Comparison of Enzymatic Method Rapid Yeast Plus System with RFLP-PCR for Identification of Isolated Yeast from Vulvovaginal Candidiasis

Abstract

Objectives: To compare two identification methods, i.e., restriction fragment length polymorphism (RFLP)-PCR analysis and enzymatic method Rapid TM Yeast Plus System to identify different species causing vulvovaginal candidiasis (VVC).

Materials and methods: Vaginal discharges of women who had attended the gynecology outpatient clinic of Mobini Hospital in Sabzevar, Iran were collected using cotton swabs and were cultured on Sabouraud dextrose agar. Isolated yeasts were identified by germ-tube testing and Rapid TM Yeast Plus System (Remel USA). For molecular identification, the isolated DNA was amplified with ITS1 and ITS4 universal primers and PCR products digested with the enzyme HpaІІ followed by agarose gel electrophoresis. Epidemiological and clinical features of women with respect to identified species were also evaluated.

Results: Out of 231 subjects enrolled, 62 VVC cases were detected. The isolated species were identified as follows: Candida albicans, 24 (38.7%), C. glabrata, 15 (24.2%), C. kefyr, 13 (21.0%) C. krusei, 9 (14.5%), and Saccharomyces cerevisiae, 1 (1.6%) by RFLP-PCR method; whereas findings by Rapid TM Yeast Plus System were C. albicans, 24 (38.7%), C. glabrata, 5 (8%), C. kefyr, 11 (17.7%) C. krusei, 2 (3.2%), S. cerevisiae, 9 (14.5%), and C. tropicalis, 6 (9.6%) as well as other nonpathogenic yeasts, 4 (6.9%).

Conclusion: Statistical comparison showed that there is no significant difference in identification of C. albicans by the two methods; although, in this study, it was not true about other species of yeasts. A correlation between clinical and laboratory findings is important as it enables us to administer an appropriate treatment on time.

Keywords: Candida; Iran; RFLP; Vulvovaginal candidiasis.

Figure 1

An example of ethidium bromide-stained gel image. Lanes 1-17 amplified ITS region PCR products Lane M: 100 bp ladder molecular size marker. Lanes 1, 59, 11 and 15-17, C. albicans; Lanes 2, 7 and 8C. kefyr, Lanes 3, 4 and 10 C. glabrata; Lanes 6, 12 C. krusei; Lanes 13, Saccharomyces cerevisiae

Figure 2

An example of PCR-RFLP patterns for Candida isolates Lane M: 100 bp ladder molecular size marker; lanes 1-18. lanes lanes 1, 2, 16 and -17 C. krusei; Lanes 9, 11 and 13, C. glabrata; Lanes 3 -5, 7, 8, 10,12,14,15 and 18, C.albicans; 9; Lane 6 C. kefyr .