Chronic recurrent vulvovaginitis is not only due to Candida

Antifungal Testing of Vaginal Candida Isolates in Pregnant Women: A Retrospective, Single-Center Study in Adana, Türkiye

Clinical and mycological data are essential for the optimal management of patients with Candida vaginitis (CV), particularly in cases of (i) azole-resistant C. albicans vaginitis, (ii) recurrent CV, and (iii) CV in pregnant women. The present retrospective single-center study investigated the antifungal activity of six commonly used antifungals against randomly selected vaginal isolates recovered from 68 pregnant women in Adana, Türkiye, including C. albicans, petite C. glabrata, non-petite C. glabrata, and C. krusei, using the disk diffusion method at pH 4 and 7. Furthermore, the antifungal activities of fluconazole and itraconazole were also assessed using the broth microdilution method. For all isolates, the mean inhibition zone diameters were narrower for itraconazole and ketoconazole and larger for miconazole at pH 4 than pH 7 (p < 0.05). For nystatin, zone diameters were wider in C. albicans and petite C. glabrata at pH 4 (p < 0.001 and p < 0.001). Remarkably, clotrimazole was more active at pH 4 than at pH 7, except against non-petite C. glabrata isolates. Based on the broth microdilution results, the resistance rate was higher at pH 4 than at pH 7 in all isolates. Candida glabrata petite isolates exhibited MIC values 2 to 5 times higher than those of the non-petite isolates for both fluconazole and itraconazole. This study highlights the potent activity of topical antifungals (miconazole, nystatin, and clotrimazole) for the treatment of CV in pregnant women and highlights the need to identify petite and non-petite mutants of vaginal C. glabrata isolates to obtain more reliable data and for antifungal susceptibility testing prior to decision-making. The results of the two antifungal susceptibility methods were compared for C. albicans and C. glabrata isolates, and the reliability of the disk diffusion test was discussed.

Epidemiology of Vulvovaginal Candidiasis in Greece: A 2-Year Single-Centre Study

BACKGROUND

The epidemiology of vulvovaginal candidiasis (VVC) in Greece remains poorly reported and outdated.

OBJECTIVES

We therefore conducted a 2-year retrospective survey to assess the epidemiological aspects of the infection among symptomatic Greek patients.

PATIENTS/METHODS

High vaginal swab samples were collected from adult women with clinically suspected VVC attending a private diagnostic laboratory in Athens. VVC was confirmed through microscopic examination of a wet mount preparation revealing yeasts and Candida-positive culture. Species were identified by MALDI-ToF MS, and in vitro susceptibility was determined according to the EUCAST-E.Def 7.4. Predisposing host factors were associated with the occurrence of the infection and isolated Candida spp. using Fisher's exact test, and epidemiological changes over time were analysed with the χ2 test for trend.

RESULTS

Among 1300 women screened, 283 VVC episodes were recorded among 233 (18%) patients, whereof 11 (5%) had recurrent VVC (RVVC) and 19 (8%) had mixed Candida infections. Coinfection with other pathogens and recent prior use of antifungals were associated with RVVC. Candida albicans was the most prevalent pathogen (50%), followed by Candida parapsilosis sensu stricto (SS) (35%), Nakaseomyces glabratus (former Candida glabrata) (10%), Pichia kudriavzevii (former Candida krusei) (3%), Candida orthopsilosis (1.5%) and Clavispora lusitaniae (former Candida lusitaniae) (0.5%). Regarding the RVVC cases, 54% were attributed to C. albicans, 37% to N. glabratus and 9% to C. parapsilosis SS. Resistance to fluconazole was found in 4% of C. albicans and 23% of N. glabratus strains with cross-resistance to other azoles. Fluconazole-resistant isolates were recovered from 5 of 11 RVVC patients, whereof 4 of 5 had previous exposure to azoles. During the study period, an increase in N. glabratus VVC and fluconazole resistance was noted.

CONCLUSIONS

VVC is common in our region, with C. albicans as the predominant species, followed by C. parapsilosis SS and N. glabratus. Fluconazole resistance is low in C. albicans but high in N. glabratus, emphasising the need for targeted antifungal strategies.

Bacterial Vaginosis and Vulvovaginal Candidiasis Pathophysiologic Interrelationship

Among the infectious causes of vulvovaginal symptoms, bacterial vaginosis (BV) and vulvovaginal candidiasis (VVC) dominate. Apart from infrequent mixed infections, both are considered independent and caused by unrelated pathogenic mechanisms. Clinical experience, however, is strongly suggestive that in some populations these infections are linked with recurrent BV (RBV) serving as the dominant etiopathogenic trigger for development of recurrent VVC (RVVC) with profound clinical and therapeutic consequences. The biologic basis for this critical interrelationship is discussed and suggests that as a consequence of BV dysbiosis, and not necessarily because of antibiotics prescribed, immune defenses are compromised, neutralizing vaginal yeast tolerance. The consequent BV-induced vaginal proinflammatory environment predisposes to mixed infection or consecutive episodes of post-treatment VVC. Recurrent BV and repeated antimicrobial drug exposure also predispose to acquired fluconazole resistance in C. albicans isolates, contributing to refractory vulvovaginal candidiasis.

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.

In vitro study to assess modulation of Candida biofilm by Escherichia coli from vaginal strains

Background

Vulvovaginal candidiasis (VVC) is caused by biofilm formation and epithelial invasion. In addition, Escherichia coli (EC) can establish a vaginal intracellular reservoir modulating Candida spp. biofilm production. We aimed to analyze the behavior of Candida albicans (CA) and EC biofilm both in single cultures and in co-cultures.

Methods

We prospectively collected CA and EC isolates from vaginal swabs over 6 months. We selected positive cultures with both CA and EC (cases) and a comparator group with either CA or EC (controls). We analyzed overall biomass production and metabolic activity in single cultures and in co-cultures based on staining assays, confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) to assess biofilm occupation. We also analyzed clinical manifestations.

Results

We cultured 455 samples, 16 (3.5%) of which had CA and EC (cases); only CA or EC (controls) was detected, respectively, in 72 (15.8%) and 98 (21.5%). Biomass production and metabolic activity were significantly more pronounced in co-cultures in both groups. CLSM and SEM, on the other hand, showed the biofilm of each species to be significantly reduced when they were cultured together, with higher values in CA (percentage biofilm reduction: CA, 95.8% vs. EC, 36.2%, p < 0.001). There were no clinically significant differences between co-infected patients and patients infected only by C. albicans.

Conclusion

Ours is the first study assessing co-cultures of CA and EC in a large collection of samples. We observed that coinfection of CA and EC was unusual (3.5%) and promoted high biomass, whereas microscopy enabled us to detect a reduction in biofilm production when microorganisms were co-cultured. No differences in symptoms were observed.

Determining Susceptibility in Candida Vaginal Isolates

Antifungal drug susceptibility tests (AST) for Candida albicans are increasingly demanded for women with refractory or recurrent Candida vaginitis due to fluconazole resistance. Given reduced activity of azole drugs at pH levels found in women with Candida vaginitis, it is proposed that AST be performed at pH 4.5, since testing at only the recommended pH 7.0 is likely to miss a significant number of clinically relevant azole-resistant C. albicans vaginal isolates.