Determining Susceptibility in Candida Vaginal Isolates

Molecular Identification of Fungal Species through Multiplex-qPCR to Determine Candidal Vulvovaginitis and Antifungal Susceptibility

Vulvovaginal candidiasis (VVC) is a prevalent condition affecting women worldwide. This study aimed to develop a rapid qPCR assay for the accurate identification of VVC etiological agents and reduced azole susceptibility. One hundred and twenty nine vaginal samples from an outpatient clinic (Bilbao, Spain) were analyzed using culture-based methods and a multiplex qPCR targeting fungal species, which identified Candida albicans as the predominant species (94.2%). Antifungal susceptibility tests revealed reduced azole susceptibility in three (3.48%) isolates. Molecular analysis identified several mutations in genes associated with azole resistance as well as novel mutations in TAC1 and MRR1 genes. In conclusion, we developed a rapid multiplex qPCR assay that detects C. albicans in vulvovaginal specimens and reported new mutations in resistance-related genes that could contribute to azole resistance.

Resistance to Fluconazole of Candida albicans in Vaginal Isolates: a 10-Year Study in a Clinical Referral Center

Review of vaginal isolates of Candida albicans that caused clinical failure in a 10-year collection of vaginal C. albicans specimens obtained in a university vaginitis referral clinic indicated an increase in fluconazole resistance. Factors contributing to azole resistance are discussed, including treatment choice associated with fluconazole-resistant C. albicans vaginal infection.

A longitudinal study on fluconazole resistance in Candida albicans vaginal isolates

BACKGROUND

Recurrent vulvovaginal candidiasis (RVVC), despite its worldwide prevalence, has limited treatment options; and a long-term prophylactic regimen utilising fluconazole is the dominant choice.

OBJECTIVES

An increase in fluconazole resistance is reported, and little information is available about the reversibility of resistance status following the withdrawal of fluconazole.

METHODS

Repeated antifungal susceptibility tests (ASTs) for fluconazole at a median interval of 3 months between them were evaluated in women with refractory or recurrent VVC patients at the Vaginitis clinic from 2012 to 2021 (10 years) and performed at pH 7 and pH 4.5 using the broth microdilution tests based on the CLSI M27-A4 reference method.

RESULTS

Of 38 patients with long-term follow-up with repeat ASTs, 13 patients (13/38, 34.2%) tested at pH 7.0 remained susceptible to fluconazole with MIC ≤2 μg/mL. Nineteen patients (19/38, 50%) remained resistant to fluconazole with MIC ≥8 μg/mL, whereas four (4/38, 10.5%) changed from susceptible to resistant and two (2/38, 5.2%) changed from resistant to susceptible over time. At pH 4.5, among the 37 patients with repeated MIC values, nine (9/37, 24.3%) remained susceptible to fluconazole and 22 (22/37, 59.5%) remained resistant. Three isolates (3/37, 8.1%) changed from susceptible to resistant, while 3 (3/37, 8.1%) changed from resistant to susceptible over time.

CONCLUSION

Fluconazole susceptibility in Candida albicans vaginal isolates obtained longitudinally in women with RVVC remains stable with rare reversal of resistance despite azole avoidance.