Molecular identification and antifungal susceptibility profiles of Candida dubliniensis and Candida africana isolated from vulvovaginal candidiasis: A single-centre experience in Iran

Analysis of Whole-Genome facilitates rapid and precise identification of fungal species

Fungal identification is a cornerstone of fungal research, yet traditional molecular methods struggle with rapid and accurate onsite identification, especially for closely related species. To tackle this challenge, we introduce a universal identification method called Analysis of whole GEnome (AGE). AGE includes two key steps: bioinformatics analysis and experimental practice. Bioinformatics analysis screens candidate target sequences named Targets within the genome of the fungal species and determines specific Targets by comparing them with the genomes of other species. Then, experimental practice using sequencing or non-sequencing technologies would confirm the results of bioinformatics analysis. Accordingly, AGE obtained more than 1,000,000 qualified Targets for each of the 13 fungal species within the phyla Ascomycota and Basidiomycota. Next, the sequencing and genome editing system validated the ultra-specific performance of the specific Targets; especially noteworthy is the first-time demonstration of the identification potential of sequences from unannotated genomic regions. Furthermore, by combining rapid isothermal amplification and phosphorothioate-modified primers with the option of an instrument-free visual fluorescence method, AGE can achieve qualitative species identification within 30 min using a single-tube test. More importantly, AGE holds significant potential for identifying closely related species and differentiating traditional Chinese medicines from their adulterants, especially in the precise detection of contaminants. In summary, AGE opens the door for the development of whole-genome-based fungal species identification while also providing guidance for its application in plant and animal kingdoms.

Molecular Testing for the Diagnosis of Bacterial Vaginosis

Previously established diagnostic approaches for the diagnosis of bacterial vaginosis (BV), such as the Amsel criteria or the Nugent scoring system, do not always correspond to modern trends in understanding the etiology and pathogenesis of polymicrobial conditions. Inter-examiner variability and interpretation of data complicate the wet mount microscopy method. Gram staining of smears does not always provide reliable information regarding bacterial taxa, biofilms, or vaginal dysbiosis. Therefore, the introduction of molecular techniques into clinical practice is extremely relevant. Molecular approaches allow not only the diagnosis of BV but also provide an assessment of microbial composition, which is especially important in the differential diagnosis of vaginal infections. The current review represents an expert opinion on BV diagnosis and is based on extensive experience in the field of vaginal infection diagnosis and treatment.

Species identification, antifungal susceptibility patterns, and vitamin D3 level in women with vaginal candidiasis: a case-control study in Iran

Vulvovaginal candidiasis (VVC) is a fungal infection that is a global issue of women's health due to its association with morbidity, infertility, and economic costs. This study aimed to compare the vitamin D3 levels between women with VVC to healthy controls and determine the species distribution and susceptibility pattern of isolates. Species identification was performed using sequencing of the ITS-rDNA regions and amplification of the HWP1 gene. Antifungal susceptibility testing was determined by the disk diffusion method. Moreover, serum vitamin D3 levels were measured using a commercial ELISA (enzyme-linked immunosorbent assay) kit. Our results indicated that vitamin D3 level in women with VVC was lower than those of healthy women (p-value < .001). Candida albicans complex (62.8 percent) was the most common species, and most species were susceptible to fluconazole, itraconazole, ketoconazole, and nystatin. In conclusion, our study revealed a potential link between vitamin D3 deficiency and VVC in women. Although our findings showed significantly lower vitamin D3 levels in women with VVC, further research is needed to establish a definitive causative relationship between vitamin D3 deficiency and VVC. Nonetheless, our study highlights the potential importance of maintaining adequate levels of vitamin D3 and the need for further exploration in this area.

