Bridging Diagnostic Gaps: Utilising HiCrome Agar and Tetrazolium Reduction Medium for the Rapid and Presumptive Identification and Speciation of Candida Species in Vulvovaginal Candidiasis in Low-Resource Environments

TL;DR

This study shows that HiCrome agar and tetrazolium reduction medium can quickly and accurately identify Candida species causing vaginal infections in low-resource settings.

Contribution

The study demonstrates the effectiveness of HiCrome agar and tetrazolium reduction medium for rapid Candida speciation in vulvovaginal candidiasis.

Findings

HiCrome agar and tetrazolium reduction medium accurately identified all Candida isolates with complete concordance to the VITEK2 system.

Candida albicans was the most common species identified, followed by Candida tropicalis, Candida glabrata, and Candida parapsilosis.

Both methods provided rapid and reliable presumptive identification suitable for low-resource environments.

Abstract

Background

Vulvovaginal candidiasis (VVC) is a common fungal infection caused by an overgrowth of Candida species, primarily Candida
albicans (C. albicans). Using HiCrome agar and tetrazolium reduction medium offers cost-effectiveness in Candida detection by eliminating the need for additional tests, reducing equipment costs compared to automated systems, and simplifying workflow with direct species identification while maintaining high specificity. They expedite detection by directly identifying Candida species based on colony colour, bypassing the multiple steps of phenotypic methods. This efficiency saves time in the laboratory, providing rapid results without the extended processing times associated with automated systems and facilitating prompt diagnosis and treatment decisions. These diagnostic tools are especially valuable in low-resource environments where a quick and accurate diagnosis of VVC is crucial for effective treatment and management of antifungal resistance.

Aims and objectives

This study aims to evaluate the efficacy of HiCrome agar and tetrazolium reduction medium's efficacy in speciating Candida species in VVC cases.

Materials and methods

A cross-sectional observational study was conducted at Saveetha Medical College and Hospitals, Chennai, India, over six months. High vaginal swabs from 126 patients suspected of VVC were collected and plated on Sabouraud dextrose agar (SDA), HiCrome Candida differential agar (Himedia, Mumbai, India), and tetrazolium reduction medium. The results were compared with those obtained from the VITEK2 compact system (bioMérieux, Marcy-l'Étoile, France).

Results

Of the 126 samples, 74.6% showed single yeast infections, 7.9% displayed mixed yeast infections, and 17.5% showed no growth. A total of 114 Candida isolates were identified. Both HiCrome agar and tetrazolium reduction medium accurately identified all isolates, with complete concordance with the VITEK2 compact system. The most commonly isolated species were C. albicans (55.2%), Candida tropicalis (32.4%), Candida glabrata (8.8%), and Candida parapsilosis (3.6%). Both media provided rapid and accurate presumptive identification in low-resource settings.

Conclusions

HiCrome agar and tetrazolium reduction medium demonstrated high sensitivity and specificity in identifying Candida species. These methods are reliable for rapid and accurate diagnosis, particularly in resource-limited settings. However, they may require supplementary tests for definitive species identification. The adoption of these diagnostic tools represents a significant advancement in clinical microbiology, improving VVC management and addressing antifungal resistance.

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