Microsatellite analysis of Candida isolates from recurrent vulvovaginal candidiasis

Candida albicans and Candida glabrata are the most common causative agents of both vulvovaginal candidiasis (VVC) and recurrent vulvovaginal candidiasis (RVVC). Studying the population structure and genotype differentiation of Candida species that cause RVVC may lead to a significant improvement in clinical management. A total of 106 isolates were collected from 55 patients who were subdivided into three groups. Group I comprised 15 patients with RVVC (n=50 isolates); group II comprised 16 patients, who had a history of at least two episodes of VVC in the last year (n=32 isolates, two from each patient); and group III comprised 24 patients (n=24 isolates) who had experienced a single episode of VVC in the previous 1 year period. C. albicans microsatellite markers CAI, CAIII and CAIV and C. glabrata RPM2, MTI and ERG3 microsatellites were amplified in a multiplex PCR. All isolates were subjected to population genetic analysis, which provided evidence that there is a predominantly clonal population structure of C. albicans in each group. However, recombination was detected to some degree in C. albicans isolates in group III. A genetic homogeneity between the different C. albicans groups was observed. Although, C. glabrata isolates showed an important genetic differentiation between group I and group III (F(ST)=0.207). Genotype analysis revealed that the dominant genotypes of C. glabrata and C. albicans strains were more prevalent in patients with RVVC. The frequent scenario for cases of recurrent infection in our study was strain replacement (53.3%). In conclusion, the identification of recurrence-associated genotypes and a specific C. glabrata population structure in the RVVC group could be a significant marker for further investigations of virulence factors and RVVC management.