Prevalence, species distribution and antifungal susceptibility of Candida albicans causing vaginal discharge among symptomatic non-pregnant women of reproductive age at a tertiary care hospital, Vietnam

Abstract

Background: Vaginal candidiasis is frequent in women of reproductive age. Accurate identification Candida provides helpful information for successful therapy and epidemiology study; however, there are very limited data from the Vietnam have been reported. This study was performed to determine the prevalence, species distribution of yeast causing vaginal discharge and antifungal susceptibility patterns of Candida albicans among symptomatic non-pregnant women of reproductive age.

Methods: Vaginal discharge samples were collected from 462 women of reproductive age in Hanoi, Vietnam between Sep 2019 and Oct 2020. Vaginal swabs from these patients were examined by direct microscopic examination (10% KOH). CHROMagar™ Candida medium and Sabouraud dextrose agar supplemented with chloramphenicol (0.5 g/l) were used to isolate yeast, and species identification was performed using morphological tests and molecular tools (PCR and sequencing). Antifungal susceptibility testing was determined according to the Clinical and Laboratory Standards Institute guidelines (M27-A3 and M27-S4).

Results: The prevalence of vaginal yeast colonization in non-pregnant women was 51.3% of 462 participants. Nine different yeast species were identified. Among these isolates, C. albicans (51.37%) was the most frequent, followed by C. parapsilosis (25.88%), C. glabrata (11.37%), C. tropicalis (4.31%), C. krusei (3.92%), C. africana (1.57%), Saccharomyces cerevisiae (0.78%), C. nivariensis (1 isolates, 0.39%), and C. lusitaniae (1 isolates, 0.39%), respectively. Among C. albicans, all 46 isolates were 100% susceptible to micafungin, caspofungin, and miconazole. The susceptibility rates to amphotericine B, 5-flucytosine, fluconazole, itraconazole and voriconazole were 95.65, 91.30, 91.30, 82.61 and 86.95%, respectively.

Conclusions: The prevalence of VVC among symptomatic non-pregnant women of reproductive age in Vietnam was higher than many parts of the world. The high frequency of non-albicans Candida species, which were often more resistant to antifungal agents, was a notable feature. Resistance rates of vaginal C. albicans isolates to antifungal agents was low. Our findings suggest that continued surveillance of changes in species distribution and susceptibility to antifungals should be routinely screened and treated.

Keywords: Antifungal susceptibility; Prevalence; Reproductive age women; Vulvovaginal candidiasis.

Fig. 1

Co-infection of Candida albicans and Candida krusei in a VVC patient on CHROMagar™ Candida medium

Fig. 2

The distribution of the yeast from VVC among non-pregnant reproductive age women

Fig. 3

Gel electrophoresis of C. albicans complex PCR products targeting the HWP1 gene. Lane 1: molecular size standard (100 bp DNA ladder); lanes 2: negative control; lane 3: positive control (C. albicans ATCC 90028); lanes 4, 5 and 7: strains SD106, SD107 and SD158 (C. albicans, 940 bp); lane 6: strain SD139 (C. africana, 700 bp)

Fig. 4

Patterns of PCR products after digestion with the restriction enzyme MspI. Lanes 1, 5, and 6: strains SD1, SD5 and SD6 (C. albicans); lane 2: strain SD2 (C. tropicalis); lanes 3 and 4: strains SD3 and SD4 (C. glabrata); lane 7: 100 bp DNA ladder; lane 8: positive control (C. albicans ATCC 90028)