Phenotypic and genotypic variations in Candida albicans isolates from Romanian patients

Phenotypes characterization and ABC genotypes distribution of clinical Candida albicans isolates

BACKGROUND

Candidemia and vaginitis are the most common types of candidiasis mostly caused by Candida albicans species. C. albicans has several genotypes and the potential ability to form different phenotype colonies on specific media. This study aimed to evaluate the genotype distribution of blood and vaginal C. albicans isolates and phenotype characteristics on Spider and yeast peptone dextrose agar medium.

METHODS

A total of 40 clinical Candida albicans isolates comprising vagina (20) and blood (20) were used. ABC typing using CA-INT-R and CA-INT-L primers was performed to span the transposable group I intron of the 25S rDNA gene. For colony phenotypic characteristics, the Spider and YPDA media were used.

RESULTS

Among the blood and vaginal isolates, genotype A (12/60%) and genotype C (10/50%) were the most common types, respectively. The highest phenotype shape frequency of the colonies in blood and vaginal samples was the ring and the lowest was the hat/ring. The dominant color phenotype in blood and vaginal samples was gray. There was a significant relationship between genotype and phenotype forms in the blood sample on YPDA medium (p = 0.02). In the Spider medium, there were no significant differences between genotypes and phenotypes.

CONCLUSION

In this study, genotype A and genotype C were predominant in blood and vaginal samples, respectively. In both groups, YPD agar medium demonstrated the most variety of phenotypes that was related to genotypes A and C. The variety of phenotypes in both groups was the same in genotypes A and C on the Spider medium.

Phenotype, genotype, and mating type determination in oral Candida albicans isolates from pediatric patients with neutropenia

Background

The most frequent species of Candida to infect and colonize patients with neutropenia is still Candida albicans. This study aimed to provide detailed information on the phenotype, genotype, and mating type of oral C. albicans isolated from neutropenic pediatric patients, and to investigate how these characteristics are related.

Methods

Two hundred fifty‐four oral samples from patients under 18 years old with neutropenia and malignancies were collected from January to October 2021. Samples were cultured on CHROMagar Candida. Isolates of C. albicans were identified with the germ tube test, chlamydospore production on cornmeal agar, and PCR‐RFLP. Genotyping of C. albicans isolates was carried out by amplifying the 25S rDNA gene with specific CAINT‐L and CA‐INT‐R primers. MTLa1 and MTLα1 primers were used to identify each mating type. Yeast peptone dextrose supplemented with phloxine B was used to identify different phenotypes.

Results

Ninety‐two (36%) patients were positive for C. albicans. The mean age of patients was 7.85. Fifty‐three (58.9%) isolates demonstrated type A, 15 (16.7%) type B, 15 (16.7%) types D/E, and 7 (7.7%) type C. Three isolates each (3.3%) were homozygous for MTLa or homozygous for MTLα. All of the MTL‐homozygous isolates were genotype A. There was a significant correlation between patients' underlying disease and genotype (p = 0.036). There was a significant correlation between mating type and genotype (p = 0.000).

Conclusion

Most of the isolates exhibited a white phenotype, noted in the literature as the most virulent. Moreover, heterozygous strains were frequent and may play a role in Candida colonization.

Genotyping, antifungal susceptibility, enzymatic activity, and phenotypic variation in Candida albicans from esophageal candidiasis

Background

Esophageal candidiasis is the most frequent form of esophagitis. The pathogenicity of Candida spp. is related to a combination of microbial factors, hydrolytic enzyme secretion and phenotypic switching. This study was designed to investigate esophageal candidiasis, antifungal activity, enzymatic activity patterns, phenotyping, and genotyping profiles of Candida albicans species.

Methods

Nine hundred thirty‐three visited patients were evaluated, and esophageal biopsies from patients were included in this study during 2019–2020. Direct smear, Gram staining, and culture on CHROMagar were performed for each sample. Isolated species were identified with conventional procedures and PCR‐RFLP. Susceptibility to antifungals was determined according to CLSI guidelines. ABC typing, phenotype switching, hemolysin, proteinase, phospholipase, and esterase activity were also determined with the appropriate protocols.

Results

Twenty‐three (2.5%) patients (mean age 55.2 years) were diagnosed with esophageal candidiasis. The species isolated were 19(82.6%) C. albicans, 3(13.1%) C. glabrata, and 1(4.3%) C. tropicalis. Genotype A (57.9%) was the predominant type in C. albicans isolates. 50% of C. albicans isolates exhibited a white phenotype. A high level of phospholipase (47.4%), hemolysin (68.4%), and proteinase activity (36.8%) was observed in the C. albicans isolates. Only three C. glabrata isolates displayed non‐wild type susceptibility to voriconazole and itraconazole.

Conclusion

This study shows that C. albicans are still the most frequent isolates from patients with esophageal candidiasis. The predominance of genotype A, the white phenotype, and strong hemolysin activity may indicate a high prevalence of pathogenicity in these isolates. Sensitivity to antifungal drugs was greatest for amphotericin and fluconazole.

Smart Supra- and Macro-Molecular Tools for Biomedical Applications

Stimuli-responsive, “smart” polymeric materials used in the biomedical field function in a bio-mimicking manner by providing a non-linear response to triggers coming from a physiological microenvironment or other external source. They are built based on various chemical, physical, and biological tools that enable pH and/or temperature-stimulated changes in structural or physicochemical attributes, like shape, volume, solubility, supramolecular arrangement, and others. This review touches on some particular developments on the topic of stimuli-sensitive molecular tools for biomedical applications. Design and mechanistic details are provided concerning the smart synthetic instruments that are employed to prepare supra- and macro-molecular architectures with specific responses to external stimuli. Five major themes are approached: (i) temperature- and pH-responsive systems for controlled drug delivery; (ii) glycodynameric hydrogels for drug delivery; (iii) polymeric non-viral vectors for gene delivery; (iv) metallic nanoconjugates for biomedical applications; and, (v) smart organic tools for biomedical imaging.

Genotype comparison of Candida albicans isolates from different clinical samples

Background: Fungal infections are a health issue paradoxically fuelled by the developments in medical care. Objectives: Our study is an investigation on the correlation between the infection site and the genotypes of Candida albicans strains isolated from Romanian patients. Methods: A total number of 301 isolates from different clinical sites were investigated in terms of genotype determination. Results: The isolates were clustered in three groups according to their genotype: 55.81% showed genotype A, 14.62% genotype B, and 29.57% genotype C. Conclusions: No significant correlation was found between the genotype and the infection site, but a significant correlation was found between genotype C and isolates from HIV patients proving that C. albicans pathogenicity probably relies on factors related to the host.