Species identification and antifungal susceptibility pattern of Candida isolates in cases of vulvovaginal candidiasis

Abstract

Vulvovaginal candidiasis (VVC) remains one of the most common infections of the female genital tract. Correct identification of the isolated Candida species is  essential to direct the empirical antifungal therapy.

Objectives: This local study was conducted to identify the spectrum of Candida species associated with VVC using different phenotypic and genotypic methods and assess their antifungal susceptibility pattern.

Materials and methods: High vaginal swabs were collected from 125 patients  presenting with a clinical picture suggestive of VVC. Swabs were subjected to Gram-stain and culture on Sabouraud dextrose agar. Species identification of Candida isolates was done using phenotypic methods including germ tube test, Rice Tween-80 agar, Chrom ID (CAN2) agar and API 20C AUX, while PCR-RFLP was used as the gold standard method. Antifungal susceptibility testing was done using the disk diffusion method.

Results: Vaginal swab cultures yielded Candida growth in 63 cases (50.4%). Candida albicans was the predominant isolated species (60.3%) while the most common non-albicans species was Candida glabrata (12.7%). Fortyfive (71.4%) and fifty-five (87.3%) Candida isolates were correctly speciated by Rice Tween-80 Agar and API 20C AUX, respectively, while fifty-seven isolates (90.5%) were correctly assigned into the 3 groups of yeasts identified by CAN2 agar.  Amphotericin B was more effective than azoles against vaginal Candida isolates.

Conclusion: C. albicans is the most common species associated with VVC. API 20C AUX was the most accurate phenotypic method for the proper identification of most Candida species whereas PCR-RFLP could properly confirm Candida species   identification genotypically.

Keywords: Vulvovaginal candidiasis; Candida species; Phenotypic methods; PCR-RFLP; Antifungal susceptibility