Prevalence of Closely Related Candida albicans Species among Patients with Vulvovaginal Candidiasis in Southern Poland Based on the hwp1 Gene Amplification

Candida albicans remains the most common species isolated from women with vulvovaginal candidiasis. However, closely related species such as Candida africana and Candida dubliniensis may also occur, although they are often misidentified. The aim of the study was to confirm the phenotypic identification of C. albicans and its closely related species isolated from women with genital tract infections by amplification of the hwp1 (hyphal wall protein 1) gene in a PCR assay. We report a detailed molecular identification of C. albicans and its closely related species among 326 patients in the Małopolska region, Poland. Initial phenotypic identifications were confirmed by amplification of the hwp1 gene. Based on molecular analysis, we revealed 307 strains (94.17%) as C. albicans and 17 as C. dubliniensis (5.22%). No strain of C. africana was detected. Two patients h ad co-infection with C. albicans and C. dubliniensis (0.61%). A PCR assay targeting the hwp1 gene was reliable for correctly identifying species among the C. albicans complex.

Arthrocolins Synergizing with Fluconazole Inhibit Fluconazole-Resistant Candida albicans by Increasing Riboflavin Metabolism and Causing Mitochondrial Dysfunction and Autophagy

Our previous study reported that seminaturally occurring arthrocolins A to C with unprecedented carbon skeletons could restore the antifungal activity of fluconazole against fluconazole-resistant Candida albicans. Here, we showed that arthrocolins synergized with fluconazole, reducing the fluconazole minimum and dramatically augmenting the survivals of 293T human cells and nematode Caenorhabditis elegans infected with fluconazole-resistant C. albicans. Mechanistically, fluconazole can induce fungal membrane permeability to arthrocolins, leading to the intracellular arthrocolins that were critical to the antifungal activity of the combination therapy by inducing abnormal cell membranes and mitochondrial dysfunctions in the fungus. Transcriptomics and reverse transcription-quantitative PCR (qRT-PCR) analysis indicated that the intracellular arthrocolins induced the strongest upregulated genes that were involved in membrane transports while the downregulated genes were responsible for fungal pathogenesis. Moreover, riboflavin metabolism and proteasomes were the most upregulated pathways, which were accompanied by inhibition of protein biosynthesis and increased levels of reactive oxygen species (ROS), lipids, and autophagy. Our results suggested that arthrocolins should be a novel class of synergistic antifungal compounds by inducing mitochondrial dysfunctions in combination with fluconazole and provided a new perspective for the design of new bioactive antifungal compounds with potential pharmacological properties. IMPORTANCE The prevalence of antifungal-resistant Candida albicans, which is a common human fungal pathogen causing life-threatening systemic infections, has become a challenge in the treatment of fungal infections. Arthrocolins are a new type of xanthene obtained from Escherichia coli fed with a key fungal precursor toluquinol. Different from those artificially synthesized xanthenes used as important medications, arthrocolins can synergize with fluconazole against fluconazole-resistant Candida albicans. Fluconazole can induce the fungal permeability of arthrocolins into fungal cells, and then the intracellular arthrocolins exerted detrimental effects on the fungus by inducing fungal mitochondrial dysfunctions, leading to dramatically reduced fungal pathogenicity. Importantly, the combination of arthrocolins and fluconazole are effective against C. albicans in two models, including human cell line 293T and nematode Caenorhabditis elegans. Arthrocolins should be a novel class of antifungal compounds with potential pharmacological properties.

Vulvovaginal candidiasis in Iranian women: Molecular identification and antifungal susceptibility pattern

AIM

Vulvovaginal candidiasis (VVC), is a common fungal infection that remains a global concern. The objectives of this study were molecular identification and assessment of the antifungal susceptibility profile of Candida species, causing VVC in southeast Iran.

METHODS

A cross-sectional investigation was carried out on 119 nonpregnant females suspected of VVC between February 2019 and May 2021. Yeast samples were characterized to the species level by conventional and molecular methods. All Candida isolates were examined for in vitro susceptibility profile to six conventional antifungal drugs using Clinical and Laboratory Standards Institute guidelines.

