Frequency and expression of ALS and HWP1 genotypes in Candida albicans strains isolated from Mexican patients suffering from vaginal candidosis

Abstract

To detect the frequency and expression of eight ALS (agglutinin-like sequence) genes and the HWP1 genotype in a group of Candida albicans strains isolated from Mexican women suffering from vaginal candidosis. A group of 264 women (age 15-57 years) with vaginal infections were evaluated. C. albicans was identified by PCR amplification of the rRNA internal transcribed spacer regions ITS1 and ITS2. The ALS and HWP1 genes were identified by conventional PCR, and their expression levels were determined by real-time PCR after growing C. albicans strains in reconstituted human vaginal epithelium (RHVE). C. albicans was identified in 50 women (18.9%). The genotypic frequencies were ALS1 100%, ALS2 60%, ALS3 36%, ALS4 54%, ALS5 70%, ALS6 56%, ALS7 64%, ALS9 66% and HWP1 92%. The most frequently expressed genes in the strains harbouring all of the genes were ALS4 (100%), ALS1 (87.5%), ALS2 (87.5%), ALS3 (87.5%), ALS5 (87.5%), ALS7 (87.5%) and HWP1 (75.0%). Nineteen per cent of the vaginal infections were caused by C. albicans, and a high proportion of the strains carried genes encoding proteins involved in adhesion to epithelia. The ALS and HWP1 genes were expressed in RHVE, suggesting that the Als and Hwp1 proteins play an important role in the pathogenesis of the infection.