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

Abstract

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. MTL a1 and MTL α1 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 MTL a 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.

Phenotypes characterization and ABC genotypes distribution of clinical Candida albicans isolates

“…Also, Tao et al reported that white colonies had less proteinase activity, while gray colonies had more proteinase activity 44 . In other studies, white and white/gray colors were reported as dominant phenotypic colors 24,43 . In our study, the dominant color of the phenotype in blood and vaginal samples was gray.…”

“…44 In other studies, white and white/gray colors were reported as dominant phenotypic colors. 24,43 In our study, the dominant color of the phenotype in blood and vaginal samples was gray. Although many studies have been done in the field of phenotypic and genotypic Candida albicans, there is a need for more investigation such as their interaction with the host.…”

“…For example, in the study of Antony et al, the activity of proteinase and phospholipase enzymes were higher in the wrinkle and smooth colony morphology forms of Lee's medium, respectively 41 . In other studies, Nemati et al and Jafarian et al smooth form of the colony was introduced as the dominant form on YPD agar medium containing phloxine B 42,43 . The previous research on the phenotype shape of the Candida species demonstrates that the smooth form could stick better to mucosal epithelial cells, presumably because of better formation of germ tubes rather than hyphal forms (star shape) 41 .…”

“… 41 In other studies, Nemati et al and Jafarian et al smooth form of the colony was introduced as the dominant form on YPD agar medium containing phloxine B. 42 , 43 The previous research on the phenotype shape of the Candida species demonstrates that the smooth form could stick better to mucosal epithelial cells, presumably because of better formation of germ tubes rather than hyphal forms (star shape). 41 In our study, several types of phenotypes on different media were observed and the star shape in vaginal isolates was dominant.…”

Species Identification of Candida Isolates from Critically Ill Patients by Rapid Commercial and Genotypic Methods

“…Besides, biochemical reactions as sugar assimilation and fermentation have been used to differentiate between Candida spp. These detection methods are tiresome and time-consuming 10 . Several commercial diagnostic techniques are now available as chromogenic media, API 20 C and automated Vitek-2 Compact system which can help in precise identification of Candida spp 11 .…”