RESULTS

Out of 119 subjects, 52 (43.7%) cases were affected by VVC, out of whom 11 (21.15%) cases had recurrent vulvovaginal candidiasis (RVVC). The species distribution was as follows; Candida albicans (n = 21; 40.4%), C. glabrata (n = 11; 21.2%), C. tropicalis (n = 9; 17.3%), C. parapsilosis (n = 5; 9.7%), C. africana (n = 3; 5.7%), C. famata (n = 1; 1.9%), C. lusitaniae (n = 1; 1.9%), and C. dubliniensis (n = 1; 1.9%). The resistance rate of Candida isolates to fluconazole, itraconazole, and voriconazole were 15.38%, 11.5%, and 3.8%, respectively. Resistance to fluconazole was obtained in 46% (5/11) of RVVC cases but only in 7% (3/41) of VVC cases.

CONCLUSION

This study demonstrated that the majority of VVC cases were caused by non-albicans Candida species which also were resistant to some antifungal agents. Hence, our findings revealed the importance of conducting periodical epidemiological studies to determine changes in species distribution. Moreover, for effective management of treatment and infection, it is imperative to evaluate the susceptibility profiles of Candida species isolated from VVC patients.

Epidemiology, prevalence, and associated factors of oral candidiasis in HIV patients from southwest Iran in post-highly active antiretroviral therapy era

Background

Oral candidiasis (OC) is one of the most common opportunistic fungal infections among people living with HIV/AIDS (PLWHA). The prevalence of OC and Candida profiles among HIV-infected patients might be changing in the era of Highly Active Antiretroviral Therapy (HAART). This study aimed to identify Candida spp., determine OC prevalence and associated risk factors for PLWHA.

Materials and methods

Oral candidiasis prevalence was explored in oral swabs of 276 patients who referred for consultation at Behavioral Diseases Counseling Center (BDCC). Clinical symptoms, culture and molecular assays were used for OC detection. In statistical analysis, we assessed socio-demographic characteristics, clinical information and treatment history of some infections.

Results

The overall prevalence of OC was 41%. Candida albicans (64.6%) was the most common species, followed by C. glabrata (26.5%) and C. dubliniensis (19.5%). Candida famata, C. africana, and C. stellatoidea as the first fungi isolated from OC in PLWHA from southwest Iran. In 36.3% of patients, mixed cultures of more than one species were observed. Body mass index (BMI) (OR = 0.947; CI = 0.89–0.99; p = 0.045) and CD4 count ≤ 200 cells/mm3 (OR = 4.365; CI = 1.73–10.98; p = 0.002) were the predictors of OC in the final model of multiple logistic regression analysis. Education level, addiction status, sexual behaviors, chest X-ray, other infections and WHO clinical stage were other important risk factors for OC.

Conclusion

Oral candidiasis remains a significant opportunistic infection in post-HAART era among PLWHA. Despite the increasing prevalence of NAC species, C. albicans (64.6%) was still the predominant species. Our results showed that low BMI with OC indicates treatment failure (i.e., failure to increase CD4 count or suppress viral load). Also, low CD4 counts (≤200 cells/mm3) in HIV patients show an impaired immune status, and our findings emphasize that OC can be a clinical indicator of HIV infection in individuals who do not know their HIV status or have failed treatment.

Distinct host immune responses in recurrent vulvovaginal candidiasis and vulvovaginal candidiasis

Recurrent vulvovaginal candidiasis (RVVC) and vulvovaginal candidiasis (RVVC) are one of the most common gynecological infections, primarily caused by Candida species. Although risk factors of RVVC and VVC have been identified in many studies, antifungal immunological mechanisms are still not fully understood. We performed a 1-year prospective study in a local hospital to monitor 98 patients clinically diagnosed with gynecological Candida infection. The results showed that 20.41% (20/98) are with RVVC, and 79.59% (78/98) patients have VVC. C. albicans accounts for 90% and 96.1% of all strains isolated collected from RVVC and VVC patients, respectively. Antifungal susceptibility testing showed no significant difference in Candida species between RVVC and VVC patients. However, the serum levels of IFN-γ, TNF-α, and IL-17F in the RVVC group were significantly lower than those of the VVC group, while IL-4, IL-6, and IL-10 were higher in the RVVC patients than VVC patients. IL-17A and IL-2 levels were comparable between the two groups. Taken together, our results suggest that the host-immune responses, especially Th1/2 immunity, may play important roles in prognosis of RVVC and VVC.

