLM6 (Abbes et al, 2012), and Cg6 (Grenouillet et al, 2007) were amplified. The forward primers were tagged with fluorophores (FAM, HEX, or ATTO565).…”

Molecular Epidemiology and Antifungal Susceptibility of Candida glabrata in China (August 2009 to July 2014): A Multi-Center Study

“…Yet within C. glarbata sensus strcito per se , intra-species delineation is useful, not only for molecular epidemiological studies but for investigation of biological niches and determining the route of infection transmission. Several molecular typing methods, e.g., pulse field gel electrophoresis (PFGE), multilocus sequence typing (MLST) assays and microsatellite analysis have been established to determine genetic relatedness of C. glabrata (Dodgson et al, 2003; Foulet et al, 2005; Lin et al, 2007; Brisse et al, 2009; Enache-Angoulvant et al, 2010; Abbes et al, 2012). Of these, MLST is a highly discriminatory tool that can be standardized to allow objective comparison of results between centers.…”