Candida dubliniensis fungemia in a patient with severe COVID-19: A case report

Candida dubliniensis phenotypically mimics Candida albicans in its microbiological features; thus, its clinical characteristics have yet to be fully elucidated. Here we report the case of a 68-year-old Japanese man who developed C. dubliniensis fungemia during treatment for severe coronavirus disease 2019 (COVID-19). The patient was intubated and received a combination of immunosuppressants, including high-dose methylprednisolone and two doses of tocilizumab, as well as remdesivir, intravenous heparin, and ceftriaxone. A blood culture on admission day 11 revealed Candida species, which was confirmed as C. dubliniensis by mass spectrometry. An additional sequencing analysis of the 26S rDNA and ITS regions confirmed that the organism was 100% identical to the reference strain of C. dubliniensis (ATCC MYA-646). Considering the simultaneous isolation of C. dubliniensis from a sputum sample, the lower respiratory tract could be an entry point for candidemia. Although treatment with micafungin successfully eradicated the C. dubliniensis fungemia, the patient died of COVID-19 progression. In this case, aggressive immunosuppressive therapy could have caused the C. dubliniensis fungemia. Due to insufficient clinical reports on C. dubliniensis infection based on definitive diagnosis, the whole picture of the cryptic organism is still unknown. Further accumulation of clinical and microbiological data of the pathogen is needed to elucidate their clinical significance.

Otomycosis in the South of Iran with a High Prevalence of Tympanic Membrane Perforation: A Hospital-Based Study

INTRODUCTION

Otomycosis is a superficial infection of the external ear caused by fungal pathogens. The genera Aspergillus and Candida are considered the main fungal causative agents, with the predominance of Aspergillus section Nigri. The present study aimed to evaluate the clinical symptoms of patients with otomycosis and predisposing factors and to identify fungal etiological agents using molecular approaches. We also present an overview of published papers on tympanic membrane perforation (TMP) secondary to otomycosis.

MATERIALS AND METHODS

An otorhinolaryngologist collected specimens from external ear canals of patients with suspected otomycosis based on the patient's history and clinical examinations. The specimens were collected using sterile swabs. Fungal isolates were confirmed in clinical specimens by direct microscopy and culture methods. Fungal isolates were identified based on molecular approaches.

RESULTS

In total, specimens from 211 patients with suspected otomycosis were examined. The presence of fungi was confirmed in about 51% of patients based on fungal elements in direct microscopy and culture-positive fungi. Aspergillus tubingensis was the most commonly isolated species (52.77%), followed by Aspergillus niger (25.92%). Otomycosis due to infection with Candida species was observed in 16% of cases. Of note, in 36.11% of cases, otomycosis was associated with TMP.

CONCLUSION

A mycological examination is indispensable for a correct diagnosis in patients with otitis extern. TMP should be considered in patients with otomycosis, as it appears to be relatively common in this population.

Differentiation of Candida albicans complex species isolated from invasive and non-invasive infections using HWP1 gene size polymorphism

Background and Purpose

Taxonomy of Candida is controversial and has changed due to the investigation of the novel species. Candida africana and Candida dubliniensis are new members of the C. albicans complex that are currently gaining both clinical and epidemiologic significance. This study aimed to report the prevalence of C. africana among the strains isolated from patients using hyphal wall protein 1 (HWP1) gene size polymorphism.

Materials and Methods

In total, 235 yeasts confirmed as C. albicans complex based on chromogenic media and internal transcribed spacers sequencing isolated from various clinical forms of invasive and non-invasive candidiasis mainly candidemia were re-identified using HWP1 gene polymorphisms. The HWP1-polymerase chain reaction amplicons were re-confirmed by sequencing and BLAST analysis.

Results

Based on the HWP1 gene size polymorphism, 223 strains were identified as C. albicans (94.89%) from which 7 isolates produced two DNA fragments (850 and 941 bp). The C. dubliniensis (n=4, 1.7%), C. africana (n=1, 0.42%), and mix of C. albicans and C. africana (n=7, 2.97%) were also identified.

Conclusion

It can be said that C. albicans remains the most common Candida species, while C. dubliniensis and C. africana are rarely found among the patient isolates. Due to limited information on the molecular epidemiology of this novel yeast, more studies using molecular methods are recommended.

In Vitro Antifungal Activity of Luliconazole, Efinaconazole, and Nine Comparators Against Aspergillus and Candida Strains Isolated from Otomycosis

Background: Aspergillus and Candida species are the most commonly identified fungal pathogens in otomycosis. However, we usually encounter some difficulties in its treatment because many patients show resistance to antifungal agents and present a high recurrence rate. Objectives: The current research was conducted to compare the in vitro activities of luliconazole (LUL), and efinaconazole (EFN) and the nine comparators on Aspergillus and Candida strains isolated from otomycosis. Methods: The in vitro activities of nine common antifungal drugs (amphotericin B (AMB), voriconazole (VRC), fluconazole (FLU), itraconazole (ITC), ketoconazole (KTO), clotrimazole (CLO), nystatin (NYS), terbinafine (TRB), and caspofungin (CAS)) and two novel new azoles (LUL and EFN) against 108 clinical isolates of Aspergillus and Candida species obtained from otomycosis were assessed according to the CLSI broth microdilution document. Results: The LUL and EFN had the geometric mean minimum inhibitory concentrations (GM MICs) of 0.098 and 0.109 μg/mL against all Aspergillus strains, respectively. Furthermore, the GM MICs of all Candida isolates for LUL, EFN, CAS, CLO, VRC, AMB, ITC, KTO, FLU, NYS, and TRB were calculated to be 0.133, 0.144, 0.194, 0.219, 0.475, 0.537, 0.655, 1.277, 4.905, 9.372, and 13.592 μg/mL, respectively. Additionally, 6 (35.29%), 2 (11.7%), and 1 (5.88%) Candida isolates were resistant to FLU, CAS, and VRC, respectively. Conclusions: As the findings indicated, LUL and EFN showed the lowest GM MIC values against the examined species. Accordingly, these novel imidazole and triazole antifungal agents can be regarded as proper candidates for the treatment of otomycosis caused by Aspergillus and Candida strains.

Molecular identification and antifungal susceptibility profiles of Candida dubliniensis and Candida africana isolated from vulvovaginal candidiasis: A single-centre experience in Iran

Background

Vulvovaginal candidiasis (VVC) is a common and debilitating long‐term illness affecting million women worldwide. This disease is caused mainly by Candida albicans and a lesser extent by other species, including the two phylogenetically closely related pathogens Candida africana and Candida dubliniensis.

Objectives

In this study, we report detailed molecular epidemiological data about the occurrence of these two pathogenic yeasts in Iranian patients affected by VVC, or its chronic recurrent form (RVVC), and provide, for the first time, data on the antifungal activity of two new drugs, efinaconazole (EFN) and luliconazole (LUL).

Methods

A total of 133 vaginal yeast isolates, presumptively identified as Calbicans by phenotypic and restriction analysis of rDNA, were further analysed by using a specific molecular method targeting the HWP1 gene. All Cafricana and Cdubliniensis isolates were also tested for their in vitro susceptibility to a panel of modern and classical antifungal drugs.

Results and Conclusions

Based on the molecular results, among 133 germ‐tube positive isolates, we identify 119 Calbicans (89.47%), 11 Cafricana (8.27%) and 3 Cdubliniensis (2.26%) isolates. Cafricana and Cdubliniensis showed low MIC values for most of the antifungal drugs tested, especially for EFN and LUL, which exhibited a remarkable antifungal activity. High MIC values were observed only for nystatin and terbinafine. Although Calbicans remains the most common Candida species recovered from Iranian VVC/RVVC patients, our data show that its prevalence may be slightly overestimated due to the presence of difficult‐to‐identify closely related yeast, especially Cafricana.